UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM N-CSR CERTIFIED SHAREHOLDER REPORT OF REGISTERED MANAGEMENT INVESTMENT COMPANIES 		Investment Company Act file number 811-21108 Pioneer Series Trust X (Exact name of registrant as specified in charter) 60 State Street, Boston, MA 02109 (Address of principal executive offices) (ZIP code) Terrence J. Cullen, Pioneer Investment Management, Inc., 60 State Street, Boston, MA 02109 (Name and address of agent for service) Registrant's telephone number, including area code: (617) 742-7825 Date of fiscal year end: March 31 Date of reporting period: April 1, 2016 through March 31, 2017 Form N-CSR is to be used by management investment companies to file reports with the Commission not later than 10 days after the transmission to stockholders of any report that is required to be transmitted to stockholders under Rule 30e-1 under the Investment Company Act of 1940 (17 CFR 270.30e-1). The Commission may use the information provided on Form N-CSR in its regulatory, disclosure review, inspection, and policymaking roles. A registrant is required to disclose the information specified by Form N-CSR, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-CSR unless the Form displays a currently valid Office of Management and Budget ("OMB") control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. ss. 3507. ITEM 1. REPORTS TO STOCKHOLDERS. Pioneer Dynamic Credit Fund -------------------------------------------------------------------------------- Annual Report | March 31, 2017 -------------------------------------------------------------------------------- Ticker Symbols: Class A RCRAX Class C RCRCX Class Y RCRYX [LOGO] PIONEER Investments(R) visit us: us.pioneerinvestments.com Table of Contents President's Letter 2 Portfolio Management Discussion 4 Portfolio Summary 10 Prices and Distributions 11 Performance Update 12 Comparing Ongoing Fund Expenses 15 Schedule of Investments 17 Financial Statements 37 Notes to Financial Statements 44 Report of Independent Registered Public Accounting Firm 64 Approval of New and Interim Management Agreements 66 Trustees, Officers and Service Providers 74 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 1 President's Letter After an overall strong year for leading market indices in 2016, U.S. markets continued to generate positive returns over the first calendar quarter of 2017, with so-called "risk" assets, such as equities and credit-sensitive bonds, posting solid gains. In the first quarter, U.S. equities, as measured by the Standard & Poor's 500 Index, returned slightly more than 6%, while high-yield securities dominated bond market performance. The transfer of power in Washington, D.C. in January had little or no effect on the markets in the first quarter, as the post-election momentum we witnessed late in the fourth quarter of 2016 slowed only when oil prices slumped in March, due to both higher-than-expected inventories and concerns over whether OPEC (Organization of Petroleum Exporting Countries) would continue its supply cuts in June. Not even the Federal Reserve System's (the Fed's) highly anticipated rate hike during the month of March, its second in three months, nor Britain's trigger of Article 50 to begin the "Brexit" process caused any dramatic sell-off of risk assets. While U.S. gross domestic product (GDP) did slow in the first quarter, the expectation is for GDP to accelerate in the second quarter, with a strong consumer leading the way. Pioneer believes the U.S. economy may lead all developed nations in 2017, with GDP growth in excess of 2% for the year. President Trump has proposed decidedly pro-business policies, such as lower taxes, higher infrastructure spending, and less regulation, though we believe the economy may realize the benefits of those policies, if enacted, more so in 2018 than in 2017. Conversely, the effects of the President's potentially restrictive trade policies could offset some of the benefits of the pro-growth fiscal policies. Even so, we believe solid domestic employment figures should continue to support consumption and the housing market, and that stronger corporate profits and increased government spending may contribute to economic growth in 2018 and beyond. Increasing global Purchasing Manager Indices (PMIs) suggest that growth in global economies is also improving. (PMIs are used to measure the economic health of the manufacturing sector.) There are, as always, some risks to our outlook. First, the market already has priced in a good deal of the Trump economic reform platform, and that could lead to near-term disappointment if Congressional follow-through does not happen this year. The future of the Affordable Care Act is another potential concern. The first attempt to repeal/replace it failed, but any new proposed 2 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 legislation will undoubtedly have an effect on the health care sector, one of the largest segments of the US economy. Geopolitical risks, of course, remain a potential headwind, given ongoing strife in the Middle East and renewed tensions on the Korean Peninsula. While our current outlook is generally optimistic, conditions can and often do change, and while passive investment strategies may have a place in one's overall portfolio, it is our view that all investment decisions are active choices. Throughout Pioneer's history, we have believed in the importance of active management. The active decisions to invest in equities or fixed-income securities are made by a team of experienced investment professionals focusing on identifying value across global markets using proprietary research, careful risk management, and a long-term perspective. We believe our shareowners can benefit from the experience and tenure of our investment teams as well as the insights generated from our extensive research process. As always, and particularly during times of market uncertainty, we encourage you to work with your financial advisor to develop an overall investment plan that addresses both your short- and long-term goals, and to implement such a plan in a disciplined manner. We greatly appreciate the trust you have placed in us and look forward to continuing to serve you in the future. Sincerely, /s/ Lisa M. Jones Lisa M. Jones President and CEO Pioneer Investment Management USA Inc. March 31, 2017 Any information in this shareowner report regarding market or economic trends or the factors influencing the Fund's historical or future performance are statements of opinion as of the date of this report. Past performance is no guarantee of future results. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 3 Portfolio Management Discussion | 3/31/17 More credit-sensitive securities rallied over virtually the entire 12-month period ended in March 31, 2017, while U.S. Treasuries and other higher-quality debt underperformed as rising interest rates eroded prices. In the following interview, Michael Temple and Kevin Choy discuss the principal factors that affected the performance of the Pioneer Dynamic Credit Fund during the 12-month period. Mr. Temple, a senior vice president, portfolio manager, and Director of Fixed-Income Credit Research at Pioneer, is responsible for the day-to-day management of the Fund, along with Mr. Choy, a vice president and portfolio manager at Pioneer. Q How did the Fund perform during the 12-month period ended March 31, 2017? A Pioneer Dynamic Credit Fund's Class A shares returned 11.13% at net asset value during the 12-month period ended March 31, 2017, while the Fund's benchmark, the Bank of America Merrill Lynch U.S. Dollar 3-Month LIBOR Index (the BofA ML Index), returned 0.74%. During the same period, the average return of the 289 mutual funds in Lipper's Alternative Credit Focus Funds category was 6.69%, and the average return of the 363 mutual funds in Morningstar's Non-Traditional Bond Funds category was 6.47%. Q How would you describe the investment environment during the 12-month period ended March 31, 2017, and what were the principal factors that affected the Fund's performance during the period? A The Fund's focus on the more credit-sensitive sectors of the fixed-income market, aided by an increased emphasis on owning below-investment-grade debt, helped drive strong performance over the 12 months. The rally in credit-sensitive debt was underway before the Fund's fiscal year began in April 2016. Credit spreads already were tightening after global oil prices had stabilized and then begun to increase in February 2016. (Credit spreads are commonly defined as the differences in yield between Treasuries and other types of fixed-income securities with similar maturities). This caused prices of high-yield corporate bonds and other credit-sensitive debt to rise, as worries about a global economic slowdown receded. Investors also gained confidence that the U.S. Federal Reserve (the Fed) and other major central banks would leave interest rates at low levels, thereby encouraging a continued economic recovery. In fact, the Fed, after initially suggesting that it might raise rates a few times during 2016, soon reversed course and signaled that it would put any rate increases on hold until it had confidence that economic growth trends were sustainable. 4 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 In the second half of the Fund's fiscal year, the results of the U.S. Presidential Election affected the credit markets, as credit spreads resumed their rally while U.S. Treasuries sold off on the expectation of higher economic growth and inflation under a Trump administration. Over the full 12-month period ended March 31, 2017, the yield-to-worst of domestic high-yield corporate bonds fell by 234 basis points (bps), from 818 bps to 584 bps. (Yield to worst is the lowest potential yield that can be received on a bond without the issuer defaulting. A basis point is equal to 1/100th of a percentage point.) The yield-to-worst tightening was principally due to declines in credit spreads more than offsetting an increase in U.S. Treasury interest rates. Over the 12-month period, high-yield corporate bond credit spreads tightened by 273 bps, from 656 bps to 383 bps. With regard to performance, we had already increased the Fund's emphasis on credit-sensitive debt prior to the start of the fiscal year, moving from very little portfolio exposure to higher-yielding corporates, to a large exposure. We also emphasized investments in the midstream segment of the energy sector. Significant investments in that area included pipeline companies such as Williams Companies, Enbridge Energy Partners, and ONEOK, all three of which performed well and made prominent contributions to the Fund's performance during the 12-month period. The portfolio's increased exposure to credit-sensitive debt helped to drive the Fund's performance as credit spreads tightened over the course of period. The portfolio's energy names were supported by the rebound and stabilization of energy/commodity prices. From the beginning to the end of the 12-month period, and as credit spreads tightened, we reallocated the Fund's exposure from high-yield debt into other sectors. For example, we moderately increased the Fund's exposure to investment-grade debt, bank loans, and insurance linked securities. Also during the Fund's fiscal year, we shortened the duration of the portfolio in an effort to reduce the risk of rising interest rates. (Duration is a measure of the sensitivity of the price, or the value of principal, of a fixed-income investment to a change in interest rates, expressed as a number of years.) At the end of the period, on March 31, 2017, the Fund's duration was 3.6 years. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 5 Q What types of specific investments, or investment strategies, had the most influence, positive or negative, on the Fund's benchmark-relative performance during the 12-month period ended March 31, 2017? A Sector positioning - specifically the Fund's exposure to high-yield and investment-grade corporates - had a major positive impact on relative returns, as did industry and security selection among the Fund's corporate holdings. Positioning in energy industry midstream names also aided relative performance significantly. Many of the investments were in pipeline companies - such as Williams, Enbridge Energy, and ONEOK - as we mentioned earlier. Outside of the energy sector, one notable name that performed well for the Fund was Sprint Corporation, a wireless and wireline communications carrier. Improved subscriber metrics and a stronger balance-sheet liquidity profile helped to improve the company's fundamentals and credit quality over the 12-month period. While almost any credit-sensitive security in the portfolio helped the Fund's relative performance during the 12-month period, almost any holding outside the credit-sensitive sectors tended to fare less well and detract from the Fund's relative results. Q Did the Fund invest in any derivative securities during the 12-month period ended March 31, 2017? A Yes, we invested in four types of derivatives during the period: U.S. Treasury futures, credit default swaps, forward foreign currency contracts, and options. We invested in Treasury futures to manage the Fund's interest-rate duration. The Treasury futures/duration strategy helped support the Fund's performance during the period. We used credit default swaps (CDS) to manage the Fund's exposure to high-yield debt. The CDS strategy also supported performance as the swaps had a positive influence on results. Because we wanted to guard against the risk of events shocking the markets and causing a dramatic decline in the values of credit-sensitive securities, we invested in the options contracts to hedge the portfolio against a sharp market reversal. The cost of the options - which function as an attempt to mitigate portfolio losses in a significant market sell-off - was a drag on the Fund's relative performance. The result was to be expected, however, given that we 6 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 did not have any notable declines in the market over the full 12 months. The forward foreign currency contracts had no effect on the Fund's performance during the period. Q Did the Fund's income generation, or yield, change during the 12-month period ended March 31, 2017? A Yes. The current income generated by the Fund's investments fell during the period as yield spreads tightened, and so the Fund's dividend* distributions declined. Q What is your investment outlook? A Entering a new fiscal year for the Fund, we face a very different investment environment than we did in March 2016, when short-term interest rates remained low and credit-sensitive debt looked very attractive. Now, credit spread levels are tighter, and thus, less compelling, while there is potential for rising inflationary pressures and higher U.S. Treasury yields. Looking ahead, we think key indicators should continue to show a reasonably strong, growing economy, with gross domestic product (GDP) probably expanding at a 2% to 2.5% annual rate, while inflation could continue to creep higher. While we have a stable-to-positive view of the economic environment and the fundamentals of the credit sectors, we do not foresee a significant tightening of credit spreads in the near term. Given our view that significant performance potential from the credit sectors has become more limited, we have reduced the Fund's credit exposure to a more neutral positioning. Consistent with our investment discipline, we will continue to focus on intensive credit research and try to take advantage of the best ideas our analysts' research uncovers. We will continue to place an emphasis on the investment themes in which we have the highest conviction, and that we believe may have the potential to help the Fund generate solid risk-adjusted returns. * Dividends are not guaranteed. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 7 Please refer to the Schedule of Investments on pages 17-36 for a full listing of Fund securities. All investments are subject to risk, including the possible loss of principal. In the past several years, financial markets have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty. These conditions may continue, recur, worsen or spread. Pioneer Dynamic Credit Fund has the ability to invest in a wide variety of debt securities. The Fund may invest in underlying funds, including ETFs. In addition to the Fund's operating expenses, you will indirectly bear the operating expenses of investments in any underlying funds. The Fund and some of the underlying funds utilize strategies that have a leveraging effect on the Fund, which increases the volatility of investment returns and subjects the Fund to magnified losses if the Fund's or an underlying fund's investments decline in value. The Fund and some of the underlying funds may use derivatives, such as options and futures, which can be illiquid, may disproportionately increase losses, and have a potentially large impact on Fund performance. The Fund may invest in inflation-linked securities. As inflationary expectations increase, inflation-linked securities may become more attractive, because they protect future interest payments against inflation. Conversely, as inflationary concerns decrease, inflation-linked securities will become less attractive and less valuable. The Fund may invest in credit default swaps, which may in some cases be illiquid, and they increase credit risk since the Fund has exposure to both the issuer of the referenced obligation and the counterparty to the credit default swap. The Fund may invest in floating-rate loans. The value of collateral, if any, securing a floating-rate loan can decline or may be insufficient to meet the issuer's obligations or may be difficult to liquidate. The Fund may invest in event-linked bonds. The return of principal and the payment of interest on event-linked bonds are contingent on the nonoccurrence of a pre-defined "trigger" event, such as a hurricane or an earthquake of a specific magnitude. 8 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 The Fund may invest in zero coupon bonds and payment-in-kind securities, which may be more speculative and fluctuate more in value than other fixed income securities. The accrual of income from these securities are payable as taxable annual dividends to shareholders. Investments in equity securities are subject to price fluctuation. Investments in fixed-income securities involve interest rate, credit, inflation, and reinvestment risks. As interest rates rise, the value of fixed-income securities generally falls. The Fund may invest in mortgage-backed securities, which during times of fluc- tuating interest rates may increase or decrease more than other fixed-income securities. Mortgage-backed securities are also subject to pre-payments. Prepayment risk is the chance that an issuer may exercise its right to prepay its security, if falling interest rates prompt the issuer to do so. Forced to reinvest the unanticipated proceeds at lower interest rates, the Fund would experience a decline in income and lose the opportunity for additional price appreciation. High-yield bonds possess greater price volatility, illiquidity, and possibility of default. There is no assurance that these and other strategies used by the Fund or underlying funds will be successful. The Fund is not intended to outperform stocks and bonds during strong market rallies. These risks may increase share price volatility. Please see the prospectus for a more complete discussion of the Fund's risks. Before investing, consider the product's investment objectives, risks, charges and expenses. Contact your advisor or Pioneer Investments for a prospectus or summary prospectus containing this information. Read it carefully. Any information in this shareholder report regarding market or economic trends or the factors influencing the Fund's historical or future performance are statements of opinion as of the date of this report. Past performance is no guarantee of future results. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 9 Portfolio Summary | 3/31/17 Portfolio Diversification* -------------------------------------------------------------------------------- (As a percentage of total investment portfolio) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] U.S. Corporate Bonds 51.0% Senior Secured Loans 12.2% International Corporate Bonds 11.6% U.S. Government Securities 8.9% Collateralized Mortgage Obligations 6.1% Asset Backed Securities 3.3% Closed End Fund 2.5% Foreign Government Bonds 1.8% Convertible Preferred Stocks 1.0% Temporary Cash Investment 0.9% U.S. Common Stocks 0.6% Municipal Bonds 0.1% Convertible Corporate Bonds 0.0%** * Includes investments in Insurance-linked securities totaling 4.3% of total investment portfolio. ** Amount rounds to less than 0.1%. 10 Largest Holdings -------------------------------------------------------------------------------- (As a percentage of total long-term holdings)*** 1. Pioneer ILS Interval Fund (h) 2.52% -------------------------------------------------------------------------------- 2. U.S. Treasury Notes, 1.125%, 6/30/21 2.40 -------------------------------------------------------------------------------- 3. U.S. Treasury Bills, 4/6/17 2.02 -------------------------------------------------------------------------------- 4. Citigroup, Inc., Floating Rate Note, (Perpetual) 1.48 -------------------------------------------------------------------------------- 5. U.S. Treasury Bills, 4/13/17 1.45 -------------------------------------------------------------------------------- 6. CenturyLink, Inc., 5.8%, 3/15/22 1.37 -------------------------------------------------------------------------------- 7. HCA, Inc., 5.25%, 4/15/25 1.33 -------------------------------------------------------------------------------- 8. U.S. Treasury Bonds, 4.5%, 2/15/36 1.32 -------------------------------------------------------------------------------- 9. EnLink Midstream Partners LP, 4.15%, 6/1/25 1.30 -------------------------------------------------------------------------------- 10. Centene Corp., 4.75%, 1/15/25 1.18 -------------------------------------------------------------------------------- *** This list excludes temporary cash investments and derivative instruments. The Fund is actively managed, and current holdings may be different. The holdings listed should not be considered recommendations to buy or sell any security listed. (h) Affiliated funds managed by Pioneer Investment Management, Inc. 10 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Prices and Distributions | 3/31/17 Net Asset Value per Share -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Class 3/31/17 3/31/16 -------------------------------------------------------------------------------- A $9.39 $8.99 -------------------------------------------------------------------------------- C $9.36 $8.97 -------------------------------------------------------------------------------- Y $9.42 $9.03 -------------------------------------------------------------------------------- Distributions per Share: 4/1/16-3/31/17 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Short-Term Long-Term Class Dividends Capital Gains Capital Gains -------------------------------------------------------------------------------- A $0.5789 $ -- $ -- -------------------------------------------------------------------------------- C $0.5061 $ -- $ -- -------------------------------------------------------------------------------- Y $0.6111 $ -- $ -- -------------------------------------------------------------------------------- The Bank of America Merrill Lynch U.S. Dollar 3-Month LIBOR Index is an unmanaged index that tracks the performance of a synthetic asset paying the London Interbank Offered Rate (LIBOR), with a constant 3-month average maturity. The index is based on the assumed purchase at par value of a synthetic instrument having exactly its stated maturity and with a coupon equal to that day's 3-month LIBOR rate. Index returns assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. It is not possible to invest directly in an index. The index defined here pertains to the "Value of $10,000 Investment" and "Value of $5 Million Investment" charts on pages 12-14. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 11 Performance Update | 3/31/17 Class A Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class A shares of Pioneer Dynamic Credit Fund at public offering price during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML Net Public U.S. Dollar Asset Offering 3-Month Value Price LIBOR Period (NAV) (POP) Index -------------------------------------------------------------------------------- Life-of-Class (4/29/11) 3.65% 2.85% 0.39% 5 Years 4.26 3.31 0.40 1 Year 11.13 6.17 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 1.19% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Dynamic BofA ML U.S. Dollar Credit Fund 3-Month LIBOR Index 4/11 $ 9,550 $10,000 3/12 $ 9,587 $10,032 3/13 $10,569 $10,075 3/14 $10,880 $10,103 3/15 $10,803 $10,126 3/16 $10,627 $10,159 3/17 $11,810 $10,234 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. NAV results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. POP returns reflect deduction of maximum 4.50% sales charge. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 12 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Performance Update | 3/31/17 Class C Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class C shares of Pioneer Dynamic Credit Fund during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML U.S. Dollar 3-Month If If LIBOR Period Held Redeemed Index -------------------------------------------------------------------------------- Life-of-Class (4/29/11) 2.83% 2.83% 0.39% 5 Years 3.46 3.46 0.40 1 Year 10.18 10.18 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 1.95% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Dynamic BofA ML U.S. Dollar Credit Fund 3-Month LIBOR Index 4/11 $10,000 $10,000 3/12 $9,953 $10,032 3/13 $10,893 $10,075 3/14 $11,132 $10,103 3/15 $10,957 $10,126 3/16 $10,710 $10,159 3/17 $11,801 $10,234 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class C shares held for less than one year are subject to a 1% contingent deferred sales charge (CDSC). "If Held" results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 13 Performance Update | 3/31/17 Class Y Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $5 million investment made in Class Y shares of Pioneer Dynamic Credit Fund during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML Net U.S. Dollar Asset 3-Month Value LIBOR Period (NAV) Index -------------------------------------------------------------------------------- Life-of-Class (4/29/11) 4.02% 0.39% 5 Years 4.58 0.40 1 Year 11.35 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross Net -------------------------------------------------------------------------------- 0.96% 0.85% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Pioneer Dynamic BofA ML U.S. Dollar Credit Fund 3-Month LIBOR Index 4/11 $5,000,000 $5,000,000 3/12 $5,047,246 $5,016,143 3/13 $5,586,945 $5,037,507 3/14 $5,768,187 $5,051,252 3/15 $5,743,143 $5,063,025 3/16 $5,670,517 $5,079,487 3/17 $6,313,902 $5,116,913 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class Y shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The net expense ratio reflects the contractual expense limitation currently in effect through August 1, 2017, for Class Y shares. There can be no assurance that Pioneer will extend the expense limitation beyond such time. Please see the prospectus for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 14 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Comparing Ongoing Fund Expenses As a shareowner in the Fund, you incur two types of costs: (1) ongoing costs, including management fees, distribution and/or service (12b-1) fees, and other Fund expenses; and (2) transaction costs, including sales charges (loads) on purchase payments. This example is intended to help you understand your ongoing expenses (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. The example is based on an invest- ment of $1,000 at the beginning of the Fund's latest six-month period and held throughout the six months. Using the Tables -------------------------------------------------------------------------------- Actual Expenses The first table below provides information about actual account values and actual expenses. You may use the information in this table, together with the amount you invested, to estimate the expenses that you paid over the period as follows: (1) Divide your account value by $1,000 Example: an $8,600 account value (divided by) $1,000 = 8.6 (2) Multiply the result in (1) above by the corresponding share class's number in the third row under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period. Expenses Paid on a $1,000 Investment in Pioneer Dynamic Credit Fund Based on actual returns from October 1, 2016, through March 31, 2017. -------------------------------------------------------------------------------- Share Class A C Y -------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 Value on 10/1/16 -------------------------------------------------------------------------------- Ending Account Value $1,033.19 $1,029.14 $1,033.70 (after expenses) on 3/31/17 -------------------------------------------------------------------------------- Expenses Paid $ 5.98 $ 9.81 $ 4.31 During Period* -------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized net expense ratio of 1.18%, 1.94% and 0.85% for Class A, Class C and Class Y Shares, respectively, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half year period). Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 15 Hypothetical Example for Comparison Purposes The table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds. Please note that the expenses shown in the tables are meant to highlight your ongoing costs only and do not reflect any transaction costs, such as sales charges (loads) that are charged at the time of the transaction. Therefore, the table below is useful in comparing ongoing costs only and will not help you determine the relative total costs of owning different funds. In addition, if these transaction costs were included, your costs would have been higher. Expenses Paid on a $1,000 Investment in Pioneer Dynamic Credit Fund Based on a hypothetical 5% return per year before expenses, reflecting the period from October 1, 2016, through March 31, 2017. -------------------------------------------------------------------------------- Share Class A C Y -------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 Value on 10/1/16 -------------------------------------------------------------------------------- Ending Account Value $1,019.05 $1,015.26 $1,020.69 (after expenses) on 3/31/17 -------------------------------------------------------------------------------- Expenses Paid $ 5.94 $ 9.75 $ 4.28 During Period* -------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized net expense ratio of 1.18%, 1.94% and 0.85% for Class A, Class C and Class Y Shares, respectively, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half year period). 16 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Schedule of Investments | 3/31/17 -------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value -------------------------------------------------------------------------------------------------------- CONVERTIBLE CORPORATE BONDS -- 0.0%+ MATERIALS -- 0.0%+ Steel -- 0.0%+ EUR 79,012 New World Resources NV, 4.0%, 10/7/20 (144A) (4.0% cash, 8.0% PIK) (PIK) $ 8 --------------- Total Materials $ 8 -------------------------------------------------------------------------------------------------------- TOTAL CONVERTIBLE CORPORATE BONDS (Cost $64,421) $ 8 -------------------------------------------------------------------------------------------------------- CONVERTIBLE PREFERRED STOCKS -- 1.1% BANKS -- 1.1% Diversified Banks -- 1.1% 900 Bank of America Corp., 7.25%, (Perpetual) $ 1,075,554 1,530 Wells Fargo & Co., 7.5% (Perpetual) 1,897,200 --------------- $ 2,972,754 --------------- Total Banks $ 2,972,754 -------------------------------------------------------------------------------------------------------- TOTAL CONVERTIBLE PREFERRED STOCKS (Cost $3,120,105) $ 2,972,754 -------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------- Shares -------------------------------------------------------------------------------------------------------- COMMON STOCKS -- 0.0%+ CAPITAL GOODS -- 0.0% + Industrial Machinery -- 0.0%+ 3,071 Liberty Tire Recycling LLC (d) $ 31 --------------- Total Capital Goods $ 31 -------------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.0%+ Diversified Support Services -- 0.0%+ 4 IAP Worldwide Services, Inc. $ 4,854 --------------- Total Commercial Services & Supplies $ 4,854 -------------------------------------------------------------------------------------------------------- TOTAL COMMON STOCKS (Cost $3,087) $ 4,885 -------------------------------------------------------------------------------------------------------- -------------------------------------------------------------------------------------------------------- Principal Amount ($)(j) -------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- 3.3% CONSUMER SERVICES -- 0.1% Hotels, Resorts & Cruise Lines -- 0.1% 323,297 Westgate Resorts 2014-1 LLC, 5.5%, 12/20/26 (144A) $ 323,330 --------------- Total Consumer Services $ 323,330 -------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 17 Schedule of Investments | 3/31/17 (continued) -------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value -------------------------------------------------------------------------------------------------------- BANKS -- 3.2% Thrifts & Mortgage Finance -- 3.2% 1,200,000 Ascentium Equipment Receivables 2016-2 Trust, 6.79%, 10/10/24 (144A) $ 1,260,545 499,993 Axis Equipment Finance Receivables III LLC, 5.27%, 5/20/20 (144A) 480,392 680,000 Engs Commercial Finance Trust 2016-1, 5.22%, 1/22/24 (144A) 665,309 164,042 7.78 GE Mortgage Services LLC, Floating Rate Note, 3/25/27 98,930 111,977 GLC Trust 2013-1, 3.0%, 7/15/21 (144A) 110,521 175,000 InSite Issuer LLC Class C Series 16-1A, 7.5%, 11/15/46 177,699 750,000 Leaf Receivables Funding 10 LLC, 5.21%, 7/15/21 (144A) 744,321 710,500 Navitas Equipment Receivables LLC 2015-1, 5.75%, 5/17/21 (144A) 702,886 600,000 5.48 NCF Dealer Floorplan Master Trust, Floating Rate Note, 10/20/20 (144A) 595,980 194,075 RASC Series 2003-KS5 Trust, 4.96%, 7/25/33 (Step) 192,494 55,454 6.55 Security National Mortgage Loan Trust 2007-1, Floating Rate Note, 4/25/37 (144A) 55,265 1,200,000 4.16 Silver Bay Realty 2014-1 Trust, Floating Rate Note, 9/18/31 (144A) 1,201,409 1,502,701 Solarcity Lmc Series VI LLC, 4.8%, 9/21/48 (144A) 1,510,754 999,013 VOLT XXV LLC, 4.5%, 6/26/45 (Step) (144A) 969,658 --------------- $ 8,766,163 --------------- Total Banks $ 8,766,163 -------------------------------------------------------------------------------------------------------- TOTAL ASSET BACKED SECURITIES (Cost $9,120,974) $ 9,089,493 -------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- 6.1% BANKS -- 6.0% Thrifts & Mortgage Finance -- 6.0% 71,644 3.09 Bear Stearns ALT-A Trust 2003-3, Floating Rate Note, 10/25/33 $ 70,776 86,712 5.21 Bear Stearns Commercial Mortgage Securities Trust 2005-PWR7, Floating Rate Note, 2/11/41 86,572 1,600,000 5.12 Bear Stearns Commercial Mortgage Securities Trust 2005-TOP20, Floating Rate Note, 10/12/42 1,569,726 33,384 5.94 CHL Mortgage Pass-Through Trust 2002-32, Floating Rate Note, 1/25/33 34,251 1,000,000 3.21 Citigroup Commercial Mortgage Trust 2014-GC23 REMICS, Floating Rate Note, 7/12/47 (144A) 640,475 400,000 Citigroup Commercial Mortgage Trust 2016-SMPL, 4.509%, 9/10/31 388,372 The accompanying notes are an integral part of these financial statements. 18 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 -------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value -------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 715,000 5.88 COBALT CMBS Commercial Mortgage Trust 2007-C3, Floating Rate Note, 5/15/46 $ 696,317 220,000 5.88 COBALT CMBS Commercial Mortgage Trust 2007-C3, Floating Rate Note, 5/15/46 156,200 1,000,000 5.81 COMM 2007-C9 Mortgage Trust, Floating Rate Note, 12/10/49 (144A) 989,020 500,000 3.96 COMM 2014-UBS6 Mortgage Trust REMICS, Floating Rate Note, 12/10/47 (144A) 414,295 303,157 5.47 Credit Suisse First Boston Mortgage Securities Corp., Floating Rate Note, 6/25/33 3 1,126,099 5.10 Credit Suisse First Boston Mortgage Securities Corp., Floating Rate Note, 8/15/38 1,130,416 2,050,000 5.10 Credit Suisse First Boston Mortgage Securities Corp., Floating Rate Note, 8/15/38 1,726,089 500,000 3.58 CSAIL 2015-C4 Commercial Mortgage Trust REMICS, Floating Rate Note, 11/15/48 423,196 275,234 5.60 EQTY 2014-MZ Mezzanine Trust, Floating Rate Note, 5/10/19 (144A) 269,910 270,168 Global Mortgage Securitization, Ltd., 5.25%, 11/25/32 (144A) 121,332 99,555 Global Mortgage Securitization, Ltd., 5.25%, 11/25/32 (144A) 19,184 428,259 Global Mortgage Securitization, Ltd., 5.25%, 4/25/32 (144A) 413,619 87,333 Global Mortgage Securitization, Ltd., 5.25%, 4/25/32 (144A) 52,114 570,000 5.00 GMAT 2013-1 Trust, Floating Rate Note, 8/25/53 538,857 705,000 3.68 GS Mortgage Securities Trust 2014-GSFL, Floating Rate Note, 7/15/31 (144A) 708,438 81,310 Homeowner Assistance Program Reverse Mortgage Loan Trust 2013-RM1, 4.0%, 5/26/53 (144A) 80,802 1,850,000 7.14 JP Morgan Chase Commercial Mortgage Securities Trust 2014-CBM MZ, Floating Rate Note, 10/15/19 (144A) 1,860,433 300,000 3.10 JPMDB Commercial Mortgage Securities Trust 2016-C4, Floating Rate Note, 12/15/49 (144A) 218,410 573,364 4.00 La Hipotecaria Panamanian Mortgage Trust 2007-1, Floating Rate Note, 12/23/36 (144A) 559,029 173,394 Merrill Lynch Mortgage Investors Trust Series 2006-AF1, 5.75%, 8/25/36 134,852 300,000 3.00 Morgan Stanley Capital I Trust 2016-BNK2, Floating Rate Note, 11/15/49 (144A) 236,804 500,000 Morgan Stanley Capital I Trust 2016-UBS9, 3.0%, 3/15/49 (144A) 384,542 733,042 ORES 2014-LV3 LLC, 6.0%, 3/27/24 (144A) 730,828 830,456 2.16 RESI Finance LP 2003-D, Floating Rate Note, 12/10/35 (144A) 690,249 The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 19 Schedule of Investments | 3/31/17 (continued) ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 750,000 Wells Fargo Commercial Mortgage Trust 2016-BNK1, 3.0%, 8/15/49 (144A) $ 620,813 200,000 4.35 WFRBS Commercial Mortgage Trust 2013-C12, Floating Rate Note, 3/15/48 (144A) 182,353 --------------- $ 16,148,277 --------------- Total Banks $ 16,148,277 ------------------------------------------------------------------------------------------------------------- GOVERNMENT -- 0.1% Government -- 0.1% 377,805 2.59 FREMF Mortgage Trust 2015-KLSF REMICS, Floating Rate Note, 11/25/22 (144A) $ 381,439 --------------- Total Government $ 381,439 ------------------------------------------------------------------------------------------------------------- TOTAL COLLATERALIZED MORTGAGE OBLIGATIONS (Cost $17,355,067) $ 16,529,716 ------------------------------------------------------------------------------------------------------------- CORPORATE BONDS -- 62.5% ENERGY -- 11.2% Oil & Gas Refining & Marketing -- 1.3% 3,505,000 EnLink Midstream Partners LP, 4.15%, 6/1/25 $ 3,462,831 ------------------------------------------------------------------------------------------------------------- Oil & Gas Storage & Transportation -- 9.9% 2,575,000 Boardwalk Pipelines LP, 4.95%, 12/15/24 $ 2,711,748 1,965,000 Cheniere Corpus Christi Holdings LLC, 5.875%, 3/31/25 (144A) 2,048,512 2,125,000 Enbridge Energy Partners LP, 7.375%, 10/15/45 2,591,397 2,690,000 Energy Transfer Equity LP, 5.5%, 6/1/27 2,811,050 780,000 Kinder Morgan, Inc. Delaware, 4.3%, 6/1/25 796,854 750,000 Kinder Morgan, Inc. Delaware, 5.3%, 12/1/34 752,680 1,360,000 Kinder Morgan, Inc. Delaware, 5.55%, 6/1/45 1,389,577 2,670,000 MPLX LP, 4.875%, 12/1/24 2,808,672 1,450,000 ONEOK, Inc., 6.875%, 9/30/28 1,573,250 925,000 ONEOK, Inc., 7.5%, 9/1/23 1,080,086 1,770,000 Plains All American Pipeline LP, 4.65%, 10/15/25 1,823,272 2,100,000 Sabine Pass Liquefaction LLC, 5.875%, 6/30/26 (144A) 2,315,433 2,000,000 Sabine Pass Liquefaction LLC, 6.25%, 3/15/22 2,219,560 1,800,000 Williams Partners LP, 6.3%, 4/15/40 2,017,267 --------------- $ 26,939,358 --------------- Total Energy $ 30,402,189 ------------------------------------------------------------------------------------------------------------- MATERIALS -- 2.7% Metal & Glass Containers -- 0.7% 1,666,000 Ball Corp., 5.25%, 7/1/25 $ 1,763,878 ------------------------------------------------------------------------------------------------------------- Paper Packaging -- 0.5% 1,300,000 Sealed Air Corp., 5.5%, 9/15/22 (144A) $ 1,378,000 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 20 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- Diversified Metals & Mining -- 0.3% 900,000 Vedanta Resources Plc, 6.375%, 7/30/22 (144A) $ 904,500 ------------------------------------------------------------------------------------------------------------- Steel -- 1.2% 2,010,000 ArcelorMittal, 6.0%, 3/1/21 $ 2,170,800 1,000,000 Commercial Metals Co., 4.875%, 5/15/23 1,020,000 EUR 38,709 0.00 New World Resources NV, Floating Rate Note, 10/7/20 (d) -- EUR 29,032 0.00 New World Resources NV, Floating Rate Note, 10/7/20 (d) -- --------------- $ 3,190,800 --------------- Total Materials $ 7,237,178 ------------------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 2.0% Building Products -- 1.1% 1,480,000 Masco Corp., 4.45%, 4/1/25 $ 1,544,735 1,445,000 Standard Industries, Inc., 5.375%, 11/15/24 (144A) 1,463,958 --------------- $ 3,008,693 ------------------------------------------------------------------------------------------------------------- Construction & Engineering -- 0.4% 1,005,000 Amsted Industries, Inc., 5.0%, 3/15/22 (144A) $ 1,010,025 ------------------------------------------------------------------------------------------------------------- Industrial Machinery -- 0.5% 1,445,000 Cleaver-Brooks, Inc., 8.75%, 12/15/19 (144A) $ 1,488,350 --------------- Total Capital Goods $ 5,507,068 ------------------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.8% Diversified Support Services -- 0.8% 2,080,000 Ritchie Bros Auctioneers, Inc., 5.375%, 1/15/25 (144A) $ 2,126,800 --------------- Total Commercial Services & Supplies $ 2,126,800 ------------------------------------------------------------------------------------------------------------- AUTOMOBILES & COMPONENTS -- 1.1% Tires & Rubber -- 0.6% 1,680,000 Goodyear Tire, 4.875%, 5/15/27 $ 1,680,000 ------------------------------------------------------------------------------------------------------------- Automobile Manufacturers -- 0.5% 1,315,000 ZF North America Capital, Inc., 4.75%, 4/29/25 (144A) $ 1,361,025 --------------- Total Automobiles & Components $ 3,041,025 ------------------------------------------------------------------------------------------------------------- CONSUMER DURABLES & APPAREL -- 0.3% Homebuilding -- 0.3% 765,000 DR Horton, Inc., 5.75%, 8/15/23 $ 858,129 --------------- Total Consumer Durables & Apparel $ 858,129 ------------------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.8% Casinos & Gaming -- 0.8% 2,000,000 International Game Technology Plc, 6.5%, 2/15/25 (144A) $ 2,130,000 --------------- Total Consumer Services $ 2,130,000 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 21 Schedule of Investments | 3/31/17 (continued) ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- MEDIA -- 6.9% Broadcasting -- 1.1% 1,500,000 CCO Holdings LLC, 5.125%, 5/1/27 (144A) $ 1,507,500 1,275,000 CCO Holdings LLC, 5.5%, 5/1/26 (144A) 1,319,625 --------------- $ 2,827,125 ------------------------------------------------------------------------------------------------------------- Cable & Satellite -- 5.8% 2,105,000 Altice US Finance I Corp., 5.5%, 5/15/26 (144A) $ 2,162,888 1,985,000 CSC Holdings LLC, 5.5%, 4/15/27 (144A) 2,017,256 2,550,000 DISH DBS Corp., 5.875%, 7/15/22 2,679,081 2,255,000 Hughes Satellite Systems Corp., 5.25%, 8/1/26 (144A) 2,249,362 1,725,000 Sirius XM Radio, Inc., 5.375%, 7/15/26 (144A) 1,763,812 2,275,000 Time Warner Cable LLC, 4.5%, 9/15/42 2,061,796 2,800,000 Videotron, Ltd., 5.375%, 6/15/24 (144A) 2,908,500 --------------- $ 15,842,695 --------------- Total Media $ 18,669,820 ------------------------------------------------------------------------------------------------------------- RETAILING -- 0.5% Internet Retail -- 0.5% 1,300,000 Expedia, Inc., 4.5%, 8/15/24 $ 1,360,808 --------------- Total Retailing $ 1,360,808 ------------------------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 2.4% Brewers -- 0.8% 2,020,000 Anheuser-Busch InBev Finance, Inc., 2.65%, 2/1/21 $ 2,035,190 ------------------------------------------------------------------------------------------------------------- Packaged Foods & Meats -- 1.0% 1,000,000 Dole Food Co., Inc., 7.25%, 5/1/19 (144A) $ 1,018,750 1,690,000 Post Holdings, Inc., 5.5%, 3/1/25 (144A) 1,698,450 --------------- $ 2,717,200 ------------------------------------------------------------------------------------------------------------- Tobacco -- 0.6% 1,515,000 Reynolds American, Inc., 4.85%, 9/15/23 $ 1,643,842 --------------- Total Food, Beverage & Tobacco $ 6,396,232 ------------------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 6.2% Health Care Facilities -- 2.5% 3,340,000 HCA, Inc., 5.25%, 4/15/25 $ 3,548,750 1,740,000 Kindred Healthcare, Inc., 8.0%, 1/15/20 1,768,275 1,225,000 RegionalCare Hospital Partners Holdings, Inc., 8.25%, 5/1/23 (144A) 1,307,075 --------------- $ 6,624,100 ------------------------------------------------------------------------------------------------------------- Managed Health Care -- 2.9% 3,140,000 Centene Corp., 4.75%, 1/15/25 $ 3,157,678 1,780,000 Molina Healthcare, Inc., 5.375%, 11/15/22 1,845,629 1,465,000 Well Care Health., 5.25%, 4/1/25 1,499,134 1,415,000 WellCare Health Plans, Inc., 5.75%, 11/15/20 1,456,035 --------------- $ 7,958,476 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 22 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- Health Care Technology -- 0.8% 2,150,000 Quintiles IMS, Inc., 5.0%, 10/15/26 (144A) $ 2,158,062 --------------- Total Health Care Equipment & Services $ 16,740,638 ------------------------------------------------------------------------------------------------------------- PHARMACEUTICALS, BIOTECHNOLOGY & LIFE SCIENCES -- 0.9% Pharmaceuticals -- 0.9% 1,250,000 Endo, Ltd., 6.0%, 7/15/23 (144A) $ 1,093,750 540,000 Horizon Pharma, Inc., 6.625%, 5/1/23 529,200 245,000 Valeant Pharmaceuticals, 6.5%, 3/15/22 252,044 700,000 Valeant Pharmaceuticals, 7.0%, 3/15/24 718,375 --------------- $ 2,593,369 --------------- Total Pharmaceuticals, Biotechnology & Life Sciences $ 2,593,369 ------------------------------------------------------------------------------------------------------------- BANKS -- 5.5% Diversified Banks -- 4.8% 1,445,000 6.30 Bank of America Corp., Floating Rate Note, (Perpetual) $ 1,571,438 1,260,000 7.62 BNP Paribas SA, Floating Rate Note, (Perpetual) (144A) 1,338,750 3,780,000 5.90 Citigroup, Inc., Floating Rate Note, (Perpetual) 3,945,375 2,730,000 8.12 Credit Agricole SA, Floating Rate Note, (Perpetual) (144A) 2,907,450 1,500,000 7.70 Intesa Sanpaolo S.p.A., Floating Rate Note, (Perpetual) (144A) 1,432,500 1,567,000 JPMorgan Chase & Co., 5.625%, 8/16/43 1,784,705 --------------- $ 12,980,218 ------------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- 0.7% 2,000,000 Provident Funding Associates LP, 6.75%, 6/15/21 (144A) $ 2,040,000 --------------- Total Banks $ 15,020,218 ------------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 4.6% Other Diversified Financial Services -- 1.4% 1,000,000 Fixed Income Trust Series 2013-A, 10/15/97 (Step) (144A) (c) (d) $ 954,758 2,533,000 6.75 JPMorgan Chase & Co., Floating Rate Note, (Perpetual) 2,792,632 100,000 7.70 Tiers Trust, Floating Rate Note, 10/15/97 (144A) (d) 108,864 --------------- $ 3,856,254 ------------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.7% 1,120,000 Nationstar Mortgage LLC, 6.5%, 6/1/22 $ 1,120,000 825,000 Nationstar Mortgage LLC, 6.5%, 7/1/21 835,312 --------------- $ 1,955,312 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 23 Schedule of Investments | 3/31/17 (continued) ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- Consumer Finance -- 0.6% 1,565,000 General Motors Financial Co, Inc., 3.7%, 5/9/23 $ 1,570,900 --------------- $ 1,570,900 ------------------------------------------------------------------------------------------------------------- Asset Management & Custody Banks -- 0.4% 950,000 JBS Investment Management, Ltd., 7.25%, 4/3/24 $ 983,250 ------------------------------------------------------------------------------------------------------------- Investment Banking & Brokerage -- 1.0% 2,290,000 UBS AG, 7.625%, 8/17/22 $ 2,647,698 ------------------------------------------------------------------------------------------------------------- Diversified Capital Markets -- 0.5% 1,330,000 Park Aerospace Holdings, Ltd., 5.25%, 8/15/22 (144A) $ 1,383,200 --------------- Total Diversified Financials $ 12,396,614 ------------------------------------------------------------------------------------------------------------- INSURANCE -- 5.8% Life & Health Insurance -- 0.6% 1,500,000 5.88 Prudential Financial, Inc., Floating Rate Note, 9/15/42 $ 1,630,125 ------------------------------------------------------------------------------------------------------------- Multi-line Insurance -- 1.0% 2,500,000 Liberty Mutual Group, Inc., 4.25%, 6/15/23 (144A) $ 2,625,538 ------------------------------------------------------------------------------------------------------------- Reinsurance -- 4.2% 500,000 Arlington Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 8/31/16 (f) (g) $ 24,300 250,000 4.19 Atlas IX Capital DAC, Floating Rate Note, 1/17/19 (Cat Bond) (144A) 253,850 500,000 Berwick Segregated Account (Artex SAC Ltd.), Variable Rate Note, 1/22/16 (f) (g) 15,000 500,000 7.06 Caelus Re, Ltd., Floating Rate Note, 4/7/17 (Cat Bond) (144A) 499,600 500,000 Carnosutie 2017,Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 11/30/21 (f) (g) 505,300 500,000 Carnoustie 2016-N,Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 11/30/20 (f) (g) 54,100 1,500,000 Carnoustie Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 2/19/16 (f) (g) 30,600 250,000 5.35 Citrus Re, Ltd., Floating Rate Note, 4/18/17 (Cat Bond) (144A) 250,050 350,000 4.48 Citrus Re, Ltd., Floating Rate Note, 4/24/17 (Cat Bond) (144A) 350,175 250,000 Cypress Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/10/17 (f) (g) 221,325 400,000 6.23 Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) (144A) 399,960 250,000 8.98 Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) (144A) 248,575 250,000 7.23 Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) (144A) 249,375 The accompanying notes are an integral part of these financial statements. 24 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 52,500 3.37 Gator Re, Ltd., Floating Rate Note, 1/9/20 (Cat Bond) (144A) $ 7,875 250,000 2.52 Golden State Re II, Ltd., Floating Rate Note, 1/8/19 (Cat Bond) (144A) 249,300 2,000,000 Gullane Segregated Account (Artex SAC Ltd.), Variable Rate Note 11/30/21 (f) (g) 2,026,000 EUR 250,000 12.00 Horse Capital I DAC, Floating Rate Note, 6/15/20 (Cat Bond) (144A) 268,168 400,000 5.24 Kilimanjaro Re, Ltd., Floating Rate Note, 4/30/18 (Cat Bond) (144A) 402,960 350,000 5.00 Kilimanjaro Re, Ltd., Floating Rate Note, 4/30/18 (Cat Bond) (144A) 352,625 250,000 0.00 Limestone Re, Ltd., 8/31/21 (Cat Bond) 250,775 250,000 Lorenz Re, Ltd., Variable Rate Notes, 3/31/18 (f) (g) 1,450 2,000,000 Pangaea Re, Series 2015-1, Principal at Risk Notes, 2/1/19 (f) (g) 9,000 2,000,000 Pangaea Re, Series 2015-2, Principal at Risk Notes, 11/30/19 (f) (g) 161,400 1,000,000 Pangaea Re., Variable Rate Notes, 11/30/21 (f) (g) 1,023,400 1,000,000 Pangaea Re., Variable Rate Notes, 2/1/20 (f) (g) 139,000 700,000 Prestwick Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/1/16 (f) (g) 20,440 250,000 5.03 Residential Reinsurance 2016, Ltd., Floating Rate Note, 12/6/23 (Cat Bond) (144A) 249,600 250,000 0.00 Resilience Re, Ltd., 1/12/18 (Cat Bond) 236,175 250,000 4.50 Resilience Re, Ltd., Floating Rate Note, 1/9/19 (Cat Bond) 250,000 AUD 300,000 RW0009 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/10/17 (f) (g) 216,976 500,000 3.97 Sanders Re, Ltd., Floating Rate Note, 6/7/17 (Cat Bond) (144A) 500,800 500,000 Silverton Re, Ltd., Variable Rate Notes, 9/18/18 (144A) (f) (g) 24,400 1,200,000 St. Andrews Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 1/22/16 (f) (g) 23,640 250,000 Sunningdale 2017 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 1/16/18 (f) (g) 229,150 250,000 4.00 Ursa Re, Ltd., Floating Rate Note, 12/10/19 (Cat Bond) (144A) 252,325 1,250,000 Versutus 2016, Class A-1, Variable Rate Notes, 11/30/20 (f) (g) 51,000 1,500,000 Versutus Ltd., Series 2017-A, Variable Rate Notes, 11/30/2021 (f) (g) 1,530,600 --------------- $ 11,579,269 --------------- Total Insurance $ 15,834,932 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 25 Schedule of Investments | 3/31/17 (continued) ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT -- 0.5% Semiconductor Equipment -- 0.5% 1,250,000 Sensata Technologies BV, 5.0%, 10/1/25 (144A) $ 1,259,375 --------------- Total Semiconductors & Semiconductor Equipment $ 1,259,375 ------------------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 6.3% Integrated Telecommunication Services -- 4.8% 3,555,000 CenturyLink, Inc., 5.8%, 3/15/22 $ 3,666,094 1,865,000 Frontier Communications Corp., 10.5%, 9/15/22 1,888,312 1,800,000 GCI, Inc., 6.75%, 6/1/21 1,845,000 1,400,000 Level 3 Financing, Inc., 5.375%, 5/1/25 1,424,500 1,970,000 Sprint Capital Corp., 6.875%, 11/15/28 2,080,812 2,000,000 Verizon Communications, Inc., 2.625%, 2/21/20 2,024,818 --------------- $ 12,929,536 ------------------------------------------------------------------------------------------------------------- Wireless Telecommunication Services -- 1.5% 1,865,000 T-Mobile USA, Inc., 6.5%, 1/15/24 $ 2,014,200 1,400,000 T-Mobile USA, Inc., 6.625%, 4/1/23 1,494,052 300,000 Unison Ground Lease Funding LLC, 5.78%, 3/16/43 (144A) 296,487 400,000 WCP Issuer llc, 6.657%, 8/15/20 (144A) 412,544 --------------- $ 4,217,283 --------------- Total Telecommunication Services $ 17,146,819 ------------------------------------------------------------------------------------------------------------- UTILITIES -- 3.6% Electric Utilities -- 0.5% 1,190,000 8.13 Enel S.p.A., Floating Rate Note, 9/24/73 (144A) $ 1,368,500 ------------------------------------------------------------------------------------------------------------- Gas Utilities -- 1.1% 1,400,000 DCP Midstream Operating LP, 3.875%, 3/15/23 $ 1,344,000 300,000 DCP Midstream Operating LP, 5.6%, 4/1/44 276,000 1,500,000 Ferrellgas LP, 6.75%, 6/15/23 1,410,000 --------------- $ 3,030,000 ------------------------------------------------------------------------------------------------------------- Independent Power Producers & Energy Traders -- 2.0% 1,320,000 AES Corp. Virginia, 5.5%, 3/15/24 $ 1,339,800 2,145,000 Calpine Corp., 5.75%, 1/15/25 2,131,594 1,910,000 NRG Energy, Inc., 6.625%, 1/15/27 (144A) 1,905,225 --------------- $ 5,376,619 --------------- Total Utilities $ 9,775,119 ------------------------------------------------------------------------------------------------------------- REAL ESTATE -- 0.4% Specialized REIT -- 0.4% 1,000,000 DuPont Fabros Technology LP, 5.875%, 9/15/21 $ 1,040,000 --------------- Total Real Estate $ 1,040,000 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 26 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- TOTAL CORPORATE BONDS (Cost $163,182,748) $ 169,536,333 ------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- 8.9% 3,860,000 U.S. Treasury Bills, 4/13/17 (c) $ 3,859,224 2,100,000 U.S. Treasury Bills, 4/20/17 (c) 2,099,278 1,350,000 U.S. Treasury Bills, 4/27/17 (c) 1,349,343 5,400,000 U.S. Treasury Bills, 4/6/17 (c) 5,399,725 2,780,000 U.S. Treasury Bonds, 4.5%, 2/15/36 3,525,604 1,665,000 0.93 U.S. Treasury Note, Floating Rate Note, 10/31/17 1,666,738 6,600,000 U.S. Treasury Notes, 1.125%, 6/30/21 6,408,963 ------------------------------------------------------------------------------------------------------------- TOTAL U.S. GOVERNMENT AND AGENCY OBLIGATIONS (Cost $24,335,131) $ 24,308,875 ------------------------------------------------------------------------------------------------------------- FOREIGN GOVERNMENT BONDS -- 1.9% ARS 10,040,000 Argentine Bonos del Tesoro, 15.5%, 10/17/26 $ 678,966 ARS 9,350,000 Argentine Bonos del Tesoro, 22.75%, 3/5/18 631,474 BRL 1,909,000 Brazilian Government International Bond, 10.25%, 1/10/28 619,577 1,500,000 Ecuador Government International Bond, 7.95%, 6/20/24 1,410,000 1,125,000 Oman Government Bond, 3.875%, 3/8/22 (144A) 1,137,488 560,000 Oman Government Bond, 6.5%, 3/8/47 (144A) 590,800 ------------------------------------------------------------------------------------------------------------- TOTAL FOREIGN GOVERNMENT BONDS (Cost $4,912,762) $ 5,068,305 ------------------------------------------------------------------------------------------------------------- MUNICIPAL BONDS -- 0.2% (i) Municipal Development -- 0.1% 250,000 0.88 Mississippi Business Finance Corp., Floating Rate Note, 12/1/30 $ 250,000 ------------------------------------------------------------------------------------------------------------- Higher Municipal Education -- 0.1% 250,000 0.67 Connecticut State Health & Educational Facility Authority, Floating Rate Note, 7/1/36 $ 250,000 ------------------------------------------------------------------------------------------------------------- TOTAL MUNICIPAL BONDS (Cost $500,000) $ 500,000 ------------------------------------------------------------------------------------------------------------- SENIOR FLOATING RATE LOAN INTERESTS -- 11.8%** MATERIALS -- 0.4% Paper Packaging -- 0.1% 200,000 6.65 Caraustar Industries, Inc., Term Loan (First Lien), 3/9/22 $ 202,000 ------------------------------------------------------------------------------------------------------------- Diversified Metals & Mining -- 0.3% 916,689 3.75 Fortescue Metals Group Ltd., Bank Loan, 6/30/19 $ 922,762 --------------- Total Materials $ 1,124,762 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 27 Schedule of Investments | 3/31/17 (continued) ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 1.9% Aerospace & Defense -- 0.4% 1,000,000 5.65 The SI Organization, Inc., Term Loan (First Lien), 11/19/19 $ 1,015,938 ------------------------------------------------------------------------------------------------------------- Building Products -- 0.2% 653,188 4.00 Builders Firstsource Inc., Term Loan (First Lien), 3/29/24 $ 653,678 ------------------------------------------------------------------------------------------------------------- Construction & Farm Machinery & Heavy Trucks -- 0.3% 895,466 5.00 Navistar, Inc., Tranche B Term Loan, 8/7/20 $ 907,033 ------------------------------------------------------------------------------------------------------------- Industrial Machinery -- 0.5% 1,314,690 5.23 NN, Inc., Tranche B Term Loan, 10/19/22 $ 1,316,950 ------------------------------------------------------------------------------------------------------------- Trading Companies & Distributors -- 0.5% 1,315,029 3.73 Univar USA, Inc., Term B-2 Loan, 7/1/22 $ 1,318,317 --------------- Total Capital Goods $ 5,211,916 ------------------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.8% Environmental & Facilities Services -- 0.8% 1,872,605 5.15 Wheelabrator, Term B Loan, 10/15/21 $ 1,892,112 84,291 5.15 Wheelabrator, Term C Loan, 10/15/21 85,169 --------------- $ 1,977,281 ------------------------------------------------------------------------------------------------------------- Diversified Support Services -- 0.0%+ 27,972 5.08 IAP Worldwide Services, Inc., Term Loan, 7/18/19 $ 26,573 ------------------------------------------------------------------------------------------------------------- Security & Alarm Services -- 0.0%+ 29,624 4.01 Garda World Security Corp., Term B Loan, 11/1/20 $ 29,741 21,585 4.01 Garda World Security Corp., Term B Loan, 11/8/20 21,670 --------------- $ 51,411 --------------- Total Commercial Services & Supplies $ 2,055,265 ------------------------------------------------------------------------------------------------------------- TRANSPORTATION -- 0.4% Marine -- 0.4% 473,785 9.75 Commercial Barge Line Co., Initial Term Loan, 11/6/20 $ 440,620 500,000 6.00 Navios Maritime Partners LP, Term Loan (First Lien), 9/6/20 495,625 --------------- $ 936,245 --------------- Total Transportation $ 936,245 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 28 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- AUTOMOBILES & COMPONENTS -- 0.7% Auto Parts & Equipment -- 0.7% 398,984 5.90 Electrical Components International, Inc., Loan, 4/17/21 $ 402,226 638,539 4.75 Federal-Mogul Corporation, Tranche C Term, 4/15/21 637,342 900,735 3.62 Tower Automotive Holdings USA, LLC, Term Loan (First Lien), 3/6/24 900,172 --------------- $ 1,939,740 --------------- Total Automobiles & Components $ 1,939,740 ------------------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 2.1% Casinos & Gaming -- 0.4% 1,000,000 4.85 Scientific Games International, Inc., Initial Term B-3 Loan, 10/1/21 $ 1,013,646 ------------------------------------------------------------------------------------------------------------- Leisure Facilities -- 0.4% 1,155,583 6.00 L.A. Fitness International, LLC, Tranche B Term Loan (First Lien), 4/25/20 $ 1,166,417 ------------------------------------------------------------------------------------------------------------- Education Services -- 1.3% 819,651 8.51 Laureate Education, Inc., Series 2021 Extended Term Loan, 3/23/21 $ 828,488 1,836,125 5.00 McGraw-Hill Global Education Holdings LLC, Term B Loan (First Lien), 5/2/22 1,819,677 895,396 4.55 Nord Anglia Education, Initial Term Loan, 3/31/21 905,190 --------------- $ 3,553,355 --------------- Total Consumer Services $ 5,733,418 ------------------------------------------------------------------------------------------------------------- MEDIA -- 0.6% Advertising -- 0.4% 992,327 6.75 Affinion Group, Inc., Tranche B Term Loan, 4/30/18 $ 990,068 ------------------------------------------------------------------------------------------------------------- Movies & Entertainment -- 0.2% 500,000 3.49 Rovi Solutions Corp., Term B Loan, 7/2/21 $ 502,396 --------------- Total Media $ 1,492,464 ------------------------------------------------------------------------------------------------------------- RETAILING -- 0.8% Home Improvement Retail -- 0.5% 1,196,202 4.50 Apex Tool Group LLC, Term Loan, 2/1/20 $ 1,188,725 ------------------------------------------------------------------------------------------------------------- Automotive Retail -- 0.3% 870,281 4.61 CWGS Group LLC, Term Loan, 11/3/23 $ 876,808 --------------- Total Retailing $ 2,065,533 ------------------------------------------------------------------------------------------------------------- FOOD & STAPLES RETAILING -- 0.2% Food Retail -- 0.2% 622,792 4.30 Albertsons LLC, 2016-1 Term B-6 Loan, 6/23/23 $ 627,268 --------------- Total Food & Staples Retailing $ 627,268 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 29 Schedule of Investments | 3/31/17 (continued) ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 0.1% Packaged Foods & Meats -- 0.1% 225,000 3.00 Dole Food Company, Inc., Term Loan (First Lien), 3/23/24 $ 226,688 --------------- Total Food, Beverage & Tobacco $ 226,688 ------------------------------------------------------------------------------------------------------------- HOUSEHOLD & PERSONAL PRODUCTS -- 0.4% Personal Products -- 0.4% 1,000,000 4.48 Revlon Consumer Products Corp., Initial Term B Loan, 7/22/23 $ 1,002,083 --------------- Total Household & Personal Products $ 1,002,083 ------------------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.7% Health Care Supplies -- 0.2% 1 4.59 Immucor, Inc., 8/19/18 $ 1 500,000 4.40 Sterigenics-Nordion Holdings LLC, Initial Term Loan, 4/27/22 501,875 --------------- $ 501,876 ------------------------------------------------------------------------------------------------------------- Health Care Services -- 0.3% 465,155 6.50 BioScrip, Inc., Initial Term B Loan, 7/31/20 $ 460,213 279,093 6.50 BioScrip, Inc., Term Loan, 7/31/20 276,128 --------------- $ 736,341 ------------------------------------------------------------------------------------------------------------- Health Care Facilities -- 0.2% 550,000 4.06 Concentra, Inc., Tranche B Term Loan (First Lien), 5/8/22 $ 553,781 20,250 4.50 Select Medical Corp., Term Loan (First Lien), 2/13/24 20,465 --------------- $ 574,246 ------------------------------------------------------------------------------------------------------------- Managed Health Care -- 0.0%+ 19,151 10.25 MMM Holdings, Inc., Term Loan, 10/9/17 (e) $ 18,768 13,922 10.25 MSO of Puerto Rico, Inc., MSO Term Loan, 12/12/17 (e) 13,644 --------------- $ 32,412 --------------- Total Health Care Equipment & Services $ 1,844,875 ------------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 0.4% Other Diversified Financial Services -- 0.2% 639,249 3.79 Fly Funding II Sarl, Loan, 8/9/19 $ 642,712 ------------------------------------------------------------------------------------------------------------- Diversified Capital Markets -- 0.2% 500,000 3.18 Outfront Media Capital LLC, Term Loan (First Lien), 3/10/24 $ 503,906 --------------- Total Diversified Financials $ 1,146,618 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 30 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 1.4% Application Software -- 1.1% 1,000,000 7.65 Applied Systems, Inc., Initial Term Loan (Second Lien), 1/23/22 $ 1,008,333 1,160,344 4.79 MA FinanceCo LLC, Initial Tranche B-2 Term Loan, 11/20/21 1,171,015 745,869 6.40 STG-Fairway Acquisitions, Inc., Term Loan (First Lien), 6/30/22 728,155 --------------- $ 2,907,503 ------------------------------------------------------------------------------------------------------------- Systems Software -- 0.3% 966,349 5.00 Sybil Software LLC, Initial Dollar Term Loan, 8/3/22 $ 974,427 --------------- Total Software & Services $ 3,881,930 ------------------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 0.1% Integrated Telecommunication Services -- 0.1% 81,768 4.75 Securus Technologies Holdings, Inc., Initial Term Loan (First Lien), 4/30/20 $ 81,921 300,000 2.75 SFR Group SA, Term Loan (First Lien), 6/22/25 299,325 --------------- $ 381,246 --------------- Total Telecommunication Services $ 381,246 ------------------------------------------------------------------------------------------------------------- UTILITIES -- 0.8% Electric Utilities -- 0.8% 1,000,000 5.00 TPF II Power, LLC, Term Loan, 10/2/21 $ 1,005,875 228,429 3.73 Vistra Operations Co LLC, Initial Term C Loan, 8/4/23 228,143 999,068 3.73 Vistra Operations Co LLC, Initial Term Loan, 8/4/23 997,819 --------------- $ 2,231,837 --------------- Total Utilities $ 2,231,837 ------------------------------------------------------------------------------------------------------------- TOTAL SENIOR FLOATING RATE LOAN INTERESTS (Cost $31,521,846) $ 31,901,888 ------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------- Shares ------------------------------------------------------------------------------------------------------------- CLOSED-END FUND -- 2.5% INSURANCE -- 2.5% Property & Casualty Insurance -- 2.5% 646,059 Pioneer ILS Interval Fund (h) $ 6,725,477 --------------- Total Insurance $ 6,725,477 ------------------------------------------------------------------------------------------------------------- TOTAL CLOSED-END FUND (Cost $6,700,000) $ 6,725,477 ------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 31 Schedule of Investments | 3/31/17 (continued) ------------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($)(j) (unaudited) Value ------------------------------------------------------------------------------------------------------------- TEMPORARY CASH INVESTMENTS -- 1.0% Commercial Paper -- 0.3% 680,000 ONEOK Partners LP, Commercial Paper, 4/3/17 (c) $ 679,938 ------------------------------------------------------------------------------------------------------------- Certificate of Deposit -- 0.2% 665,000 1.26 Sumitomo Mitsui, Floating Rate Note, 11/1/16 $ 665,022 ------------------------------------------------------------------------------------------------------------- Repurchase Agreements -- 0.5% 1,350,000 $1,350,000 ScotiaBank, 0.81%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by the following: $1,365,484 Federal National Mortgage Association (ARM), 2.38% - 3.047%, 6/1/40 - 10/1/46 $11,609 Federal National Mortgage Association, 3.0% - 4.0%, 2/1/42 - 12/1/46 $ 1,350,000 ------------------------------------------------------------------------------------------------------------- TOTAL TEMPORARY CASH INVESTMENTS (Cost $2,694,951) $ 2,694,960 ------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------- Number of Strike Expiration Contracts Description Counterparty Price Date ------------------------------------------------------------------------------------------------------------- PUT OPTIONS PURCHASED -- 0.1% 90 S & P 500 Index Citigroup Global Markets, Inc. $2,175 4/21/17 $ 10,800 110 S & P 500 Index Citigroup Global Markets, Inc. 2,250 6/16/17 195,800 90 S & P 500 Index Citigroup Global Markets, Inc. 2,250 5/19/17 96,300 --------------- $ 302,900 ------------------------------------------------------------------------------------------------------------- TOTAL PUT OPTIONS PURCHASED (Premiums paid $679,770) $ 302,900 ------------------------------------------------------------------------------------------------------------- TOTAL INVESTMENT IN SECURITIES -- 99.4% (Cost $264,190,862) (a) $ 269,635,594 ------------------------------------------------------------------------------------------------------------- ------------------------------------------------------------------------------------------------------------- Number of Strike Expiration Contracts Description Counterparty Price Date ------------------------------------------------------------------------------------------------------------- PUT OPTIONS WRITTEN -- (0.0)% (90) S & P 500 Index Citigroup Global Markets, Inc. $2,025 4/21/17 $ (4,770) (110) S & P 500 Index Citigroup Global Markets, Inc. 2,100 6/16/17 (74,250) (90) S & P 500 Index Citigroup Global Markets, Inc. 2,100 5/19/17 (27,900) --------------- $ (106,920) ------------------------------------------------------------------------------------------------------------- TOTAL PUT OPTIONS WRITTEN (Premiums received $(262,724)) $ (106,920) ------------------------------------------------------------------------------------------------------------- OTHER ASSETS & LIABILITIES -- 0.6% $ 1,754,320 ------------------------------------------------------------------------------------------------------------- NET ASSETS -- 100.0% $ 271,282,994 ============================================================================================================= + Amount rounds to less than 0.1%. REIT Real Estate Investment Trust. (Step) Bond issued with an initial coupon rate which converts to a higher rate at a later date. The accompanying notes are an integral part of these financial statements. 32 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 (Cat Bond) Catastrophe or event-linked bond. At March 31, 2017, the value of these securities amounted to $5,272,188 or 1.9% of net assets. (Perpetual) Security with no stated maturity date. REMICS Real Estate Mortgage Investment Conduits. (PIK) Represents a pay in kind security. (144A) Security is exempt from registration under Rule 144A of the Securities Act of 1933. Such securities may be resold normally to qualified institutional buyers in a transaction exempt from registration. At March 31, 2017, the value of these securities amounted to $80,916,920 or 29.8% of net assets. ** Senior floating rate loan interests in which the Fund invests generally pay interest at rates that are periodically redetermined by reference to a base lending rate plus a premium. These base lending rates are generally (i) the lending rate offered by one or more major European banks, such as LIBOR (London InterBank Offered Rate), (ii) the prime rate offered by one or more major U.S. banks, (iii) the certificate of deposit or (iv) other base lending rates used by commercial lenders. The rate shown is the coupon rate at period end. (a) At March 31, 2017, the net unrealized appreciation on investments based on cost for federal income tax purposes of $263,539,789 was as follows: Aggregate gross unrealized appreciation for all investments in which there is an excess of value over tax cost $ 8,524,756 Aggregate gross unrealized depreciation for all investments in which there is an excess of tax cost over value (2,428,951) ----------- Net unrealized appreciation $ 6,095,805 =========== (b) Debt obligation with a variable interest rate. Rate shown is rate at period end. (c) Security issued with a zero coupon. Income is earned through accretion of discount. (d) Security is valued using fair value methods (other than prices supplied by independent pricing services or broker-dealers). See Notes to Financial Statements -- Note 1A. (e) Security is in default. (f) Structured reinsurance investment. At March 31, 2017, the value of these securities amounted to $6,307,081 or 2.3% of net assets. See Notes to Financial Statements -- Note 1I. (g) Rate to be determined. (h) Affiliated funds managed by Pioneer Investment Management, Inc. (i) Consists of Revenue Bonds unless otherwise indicated. (j) Principal amounts are denominated in U.S. Dollars unless otherwise noted: AUD Australian Dollar ARS Argentine Peso BRL Brazilian Real EUR Euro Purchases and sales of securities (excluding temporary cash investments) for the year ended March 31, 2017 were as follows: -------------------------------------------------------------------------------- Purchases Sales -------------------------------------------------------------------------------- Long-Term U.S. Government $ 47,720,976 $ 35,727,703 Other Long-Term Securities 240,483,485 268,639,654 The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 33 Schedule of Investments | 3/31/17 (continued) The Fund is permitted to engage in purchase and sale transactions ("cross trades") with certain Funds and accounts for which Pioneer Investment Management, Inc. (PIM), serves as the Fund's investment adviser, as set forth in Rule 17a-7 under the Investment Company Act of 1940, pursuant to procedures adopted by the Board of Trustees. Under these procedures, cross trades are effected at current market prices. During the year ended March 31, 2017, the Fund engaged in purchases and sales pursuant to these procedures amounting to $1,870,758 and $27,697,888, respectively, which resulted in a net realized gain of $5,305. CENTRALLY CLEARED CREDIT DEFAULT SWAP AGREEMENT - SELL PROTECTION ---------------------------------------------------------------------------------------------------------------- Premiums Notional Obligation Credit Expiration Received Unrealized Principal ($)(1) Counterparty Entity/Index Coupon Rating(2) Date (Paid) Appreciation ---------------------------------------------------------------------------------------------------------------- 30,000,000 Chicago Markit CDX 5.00% B+ 6/20/22 $2,161,470 $48,530 Mercantile North America Exchange High Yield Index ---------------------------------------------------------------------------------------------------------------- $2,161,470 $48,530 ================================================================================================================ CREDIT DEFAULT SWAP AGREEMENTS - SELL PROTECTION ---------------------------------------------------------------------------------------------------------------- Premiums Unrealized Notional Obligation Credit Expiration Received Appreciation Principal ($)(1) Counterparty Entity/Index Coupon Rating(2) Date (Paid) (Depreciation) ---------------------------------------------------------------------------------------------------------------- 3,880,000 Goldman Markit CDX 5.00% BBB+ 12/20/17 $(454,688) $532,252 Sachs North America International Investment Grade Index 1,150,000 JPMorgan Chesapeake 5.00% B- 6/20/17 (46,000) 58,879 Chase Energy Corp Bank NA 4,835,000 Goldman Ally Financial 5.00% BB+ 6/20/22 623,277 8,976 Sachs Inc. International ---------------------------------------------------------------------------------------------------------------- $ 122,589 $600,107 ================================================================================================================ (1) The notional amount is the maximum amount that a seller of credit protection would be obligated to pay upon occurrence of a credit event. (2) Based on Standard & Poor's rating of the issuer or the weighted average of all the underlying securities in the index. Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below. Level 1 - quoted prices in active markets for identical securities. Level 2 - other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.) See Notes to Financial Statements -- Note 1A. Level 3 - significant unobservable inputs (including the Fund's own assumptions in determining fair value of investments) See Notes to Financial Statements -- Note 1A. The accompanying notes are an integral part of these financial statements. 34 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 The following is a summary of the inputs used as of March 31, 2017, in valuing the Fund's investments: ---------------------------------------------------------------------------------------------------- Level 1 Level 2 Level 3 Total ---------------------------------------------------------------------------------------------------- Convertible Corporate Bonds $ -- $ 8 $ -- $ 8 Convertible Preferred Stocks 2,972,754 -- -- 2,972,754 Common Stocks Capital Goods Industrial Machinery -- -- 31 31 Commercial Services & Supplies Diversified Support Services -- 4,854 -- 4,854 Asset Backed Securities -- 9,089,493 -- 9,089,493 Collateralized Mortgage Obligations -- 16,529,716 -- 16,529,716 Corporate Bonds Materials Steel -- 3,190,800 --* 3,190,800 Diversified Financials Other Diversified Financial Services -- 2,792,632 1,063,622 3,856,254 Insurance Reinsurance -- 4,535,238 7,044,031 11,579,269 All Other Corporate Bonds -- 150,910,010 -- 150,910,010 U.S. Government and Agency Obligations -- 24,308,875 -- 24,308,875 Foreign Government Bonds -- 5,068,305 -- 5,068,305 Municipal Bonds -- 500,000 -- 500,000 Senior Floating Rate Loan Interests -- 31,901,888 -- 31,901,888 Closed-End Fund -- 6,725,477 -- 6,725,477 Commercial Paper -- 679,938 -- 679,938 Certificate of Deposit -- 665,022 -- 665,022 Repurchase Agreement -- 1,350,000 -- 1,350,000 Put Options Purchased 302,900 -- -- 302,900 ---------------------------------------------------------------------------------------------------- Total $ 3,275,654 $ 258,252,256 $ 8,107,684 $ 269,635,594 ==================================================================================================== Other Financial Instruments Unrealized appreciation on credit default swaps $ -- $ 600,107 $ -- $ 600,107 Unrealized appreciation on centrally cleared credit default swaps -- 48,530 -- 48,530 Unrealized appreciation on futures contracts 67,312 -- -- 67,312 Unrealized depreciation on futures contracts (150,056) -- -- (150,056) Unrealized appreciation on forward foreign currency contracts -- 199,169 -- 199,169 Unrealized depreciation on forward foreign currency contracts -- (294,231) -- (294,231) Put options written (106,920) -- -- (106,920) ---------------------------------------------------------------------------------------------------- Total $ (189,664) $ 553,575 $ -- $ 363,911 ==================================================================================================== * Securities valued at $0 The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 35 Schedule of Investments | 3/31/17 (continued) The following is a reconciliation of assets valued using significant unobservable inputs (Level 3): -------------------------------------------------------------------------------------------------------- Convertible Corporate Preferred Common Corporate Bonds Stocks Stocks Bonds Total -------------------------------------------------------------------------------------------------------- Balance as of 3/31/16 $ 12,499 $ 6,250 $ 531 $ 9,602,199 $ 9,621,479 Realized gain (loss)(1) -- -- 24,471 (17,535) 6,936 Change in unrealized appreciation (depreciation)(2) -- -- 7,767 945,263 953,030 Purchases -- -- -- 6,357,254 6,357,254 Sales -- -- (32,738) (8,785,778) (8,818,516) Transfers in to Level 3* -- -- -- -- -- Transfers out of Level 3* (12,499) -- -- -- (12,499) Transfers in and out of Level 3 categories** -- (6,250) -- 6,250 -- -------------------------------------------------------------------------------------------------------- Balance as of 3/31/17 $ -- $ -- $ 31 $ 8,107,653 $ 8,107,684 ======================================================================================================== (1) Realized gain (loss) on these securities is included in the net realized gain (loss) from investments in the Statement of Operations. (2) Unrealized appreciation (depreciation) on these securities is included in the change in unrealized appreciation (depreciation) on investments in the Statement of Operations. ** Transfers are calculated on the beginning of period values. The change in the level designation within the fair value hierarchy was due to a change in classification from a Catastrophe Bond to a Sidecar. * During the year ended March 31, 2017, an investment having a value of $12,499 was transferred from Level 3 to Level 2. The change in the level designation within the fair value hierarchy was due to valuing the security using observable inputs. There were no other transfers between levels 1, 2 and 3. Net change in unrealized appreciation (depreciation) of investments still held as of 3/31/17 $481,369 ======== The accompanying notes are an integral part of these financial statements. 36 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Statement of Assets and Liabilities | 3/31/17 ASSETS: Investment in securities of unaffiliated issuers, at value (cost $257,490,862) $ 262,910,117 Investment in securities of affiliated issuers, at value (cost $6,700,000) 6,725,477 ------------------------------------------------------------------------------------------------------ Total investment in securities, at value (cost $264,190,862) 269,635,594 Cash 1,342,607 Foreign currencies, at value (cost $74,947) 75,182 Restricted cash* 4,209,236 Receivables -- Investment securities sold 2,651,710 Fund shares sold 1,543,690 Interest 2,470,060 Dividends 16,313 Swap contracts, premiums paid 623,277 Unrealized appreciation on forward foreign currency contracts 199,169 Unrealized appreciation on swap contracts 600,107 Due from Pioneer Investment Management, Inc. 119,635 Other assets 40,385 ------------------------------------------------------------------------------------------------------ Total assets $ 283,526,965 ====================================================================================================== LIABILITIES: Payables -- Investment securities purchased $ 9,163,393 Fund shares repurchased 950,245 Distributions 181,289 Trustee fees 40 Unrealized depreciation on forward foreign currency contracts 294,231 Swap contracts, premiums paid 500,688 Due to broker 810,000 Written options (premiums received $262,724) 106,920 Variation margin on futures contracts 3,403 Variation margin on centrally cleared swap contract 5,039 Due to affiliates 43,315 Accrued expenses 185,408 ------------------------------------------------------------------------------------------------------ Total liabilities $ 12,243,971 ====================================================================================================== NET ASSETS: Paid-in capital $ 317,784,017 Distributions in excess of net investment income (1,630,788) Accumulated net realized loss on investments, foreign currency transactions, written options, swap contracts and futures contracts (50,942,632) Net unrealized appreciation on investments 5,444,732 Net unrealized depreciation on futures contracts (82,744) Net unrealized appreciation on written options 155,804 Net unrealized depreciation on forward foreign currency contracts and other assets and liabilities denominated in foreign currencies (94,032) Unrealized appreciation on swap contracts 648,637 ------------------------------------------------------------------------------------------------------ Net assets $ 271,282,994 ====================================================================================================== NET ASSET VALUE PER SHARE: (No par value, unlimited number of shares authorized) Class A (based on $35,375,313/3,768,027 shares) $ 9.39 Class C (based on $37,510,112/4,008,154 shares) $ 9.36 Class Y (based on $198,397,569/21,050,512 shares) $ 9.42 MAXIMUM OFFERING PRICE: Class A ($9.39 (divided by) 95.5%) $ 9.83 ====================================================================================================== * Represents restricted cash deposited at the custodian and/or counterparty for derivative contracts. The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 37 Statement of Operations For the Year Ended 3/31/17 INVESTMENT INCOME: Interest $ 15,570,206 Dividends (including from affiliated issuer of $188,918) 453,153 ----------------------------------------------------------------------------------------------------- Total investment income $ 16,023,359 ----------------------------------------------------------------------------------------------------- EXPENSES: Management fees $ 1,866,281 Transfer agent fees Class A 28,122 Class C 33,639 Class Y 188,831 Distribution fees Class A 100,755 Class C 411,223 Shareholder communications expense 7,417 Administrative expense 108,689 Custodian fees 58,170 Registration fees 116,233 Professional fees 79,098 Printing expense 37,034 Fees and expenses of nonaffiliated Trustees 7,964 Miscellaneous 78,476 ----------------------------------------------------------------------------------------------------- Total expenses $ 3,121,932 Less fees waived and expenses reimbursed by Pioneer Investment Management, Inc. (221,459) ----------------------------------------------------------------------------------------------------- Net expenses $ 2,900,473 ----------------------------------------------------------------------------------------------------- Net investment income $ 13,122,886 ----------------------------------------------------------------------------------------------------- REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS, SWAP CONTRACTS, WRITTEN OPTIONS, FUTURES CONTRACTS AND FOREIGN CURRENCY TRANSACTIONS: Net realized gain (loss) on: Investments $(11,828,112) Swap contracts 7,897,163 Written options 8,017,472 Futures contracts 843,096 Forward foreign currency contracts and other assets and liabilities denominated in foreign currencies (1,458,918) $ 3,470,701 ----------------------------------------------------------------------------------------------------- Change in net unrealized appreciation (depreciation) on: Investments (including from affiliated issuer of $25,477) $ 16,838,917 Swap contracts (2,123,084) Written options (3,400,117) Futures contracts (53,126) Forward foreign currency contracts and other assets and liabilities denominated in foreign currencies 1,245,142 $ 12,507,732 ----------------------------------------------------------------------------------------------------- Net realized and unrealized gain (loss) on investments, swap contracts, written options, futures contracts and foreign currency transactions $ 15,978,433 ----------------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 29,101,319 ===================================================================================================== The accompanying notes are an integral part of these financial statements. 38 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Statements of Changes in Net Assets ------------------------------------------------------------------------------------------------- Year Ended Year Ended 3/31/17 3/31/16 ------------------------------------------------------------------------------------------------- FROM OPERATIONS: Net investment income (loss) $ 13,122,886 $ 20,410,503 Net realized gain (loss) on investments, swap contracts, written options, futures contracts and foreign currency transactions 3,470,701 (29,219,798) Change in net unrealized appreciation (depreciation) on investments, swap contracts, written options, futures contracts, and foreign currency transactions 12,507,732 81,040 ------------------------------------------------------------------------------------------------- Net increase (decrease) in net assets resulting from operations $ 29,101,319 $ (8,728,255) ------------------------------------------------------------------------------------------------- DISTRIBUTIONS TO SHAREOWNERS: Net investment income: Class A ($0.58 and $0.39 per share, respectively) $ (2,480,006) $ (2,618,684) Class C ($0.51 and $0.32 per share, respectively) (2,238,521) (1,878,294) Class Y ($0.61 and $0.43 per share, respectively) (12,489,189) (13,331,860) Class Z* ($0.00 and $0.09 per share, respectively) -- (1,754) ------------------------------------------------------------------------------------------------- Total distributions to shareowners $ (17,207,716) $ (17,830,592) ------------------------------------------------------------------------------------------------- FROM FUND SHARE TRANSACTIONS: Net proceeds from sale or exchange of shares $ 86,714,586 $ 72,835,334 Reinvestment of distributions 13,886,223 14,313,443 Cost of shares repurchased (136,464,160) (325,894,551) ------------------------------------------------------------------------------------------------- Net decrease in net assets resulting from Fund share transactions $ (35,863,351) $(238,745,774) ------------------------------------------------------------------------------------------------- Net decrease in net assets $ (23,969,748) $(265,304,621) NET ASSETS: Beginning of year 295,252,742 560,557,363 ------------------------------------------------------------------------------------------------- End of year $ 271,282,994 $ 295,252,742 ------------------------------------------------------------------------------------------------- Undistributed (distributions in excess of) net investment income $ (1,630,788) $ 1,219,897 ================================================================================================= * Class Z shares converted to Class Y shares on August 7, 2015. The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 39 Statements of Changes in Net Assets (continued) ------------------------------------------------------------------------------------------------------ Year Ended Year Ended Year Ended Year Ended 3/31/17 3/31/17 3/31/16 3/31/16 Shares Amount Shares Amount ------------------------------------------------------------------------------------------------------ Class A Shares sold 1,214,069 $ 11,415,582 1,244,960 $ 11,593,608 Reinvestment of distributions 248,351 2,309,664 264,559 2,423,099 Less shares repurchased (2,956,245) (27,483,023) (5,935,740) (55,248,307) ------------------------------------------------------------------------------------------------------ Net decrease (1,493,825) $(13,757,777) (4,426,221) $ (41,231,600) ====================================================================================================== Class C Shares sold 522,227 $ 4,883,417 438,954 $ 4,062,878 Reinvestment of distributions 209,119 1,939,023 179,912 1,634,242 Less shares repurchased (1,654,198) (15,310,288) (3,132,815) (28,907,096) ------------------------------------------------------------------------------------------------------ Net decrease (922,852) $ (8,487,848) (2,513,949) $ (23,209,976) ====================================================================================================== Class Y Shares sold 7,500,358 $ 70,415,587 6,124,396 $ 57,175,301 Reinvestment of distributions 1,031,639 9,637,536 1,114,428 10,254,516 Less shares repurchased (10,048,147) (93,670,849) (26,154,979) (241,550,847) ------------------------------------------------------------------------------------------------------ Net decrease (1,516,150) $(13,617,726) (18,916,155) $(174,121,030) ====================================================================================================== Class Z* Shares sold or exchanged -- $ -- 375 $ 3,547 Reinvestment of distributions -- -- 168 1,586 Less shares repurchased -- -- (20,094) (188,301) ------------------------------------------------------------------------------------------------------ Net decrease -- $ -- (19,551) $ (183,168) ====================================================================================================== * Class Z shares converted to Class Y shares on August 7, 2015. The accompanying notes are an integral part of these financial statements. 40 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Financial Highlights -------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 -------------------------------------------------------------------------------------------------------------------------- Class A Net asset value, beginning of period $ 8.99 $ 9.54 $ 9.94 $ 10.04 $ 9.63 -------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.44(a) $ 0.42(a) $ 0.40 $ 0.41 $ 0.51 Net realized and unrealized gain (loss) on investments 0.54 (0.58) (0.47) (0.12) 0.45 -------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.98 $ (0.16) $ (0.07) $ 0.29 $ 0.96 -------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.58) $ (0.39) $ (0.33) $ (0.37) $ (0.55) Net realized gain -- -- -- (0.02) -- -------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.58) $ (0.39) $ (0.33) $ (0.39) $ (0.55) -------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.40 $ (0.55) $ (0.40) $ (0.09) $ 0.41 -------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.39 $ 8.99 $ 9.54 $ 9.94 $ 10.04 ========================================================================================================================== Total return* 11.13% (1.62)% (0.71)% 2.95% 10.24% Ratio of net expenses to average net assets 1.18% 1.19% 1.14% 1.19% 1.20% Ratio of net investment income (loss) to average net assets 4.71% 4.52% 3.76% 3.89% 5.05% Portfolio turnover rate 114% 56% 81% 95% 30% Net assets, end of period (in thousands) $35,375 $47,311 $92,376 $161,097 $47,233 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 1.19% 1.19% 1.14% 1.19% 1.48% Net investment income (loss) to average net assets 4.70% 4.52% 3.76% 3.89% 4.77% ========================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. (a) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 41 Financial Highlights (continued) -------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 -------------------------------------------------------------------------------------------------------------------------- Class C Net asset value, beginning of period $ 8.97 $ 9.51 $ 9.92 $ 10.02 $ 9.61 -------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.36(a) $ 0.36(a) $ 0.31 $ 0.34 $ 0.44 Net realized and unrealized gain (loss) on investments 0.54 (0.58) (0.46) (0.13) 0.45 -------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.90 $ (0.22) $ (0.15) $ 0.21 $ 0.89 -------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.51) $ (0.32) $ (0.26) $ (0.29) $ (0.48) Net realized gain -- -- -- (0.02) -- -------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.51) $ (0.32) $ (0.26) $ (0.31) $ (0.48) -------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.39 $ (0.54) $ (0.41) $ (0.10) $ 0.41 -------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.36 $ 8.97 $ 9.51 $ 9.92 $ 10.02 ========================================================================================================================== Total return* 10.18% (2.25)% (1.58)% 2.19% 9.44% Ratio of net expenses to average net assets 1.94% 1.95% 1.90% 1.93% 1.95% Ratio of net investment income (loss) to average net assets 3.94% 3.86% 3.04% 3.18% 4.29% Portfolio turnover rate 114% 56% 81% 95% 30% Net assets, end of period (in thousands) $37,510 $44,207 $70,793 $91,491 $28,796 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 1.95% 1.95% 1.90% 1.93% 2.23% Net investment income (loss) to average net assets 3.93% 3.86% 3.04% 3.18% 4.01% ========================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. (a) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 42 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 -------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 -------------------------------------------------------------------------------------------------------------------------- Class Y Net asset value, beginning of period $ 9.03 $ 9.58 $ 9.98 $ 10.08 $ 9.66 -------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.47(a) $ 0.46(a) $ 0.41 $ 0.44 $ 0.55 Net realized and unrealized gain (loss) on investments 0.53 (0.58) (0.45) (0.12) 0.45 -------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 1.00 $ (0.12) $ (0.04) $ 0.32 $ 1.00 -------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.61) $ (0.43) $ (0.36) $ (0.40) $ (0.58) Net realized gain -- -- -- (0.02) -- -------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.61) $ (0.43) $ (0.36) $ (0.42) $ (0.58) -------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.39 $ (0.55) $ (0.40) $ (0.10) $ 0.42 -------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.42 $ 9.03 $ 9.58 $ 9.98 $ 10.08 ========================================================================================================================== Total return* 11.35% (1.26)% (0.43)% 3.24% 10.69% Ratio of net expenses to average net assets 0.85% 0.85% 0.85% 0.85% 0.85% Ratio of net investment income (loss) to average net assets 5.01% 4.90% 4.10% 4.24% 5.52% Portfolio turnover rate 114% 56% 81% 95% 30% Net assets, end of period (in thousands) $198,398 $203,736 $397,203 $395,245 $131,013 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 0.96% 0.96% 0.93% 0.97% 1.21% Net investment income (loss) to average net assets 4.90% 4.79% 4.02% 4.12% 5.16% ========================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. (a) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 43 Notes to Financial Statements |3/31/17 1. Organization and Significant Accounting Policies Pioneer Dynamic Credit Fund (the Fund) is one of three portfolios comprising Pioneer Series Trust X, a Delaware statutory trust. The Fund is registered under the Investment Company Act of 1940 as a diversified, open-end management investment company. The investment objective of the Fund is to seek a high level of current income. Capital appreciation is a secondary objective. The Fund offers three classes of shares designated as Class A, Class C and Class Y shares. Class Z shares were converted to Class Y shares on August 7, 2015. Each class of shares represents an interest in the same portfolio of investments of the Fund and has identical rights (based on relative net asset values) to assets and liquidation proceeds. Share classes can bear different rates of class-specific fees and expenses, such as transfer agent and distribution fees. Differences in class-specific fees and expenses will result in differences in net investment income and, therefore, the payment of different dividends from net investment income earned by each class. The Amended and Restated Declaration of Trust of the Fund gives the Board of Trustees the flexibility to specify either per-share voting or dollar-weighted voting when submitting matters for shareholder approval. Under per-share voting, each share of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a shareholder's voting power is determined not by the number of shares owned, but by the dollar value of the shares on the record date. Each share class has exclusive voting rights with respect to matters affecting only that class, including with respect to the distribution plan for that class. There is no distribution plan for Class Y shares. The Fund's financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) that require the management of the Fund to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of income, expenses and gains and losses on investments during the reporting period. Actual results could differ from those estimates. The Fund is an investment company and follows investment company accounting and reporting guidance under U.S. GAAP. The following is a summary of significant accounting policies followed by the Fund in the preparation of its financial statements: 44 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 A. Security Valuation The net asset value of the Fund is computed once daily, on each day the New York Stock Exchange (NYSE) is open, as of the close of regular trading on the NYSE. Fixed-income securities are valued by using prices supplied by independent pricing services, which consider such factors as market prices, market events, quotations from one or more brokers, Treasury spreads, yields, maturities and ratings, or may use a pricing matrix or other fair value methods or techniques to provide an estimated value of the security or instrument. A pricing matrix is a means of valuing a debt security on the basis of current market prices for other debt securities, historical trading patterns in the market for fixed-income securities and/or other factors. Non-U.S. debt securities that are listed on an exchange will be valued at the bid price obtained from an independent third party pricing service. When independent third party pricing services are unable to supply prices, or when prices or market quotations are considered to be unreliable, the value of that security may be determined using quotations from one or more broker-dealers. Loan interests are valued in accordance with guidelines established by the Board of Trustees at the mean between the last available bid and asked prices from one or more brokers or dealers as obtained from Loan Pricing Corporation, an independent third party pricing service. If price information is not available from Loan Pricing Corporation, or if the price information is deemed to be unreliable, price information will be obtained from an alternative loan interest pricing service. If no reliable price quotes are available from either the primary or alternative pricing service, broker quotes will be solicited. Event-linked bonds or catastrophe bonds are valued at the bid price obtained from an independent third party pricing service. Other insurance linked securities (including sidecars, collateralized reinsurance and industry loss warranties) may be valued at the bid price obtained from an independent pricing service, or through a third party using a pricing matrix, insurance industry valuation models, or other fair value methods or techniques to provide an estimated value of the instrument. The value of foreign securities is translated into U.S. dollars based on foreign currency exchange rate quotations supplied by a third party pricing source. Trading in non-U.S. equity securities is substantially completed each day at various times prior to the close of the NYSE. The values of such securities used in computing the net asset value of the Fund's shares are determined as of such times. The Fund may use a fair value model developed by an independent pricing service to value non-U.S. equity securities. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 45 Swap contracts, including interest rate swaps, caps and floors (other than centrally cleared swap contracts) are valued at the dealer quotations obtained from reputable International Swap Dealer Association members. Centrally cleared swaps are valued at the daily settlement price provided by the central clearing counterparty. Futures contracts are generally valued at the closing settlement price established by the exchange on which they are traded. Option contracts are generally valued at the mean between the last bid and ask prices on the principal exchange where they are traded. Over-the-counter ("OTC") options and options on swaps ("swaptions") are valued using prices supplied by independent pricing services, which consider such factors as market prices, market events, quotations from one or more brokers, Treasury spreads, yields, maturities and ratings, or may use a pricing matrix or other fair value methods or techniques to provide an estimated value of the security or instrument. Forward foreign currency exchange contracts are valued daily using the foreign exchange rate or, for longer term forward contract positions, the spot currency rate and the forward points on a daily basis, in each case provided by a third party pricing service. Contracts whose forward settlement date falls between two quoted days are valued by interpolation. Shares of open-end registered investment companies (including money market mutual funds) are valued at such funds' net asset value. Repurchase agreements are valued at par. Cash may include overnight time deposits at approved financial institutions. Shares of closed-end interval funds that offer their shares at net asset value are valued at such funds' net asset value. Securities or loan interests for which independent pricing services or broker-dealers are unable to supply prices or for which market prices and/or quotations are not readily available or are considered to be unreliable are valued by a fair valuation team comprised of certain personnel of Pioneer Investment Management, Inc. (PIM), the Fund's investment adviser and a wholly owned indirect subsidiary of UniCredit S.p.A. (UniCredit), pursuant to procedures adopted by the Fund's Board of Trustees. PIM's fair valuation team uses fair value methods approved by the Valuation Committee of the Board of Trustees. PIM's fair valuation team is responsible for monitoring developments that may impact fair valued securities and for discussing and assessing fair values on an ongoing basis, and at least quarterly, with the Valuation Committee of the Board of Trustees. Inputs used when applying fair value methods to value a security may include credit ratings, the financial condition of the company, current market conditions and comparable securities. The Fund may use fair value methods 46 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 if it is determined that a significant event has occurred after the close of the exchange or market on which the security trades and prior to the determination of the Fund's net asset value. Examples of a significant event might include political or economic news, corporate restructurings, natural disasters, terrorist activity or trading halts. Thus, the valuation of the Fund's securities may differ significantly from exchange prices and such differences could be material. At March 31, 2017, five securities were valued using fair value methods (in addition to securities valued using prices supplied by independent pricing services, broker-dealers or using a third party insurance industry pricing model) representing 0.4% of net assets. B. Investment Income and Transactions Principal amounts of mortgage-backed securities are adjusted for monthly paydowns. Premiums and discounts related to certain mortgage-backed securities are amortized or accreted in proportion to the monthly paydowns. All discounts/premiums on purchase prices of debt securities are accreted/amortized for financial reporting purposes over the life of the respective securities, and such accretion/amortization is included in interest income. Dividend income is recorded on the ex-dividend date, except that certain dividends from foreign securities where the ex-dividend date may have passed are recorded as soon as the Fund becomes aware of the ex-dividend data in the exercise of reasonable diligence. Interest income, including interest on income bearing cash accounts, is recorded on the accrual basis, net of unrecoverable foreign taxes withheld at the applicable country rates. Security transactions are recorded as of trade date. Gains and losses on sales of investments are calculated on the identified cost method for both financial reporting and federal income tax purposes. C. Foreign Currency Translation The books and records of the Fund are maintained in U.S. dollars. Amounts denominated in foreign currencies are translated into U.S. dollars using current exchange rates. Net realized gains and losses on foreign currency transactions, if any, represent, among other things, the net realized gains and losses on foreign currency contracts, disposition of foreign currencies and the difference between the amount of income accrued and the U.S. dollars actually received. Further, the effects of changes in foreign currency exchange rates on investments are not segregated in the statement of operations from the effects of changes in the market price of those securities but are included with the net realized and unrealized appreciation or depreciation on investments. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 47 D. Forward Foreign Currency Contracts The Fund may enter into forward foreign currency contracts (contracts) for the purchase or sale of a specific foreign currency at a fixed price on a future date. All contracts are marked to market daily at the applicable exchange rates, and any resulting unrealized appreciation or depreciation are recorded in the Fund's financial statements. The Fund records realized gains and losses at the time a contract is offset by entry into a closing transaction or extinguished by delivery of the currency. Risks may arise upon entering into these contracts from the potential inability of counterparties to meet the terms of the contract and from unanticipated movements in the value of foreign currencies relative to the U.S. dollar (see Note 5). E. Federal Income Taxes It is the Fund's policy to comply with the requirements of the Internal Revenue Code applicable to regulated investment companies and to distribute all of its net taxable income and net realized capital gains, if any, to its shareowners. Therefore, no provision for federal income taxes is required. As of March 31, 2017, the Fund had not accrued any interest or penalties with respect to uncertain tax positions, which, if applicable, would be recorded as an income tax expense in the Statement of Operations. Tax returns filed within the prior three years are subject to examination by Federal and State tax authorities. The amount and character of income and capital gain distributions to shareowners are determined in accordance with federal income tax rules, which may differ from U.S. GAAP. Distributions in excess of net investment income or net realized gains are temporary overdistributions for financial statement purposes resulting from differences in the recognition or classification of income or distributions for financial statement and tax purposes. Capital accounts within the financial statements are adjusted for permanent book/tax differences to reflect tax character, but are not adjusted for temporary differences. At March 31, 2017, the Fund reclassified $1,234,145 to decrease distributions in excess of net investment income and $1,234,145 to increase accumulated net realized loss on investments, foreign currency transactions, written options, swap contracts and futures contracts to reflect permanent book/tax differences. These adjustments have no impact on net assets or the results of operations. At March 31, 2017, the Fund was permitted to carry forward indefinitely $19,765,650 of short-term losses and $31,317,009 of long-term losses under the Regulated Investment Company Modernization Act of 2010 without limitation. 48 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 The tax character of distributions paid during the years ended March 31, 2017 and March 31, 2016 was as follows: ---------------------------------------------------------------------------- 2017 2016 ---------------------------------------------------------------------------- Distributions paid from: Ordinary income $17,207,716 $17,830,592 ---------------------------------------------------------------------------- Total $17,207,716 $17,830,592 ============================================================================ The following shows components of distributable earnings on a federal income tax basis at March 31, 2017. ---------------------------------------------------------------------------- 2017 ---------------------------------------------------------------------------- Undistributed ordinary income $ 41,933 Capital loss carryforward (51,082,659) Current year dividend payable (181,289) Unrealized appreciation 4,720,992 ---------------------------------------------------------------------------- Total $(46,501,023) ============================================================================ The difference between book-basis and tax-basis net unrealized appreciation is attributable to the tax adjustments relating to catastrophe bonds and credit default swaps, the mark-to-market of forward currency, option, interest on defaulted bonds and futures contracts. F. Fund Shares The Fund records sales and repurchases of its shares as of trade date. Pioneer Funds Distributor, Inc. (PFD), the principal underwriter for the Fund and a wholly owned indirect subsidiary of UniCredit, earned $7,780 in underwriting commissions on the sale of Class A shares during the year ended March 31, 2017. G. Class Allocations Income, common expenses, and realized and unrealized gains and losses are calculated at the Fund level and allocated daily to each class of shares based on its respective percentage of adjusted net assets at the beginning of the day. Distribution fees are calculated based on the average daily net asset value attributable to Class A and Class C shares of the Fund, respectively (see Note 4). Class Y shares do not pay distribution fees. All expenses and fees paid to the Fund's transfer agent, for its services are allocated among the classes of shares based on the number of accounts in each class and the ratable allocation of related out-of-pocket expenses (see Note 3). The Fund declares as daily dividends substantially all of its net investment income. All dividends are paid on a monthly basis. Short-term capital gain distributions, if any, may be declared with the daily dividends. Distributions to shareowners are recorded as of the ex-dividend date. Distributions paid by Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 49 the Fund with respect to each class of shares are calculated in the same manner and at the same time except that net investment income dividends to Class A, Class C and Class Y shares can reflect different transfer agent and distribution expense rates. H. Risks The value of securities held by the fund may go up or down, sometimes rapidly or unpredictably, due to general market conditions, such as real or perceived adverse economic, political or regulatory conditions, inflation, changes in interest rates, lack of liquidity in the bond markets or adverse investor sentiment. In the past several years, financial markets have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty. These conditions may continue, recur, worsen or spread. When interest rates rise, the prices of fixed-income securities in the Fund will generally fall. Conversely, when interest rates fall, the prices of fixed-income securities in the Fund will generally rise. Interest rates in the U.S. recently have been historically low, so the Fund faces a heightened risk that interest rates may rise. A general rise in interest rates may cause investors to move out of fixed income securities on a large scale, which could adversely affect the price and liquidity of fixed income securities and could also result in increased redemptions from the Fund. Investments in the Fund are subject to possible loss due to the financial failure of issuers of underlying securities and the issuers' inability to meet their debt obligations. Certain securities in which the Fund invests, including floating rate loans, once sold, may not settle for an extended period (for example, several weeks or even longer). The Fund will not receive its sale proceeds until that time, which may constrain the Fund's ability to meet its obligations (including obligations to redeeming shareholders). The Fund's prospectus contains unaudited information regarding the Fund's principal risks. Please refer to that document when considering the Fund's principal risks. I. Insurance-Linked Securities (ILS) The Fund invests in event-linked bonds. Event-linked bonds are floating rate debt obligations for which the return of principal and the payment of interest are contingent on the non-occurrence of a pre-defined "trigger" event, such as a hurricane or an earthquake of a specific magnitude. The trigger event's magnitude may be based on losses to a company or industry, industry indexes or readings of scientific instruments, or may be based on specified actual losses. If a trigger event occurs, as defined within the terms of an event-linked bond, the Fund may lose a portion or all of its accrued interest and/or principal invested in such event-linked bond. The Fund is entitled to receive principal and interest payments so long as no trigger event occurs of the description and magnitude specified by the instrument. In addition to the 50 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 specified trigger events, event-linked bonds may expose the Fund to other risks, including but not limited to issuer (credit) default, adverse regulatory or jurisdictional interpretations and adverse tax consequences. The Fund's investments in ILS may include special purpose vehicles ("SPVs") or similar instruments structured to comprise a portion of a reinsurer's catastrophe-oriented business, known as quota share instruments (sometimes referred to as reinsurance sidecars), or to provide reinsurance relating to specific risks to insurance or reinsurance companies through a collateralized instrument, known as collateralized reinsurance. Structured reinsurance investments also may include industry loss warranties ("ILWs"). A traditional ILW takes the form of a bilateral reinsurance contract, but there are also products that take the form of derivatives, collateralized structures, or exchange traded instruments. Structured reinsurance investments, including quota share instruments, collateralized reinsurance investments and ILWs, generally are subject to the same risks as event-linked bonds. In addition, where the instruments are based on the performance of underlying reinsurance contracts, the Fund has limited transparency into the individual underlying contracts and therefore must rely upon the risk assessment and sound underwriting practices of the issuer. Accordingly, it may be more difficult for PIM to fully evaluate the underlying risk profile of the Fund's structured reinsurance investments and therefore the Fund's assets are placed at greater risk of loss than if PIM had more complete information. Structured reinsurance instruments generally will be considered illiquid securities by the Fund. These securities may be difficult to purchase, sell or unwind. Illiquid securities also may be difficult to value. If the Fund is forced to sell an illiquid asset, the Fund may be forced to sell at a loss. J. Futures Contracts The Fund may enter into futures transactions in order to attempt to hedge against changes in interest rates, securities prices and currency exchange rates or to seek to increase total return. Futures contracts are types of derivatives. All futures contracts entered into by the Fund are traded on a futures exchange. Upon entering into a futures contract, the Fund is required to deposit with a broker an amount of cash or securities equal to the minimum "initial margin" requirements of the associated futures exchange. The amount of cash deposited with the broker as collateral at March 31, 2017 was $537,000 and is recorded within "Restricted Cash" on the Statement of Assets and Liabilities. Subsequent payments for futures contracts ("variation margin") are paid or received by the Fund, depending on the daily fluctuation in the value of the contracts, and are recorded by the Fund as unrealized appreciation or depreciation. When the contract is closed, the Fund realizes a Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 51 gain or loss equal to the difference between the opening and closing value of the contract as well as any fluctuation in foreign currency exchange rates where applicable. Futures contracts are subject to market risk, interest rate risk and currency exchange rate risk. Changes in value of the contracts may not directly correlate to the changes in value of the underlying securities. The average value of contracts open during the year ended March 31, 2017 was $10,207,837. At March 31, 2017, open futures contracts were as follows: ------------------------------------------------------------------------------------------ Contracts Settlement Unrealized Long/ Month/ Appreciation/ Description Counterparty (Short) Year Value (Depreciation) ------------------------------------------------------------------------------------------ U.S. 2 Yr Note Citibank NA 79 6/17 $ 17,099,797 $ (12,344) U.S. 5 Yr Note Citibank NA 159 6/17 18,718,524 (30,070) U.S. Ultra Bond Citibank NA (35) 6/17 (5,621,875) 45,554 U.S. 10 Yr Note Citibank NA (21) 6/17 (2,615,813) 5,896 U.S. 10 Yr Ultra Bond Citibank NA (56) 6/17 (7,497,875) 15,862 EURO-BOBL Bond Citibank NA (164) 6/17 (23,093,679) (107,642) ------------------------------------------------------------------------------------------ Total $ (3,010,921) $ (82,744) ========================================================================================== K. Repurchase Agreements Repurchase agreements are arrangements under which the Fund purchases securities from a broker-dealer or a bank, called the counterparty, upon the agreement of the counterparty to repurchase the securities from the Fund at a later date, and at a specific price, which is typically higher than the purchase price paid by the Fund. The securities purchased serve as the Fund's collateral for the obligation of the counterparty to repurchase the securities. The value of the collateral, including accrued interest, is required to be equal to or in excess of the repurchase price. The collateral for all repurchase agreements is held in safekeeping in the customer-only account of the Fund's custodian or a subcustodian of the Fund. PIM is responsible for determining that the value of the collateral remains at least equal to the repurchase price. In the event of a default by the counterparty, the Fund is entitled to sell the securities, but the Fund may not be able to sell them for the price at which they were purchased, thus causing a loss to the Fund. Additionally, if the counterparty becomes insolvent, there is some risk that the Fund will not have a right to the securities, or the immediate right to sell the securities. Open repurchase agreements as of March 31, 2017 are listed at the end of the Fund's Schedule of Investments. L. Credit Default Swap Agreements A credit default swap is a contract between a buyer of protection and a seller of protection against a pre-defined credit event on an underlying reference obligation, which may be a single security or a basket or index of securities. The Fund may sell or buy credit default swap contracts to seek to increase the 52 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Fund's income, or to attempt to hedge the risk of default on portfolio securities. A credit default swap index is used to hedge risk or take a position on a basket of credit entities or indices. As a seller of protection, the Fund would be required to pay the notional (or other agreed-upon) value of the referenced debt obligation to the counterparty in the event of a default by a U.S. or foreign corporate issuer of a debt obligation, which would likely result in a loss to the Fund. In return, the Fund would receive from the counterparty a periodic stream of payments during the term of the contract provided that no event of default occurred. The maximum exposure of loss to the seller would be the notional value of the credit default swaps outstanding. If no default occurs, the Fund would keep the stream of payments and would have no payment obligation. The Fund may also buy credit default swap contracts in order to hedge against the risk of default of debt securities, in which case the Fund would function as the counterparty referenced above. When the Fund enters into a credit default swap contract, the protection buyer makes an upfront or periodic payment to the protection seller in exchange for the right to receive a contingent payment. An upfront payment made by the Fund, as the protection buyer, is recorded as an asset in the Statement of Assets and Liabilities. Periodic payments received or paid by the Fund are recorded as realized gains or losses in the Statement of Operations. Credit default swap contracts are marked-to-market daily using valuations supplied by independent sources and the change in value, if any, is recorded as unrealized appreciation or depreciation in the Statement of Assets and Liabilities. Payments received or made as a result of a credit event or upon termination of the contract are recognized, net of the appropriate amount of the upfront payment, as realized gains or losses in the Statement of Operations. Credit default swap contracts involving the sale of protection may involve greater risks than if the Fund had invested in the referenced debt instrument directly. Credit default swap contracts are subject to general market risk, liquidity risk, counterparty risk and credit risk. If the Fund is a protection buyer and no credit event occurs, it will lose its investment. If the Fund is a protection seller and a credit event occurs, the value of the referenced debt instrument received by the Fund, together with the periodic payments received, may be less than the amount the Fund pays to the protection buyer, resulting in a loss to the Fund. Certain swap contracts that are cleared through a central clearinghouse are referred to as centrally cleared swaps. All payments made or received by the Fund are pursuant to a centrally cleared swap contract with the central clearing party rather than the original counterparty. Upon entering into a centrally cleared swap contract, the Fund is required to make an initial Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 53 margin deposit, either in cash or in securities. The daily change in value on open centrally cleared contracts is recorded as variation margin on centrally cleared swaps on the Statement of Assets and Liabilities. The amount of cash deposited with a broker as collateral at March 31, 2017 was $2,858,747 and is recorded within "Restricted Cash" on the Statement of Assets and Liabilities. Open credit default swap contracts at March 31, 2017 are listed in the Schedule of Investments. The average value of swap contracts open during the year ended March 31, 2017 was $1,753,908. M. Purchased Options The Fund may purchase put and call options to seek increase total return. Purchased call and put options entitle the Fund to buy and sell a specified number of shares or units of a particular security, currency or index at a specified price at a specific date or within a specific period of time. Upon the purchase of a call or put option, the premium paid by the Fund is included in the Statement of Assets and Liabilities as an investment. All premiums are marked-to-market daily, and any unrealized gains or losses are recorded in the Fund's financial statements. As the purchaser of an index option, the Fund has the right to receive a cash payment equal to any depreciation in the value of the index below the strike price of the option (in the case of a put) or equal to any appreciation in the value of the index over the strike price of the option (in the case of a call) as of the valuation date of the option. Premiums paid for purchased calls and put options which have expired are treated as realized losses on investments in the Statement of Operations. Upon the exercise or closing of a purchased put option, the premium is offset against the proceeds on the sale of the underlying security or financial instrument in order to determine the realized gain or loss on investments. Upon the exercise or closing of a purchased call option, the premium is added to the cost of the security or financial instrument. The risk associated with purchasing options is limited to the premium originally paid. The average value of purchased options open for the year ended March 31, 2017 was $742,918. Purchased option contracts outstanding at period end are listed in the Schedule of Investments. N. Option Writing The Fund may write put and covered call options to seek to increase total return. When an option is written, the Fund receives a premium and becomes obligated to purchase or sell the underlying security at a fixed price upon the exercise of the option. When the Fund writes an option, an amount equal to the premium received by the Fund is recorded as a liability and is subsequently adjusted to the current value of the option written. Premiums 54 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 received from writing options that expire unexercised are treated by the Fund on the expiration date as realized gains from investments. The difference between the premium and the amount paid on effecting a closing purchase transaction, including brokerage commissions, is also treated as a realized gain or, if the premium is less than the amount paid for the closing purchase transaction, as a realized loss. If a call option is exercised, the premium is added to the proceeds from the sale of the underlying security in determining whether the Fund has realized a gain or loss. The Fund as writer of an option bears the market risk of an unfavorable change in the price of the security underlying the written option. The average value of written option contracts open during the year ended March 31, 2017 was $(354,214). Written option contracts outstanding at March 31, 2017 are listed in the Schedule of Investments. The Fund held three written options that were open at March 31, 2017. If the options were exercised at March 31, 2017, the maximum amount the Fund would have been required to pay was $262,724. Transactions in written options for the year ended March 31, 2017 are summarized as follows: ------------------------------------------------------------------------------------ Number of Premiums Contracts Received ------------------------------------------------------------------------------------ Options open at beginning of period (3,164) $(3,744,961) Options opened (10,804) (6,238,108) Options exercised 9,864 5,469,082 Options closed -- -- Options expired 3,814 4,251,263 ------------------------------------------------------------------------------------ Options open at end of period (290) $ (262,724) ==================================================================================== 2. Management Agreement PIM manages the Fund's portfolio. Management fees are calculated daily at the annual rate equal to 0.70% of the Fund's average daily net assets up to $1 billion and 0.65% on assets over $1 billion. For the year ended March 31, 2017, the effective management fee (excluding waivers and/or assumption of expenses and acquired fund fees and expenses) was equivalent to 0.68% of the Fund's average daily net assets. PIM has contractually agreed to limit ordinary operating expenses (ordinary operating expenses means all fund expenses other than extraordinary expenses, such as litigation, taxes, brokerage commissions and acquired fund fees and expenses) of the Fund to the extent required to reduce Fund expenses to 1.20% and 0.85% of the average daily net assets attributable to Class A and Class Y shares. Fees waived and expenses reimbursed during the year ended March 31, 2017 are reflected on the Statement of Operations. These expense Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 55 limitations are in effect through August 1, 2018. There can be no assurance that PIM will extend the expense limitation agreement for a class of shares beyond the date referred to above. In addition, under the management and administration agreements, certain other services and costs, including accounting, regulatory reporting, and insurance premiums, are paid by the Fund as administrative reimbursements. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $40,787 in management fees, administrative costs and certain other reimbursements payable to PIM at March 31, 2017. 3. Transfer Agent Boston Financial Data Services, Inc. serves as the transfer agent to the Fund at negotiated rates. Transfer agent fees and payables shown on the Statement of Operations and the Statement of Assets and Liabilities, respectively, include sub-transfer agent expenses incurred through the Fund's omnibus relationship contracts. In addition, the Fund reimbursed the transfer agent for out-of-pocket expenses incurred by the transfer agent related to shareholder communications activities such as proxy and statement mailings and outgoing phone calls. For the year ended March 31, 2017, such out-of-pocket expenses by class of shares were as follows: -------------------------------------------------------------------------------- Shareholder Communications: -------------------------------------------------------------------------------- Class A $4,316 Class C 2,775 Class Y 326 -------------------------------------------------------------------------------- Total $7,417 ================================================================================ 4. Distribution Plan The Fund has adopted a Distribution Plan pursuant to Rule 12b-1 of the Investment Company Act of 1940 with respect to its Class A and Class C shares. Pursuant to the Plan, the Fund pays PFD 0.25% of the average daily net assets attributable to Class A shares as compensation for personal services and/or account maintenance services or distribution services with regard to Class A shares. Pursuant to the Plan, the Fund also pays PFD 1.00% of the average daily net assets attributable to Class C shares. The fee for Class C shares consists of a 0.25% service fee and a 0.75% distribution fee paid as compensation for personal services and/or account maintenance services or distribution services with regard to Class C shares. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $2,528 in distribution fees payable to PFD at March 31, 2017. 56 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 In addition, redemptions of each class of shares (except Class Y shares) may be subject to a contingent deferred sales charge (CDSC). A CDSC of 1.00% may be imposed on redemptions of certain net asset value purchases of Class A shares within 12 months of purchase. Redemptions of Class C shares within 12 months of purchase are subject to a CDSC of 1.00%, based on the lower of cost or market value of shares being redeemed. Shares purchased as part of an exchange remain subject to any CDSC that applied to the original purchase of those shares. There is no CDSC for Class Y shares. Proceeds from the CDSCs are paid to PFD. For the year ended March 31, 2017, CDSCs in the amount of $1,254 were paid to PFD. 5. Forward Foreign Currency Contracts At March 31, 2017, the Fund had entered into various forward foreign currency contracts that obligate the Fund to deliver or take delivery of currencies at specified future maturity dates. Alternatively, prior to the settlement date of a forward foreign currency contract, the Fund may close out such contract by entering into an offsetting contract. The average value of contracts open during the year ended March 31, 2017 was $(5,883,795). As of March 31, 2017, outstanding forward foreign currency contracts were as follows: ---------------------------------------------------------------------------------------------------- Currency Currency In Settlement Unrealized Sold Deliver Purchased Exchange for Counterparty Date Appreciation ---------------------------------------------------------------------------------------------------- USD (3,971,648) GBP 3,167,259 State Street Bank 5/10/2017 $ 1,560 And Trust Co. USD (676,293) CLP 450,404,333 Bank of 6/9/2017 3,883 America NA EUR (574,069) USD 618,720 State Street Bank 4/26/2017 4,785 And Trust Co. USD (1,350,775) INR 91,085,433 JP Morgan Chase 6/6/2017 41,363 Bank NA CAD (5,377,921) USD 4,097,765 State Street Bank 4/25/2017 49,367 And Trust Co. CLP (450,404,333) USD 680,215 State Street Bank 6/9/2017 39 And Trust Co. EUR (2,435,893) USD 2,626,821 State Street Bank 4/28/2017 21,530 And Trust Co. NZD (2,891,760) USD 2,027,349 State Street Bank 6/30/2017 4,220 And Trust Co. AUD (1,782,613) USD 1,367,216 State Street Bank 4/24/2017 4,542 And Trust Co. USD (1,449,119) RUB 86,315,065 JP Morgan Chase 6/5/2017 62,171 Bank NA USD (653,072) PLN 2,598,145 Brown Brothers 4/18/2017 2,727 Harriman & Co. USD (1,419,071) IDR 19,083,949,745 Bank of 6/6/2017 2,982 America NA ---------------------------------------------------------------------------------------------------- Total $199,169 ==================================================================================================== Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 57 ------------------------------------------------------------------------------------------------------------ Currency Currency In Settlement Unrealized Sold Deliver Purchased Exchange for Counterparty Date Depreciation ------------------------------------------------------------------------------------------------------------ USD (2,773,774) JPY 306,731,990 State Street Bank 6/06/2017 $ (11,227) And Trust Co. JPY (157,484,166) USD 1,363,204 JP Morgan Chase 4/10/2017 (52,020) Bank NA USD (2,116,573) KRW 2,355,619,238 JP Morgan Chase 5/15/2017 (5,523) Bank NA USD (2,541,752) EUR 2,346,734 State Street Bank 4/28/2017 (31,820) And Trust Co. USD (2,012,532) CAD 2,672,881 State Street Bank 4/25/2017 (437) And Trust Co. GBP (3,167,390) USD 3,972,864 State Street Bank 5/10/2017 (509) And Trust Co. USD (432,306) EUR 399,742 Bank of New 4/26/2017 (4,803) York Mellon KRW (5,486,340,000) USD 4,776,545 State Street Bank 5/15/2017 (140,183) And Trust Co. PLN (2,598,145) USD 638,420 State Street Bank 4/18/2017 (17,379) And Trust Co. JPY (149,322,960) USD 1,314,531 State Street Bank 6/6/2017 (30,330) And Trust Co. ------------------------------------------------------------------------------------------------------------ Total $(294,231) ============================================================================================================ AUD Australian Dollar CAD Canadian Dollar CLP Chilean Peso EUR Euro GBP British Pounds IDR Indonesian Rupiah INR Indian Rupee JPY Japanese Yen KRW South Korean Won NZD New Zealand Dollar PLN Polish Zloty RUB Russian Ruble 6. Assets and Liabilities Offsetting The Fund has entered into an International Swaps and Derivatives Association, Inc. Master Agreement ("ISDA Master Agreement") or similar agreement with substantially all its derivative counterparties. An ISDA Master Agreement is a bilateral agreement between the Fund and a counterparty that governs the trading of certain OTC derivatives and typically contains, among other things, close-out and set-off provisions which apply upon the occurrence of event of a default and/or termination event as defined under the relevant ISDA Master Agreement. The ISDA Master Agreement may also give a party the right to terminate all transactions traded under such agreement if, among other things, there is deterioration in the credit quality of the other party. Upon an event of default or a termination of the ISDA Master Agreement, the non-defaulting party has the right to close out all transactions under such agreement and to net amounts owed under each transaction to determine one net amount 58 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 payable by one party to the other. The right to close out and net payments across all transactions under the ISDA Master Agreement could result in a reduction of the Fund's credit risk to its counterparty equal to any amounts payable by the Fund under the applicable transactions, if any. However, the Fund's right to setoff may be restricted or prohibited by the bankruptcy or insolvency laws of the particular jurisdiction to which each specific ISDA of each counterparty is subject. The collateral requirements for derivatives transactions under an ISDA Master Agreement are governed by a credit support annex to the ISDA Master Agreement. Collateral requirements are generally determined at the close of business each day and are typically based on changes in market values for each transaction under an ISDA Master Agreement and netted into one amount for such agreement. Generally, the amount of collateral due from or to a counterparty is subject to threshold (a "minimum transfer amount") before a transfer is required, which may vary by counterparty. Collateral pledged for the benefit of the Fund and/or counterparty is held in segregated accounts by the Fund's custodian and cannot be sold, re-pledged, assigned or otherwise used while pledged. Cash that has been segregated to cover the Fund's collateral obligations, if any, will be reported separately in the Statement of Assets and Liabilities as "Restricted cash." Securities pledged by the Fund as collateral, if any, are identified as such in the Schedule of Investments. Financial instruments subject to an enforceable master netting agreement such as an ISDA Master Agreement have been offset on the Statement of Assets and Liabilities. The following charts show gross assets and liabilities of the Fund as of March 31, 2017. ----------------------------------------------------------------------------------------------- Derivative Assets Derivatives Non-Cash Cash Net Amount Subject to Master Available for Collateral Collateral of Derivative Counterparty Netting Agreement Offset Received (a) Received (a) Assets (b) ----------------------------------------------------------------------------------------------- Bank of America NA $ 6,865 $ -- $ -- $ -- $ 6,865 Bank of New York Mellon -- -- -- -- -- Brown Brothers Harriman & Co. 2,727 -- -- -- 2,727 Goldman Sachs International 541,228 -- -- 810,000 1,351,228 JP Morgan Chase Bank NA 162,413 (57,543) -- -- 104,870 State Street Bank And Trust Co. 86,043 (86,043) -- -- -- ----------------------------------------------------------------------------------------------- Total $ 799,276 $ (143,586) $ -- $ 810,000 $ 1,465,690 =============================================================================================== Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 59 --------------------------------------------------------------------------------------------------------------- Derivative Liabilities Derivatives Non-Cash Cash Net Amount Subject to Master Available for Collateral Collateral of Derivative Counterparty Netting Agreement Offset Pledged (a) Pledged (a) Liabilities (c) --------------------------------------------------------------------------------------------------------------- Bank of America NA $ -- $ -- $-- $-- $ -- Bank of New York Mellon 4,803 -- -- -- 4,803 Brown Brothers Harriman & Co. -- -- -- -- -- Goldman Sachs International -- -- -- -- -- JP Morgan Chase Bank NA 57,543 (57,543) -- -- -- State Street Bank And Trust Co. 231,885 (86,043) -- -- 145,842 --------------------------------------------------------------------------------------------------------------- Total $ 294,231 $ (143,586) $-- $-- $150,645 =============================================================================================================== (a) The amount presented here may be less than the total amount of collateral received/pledged as the net amount of derivative assets and liabilities cannot be less than $0. (b) Represents the net amount due from the counterparty in the event of default. (c) Represents the net amount payable to the counterparty in the event of default. 7. Additional Disclosures about Derivative Instruments and Hedging Activities: The Fund's use of derivatives may subject it to the following risks: Interest rate risk relates to the fluctuations in the value of interest-bearing securities due to changes in the prevailing levels of market interest rates. Credit risk relates to the ability of the issuer of a financial instrument to make further principal or interest payments on an obligation or commitment that it has to the Fund. Foreign exchange rate risk relates to fluctuations in the value of an asset or liability due to changes in currency exchange rates. Equity risk relates to the fluctuations in the value of financial instruments as a result of changes in market prices (other than those arising from interest rate risk or foreign exchange risk), whether caused by factors specific to an individual investment, its issuer, or all factors affecting all instruments traded in a market or market segment. Commodity risk relates to the risk that the value of a commodity or commodity index will fluctuate based on increases or decreases in the commodities market and factors specific to a particular industry or commodity. 60 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 The fair value of open derivative instruments (not considered to be hedging instruments for accounting disclosure purposes) by risk exposure at March 31, 2017 was as follows: ------------------------------------------------------------------------------------------------------- Foreign Statement of Assets and Interest Credit Exchange Equity Commodity Liabilities Rate Risk Risk Rate Risk Risk ------------------------------------------------------------------------------------------------------- Assets Unrealized appreciation of forward foreign currency contracts $ -- $ -- $199,169 $-- $-- Unrealized appreciation on futures contracts* 67,312 -- -- -- -- Unrealized appreciation of swap contracts -- 600,107 -- -- -- Unrealized appreciation of centrally cleared swap contract -- 48,530 -- -- -- ------------------------------------------------------------------------------------------------------- Total Value $ 67,312 $648,637 $199,169 $-- $-- ======================================================================================================= * Reflects unrealized appreciation/depreciation of futures contracts (see Note 1J). The current day's variation margin is disclosed on the Statement of Assets and Liabilities. ------------------------------------------------------------------------------------------------------- Foreign Statement of Assets and Interest Credit Exchange Equity Commodity Liabilities Rate Risk Risk Rate Risk Risk ------------------------------------------------------------------------------------------------------- Liabilities Unrealized depreciation of forward foreign currency contracts $ -- $-- $294,231 $ -- $-- Unrealized depreciation on futures contracts* 150,056 -- -- -- -- Written options -- -- -- 106,920 -- ------------------------------------------------------------------------------------------------------- Total Value $150,056 $-- $294,231 $106,920 $-- ======================================================================================================= * Reflects unrealized appreciation/depreciation of futures contracts (see Note 1J). The current day's variation margin is disclosed on the Statement of Assets and Liabilities. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 61 The effect of derivative instruments (not considered to be hedging instruments for accounting disclosure purposes) on the Statement of Operations by risk exposure at March 31, 2017 was as follows: ------------------------------------------------------------------------------------------------------ Foreign Interest Credit Exchange Equity Commodity Statement of Operations Rate Risk Risk Rate Risk Risk Risk ------------------------------------------------------------------------------------------------------ Net realized gain (loss) on Swap contracts $ -- $ 7,897,163 $ -- $ -- $-- Futures contracts 843,096 -- -- -- -- Written options -- -- -- 8,017,472 -- Forward foreign currency contracts** -- -- (1,369,904) -- -- ------------------------------------------------------------------------------------------------------ Total Value $ 843,096 $ 7,897,163 $(1,369,904) $ 8,017,472 $-- ====================================================================================================== Change in net unrealized appreciation (depreciation) on Swap contracts $ -- $(2,123,084) $ -- $ -- $-- Futures contracts (53,126) -- -- -- -- Written options -- -- -- (3,400,117) -- Forward foreign currency contracts** -- -- 1,268,336 -- -- ------------------------------------------------------------------------------------------------------ Total Value $ (53,126) $(2,123,084) $ 1,268,336 $(3,400,117) $-- ====================================================================================================== ** Included in the amount shown on the Statement of Operations as forward foreign currency contracts and other assets and liabilities denominated in foreign currencies. 8. Line of Credit Facility The Fund, along with certain other funds in the Pioneer Family of Funds (the Funds), participates in a committed, unsecured revolving line of credit facility. Borrowings are used solely for temporary or emergency purposes. The Fund may borrow up to the lesser of the amount available under the facility or the limits set for borrowing by the Fund's prospectus and the 1940 Act. The credit facility in which the Fund participated until February 9, 2016 was in the amount of $240 million. The credit facility in which the Fund participated until February 7, 2017, was in the amount of $220 million. Effective February 8, 2017, the Fund participated in a facility that is in the amount of $25 million. Under such facility, depending on the type of loan, interest on borrowings is payable at the London Interbank Offered Rate (LIBOR) plus 0.90% on an annualized basis, or the Alternate Base Rate, which is the greater of (a) the facility's administrative agent's daily announced prime rate on the borrowing date, (b) 2% plus the Federal Funds Rate on the borrowing date and (c) 2% plus the overnight Eurodollar rate on the borrowing date. The Funds pay an annual commitment fee to participate in a credit facility. The commitment fee is allocated among participating Funds based on an allocation schedule set forth in the credit agreement. For the year ended March 31, 2017, the Fund had no borrowings under the credit facility. 62 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 9. Unfunded Loan Commitments The Fund may enter into unfunded loan commitments. Unfunded loan commitments may be partially or wholly unfunded. During the contractual period, the Fund is obligated to provide funding to the borrower upon demand. A fee is earned by the Fund on the unfunded commitment and is recorded as interest income in the Statement of Operations. As of March 31, 2017, the Fund had the following unfunded loan commitments outstanding: ----------------------------------------------------------------------------------------- Unrealized Appreciation/ Loan Shares Cost Value Depreciation ----------------------------------------------------------------------------------------- AMC Entertainment Inc., Bridge Loan 1,250,000 $1,250,000 $1,250,000 $-- ----------------------------------------------------------------------------------------- Total $1,250,000 $1,250,000 $-- ========================================================================================= Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 63 Report of Independent Registered Public Accounting Firm To the Board of Trustees of Pioneer Series Trust X and the Shareowners of Pioneer Dynamic Credit Fund: -------------------------------------------------------------------------------- We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Pioneer Dynamic Credit Fund (the "Fund") (one of the funds constituting Pioneer Series Trust X), as of March 31, 2017, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the two years in the period then ended and the financial highlights for each of the three years in the period then ended. These financial statements and the financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits. The financial highlights for the years ended March 31, 2014, and 2013, were audited by other auditors. Those auditors expressed an unqualified opinion on those financial statements and financial highlights in their report dated May 22, 2014. We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of March 31, 2017, by correspondence with the custodian, brokers and agent banks; where replies were not received from brokers and agent banks, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion. In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Pioneer Dynamic Credit Fund as of March 31, 2017, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended and the financial highlights for each of the three years in the period then ended, in conformity with accounting principles generally accepted in the United States of America. /s/ Deloitte & Touche LLP Boston, Massachusetts May 26, 2017 64 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 ADDITIONAL INFORMATION (unaudited) The percentages of the Fund's ordinary income distributions that are exempt from nonresident alien (NRA) tax withholding resulting from qualified interest income was 88.39%. Pioneer Investment Management, Inc. (the "Adviser"), the Fund's investment adviser, is currently an indirect, wholly owned subsidiary of UniCredit S.p.A. ("UniCredit"). On December 12, 2016, UniCredit announced that it has entered into a binding agreement for the sale of its Pioneer Investments business, which includes the Adviser, to Amundi (the "Transaction"). Amundi is headquartered in Paris, France, and, as of September 30, 2016, had more than $1.1 trillion in assets under management worldwide. The closing of the Transaction is expected to happen in 2017, subject to certain regulatory and antitrust approvals, and other conditions. Under the Investment Company Act of 1940, the closing of the Transaction will cause the Fund's current investment advisory agreement with the Adviser to terminate. Accordingly, the Fund's Board of Trustees has approved a new investment advisory agreement for the Fund, which will be submitted to the shareholders of the Fund for their approval. Change in Independent Registered Public Accounting Firm Deloitte & Touche LLP, the Fund's independent registered public accounting firm, has informed the Board that it will no longer be independent with respect to the Fund upon the completion of the Transaction and, accordingly, that it intends to resign as the Fund's independent registered public accounting firm upon the completion of the Transaction. The Board will engage a new independent registered public accounting firm for the Fund upon the completion of the Transaction. During the periods that Deloitte & Touche LLP has served as the Fund's inde- pendent registered public accounting firm, including the Fund's two most recent fiscal years, Deloitte & Touche LLP's reports on the Fund's financial statements have not contained an adverse opinion or disclaimer of opinion and have not been qualified or modified as to uncertainty, audit scope or accounting principles. Further, there have been no disagreements with Deloitte & Touche LLP on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which, if not resolved to the satisfaction of Deloitte & Touche LLP, would have caused Deloitte & Touche LLP to make reference to the subject matter of the disagreement in connection with its report on the financial statements. In addition, there have been no reportable events of the kind described in Item 304(a)(1)(v) of Regulation S-K under the Securities Exchange Act of 1934. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 65 Approval of New and Interim Management Agreements Pioneer Investment Management, Inc. (PIM) serves as the investment adviser to Pioneer Dynamic Credit Fund (the Fund) pursuant to an investment management agreement between PIM and the Fund. PIM is the principal U.S. asset management business of Pioneer Investments, a group of companies owned by Pioneer Global Asset Management S.p.A. ("PGAM"). PGAM is a wholly-owned subsidiary of UniCredit S.p.A. ("UniCredit"). UniCredit and PGAM have entered into a binding agreement to sell Pioneer Investments, including PIM, to Amundi (the "Transaction"). Upon the consummation of the transaction, PIM will become an indirect wholly-owned subsidiary of Amundi and Amundi's wholly-owned subsidiary, Amundi USA, Inc. The closing of the Transaction is expected to happen in 2017. Under the Investment Company Act of 1940, the Fund's current investment management agreement (the "Current Management Agreement") will terminate automatically upon the consummation of the Transaction. In order for PIM to continue to manage the Fund after the consummation of the Transaction, the Trustees and shareholders of the Fund must approve a new investment management agreement for the Fund (the "New Management Agreement"). As discussed below, the Board of Trustees of the Fund approved the New Management Agreement at a meeting held on March 6-7, 2017. The New Management Agreement has been submitted to the shareholders of the Fund for their approval at a meeting to be held on June 13, 2017. If the shareholders of the Fund do not approve the New Management Agreement and the Transaction is completed, an interim investment management agreement between PIM and the Fund (the "Interim Management Agreement") will take effect upon the closing of the Transaction. The Board of Trustees of the Fund also approved the Interim Management Agreement at the March 6-7, 2017 meeting. Board Evaluation of the New and Interim Management Agreements The Board evaluated the Transaction and the New Management Agreement and Interim Management Agreement for the Fund. In connection with their evaluation of the Transaction and the New Management Agreement for the Fund, the Trustees requested such information as they deemed reasonably necessary, including: (a) the structure of the Transaction and the strategy underlying the Transaction; (b) the anticipated benefits of the Transaction to the Fund and its shareholders; (c) the post-Transaction plans for PIM, including Amundi's plans for integration of Pioneer Investments and PIM with its existing asset management businesses and plans for the future development of PIM; (d) the effect of the Transaction on the ongoing services provided to the Fund, including the need to select a new independent registered public 66 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 accounting firm for the Fund, and any plans to modify the operations of the Fund; (e) the stability and continuity of PIM's management and key employees, including compensation and benefits to PIM's key employees, and retention plans and incentive plan structure; (f) the post-Transaction indebtedness and financial resources of PIM; (g) Amundi's legal and operational structure, its principal shareholders and senior management, its investment management, risk management, administrative, legal and compliance functions; (h) certain regulatory matters relating to Amundi's affiliates; and (i) Amundi's commit- ment to the United States, including the role of PIM in the larger Amundi business. The Trustees also requested and obtained the following information in connec- tion with their evaluation of the Transaction and the New Management Agreement for the Fund: (i) memoranda provided by Fund counsel that summarized the legal standards and other considerations that are relevant to the Trustees in their deliberations regarding the New Management Agreement; (ii) the qualifications of the investment management teams for the Fund, as well as the level of investment by the Fund's portfolio managers in the Fund; (iii) the Fund's management fees and total expense ratios, the financial statements of PIM and its pre- and post-Transaction parent companies, profitability analyses from PIM, and analyses from PIM as to possible economies of scale; (iv) the profitability of the institutional business of PIM and PIM's affiliate, Pioneer Institutional Asset Management, Inc. ("PIAM") as compared to that of PIM's fund management business; and (v) the differences between the fees and expenses of the Fund and the fees and expenses of PIM's and PIAM's institutional accounts, as well as the different services provided by Adviser to the Fund and by PIM and PIAM to the institutional accounts. In addition, the Trustees considered the information provided at regularly scheduled meetings throughout the year regarding the Fund's performance and risk attributes, including through meetings with investment management personnel, and took into account other information related to the Fund provided to the Trustees at regularly scheduled meetings. The Trustees also considered information they had received in their review of the continuance of the Current Management Agreement for the Fund in September 2016. At meetings held on January 9, 2017 and January 10, 2017, the Trustees met with representatives of Amundi and PGAM, including separate meetings of the Trustees who are not "interested persons" of the Fund Complex ("Independent Trustees") and counsel with representatives of Amundi and PGAM, and subsequently with representatives of Amundi. In those meetings, they received an extensive presentation from the representatives of Amundi, including the chief executive officer of Amundi, describing Amundi's background and history, its global asset management activities, the growth of its business, and its status as the largest asset management firm in Europe and one of the largest globally; its capital structure and financial resources, including Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 67 information as to the financing of the Transaction; its principal investors, including its majority investor Credit Agricole S.A., and Credit Agricole's long-term commitment to the asset management business; the philosophy and strategy underlying the Transaction and the complementarity of Amundi's and Pioneer Investments' respective asset management businesses; Amundi's various operating and investment committees and how they would likely interact with PIM; the proposed integration process, including the progress to date and the establishment of various integration work streams; Amundi's plans for management of PIM; Amundi's philosophy as to compensation of key employees and its general intentions with respect to incentive plans for key employees of PIM; Amundi's preliminary plans to achieve cost and other synergies; and opportunities to further develop the business of PIM and PIAM, including in the area of institutional asset management, and how that would benefit share- holders of the Pioneer Funds. In those meetings, the representatives of Amundi confirmed their intention that the Chief Executive Officer and Chief Investment Officer of PIM would remain in their current positions, and confirmed that they do not currently foresee major changes in the day-to-day investment management operations of PIM with respect to the Fund as a direct result of the Transaction. They discussed incentive arrangements for key personnel that would continue after the closing of the Transaction and their plans to establish a new long-term incentive plan following the closing. They also generally discussed ways in which PIM could potentially draw on the expanded global resources of Amundi post-Transaction. At those meetings, the Independent Trustees identified certain areas to which they requested further information, including as to trading and execution of securities transactions, research and portfolio management and potential changes in investment process, particularly where asset classes managed by PIM would overlap with asset classes managed by Amundi, the continued availability of resources currently at Pioneer Investments or elsewhere within Amundi to assist in management of certain Funds, and any anticipated significant changes in operations. The Independent Trustees considered the uncertainty as to whether the Fund's independent registered public accounting firm could continue to act in that capacity after the closing of the Transaction. The Independent Trustees also met with counsel to review the information they had received to date and to discuss next steps. Subsequently, the Trustees received further information from Amundi, including written responses to questions raised by the Independent Trustees, and received from PIM the information requested of it. The Independent Trustees reviewed the information provided with counsel at telephonic meetings held on February 16, 2017 and February 27, 2017. The Trustees held a special in-person Board meeting on March 6-7, 2017 for further consideration of the 68 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 New Management Agreements, the Interim Management Agreements and the Transaction. The Trustees met again with senior executives of Amundi at the March 6-7, 2017 meeting. At the March 6-7, 2017 meeting, based on their evaluation of the information provided by PIM and Amundi, the Trustees including the Independent Trustees voting separately, approved the New Management Agreement and the Interim Management Agreement for the Fund. In considering the New Management Agreement for the Fund, the Trustees considered various factors that they determined were relevant, including the factors described below. The Trustees did not identify any single factor as the controlling factor in their determinations. The Trustees considered the same factors with respect to the Interim Management Agreement for the Fund. Nature, Extent and Quality of Services The Trustees considered the nature, extent and quality of the services that had been provided by PIM to the Fund and that are expected to be provided by PIM to the Fund following the consummation of the Transaction. The Trustees reviewed the terms of the New Management Agreement, and noted that such terms are substantially similar to the terms of the Current Management Agreement, except for different execution dates, effective dates and termination dates. The Trustees reviewed PIM's investment approach for the Fund and its research process. The Trustees considered the resources of PIM and the personnel of PIM who provide investment management services to the Fund. They also reviewed the amount of non-investment resources and personnel of PIM that are involved in PIM's services to the Fund, including PIM's compliance and legal resources and personnel. The Trustees noted the substantial attention and high priority given by PIM's senior management to the Pioneer Fund complex. The Trustees considered that PIM supervises and monitors the performance of the Fund's service providers and provides the Fund with personnel (including Fund officers) and other resources that are necessary for the Fund's business management and operations and that PIM would continue to provide those investment management and research services and resources to the Fund following the consummation of the Transaction. The Trustees also considered that, as administrator, PIM would continue to be responsible for the administration of the Fund's business and other affairs. The Trustees considered the fees to be paid to PIM for the provision of administration services. The Trustees considered that Deloitte & Touche LLP has informed the Board that it will no longer be independent with respect to the Fund upon the completion of the Transaction and, accordingly, that it will be necessary for the Board to engage a new independent registered public accounting firm for the Fund. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 69 The Trustees considered that the Transaction is not expected to have a material adverse impact on the nature, scope and overall quality of services provided to the Fund and its shareholders, including investment management, risk management, administrative, compliance, legal and other services, as a result of the Transaction. In that regard, the Trustees considered that Amundi is one of the largest asset managers globally, and that PIM may have access to additional research and portfolio management capabilities as a result of the Transaction and that PIM, as part of Amundi, is expected to have an enhanced global presence that may contribute to an increase in the overall scale and resources of PIM. Furthermore, in considering whether the Transaction would be expected to have a material adverse impact on the nature, scope and overall quality of services provided to the Fund and its shareholders, the Trustees considered the statements by representatives of Amundi that they expect the Chief Executive Officer and Chief Investment Officer of PIM to remain in their current posi- tions and that they do not currently foresee major changes in the day-to-day investment management operations of PIM as a direct result of the Transaction, or the risk management, legal or compliance services provided by PIM, with respect to the Fund. They further considered the current incentive arrangements for key personnel of PIM that would continue after the closing of the Transaction. They also noted Amundi's stated intention to establish a new long-term incentive plan following the closing. The Trustees also took into account their experience in evaluating the proposed combination of Pioneer Investments and Santander Asset Management, which was announced in September, 2014 and abandoned in July, 2016. In light of, among other things, this experience, the Trustees determined that they were not able to identify any realistic alternatives to approving the New Management Agreement that would provide the level of services to the Fund and its shareholders that are expected to be provided by PIM after the closing of the Transaction. Based on these considerations, the Trustees concluded that the nature, extent and quality of services that PIM would continue to provide to the Fund under the New Management Agreement would be satisfactory and consistent with the terms of the New Management Agreement. Performance of the Fund In considering the Fund's performance, the Trustees regularly reviewed and discussed throughout the year data prepared by PIM and information comparing the Fund's performance with the performance of its peer group of funds, as classified by each of Morningstar, Inc. (Morningstar) and Lipper, and the performance of the Fund's benchmark index. They also discussed the Fund's performance with PIM on a regular basis. 70 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 The Trustees' regular reviews and discussions were factored into the Trustees' deliberations concerning the approval of the New Management Agreement. Management Fee and Expenses The Trustees noted that the stated management fees to be paid by the Fund are identical under the Current Management Agreement and the New Management Agreement. The Trustees considered information showing the fees and expenses of the Fund in comparison to the management fees and expense ratios of its peer group of funds as classified by Morningstar and also to the expense ratios of a peer group of funds selected on the basis of criteria determined by the Independent Trustees for this purpose using data provided by Strategic Insight Mutual Fund Research and Consulting, LLC (Strategic Insight), an independent third party. In all quintile rankings referred to below, first quintile is most favorable to the Fund's shareowners. To the extent applicable, the Trustees also considered the impact of transfer agency, sub-transfer agency, and other non-management fee expenses on the expense ratios of the Fund. The Trustees noted that they separately review the Fund's transfer agency, sub-transfer agency and intermediary arrangements and that the results of the most recent such review were considered in the consideration of the Fund's expense ratio. The Trustees considered that the Fund's management fee as of September 30, 2016 was in the third quintile relative to the management fees paid by other funds in its Morningstar category for the comparable period. The Trustees also considered the breakpoint in the management fee schedule and the reduced fee rate above a certain asset level. The Trustees considered that the expense ratio of the Fund's Class A shares as of September 30, 2016 was in the third quintile relative to its Morningstar category and in the fourth quintile relative to its Strategic Insight peer group, in each case for the comparable period. The Trustees considered that the expense ratio of the Fund's Class Y shares as of September 30, 2016 was in the third quintile relative to its Morningstar category and in the third quintile relative to its Strategic Insight peer group, in each case for the comparable period. The Trustees noted that PIM had agreed to waive fees and/or reimburse expenses in order to limit the ordinary operating expenses of the Fund. The Trustees reviewed management fees charged by PIM and PIAM to institutional and other clients, including publicly offered European funds sponsored by PIM's affiliates, unaffiliated U.S. registered investment companies (in a sub- advisory capacity), and unaffiliated foreign and domestic separate accounts. The Trustees also considered PIM's costs in providing services to the Fund and PIM's and PIAM's costs in providing services to the other clients and consid- ered the differences in management fees and profit margins for fund and Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 71 non-fund services. In evaluating the fees associated with PIM's and PIAM's client accounts, the Trustees took into account the respective demands, resources and complexity associated with the Fund and other client accounts. The Trustees noted that in some instances the fee rates for those clients were lower than the management fee for the Fund and considered that, under both the Current Management Agreement and the New Management Agreement, PIM would perform additional services for the Fund that it does not provide to those other clients or services that are broader in scope, including oversight of the Fund's other service providers and activities related to compliance and the extensive regulatory and tax regimes to which the Fund is subject. The Trustees also considered the different risks associated with PIM's management of the Fund and PIM's and PIAM's management of the other client accounts. The Trustees concluded that the management fee payable by the Fund to PIM was reasonable in relation to the nature and quality of the services to be provided by PIM. Profitability The Trustees considered information provided by PIM regarding the prof- itability of PIM with respect to the advisory services provided by PIM to the Fund, including the methodology used by PIM in allocating certain of its costs to the management of the Fund. The Trustees also considered PIM's profit margin in connection with the overall operation of the Fund. They further reviewed the financial results, including the profit margins, realized by PIM and PIAM from non-fund businesses. The Trustees considered PIM's profit margins with respect to the Fund in comparison to the limited industry data available and noted that the profitability of any adviser was affected by numerous factors, including its organizational structure and method for allocating expenses. The Trustees concluded that PIM's profitability with respect to the management of the Fund was not unreasonable. Economies of Scale The Trustees considered PIM's views relating to economies of scale in connec- tion with the Pioneer Funds as fund assets grow and the extent to which any such economies of scale are shared with the Fund and Fund shareholders. The Trustees recognize that economies of scale are difficult to identify and quantify, and that, among other factors that may be relevant, are the following: fee levels, expense subsidization, investment by PIM in research and analytical capabili- ties and PIM's commitment and resource allocation to the Fund. The Trustees noted that profitability also may be an indicator of the availability of any economies of scale, although profitability may vary for other reasons including due to reductions in expenses. The Trustees concluded that economies of scale, if any, were being appropriately shared with the Fund. 72 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Other Benefits The Trustees considered the other benefits that PIM enjoys from its relation- ship with the Fund. The Trustees considered the character and amount of fees paid or to be paid by the Fund, other than under the Current Management Agreement or the New Management Agreement, for services provided by PIM and its affiliates. The Trustees further considered the revenues and profitability of PIM's businesses other than the Fund business. To the extent applicable, the Trustees also considered the benefits to the Fund and to PIM and its affiliates from the use of "soft" commission dollars generated by the Fund to pay for research and brokerage services. The Trustees considered that following the completion of the Transaction, PIM will be the principal U.S. asset management business of Amundi, and that Amundi's worldwide asset management business will manage over $1.38 trillion in assets (including the Pioneer Funds). This may create opportunities for PIM, PIAM and Amundi that derive from PIM's relationships with the Fund, including Amundi's ability to market the services of PIM globally. The Trustees noted that PIM may have access to additional research capabilities as a result of the Transaction and Amundi's enhanced global presence that may contribute to an increase of the overall scale of PIM. The Trustees considered that PIM and the Fund are expected to receive reciprocal intangible benefits from the relationship, including mutual brand recognition and, for the Fund, direct and indirect access to the resources of a large global asset manager. The Trustees concluded that any such benefits received by PIM as a result of its relationship with the Fund were reasonable. Conclusion After consideration of the factors described above as well as other factors, the Trustees, including the Independent Trustees, concluded that the New Management Agreement and the Interim Management Agreement for the Fund, including the fees payable thereunder, were fair and reasonable and voted to approve the New Management Agreement and the Interim Management Agreement, and to recommend that shareholders approve the New Management Agreement. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 73 Trustees, Officers and Service Providers Investment Adviser Pioneer Investment Management, Inc. Custodian and Sub-Administrator Brown Brothers Harriman & Co. Independent Registered Public Accounting Firm Deloitte & Touche LLP Principal Underwriter Pioneer Funds Distributor, Inc. Legal Counsel Morgan, Lewis & Bockius LLP Shareowner Services and Transfer Agent Boston Financial Data Services, Inc. Proxy Voting Policies and Procedures of the Fund are available without charge, upon request, by calling our toll free number (1-800-225-6292). Information regarding how the Fund voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is publicly available to shareowners at us.pioneerinvestments.com. This information is also available on the Securities and Exchange Commission's web site at www.sec.gov. Trustees and Officers The Fund's Trustees and officers are listed below, together with their principal occupations during at least the past five years. Trustees who are interested persons of the Fund within the meaning of the 1940 Act are referred to as Interested Trustees. Trustees who are not interested persons of the Fund are referred to as Independent Trustees. Each of the Trustees serves as a Trustee of each of the 46 U.S. registered investment portfolios for which Pioneer serves as investment adviser (the "Pioneer Funds"). The address for all Trustees and all officers of the Fund is 60 State Street, Boston, Massachusetts 02109. The Statement of Additional Information of the Fund includes additional information about the Trustees and is available, without charge, upon request, by calling 1-800-225-6292. 74 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Independent Trustees ----------------------------------------------------------------------------------------------------------------------------------- Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ----------------------------------------------------------------------------------------------------------------------------------- Thomas J. Perna (66) Trustee since 2011. Private investor (2004 - 2008 and 2013 - Director, Broadridge Chairman of the Board Serves until a successor present); Chairman (2008 - 2013) and Chief Financial Solutions, Inc. and Trustee trustee is elected or earlier Executive Officer (2008 - 2012), Quadriserv, (investor communications retirement or removal. Inc. (technology products for securities and securities processing lending industry); and Senior Executive Vice provider for financial President, The Bank of New York (financial services industry) (2009 and securities services) (1986 - 2004) - present); Director, Quadriserv, Inc. (2005 - 2013); and Commissioner, New Jersey State Civil Service Commission (2011 - 2015) ----------------------------------------------------------------------------------------------------------------------------------- David R. Bock (73) Trustee since 2011. Managing Partner, Federal City Capital Director of New York Trustee Serves until a successor Advisors (corporate advisory services Mortgage Trust trustee is elected or earlier company) (1997 - 2004 and 2008 - present); (publicly-traded mortgage retirement or removal. Interim Chief Executive Officer, Oxford REIT) (2004 - 2009, 2012 Analytica, Inc. (privately-held research and - present); Director of consulting company) (2010); Executive Vice The Swiss Helvetia Fund, President and Chief Financial Officer, Inc. (closed-end fund) I-trax, Inc. (publicly traded health care (2010 - present); services company) (2004 - 2007); and Director of Oxford Executive Vice President and Chief Financial Analytica, Inc. (2008 - Officer, Pedestal Inc. (internet-based present); and Director of mortgage trading company) (2000 - 2002); Enterprise Community Private consultant (1995-1997), Managing Investment, Inc. Director, Lehman Brothers (investment (privately-held banking firm) (1992-1995); and Executive, The affordable housing finance World Bank (1979-1992) company) (1985 - 2010) ----------------------------------------------------------------------------------------------------------------------------------- Benjamin M. Friedman (72) Trustee since 2011. William Joseph Maier Professor of Political Trustee, Mellon Trustee Serves until a successor Economy, Harvard University (1972 - present) Institutional Funds trustee is elected or earlier Investment Trust and retirement or removal. Mellon Institutional Funds Master Portfolio (oversaw 17 portfolios in fund complex) (1989-2008) ----------------------------------------------------------------------------------------------------------------------------------- Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 75 Independent Trustees continued ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Margaret B.W. Graham (69) Trustee since 2011. Founding Director, Vice President and None Trustee Serves until a successor Corporate Secretary, The Winthrop Group, trustee is elected or earlier Inc. (consulting firm) (1982 - present); retirement or removal. Desautels Faculty of Management, McGill University (1999 - present); and Manager of Research Operations and Organizational Learning, Xerox PARC, Xerox's advance research center (1990-1994) ------------------------------------------------------------------------------------------------------------------------------------ Marguerite A. Piret (68) Trustee since 2011. President and Chief Executive Officer, Director of New America Trustee Serves until a successor Newbury Piret Company (investment banking High Income Fund, Inc. trustee is elected or earlier firm) (1981 - present) (closed-end investment retirement or removal. company) (2004 - present); and Member, Board of Governors, Investment Company Institute (2000 - 2006) ------------------------------------------------------------------------------------------------------------------------------------ Fred J. Ricciardi (70) Trustee since 2014. Consultant (investment company services) None Trustee Serves until a successor (2012 - present); Executive Vice President, trustee is elected or earlier BNY Mellon (financial and investment company retirement or removal. services) (1969 - 2012); Director, BNY International Financing Corp. (financial services) (2002 - 2012); and Director, Mellon Overseas Investment Corp. (financial services) (2009 - 2012) ------------------------------------------------------------------------------------------------------------------------------------ 76 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Interested Trustee ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Kenneth J. Taubes (58)* Trustee since 2014. Director and Executive Vice President (since None Trustee Serves until a successor 2008) and Chief Investment Officer, U.S. trustee is elected or earlier (since 2010) of Pioneer Investment retirement or removal. Management-USA (PIM-USA); Executive Vice President of Pioneer (since 2008); Executive Vice President of Pioneer Institutional Asset Management, Inc. (since 2009); and Portfolio Manager of Pioneer (since 1999) ------------------------------------------------------------------------------------------------------------------------------------ * Mr. Taubes is an Interested Trustee because he is an officer of the Fund's investment adviser and certain of its affiliates. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 77 Advisory Trustee ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Lorraine Monchak (60)** Advisory Trustee since 2014. Chief Investment Officer, 1199 SEIU Funds Trustee of Pioneer Advisory Trustee (healthcare workers union pension funds) closed-end investment (2001 - present); Vice President - companies (5 portfolios) International Investments Group, American (Sept. 2015 - present) International Group, Inc. (insurance company) (1993 - 2001); Vice President, Corporate Finance and Treasury Group, Citibank, N.A. (1980 - 1986 and 1990 - 1993); Vice President - Asset/Liability Management Group, Federal Farm Funding Corporation (government-sponsored issuer of debt securities) (1988 - 1990); Mortgage Strategies Group, Shearson Lehman Hutton, Inc. (investment bank) (1987 - 1988); and Mortgage Strategies Group, Drexel Burnham Lambert, Ltd. (investment bank) (1986 - 1987) ------------------------------------------------------------------------------------------------------------------------------------ ** Ms. Monchak is a non-voting advisory trustee. 78 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 Fund Officers ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Officer ------------------------------------------------------------------------------------------------------------------------------------ Lisa M. Jones (55) Since 2014. Serves at Chair, Director, CEO and President of Trustee of Pioneer President and Chief the discretion of the Board. PIM-USA (since September 2014); Chair, closed-end investment Executive Officer Director, CEO and President of Pioneer companies (5 portfolios) Investment Management, Inc. (since September (Sept. 2015 - present) 2014); Chair, Director, CEO and President of Pioneer Funds Distributor, Inc. (since September 2014); Chair, Director, CEO and President of Pioneer Institutional Asset Management, Inc. (since September 2014); and Chair, Director, and CEO of Pioneer Investment Management Shareholder Services, Inc. (since September 2014); Managing Director, Morgan Stanley Investment Management (2010 - 2013); and Director of Institutional Business, CEO of International, Eaton Vance Management (2005 - 2010) ------------------------------------------------------------------------------------------------------------------------------------ Christopher J. Kelley (52) Since 2011. Serves at Vice President and Associate General Counsel None Secretary and the discretion of the Board. of Pioneer since January 2008; Secretary and Chief Legal Officer Chief Legal Officer of all of the Pioneer Funds since June 2010; Assistant Secretary of all of the Pioneer Funds from September 2003 to May 2010; and Vice President and Senior Counsel of Pioneer from July 2002 to December 2007 ------------------------------------------------------------------------------------------------------------------------------------ Carol B. Hannigan (56) Since 2011. Serves at Fund Governance Director of Pioneer since None Assistant Secretary the discretion of the Board. December 2006 and Assistant Secretary of all the Pioneer Funds since June 2010; Manager - Fund Governance of Pioneer from December 2003 to November 2006; and Senior Paralegal of Pioneer from January 2000 to November 2003 ------------------------------------------------------------------------------------------------------------------------------------ Thomas Reyes (54) Since 2011. Serves at Senior Counsel of Pioneer since May 2013 and None Assistant Secretary the discretion of the Board. Assistant Secretary of all the Pioneer Funds since June 2010; and Counsel of Pioneer from June 2007 to May 2013 ------------------------------------------------------------------------------------------------------------------------------------ Mark E. Bradley (57) Since 2011. Serves at Vice President - Fund Treasury of Pioneer; None Treasurer and Chief the discretion of the Board. Treasurer of all of the Pioneer Funds since Financial March 2008; Deputy Treasurer of Pioneer from and Accounting Officer March 2004 to February 2008; and Assistant Treasurer of all of the Pioneer Funds from March 2004 to February 2008 ------------------------------------------------------------------------------------------------------------------------------------ Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 79 Fund Officers continued ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Officer ------------------------------------------------------------------------------------------------------------------------------------ Luis I. Presutti (51) Since 2011. Serves at Director - Fund Treasury of Pioneer; and None Assistant Treasurer the discretion of the Board. Assistant Treasurer of all of the Pioneer Funds ------------------------------------------------------------------------------------------------------------------------------------ Gary Sullivan (58) Since 2011. Serves at Fund Accounting Manager - Fund Treasury of None Assistant Treasurer the discretion of the Board. Pioneer; and Assistant Treasurer of all of the Pioneer Funds ------------------------------------------------------------------------------------------------------------------------------------ David F. Johnson (37) Since 2011. Serves at Fund Administration Manager - Fund Treasury None Assistant Treasurer the discretion of the Board. of Pioneer since November 2008; Assistant Treasurer of all of the Pioneer Funds since January 2009; and Client Service Manager - Institutional Investor Services at State Street Bank from March 2003 to March 2007 ------------------------------------------------------------------------------------------------------------------------------------ Jean M. Bradley (64) Since 2011. Serves at Chief Compliance Officer of Pioneer and of None Chief Compliance Officer the discretion of the Board. all the Pioneer Funds since March 2010; Chief Compliance Officer of Pioneer Institutional Asset Management, Inc. since January 2012; Chief Compliance Officer of Vanderbilt Capital Advisors, LLC since July 2012: Director of Adviser and Portfolio Compliance at Pioneer since October 2005; and Senior Compliance Officer for Columbia Management Advisers, Inc. from October 2003 to October 2005 ------------------------------------------------------------------------------------------------------------------------------------ Kelly O'Donnell (46) Since 2011. Serves at Director - Transfer Agency Compliance of None Anti-Money the discretion of the Board. Pioneer and Anti-Money Laundering Officer of Laundering Officer all the Pioneer Funds since 2006 ------------------------------------------------------------------------------------------------------------------------------------ 80 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 This page is for your notes. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 81 This page is for your notes. 82 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 This page is for your notes. Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 83 This page is for your notes. 84 Pioneer Dynamic Credit Fund | Annual Report | 3/31/17 How to Contact Pioneer We are pleased to offer a variety of convenient ways for you to contact us for assistance or information. Call us for: -------------------------------------------------------------------------------- Account Information, including existing accounts, new accounts, prospectuses, applications and service forms 1-800-225-6292 FactFone(SM) for automated fund yields, prices, account information and transactions 1-800-225-4321 Retirement plans information 1-800-622-0176 Write to us: -------------------------------------------------------------------------------- Pioneer Funds P.O. Box 55014 Boston, Massachusetts 02205-5014 Our toll-free fax 1-800-225-4240 Our internet e-mail address ask.pioneer@pioneerinvestments.com (for general questions about Pioneer only) Visit our web site: us.pioneerinvestments.com This report must be preceded or accompanied by a prospectus. The Fund files a complete schedule of investments with the Securities and Exchange Commission for the first and third quarters for each fiscal year on Form N-Q. Shareholders may view the filed Form N-Q by visiting the Commission's web site at www.sec.gov. The filed form may also be viewed and copied at the Commission's Public Reference Room in Washington, DC. Information regarding the operations of the Public Reference Room may be obtained by calling 1-800-SEC-0330. [LOGO] PIONEER Investments(R) Pioneer Investment Management, Inc. 60 State Street Boston, MA 02109 us.pioneerinvestments.com Securities offered through Pioneer Funds Distributor, Inc. 60 State Street, Boston, MA 02109 Underwriter of Pioneer Mutual Funds, Member SIPC (C) 2017 Pioneer Investments 25667-05-0517 Pioneer Fundamental Growth Fund -------------------------------------------------------------------------------- Annual Report | March 31, 2017 -------------------------------------------------------------------------------- Ticker Symbols: Class A PIGFX Class C FUNCX Class K PFGKX Class R PFGRX Class Y FUNYX [LOGO] PIONEER Investments(R) visit us: us.pioneerinvestments.com Table of Contents President's Letter 2 Portfolio Management Discussion 4 Portfolio Summary 9 Prices and Distributions 10 Performance Update 11 Comparing Ongoing Fund Expenses 16 Schedule of Investments 18 Financial Statements 24 Notes to Financial Statements 33 Report of Independent Registered Public Accounting Firm 41 Approval of New and Interim Management Agreements 44 Trustees, Officers and Service Providers 53 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 1 President's Letter After an overall strong year for leading market indices in 2016, U.S. markets continued to generate positive returns over the first calendar quarter of 2017, with so-called "risk" assets, such as equities and credit-sensitive bonds, posting solid gains. In the first quarter, U.S. equities, as measured by the Standard & Poor's 500 Index, returned slightly more than 6%, while high-yield securities dominated bond market performance. The transfer of power in Washington, D.C. in January had little or no effect on the markets in the first quarter, as the post-election momentum we witnessed late in the fourth quarter of 2016 slowed only when oil prices slumped in March, due to both higher-than-expected inventories and concerns over whether OPEC (Organization of Petroleum Exporting Countries) would continue its supply cuts in June. Not even the Federal Reserve System's (the Fed's) highly anticipated rate hike during the month of March, its second in three months, nor Britain's trigger of Article 50 to begin the "Brexit" process caused any dramatic sell-off of risk assets. While U.S. gross domestic product (GDP) did slow in the first quarter, the expectation is for GDP to accelerate in the second quarter, with a strong consumer leading the way. Pioneer believes the U.S. economy may lead all developed nations in 2017, with GDP growth in excess of 2% for the year. President Trump has proposed decidedly pro-business policies, such as lower taxes, higher infrastructure spending, and less regulation, though we believe the economy may realize the benefits of those policies, if enacted, more so in 2018 than in 2017. Conversely, the effects of the President's potentially restrictive trade policies could offset some of the benefits of the pro-growth fiscal policies. Even so, we believe solid domestic employment figures should continue to support consumption and the housing market, and that stronger corporate profits and increased government spending may contribute to economic growth in 2018 and beyond. Increasing global Purchasing Manager Indices (PMIs) suggest that growth in global economies is also improving. (PMIs are used to measure the economic health of the manufacturing sector.) There are, as always, some risks to our outlook. First, the market already has priced in a good deal of the Trump economic reform platform, and that could lead to near-term disappointment if Congressional follow-through does not happen this year. The future of the Affordable Care Act is another potential concern. The first attempt to repeal/replace it failed, but any new proposed 2 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 legislation will undoubtedly have an effect on the health care sector, one of the largest segments of the US economy. Geopolitical risks, of course, remain a potential headwind, given ongoing strife in the Middle East and renewed tensions on the Korean Peninsula. While our current outlook is generally optimistic, conditions can and often do change, and while passive investment strategies may have a place in one's overall portfolio, it is our view that all investment decisions are active choices. Throughout Pioneer's history, we have believed in the importance of active management. The active decisions to invest in equities or fixed-income securities are made by a team of experienced investment professionals focusing on identifying value across global markets using proprietary research, careful risk management, and a long-term perspective. We believe our shareowners can benefit from the experience and tenure of our investment teams as well as the insights generated from our extensive research process. As always, and particularly during times of market uncertainty, we encourage you to work with your financial advisor to develop an overall investment plan that addresses both your short- and long-term goals, and to implement such a plan in a disciplined manner. We greatly appreciate the trust you have placed in us and look forward to continuing to serve you in the future. Sincerely, Lisa M. Jones President and CEO Pioneer Investment Management USA Inc. March 31, 2017 Any information in this shareowner report regarding market or economic trends or the factors influencing the Fund's historical or future performance are statements of opinion as of the date of this report. Past performance is no guarantee of future results. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 3 Portfolio Management Discussion | 3/31/17 Equities produced healthy, positive results over the 12-month period ended March 31, 2017, led by shares of more economically cyclical companies. In the following interview, Andrew Acheson and Paul Cloonan discuss the factors that affected the performance of Pioneer Fundamental Growth Fund during the 12-month period. Mr. Acheson and Mr. Cloonan, both senior vice presidents and portfolio managers at Pioneer, are responsible for the day-to-day management of the Fund. Q How did the Fund perform during the 12-month period ended March 31, 2017? A Pioneer Fundamental Growth Fund's Class A shares returned 11.78% at net asset value during the 12-month period ended March 31, 2017, while the Fund's benchmark, the Russell 1000 Growth Index (the Russell Index), returned 15.76%. During the same period, the average return of the 665 mutual funds in Lipper's Large Cap Growth Funds category was 14.55%, and the average return of the 1,454 mutual funds in Morningstar's Large Growth Funds category was 14.85%. Q How would you describe the investment environment for domestic stocks during the 12-month period ended March 31, 2017? A Domestic stocks generated relatively modest gains during the first half of the Fund's fiscal year -- from April through September of 2016. Then, a rebound in the energy sector and expectations that short-term interest rates in major industrial nations were likely to remain low combined to drive equity performance, and that environment appeared to continue into October and early November 2016, until the somewhat surprising victory of Republican Donald Trump in the U.S. presidential election. Combined with Republicans' success in maintaining control of Congress, the Trump victory, almost overnight, appeared to trigger a sharp rally in stocks. Investors seemed to anticipate that a new Trump administration and the Republican-controlled Congress would push for more business-friendly policies, including greater infrastructure investment, reductions in corporate and individual tax rates, and the deregulation of the economy. Stocks of highly cyclical, often financially leveraged companies, particularly in the financials, materials, and industrials sectors, led the market surge, which continued through the end of 2016. The new market momentum was in large part driven by the premise that inflationary pressures were increasing, a sign of an accelerating economy with rising interest rates, all conditions that would benefit certain types of companies. In this "reflation trade" environment, lower-priced value stocks performed particularly well, while stocks of better-financed, stable growth companies underperformed. The main beneficiaries of this environment were energy companies, banks 4 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 and financial institutions, metals and mining corporations, and producers of industrial machinery and semiconductors. The more defensive parts of the market, such as the consumer staples and health care sectors, lagged over the 12-month period. In global markets, optimism improved as the effects of the early-2016 decision by the Chinese government to facilitate more growth and increase corporate lending appeared to take effect, easing earlier fears that more austere policies in China could slow economic growth throughout the world. Elsewhere, the European economy appeared to perform better than expected, despite the "Brexit" referendum result in the United Kingdom in June 2016, when the country's citizens voted to leave the European Union. While the equity market's upward momentum persisted over the first three months of 2017, market leadership moved away from stocks of cyclical companies and toward shares of better-financed, quality corporations with histories of more stable profitability and the ability to grow earnings under different types of economic climates. Q What were the most significant factors that led to the Fund's underperfor- mance of the benchmark Russell Index during the 12-month period ended March 31, 2017? A Our emphasis in the portfolio on owning shares of higher-quality companies with solid balance sheets and records of stable growth proved to be a handicap during the period, as the "reflation" trade alluded to earlier produced the strongest results in the more cyclical, value-oriented areas of the market, which we tended to de-emphasize. At the same time, the more defensive, stable growth areas of the market, such as health care and consumer staples, underperformed. More specifically, the Fund's overweights relative to the Russell Index in health care and consumer staples detracted from benchmark-relative returns during the period, as did a portfolio underweight to the strong-performing information technology sector. In addition, stock selection results in health care detracted the most from the Fund's benchmark-relative returns during the period, while stock selection within information technology was also negative relative to the Russell Index. With regard to individual positions, the three most significant detractors from the Fund's benchmark-relative results during the period were all health care-related: CVS Health, Gilead Sciences, and Allergan. CVS, a retail pharmacy chain and institutional pharmacy benefits manager, was the single-largest detractor from the Fund's relative performance, as the company's shares declined after it lost network pharmacy contracts to a rival pharmacy. The Fund's position in biotechnology corporation Gilead Sciences also detracted from benchmark-relative performance when the sales of its Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 5 hepatitis C drugs failed to meet expectations. Meanwhile, drug company Allergan's stock price dropped after its proposed merger with Pfizer fell through. The performance of both Gilead and Allergan also felt the effects of market worries about possible increased government scrutiny and regulation over drug pricing. Finally, in information technology, the Fund's position in Cognizant Technology Solutions detracted from benchmark-relative returns after the company unexpectedly announced a management change in September 2016. Since the original announcement, however, the share price of Cognizant has partially recovered. On the positive side, the Fund's most successful investment during the period was a position in media-and-production company Time Warner, owner of HBO and other premium cable channels, and a producer of movies and television programs. Time Warner's share price rose following news of its pending acquisition by AT&T. We think the deal recognizes the value of Time Warner's ability to create and produce interesting content for media distribution. Another top performer in the portfolio during the period was Analog Devices, a semiconductor company that appears to have improved its position even further with the announcement of its pending acquisition of Linear Technology. However, we became concerned about Analog's high stock valuation, and so we sold the holding and redeployed profits to acquire another semiconductor company, Broadcom, which we believed had a more attractive valuation. The Fund's position in IntercontinentaExchange (ICE), which operates several capital market exchanges around the world, including the New York Stock Exchange, was another positive contributor to benchmark-relative performance during the 12-month period. ICE is a well-managed company that has been able to integrate its various acquisitions earlier than planned, while also shifting strategy to place greater emphasis on recurring revenue sources, such as selling subscriptions for its financial data, and having less dependence on more volatile trading volumes. ICE also has been paying down its debt ahead of schedule. Q Could you discuss some of the changes you made in the Fund's portfolio during the 12-month period ended March 31, 2017? A Recent additions to the portfolio include technology companies Amphenol, Adobe Systems, and Broadcom. Amphenol specializes in the design and manufacture of connectors used in a wide range of applications, including cable television, cellular communications, data communications, and in aerospace and automotive markets. Adobe Systems dominates the market for creative software and has built up a competitive position that we think is sustainable because of strong network effects and high switching costs. Adobe has shown an ability to produce high returns on its capital; the company also has strong growth prospects and an attractive valuation. Semiconductor firm Broadcom has shown an ability to generate high returns on its investments, and has made it through a series of mergers 6 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 while enhancing its competitive advantages. We think Broadcom's stock is attractively valued and that the company has the potential to increase returns on its growth capital. Outside of information technology, new Fund positions include consulting and professional services firm Marsh & McLennan, and building products company Masco. Marsh & McLennan is a global professional services firm that provides insurance brokerage, risk management and consulting, and human resources consulting services. The tightly managed company has shown stable profitability and high returns on growth capital, while building up a strong, loyal customer base that provides a high degree of recurring revenue. Masco manufactures building and home-improvement products, including Delta faucets, the largest-selling faucet brand in the world, and Behr paints. We also recently eliminated the Fund's holdings in several companies, including industrial company 3M, which has shown signs of struggling to sustain its growth, and UPS, which we believe has been slow to adapt as the e-commerce economy shifts to more business-to-consumer deliveries. We also think newer entrants to the delivery services market could threaten UPS's position. Earlier in the period, we sold the Fund's positions in technology company EMC after its acquisition by Dell, and cosmetic company Estee Lauder, which we believe to be vulnerable in the changing competitive environment. Q Did the Fund have any investments in derivative securities during the 12-month period ended March 31, 2017? A No, we did not invest the portfolio in any derivatives during the period. Q What is your investment outlook? A Given the equity market's strong recent performance and the currently high stock valuations, we have become rather cautious about near-term opportunities. We think many of the gains in recent months are the result of investors' hopes -- hopes which may or may not be fulfilled. In 2017 thus far, we have seen continued evidence of dysfunction in Washington, despite Republican control of both the White House and the Congress. As of the end of March, the new Trump administration had been unable to win congressional support for any major legislation. At the same time, geopolitical risks -- from North Korea to Syria to Russia -- have increased. In addition, the markets are watching closely the results of 2017 national elections in Europe, including those in France, Germany, and the United Kingdom. The United States remains highly competitive among world economies, and we believe the strength of the already healthy housing and consumer sectors should help sustain current growth trends. Looking ahead, we think there is Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 7 potential for an acceleration in corporate earnings growth in the U.S. Should the Trump administration win passage of a major tax cut or infrastructure investment legislation, and push further economic deregulation, then economic growth could expand significantly. If major legislative initiatives fail, however - as was the case with health care early in the year - then we believe investor confidence could further deteriorate. Interest rates, despite recent monetary tightening by the U.S. Federal Reserve (the Fed), remain low by historical standards, and we think we have begun to see some tentative signs of rising inflationary pressures. That could lead the Fed to tighten monetary policy more aggressively, which could put a brake on the economy. For example, we already have seen evidence of rising wage levels, and any further restrictions on immigration could tighten the labor market and contribute to further wage inflation. While we are generally positive about equities, we think high current stock valuations and the heightened geopolitical risks justify a measure of caution. Even though equity markets can show renewed strength at this late point in the growth cycle, we think current conditions may warrant a more conservative positioning in the portfolio, due to the number of risks that hover over the markets. Please refer to the Schedule of Investments on pages 18-23 for a full listing of Fund securities. All investments are subject to risk, including the possible loss of principal. In the past several years, financial markets have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty. These conditions may continue, recur, worsen or spread. Investing in foreign and/or emerging markets securities involves risks relating to interest rates, currency exchange rates, economic, and political conditions. The Fund invests in a limited number of securities and, as a result, the Fund's performance may be more volatile than the performance of other funds holding more securities. At times, the Fund's investments may represent industries or industry sectors that are interrelated or have common risks, making the Fund more susceptible to any economic, political, or regulatory developments or other risks affecting those industries and sectors. These risks may increase share price volatility. Before investing, consider the product's investment objectives, risks, charges and expenses. Contact your advisor or Pioneer Investments for a prospectus or summary prospectus containing this information. Read it carefully. Any information in this shareholder report regarding market or economic trends or the factors influencing the Fund's historical or future performance are statements of opinion as of the date of this report. Past performance is no guarantee of future results. 8 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Portfolio Summary | 3/31/17 Portfolio Diversification -------------------------------------------------------------------------------- (As a percentage of total investment portfolio) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] U.S. Common Stocks 91.4% International Common Stocks 5.1% U.S. Government Securities 2.2% Temporary Cash Investment 1.0% Municipal Bonds 0.3% Sector Distribution -------------------------------------------------------------------------------- (As a percentage of equity holdings) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] Information Technology 30.1% Consumer Discretionary 22.1% Health Care 17.2% Consumer Staples 13.0% Financials 7.0% Industrials 5.4% Materials 2.9% Energy 1.9% Government 0.4% 10 Largest Holdings -------------------------------------------------------------------------------- (As a percentage of equity holdings)* 1. Apple, Inc. 7.03% -------------------------------------------------------------------------------- 2. Alphabet, Inc. 5.67 -------------------------------------------------------------------------------- 3. Microsoft Corp. 5.43 -------------------------------------------------------------------------------- 4. Amazon.com, Inc. 4.99 -------------------------------------------------------------------------------- 5. Mastercard, Inc. 4.55 -------------------------------------------------------------------------------- 6. The Home Depot, Inc. 4.43 -------------------------------------------------------------------------------- 7. Celgene Corp. 3.83 -------------------------------------------------------------------------------- 8. Time Warner, Inc. 3.78 -------------------------------------------------------------------------------- 9. Thermo Fisher Scientific, Inc. 3.41 -------------------------------------------------------------------------------- 10. CVS Health Corp. 3.35 -------------------------------------------------------------------------------- * This list excludes temporary cash investments and derivative instruments. The Fund is actively managed, and current holdings may be different. The holdings listed should not be considered recommendations to buy or sell any securities listed. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 9 Prices and Distributions |3/31/17 Net Asset Value per Share -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Class 3/31/17 3/31/16 -------------------------------------------------------------------------------- A $20.78 $19.00 -------------------------------------------------------------------------------- C $19.17 $17.63 -------------------------------------------------------------------------------- K $20.79 $19.00 -------------------------------------------------------------------------------- R $20.49 $18.76 -------------------------------------------------------------------------------- Y $20.95 $19.15 -------------------------------------------------------------------------------- Distributions per Share: 4/1/16-3/31/17 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Short-Term Long-Term Class Dividends Capital Gains Capital Gains -------------------------------------------------------------------------------- A $0.0564 $-- $0.3650 -------------------------------------------------------------------------------- C $ -- $-- $0.3650 -------------------------------------------------------------------------------- K $0.1283 $-- $0.3650 -------------------------------------------------------------------------------- R $0.0120 $-- $0.3650 -------------------------------------------------------------------------------- Y $0.1140 $-- $0.3650 -------------------------------------------------------------------------------- The Russell 1000 Growth Index is an unmanaged index that measures the performance of large-cap U.S. growth stocks. Index returns assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. It is not possible to invest directly in an index. The index defined here pertains to the "Value of $10,000 Investment" and "Value of $5 Million Investment" charts on pages 11-15. 10 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Performance Update | 3/31/17 Class A Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class A shares of Pioneer Fundamental Growth Fund at public offering price during the periods shown, compared to that of the Russell 1000 Growth Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- Net Public Russell Asset Offering 1000 Value Price Growth Period (NAV) (POP) Index -------------------------------------------------------------------------------- 10 Years 9.32% 8.67% 9.13% 5 Years 12.67 11.34 13.32 1 Year 11.78 5.35 15.76 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated February 3, 2017) -------------------------------------------------------------------------------- Gross Net -------------------------------------------------------------------------------- 1.11% 1.09% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Fundamental Russell 1000 Growth Fund Growth Index 3/07 $9,425 $10,000 3/08 $9,648 $ 9,925 3/09 $7,048 $ 6,522 3/10 $9,902 $ 9,767 3/11 $11,014 $11,551 3/12 $12,649 $12,824 3/13 $13,869 $14,117 3/14 $16,803 $17,395 3/15 $19,760 $20,194 3/16 $20,550 $20,702 3/17 $22,970 $23,964 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. NAV results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. POP returns reflect deduction of maximum 5.75% sales charge. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The net expense ratio reflects the contractual expense limitation currently in effect through August 1, 2018, for Class A shares. There can be no assurance that Pioneer will extend the expense limitation beyond such time. Please see the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 11 Performance Update | 3/31/17 Class C Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class C shares of Pioneer Fundamental Growth Fund during the periods shown, compared to that of the Russell 1000 Growth Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- Russell 1000 If If Growth Period Held Redeemed Index -------------------------------------------------------------------------------- 10 Years 8.49% 8.49% 9.13% 5 Years 11.87 11.87 13.32 1 Year 10.98 10.98 15.76 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated February 3, 2017) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 1.77% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Fundamental Russell 1000 Growth Fund Growth Index 3/07 $10,000 $10,000 3/08 $10,151 $ 9,925 3/09 $ 7,359 $ 6,522 3/10 $10,251 $ 9,767 3/11 $11,309 $11,551 3/12 $12,890 $12,824 3/13 $14,021 $14,117 3/14 $16,866 $17,395 3/15 $19,701 $20,194 3/16 $20,349 $20,702 3/17 $22,584 $23,964 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class C shares held for less than one year are also subject to a 1% contingent deferred sales charge (CDSC). "If Held" results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 12 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Performance Update | 3/31/17 Class K Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $5 million investment made in Class K shares of Pioneer Fundamental Growth Fund during the periods shown, compared to that of the Russell 1000 Growth Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- Net Russell Asset 1000 Value Growth Period (NAV) Index -------------------------------------------------------------------------------- 10 Years 9.51% 9.13% 5 Years 13.07 13.32 1 Year 12.24 15.76 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated February 3, 2017) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.67% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Pioneer Fundamental Russell 1000 Growth Fund Growth Index 3/07 $ 5,000,000 $ 5,000,000 3/08 $ 5,119,416 $ 4,962,588 3/09 $ 3,739,943 $ 3,261,213 3/10 $ 5,254,460 $ 4,883,712 3/11 $ 5,844,715 $ 5,775,258 3/12 $ 6,712,157 $ 6,411,945 3/13 $ 7,368,627 $ 7,058,743 3/14 $ 8,961,129 $ 8,697,694 3/15 $10,584,075 $10,097,036 3/16 $11,052,509 $10,351,174 3/17 $12,405,096 $11,982,185 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. The performance shown for Class K shares for the period prior to the commencement of operations of Class K shares on December 20, 2012, is the net asset value performance of the Fund's Class A shares, which has not been restated to reflect any differences in expenses, including Rule 12b-1 fees applicable to Class A shares. Since fees for Class A shares generally are higher than those of Class K shares, the performance of Class K shares prior to their inception would have been higher than the performance shown. For the period beginning December 20, 2012, the actual performance of Class K shares is reflected. Class K shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 13 Performance Update | 3/31/17 Class R Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class R shares of Pioneer Fundamental Growth Fund during the periods shown, compared to that of the Russell 1000 Growth Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- Net Russell Asset 1000 Value Growth Period (NAV) Index -------------------------------------------------------------------------------- 10 Years 9.16% 9.13% 5 Years 12.34 13.32 1 Year 11.41 15.76 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated February 3, 2017) -------------------------------------------------------------------------------- Gross Net -------------------------------------------------------------------------------- 1.43% 1.40% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Fundamental Russell 1000 Growth Fund Growth Index 3/07 $10,000 $10,000 3/08 $10,239 $ 9,925 3/09 $ 7,480 $ 6,522 3/10 $10,509 $ 9,767 3/11 $11,689 $11,551 3/12 $13,424 $12,824 3/13 $14,675 $14,117 3/14 $17,733 $17,395 3/15 $20,788 $20,194 3/16 $21,557 $20,702 3/17 $24,016 $23,964 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. The performance shown for Class R shares for the period prior to the commencement of operations of Class R shares on April 2, 2012, is based on the performance of Class A shares, reduced to reflect the higher distribution and service fees of Class R shares. For the period beginning April 2, 2012, the actual performance of Class R shares is reflected. Class R shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The net expense ratio reflects the contractual expense limitation currently in effect through August 1, 2018, for Class R shares. There can be no assurance that Pioneer will extend the expense limitation beyond such time. Please see the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 14 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Performance Update | 3/31/17 Class Y Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $5 million investment made in Class Y shares of Pioneer Fundamental Growth Fund during the periods shown, compared to that of the Russell 1000 Growth Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- Net Russell Asset 1000 Value Growth Period (NAV) Index -------------------------------------------------------------------------------- 10 Years 9.62% 9.13% 5 Years 13.00 13.32 1 Year 12.11 15.76 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated February 3, 2017) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.79% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Pioneer Fundamental Russell 1000 Growth Fund Growth Index 3/07 $ 5,000,000 $ 5,000,000 3/08 $ 5,119,416 $ 4,962,588 3/09 $ 3,739,943 $ 3,261,213 3/10 $ 5,273,044 $ 4,883,712 3/11 $ 5,897,161 $ 5,775,258 3/12 $ 6,798,715 $ 6,411,945 3/13 $ 7,477,990 $ 7,058,743 3/14 $ 9,081,347 $ 8,697,694 3/15 $10,714,353 $10,097,036 3/16 $11,174,555 $10,351,174 3/17 $12,528,143 $11,982,185 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. The performance shown for Class Y shares for the period prior to the commencement of operations of Class Y shares on April 8, 2009, is the net asset value performance of the Fund's Class A shares, which has not been restated to reflect any differences in expenses, including Rule 12b-1 fees applicable to Class A shares. Since fees for Class A shares generally are higher than those of Class Y shares, the performance of Class Y shares prior to their inception would have been higher than the performance shown. For the period beginning April 8, 2009, the actual performance of Class Y shares is reflected. Class Y shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 15 Comparing Ongoing Fund Expenses As a shareowner in the Fund, you incur two types of costs: (1) ongoing costs, including management fees, distribution and/or service (12b-1) fees, and other Fund expenses; and (2) transaction costs, including sales charges (loads) on purchase payments. This example is intended to help you understand your ongoing expenses (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. The example is based on an investment of $1,000 at the beginning of the Fund's latest six-month period and held throughout the six months. Using the Tables -------------------------------------------------------------------------------- Actual Expenses The first table below provides information about actual account values and actual expenses. You may use the information in this table, together with the amount you invested, to estimate the expenses that you paid over the period as follows: (1) Divide your account value by $1,000 Example: an $8,600 account value (divided by) $1,000 = 8.6 (2) Multiply the result in (1) above by the corresponding share class's number in the third row under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period. Expenses Paid on a $1,000 Investment in Pioneer Fundamental Growth Fund Based on actual returns from October 1, 2016, through March 31, 2017. -------------------------------------------------------------------------------- Share Class A C K R Y -------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 $1,000.00 $1,000.00 Value on 10/1/16 -------------------------------------------------------------------------------- Ending Account $1,083.03 $1,079.15 $1,085.28 $1,081.23 $1,084.34 Value (after expenses) on 3/31/17 -------------------------------------------------------------------------------- Expenses Paid $ 5.66 $ 9.18 $ 3.48 $ 7.26 $ 4.00 During Period* -------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized net expense ratio of 1.09%, 1.77%, 0.67%, 1.40% and 0.77% for Class A, Class C, Class K, Class R, and Class Y shares respectively, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half year period). 16 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Hypothetical Example for Comparison Purposes The table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds. Please note that the expenses shown in the tables are meant to highlight your ongoing costs only and do not reflect any transaction costs, such as sales charges (loads) that are charged at the time of the transaction. Therefore, the table below is useful in comparing ongoing costs only and will not help you determine the relative total costs of owning different funds. In addition, if these transaction costs were included, your costs would have been higher. Expenses Paid on a $1,000 Investment in Pioneer Fundamental Growth Fund Based on a hypothetical 5% per year return before expenses, reflecting the period from October 1, 2016, through March 31, 2017. -------------------------------------------------------------------------------- Share Class A C K R Y -------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 $1,000.00 $1,000.00 Value on 10/1/16 -------------------------------------------------------------------------------- Ending Account $1,019.50 $1,016.11 $1,021.59 $1,017.95 $1,021.09 Value (after expenses) on 3/31/17 -------------------------------------------------------------------------------- Expenses Paid $ 5.49 $ 8.90 $ 3.38 $ 7.04 $ 3.88 During Period* -------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized net expense ratio of 1.09%, 1.77%, 0.67%, 1.40% and 0.77% for Class A, Class C, Class K, Class R, and Class Y shares respectively, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half year period). Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 17 Schedule of Investments | 3/31/17 ---------------------------------------------------------------------------------------------- Shares Value ---------------------------------------------------------------------------------------------- COMMON STOCKS -- 97.8% ENERGY -- 1.9% Oil & Gas Equipment & Services -- 0.7% 473,159 Schlumberger, Ltd. $ 36,953,718 ---------------------------------------------------------------------------------------------- Oil & Gas Exploration & Production -- 1.2% 2,758,417 Cabot Oil & Gas Corp. $ 65,953,750 -------------- Total Energy $ 102,907,468 ---------------------------------------------------------------------------------------------- MATERIALS -- 2.9% Specialty Chemicals -- 2.9% 715,019 Ecolab, Inc. $ 89,620,481 504,557 International Flavors & Fragrances, Inc. 66,868,939 -------------- $ 156,489,420 -------------- Total Materials $ 156,489,420 ---------------------------------------------------------------------------------------------- CAPITAL GOODS -- 5.5% Aerospace & Defense -- 4.0% 938,706 Raytheon Co. $ 143,152,665 645,048 United Technologies Corp. 72,380,836 -------------- $ 215,533,501 ---------------------------------------------------------------------------------------------- Building Products -- 1.5% 2,255,025 Masco Corp. $ 76,648,300 -------------- Total Capital Goods $ 292,181,801 ---------------------------------------------------------------------------------------------- CONSUMER DURABLES & APPAREL -- 1.0% Footwear -- 1.0% 997,326 NIKE, Inc. (Class B) $ 55,580,978 -------------- Total Consumer Durables & Apparel $ 55,580,978 ---------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 1.9% Restaurants -- 1.9% 1,758,637 Starbucks Corp. $ 102,686,814 -------------- Total Consumer Services $ 102,686,814 ---------------------------------------------------------------------------------------------- MEDIA -- 6.7% Movies & Entertainment -- 6.7% 1,382,179 The Walt Disney Co. $ 156,725,277 2,081,077 Time Warner, Inc. 203,342,034 -------------- $ 360,067,311 -------------- Total Media $ 360,067,311 ---------------------------------------------------------------------------------------------- RETAILING -- 12.5% Internet Retail -- 5.0% 302,303 Amazon.com, Inc.* $ 268,003,702 ---------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 18 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 ---------------------------------------------------------------------------------------------- Shares Value ---------------------------------------------------------------------------------------------- Apparel Retail -- 1.7% 1,346,201 Ross Stores, Inc. $ 88,674,260 ---------------------------------------------------------------------------------------------- Home Improvement Retail -- 4.4% 1,620,645 The Home Depot, Inc. $ 237,959,305 ---------------------------------------------------------------------------------------------- Automotive Retail -- 1.4% 286,525 O'Reilly Automotive, Inc.* $ 77,315,906 -------------- Total Retailing $ 671,953,173 ---------------------------------------------------------------------------------------------- FOOD & STAPLES RETAILING -- 3.4% Drug Retail -- 3.4% 2,293,556 CVS Health Corp. $ 180,044,146 -------------- Total Food & Staples Retailing $ 180,044,146 ---------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 7.0% Soft Drinks -- 3.1% 1,469,809 PepsiCo., Inc. $ 164,412,835 ---------------------------------------------------------------------------------------------- Packaged Foods & Meats -- 1.6% 778,345 The Hershey Co. $ 85,034,191 ---------------------------------------------------------------------------------------------- Tobacco -- 2.3% 1,995,695 Reynolds American, Inc. $ 125,768,699 -------------- Total Food, Beverage & Tobacco $ 375,215,725 ---------------------------------------------------------------------------------------------- HOUSEHOLD & PERSONAL PRODUCTS -- 2.7% Household Products -- 2.7% 807,610 Colgate-Palmolive Co. $ 59,108,976 646,192 Kimberly-Clark Corp. 85,058,253 -------------- $ 144,167,229 -------------- Total Household & Personal Products $ 144,167,229 ---------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 2.8% Health Care Equipment -- 2.8% 355,258 Edwards Lifesciences Corp.* $ 33,419,120 1,443,756 Medtronic Plc 116,308,983 -------------- $ 149,728,103 -------------- Total Health Care Equipment & Services $ 149,728,103 ---------------------------------------------------------------------------------------------- PHARMACEUTICALS, BIOTECHNOLOGY & LIFE SCIENCES -- 14.5% Biotechnology -- 5.9% 1,655,163 Celgene Corp.* $ 205,951,932 965,506 Gilead Sciences, Inc.* 65,577,168 388,649 Vertex Pharmaceuticals, Inc.* 42,498,768 -------------- $ 314,027,868 ---------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 19 Schedule of Investments | 3/31/17 (continued) ---------------------------------------------------------------------------------------------- Shares Value ---------------------------------------------------------------------------------------------- Pharmaceuticals -- 5.2% 674,717 Allergan Plc $ 161,203,386 957,402 Johnson & Johnson 119,244,419 -------------- $ 280,447,805 ---------------------------------------------------------------------------------------------- Life Sciences Tools & Services -- 3.4% 1,192,870 Thermo Fisher Scientific, Inc. $ 183,224,832 -------------- Total Pharmaceuticals, Biotechnology & Life Sciences $ 777,700,505 ---------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 3.1% Specialized Finance -- 3.1% 2,752,730 Intercontinental Exchange, Inc. $ 164,805,945 -------------- Total Diversified Financials $ 164,805,945 ---------------------------------------------------------------------------------------------- INSURANCE -- 1.7% Insurance Brokers -- 1.7% 1,234,664 Marsh & McLennan Companies, Inc. $ 91,229,323 -------------- Total Insurance $ 91,229,323 ---------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 19.4% Internet Software & Services -- 5.7% 367,187 Alphabet, Inc. (Class C) $ 304,603,648 ---------------------------------------------------------------------------------------------- IT Consulting & Other Services -- 1.6% 1,449,193 Cognizant Technology Solutions Corp.* $ 86,255,967 ---------------------------------------------------------------------------------------------- Data Processing & Outsourced Services -- 4.6% 2,174,372 Mastercard, Inc. $ 244,551,619 ---------------------------------------------------------------------------------------------- Application Software -- 2.1% 856,697 Adobe Systems, Inc.* $ 111,481,981 ---------------------------------------------------------------------------------------------- Systems Software -- 5.4% 4,428,506 Microsoft Corp. $ 291,661,405 -------------- Total Software & Services $1,038,554,620 ---------------------------------------------------------------------------------------------- TECHNOLOGY HARDWARE & EQUIPMENT -- 8.6% Computer Storage & Peripherals -- 7.0% 2,628,885 Apple, Inc. $ 377,665,619 ---------------------------------------------------------------------------------------------- Electronic Components -- 1.6% 1,206,498 Amphenol Corp. $ 85,866,463 -------------- Total Technology Hardware & Equipment $ 463,532,082 ---------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 20 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 ---------------------------------------------------------------------------------------------- Shares Value ---------------------------------------------------------------------------------------------- SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT -- 2.2% Semiconductors -- 2.2% 547,654 Broadcom, Ltd. $ 119,914,319 -------------- Total Semiconductors & Semiconductor Equipment $ 119,914,319 ---------------------------------------------------------------------------------------------- TOTAL COMMON STOCKS (Cost $4,143,590,903) $5,246,758,962 ---------------------------------------------------------------------------------------------- ---------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) ---------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- 2.3% 30,000,000 U.S. Treasury Bills, 4/13/17 (c) $ 29,993,970 52,000,000 U.S. Treasury Bills, 4/20/17 (c) 51,982,112 40,195,000 U.S. Treasury Bills, 4/27/17 (c) 40,175,425 -------------- $ 122,151,507 ---------------------------------------------------------------------------------------------- TOTAL U.S. GOVERNMENT AND AGENCY OBLIGATIONS (Cost $122,148,081) $ 122,151,507 ---------------------------------------------------------------------------------------------- MUNICIPAL BONDS -- 0.1% Higher Municipal Education -- 0.0%+ 1,340,000 0.88 Maryland Health & Higher Educational Facilities Authority, Floating Rate Note, 7/1/36 $ 1,340,000 ---------------------------------------------------------------------------------------------- Municipal Medical -- 0.1% 4,680,000 0.96 Harris County Health Facilities Development Corp., Floating Rate Note, 12/1/41 $ 4,680,000 ---------------------------------------------------------------------------------------------- TOTAL MUNICIPAL BONDS (Cost $6,020,000) $ 6,020,000 ---------------------------------------------------------------------------------------------- TEMPORARY CASH INVESTMENTS -- 1.0% Repurchase Agreements -- 1.0% 31,930,000 $31,930,000 ScotiaBank, 0.81%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by the following: $6,740,630 Freddie Mac Giant, 3.0 - 3.5%, 3/1/32-11/1/46 $627,532 Federal National Mortgage Association (ARM), 2.698% - 2.755%, 2/1/45-3/1/45 $17,171,062 Federal National Mortgage Association, 2.5% - 5.8%, 7/1/23-2/1/47 $8,031,574 Government National Mortgage Association, 2.0-4.0%, 3/20/42-11/20/45 $ 31,930,000 10,360,000 $10,360,000 TD Securities USA LLC, 0.80%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by $10,567,201 Federal National Mortgage Association, 4.0%, 2/1/47 10,360,000 The accompanying notes are an integral part of these financial statements. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 21 Schedule of Investments | 3/31/17 (continued) ---------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ---------------------------------------------------------------------------------------------- Repurchase Agreements (continued) 12,145,000 $12,145,000 TD Securities USA LLC, 0.81%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by $12,387,900 Federal National Mortgage Association, 4.0%, 2/1/47 $ 12,145,000 -------------- $ 54,435,000 ---------------------------------------------------------------------------------------------- TOTAL TEMPORARY CASH INVESTMENTS (Cost $54,435,000) $ 54,435,000 ---------------------------------------------------------------------------------------------- TOTAL INVESTMENT IN SECURITIES -- 101.2% (Cost $4,326,193,984) (a) $5,429,365,469 ---------------------------------------------------------------------------------------------- OTHER ASSETS & LIABILITIES -- (1.2)% $ (65,196,043) ---------------------------------------------------------------------------------------------- NET ASSETS -- 100.0% $5,364,169,426 ============================================================================================== * Non-income producing security. + Amount rounds to less than 0.1%. (a) At March 31, 2017, the net unrealized appreciation on investments based on cost for federal income tax purposes of $4,334,508,100 was as follows: Aggregate gross unrealized appreciation for all investments in which there is an excess of value over tax cost $ 1,129,166,640 Aggregate gross unrealized depreciation for all investments in which there is an excess of tax cost over value (34,309,271) --------------- Net unrealized appreciation $ 1,094,857,369 =============== (b) Debt obligation with a variable interest rate. Rate shown is rate at period end. (c) Security issued with a zero coupon. Income is earned through accretion of discount. Purchases and sales of securities (excluding temporary cash investments) for the year ended March 31, 2017, aggregated $2,392,171,615 and $1,006,803,841, respectively. The Fund is permitted to engage in purchase and sale transactions ("cross trades") with certain Funds and accounts for which Pioneer Investment Management, Inc. (PIM), serves as the Fund's investment adviser, as set forth in Rule 17a-7 under the Investment Company Act of 1940, pursuant to procedures adopted by the Board of Trustees. Under these procedures, cross trades are effected at current market prices. During the year ended March 31, 2017, the Fund did not engage in cross trade activity. Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below. Level 1 - quoted prices in active markets for identical securities. Level 2 - other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.) See Notes to Financial Statements -- Note 1A. Level 3 - significant unobservable inputs (including the Fund's own assumptions in determining fair value of investments) See Notes to Financial Statements -- Note 1A. The accompanying notes are an integral part of these financial statements. 22 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 The following is a summary of the inputs used as of March 31, 2017, in valuing the Fund's investments: ---------------------------------------------------------------------------------------------- Level 1 Level 2 Level 3 Total ---------------------------------------------------------------------------------------------- Common Stocks $5,246,758,962 $ -- $ -- $5,246,758,962 U.S. Government and Agency Obligations -- 122,151,507 -- 122,151,507 Municipal Bonds -- 6,020,000 -- 6,020,000 Repurchase Agreements -- 54,435,000 -- 54,435,000 ---------------------------------------------------------------------------------------------- Total $5,246,758,962 $ 182,606,507 $ -- $5,429,365,469 ============================================================================================== During the year ended March 31, 2017, there were no transfers between Levels 1, 2 and 3. The accompanying notes are an integral part of these financial statements. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 23 Statement of Assets and Liabilities | 3/31/17 ASSETS: Investment in securities (cost $4,326,193,984) $5,429,365,469 Cash 9,872,499 Receivables -- Fund shares sold 17,675,767 Dividends 3,385,153 Interest 4,546 Due from Pioneer Investment Management, Inc. 8,083 Other assets 144,363 -------------------------------------------------------------------------------- Total assets $5,460,455,880 ================================================================================ LIABILITIES: Payables -- Investment securities purchased $ 75,746,493 Fund shares repurchased 19,389,404 Due to affiliates 231,593 Accrued expenses 918,964 -------------------------------------------------------------------------------- Total liabilities $ 96,286,454 ================================================================================ NET ASSETS: Paid-in capital $4,200,487,862 Undistributed net investment income 5,307,537 Accumulated net realized gain on investments 55,202,542 Net unrealized appreciation on investments 1,103,171,485 -------------------------------------------------------------------------------- Net assets $5,364,169,426 ================================================================================ NET ASSET VALUE PER SHARE: (No par value, unlimited number of shares authorized) Class A (based on $1,205,123,897/57,998,324 shares) $ 20.78 Class C (based on $465,544,933/24,282,676 shares) $ 19.17 Class K (based on $376,708,276/18,117,925 shares) $ 20.79 Class R (based on $117,931,025/5,754,408 shares) $ 20.49 Class Y (based on $3,198,861,295/152,663,608 shares) $ 20.95 MAXIMUM OFFERING PRICE: Class A ($20.78 (divided by) 94.25%) $ 22.05 ================================================================================ The accompanying notes are an integral part of these financial statements. 24 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Statement of Operations For the Year Ended 3/31/17 INVESTMENT INCOME: Interest $ 407,907 Dividends 66,643,519 ---------------------------------------------------------------------------------------------- Total investment income $ 67,051,426 ---------------------------------------------------------------------------------------------- EXPENSES: Management fees $ 27,760,888 Transfer agent fees Class A 1,532,069 Class C 390,016 Class K 24 Class R 229,049 Class Y 2,178,659 Distribution fees Class A 2,876,200 Class C 4,194,312 Class R 501,485 Shareholder communications expense 1,204,415 Administrative expense 1,441,789 Custodian fees 58,956 Registration fees 331,451 Professional fees 156,597 Printing expense 59,398 Fees and expenses of nonaffiliated Trustees 211,918 Miscellaneous 151,986 ---------------------------------------------------------------------------------------------- Total expenses $ 43,279,212 ---------------------------------------------------------------------------------------------- Less fees waived and expenses reimbursed by Pioneer Investment Management, Inc. (9,852) ---------------------------------------------------------------------------------------------- Net expenses $ 43,269,360 ---------------------------------------------------------------------------------------------- Net investment income $ 23,782,066 ---------------------------------------------------------------------------------------------- REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS: Net realized gain (loss) on investments $156,719,815 Change in net unrealized appreciation (depreciation) on investments $367,209,601 ---------------------------------------------------------------------------------------------- Net realized and unrealized gain (loss) on investments $523,929,416 ---------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $547,711,482 ============================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 25 Statements of Changes in Net Assets -------------------------------------------------------------------------------------------------- Year Ended Year Ended 3/31/17 3/31/16 -------------------------------------------------------------------------------------------------- FROM OPERATIONS: Net investment income (loss) $ 23,782,066 $ 14,197,831 Net realized gain (loss) on investments 156,719,815 9,980,418 Change in net unrealized appreciation (depreciation) on investments 367,209,601 101,973,450 -------------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 547,711,482 $ 126,151,699 -------------------------------------------------------------------------------------------------- DISTRIBUTIONS TO SHAREOWNERS: Net investment income: Class A ($0.06 and $0.05 per share, respectively) $ (3,454,370) $ (2,669,945) Class K ($0.13 and $0.12 per share, respectively) (1,872,933) (727,413) Class R ($0.01 and $0.03 per share, respectively) (67,393) (104,862) Class Y ($0.11 and $0.11 per share, respectively) (17,013,709) (9,253,189) Net realized gain: Class A ($0.37 and $0.78 per share, respectively) (21,901,386) (35,186,557) Class C ($0.37 and $0.78 per share, respectively) (8,702,792) (12,456,231) Class K ($0.37 and $0.78 per share, respectively) (5,095,362) (4,433,100) Class R ($0.37 and $0.78 per share, respectively) (1,980,050) (2,395,330) Class Y ($0.37 and $0.78 per share, respectively) (52,838,090) (63,735,165) -------------------------------------------------------------------------------------------------- Total distributions to shareowners $ (112,926,085) $ (130,961,792) -------------------------------------------------------------------------------------------------- FROM FUND SHARE TRANSACTIONS: Net proceeds from sale or exchange of shares $ 2,907,428,317 $1,753,884,150 Reinvestment of distributions 95,432,134 115,858,316 Cost of shares repurchased (1,635,411,826) (747,731,248) -------------------------------------------------------------------------------------------------- Net increase in net assets resulting from Fund share transactions $ 1,367,448,625 $1,122,011,218 -------------------------------------------------------------------------------------------------- Net increase in net assets $ 1,802,234,022 $1,117,201,125 NET ASSETS: Beginning of year 3,561,935,404 2,444,734,279 -------------------------------------------------------------------------------------------------- End of year $ 5,364,169,426 $3,561,935,404 -------------------------------------------------------------------------------------------------- Undistributed net investment income $ 5,307,537 $ 3,952,570 ================================================================================================== The accompanying notes are an integral part of these financial statements. 26 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------ Year Ended Year Ended Year Ended Year Ended 3/31/17 3/31/17 3/31/16 3/31/16 Shares Amount Shares Amount ------------------------------------------------------------------------------------------------ Class A Shares sold 28,290,513 $ 548,519,293 23,003,470 $ 435,979,169 Reinvestment of distributions 1,134,495 21,758,157 1,750,351 33,835,338 Less shares repurchased (23,684,612) (464,790,618) (14,297,823) (271,236,947) ------------------------------------------------------------------------------------------------ Net increase 5,740,396 $ 105,486,832 10,455,998 $ 198,577,560 ================================================================================================ Class C Shares sold 8,891,081 $ 159,283,437 8,598,180 $ 151,496,282 Reinvestment of distributions 407,641 7,194,885 561,864 10,079,840 Less shares repurchased (5,248,783) (94,992,423) (2,775,699) (48,911,523) ------------------------------------------------------------------------------------------------ Net increase 4,049,939 $ 71,485,899 6,384,345 $ 112,664,599 ================================================================================================ Class K Shares sold 14,720,842 $ 287,184,419 3,072,202 $ 57,993,315 Reinvestment of distributions 322,783 6,217,263 181,277 3,506,305 Less shares repurchased (3,862,478) (75,263,475) (1,412,076) (27,182,315) ------------------------------------------------------------------------------------------------ Net increase 11,181,147 $ 218,138,207 1,841,403 $ 34,317,305 ================================================================================================ Class R Shares sold 2,975,998 $ 56,835,178 2,856,682 $ 53,709,457 Reinvestment of distributions 62,318 1,175,352 90,416 1,726,047 Less shares repurchased (1,522,340) (29,269,528) (685,360) (12,873,092) ------------------------------------------------------------------------------------------------ Net increase 1,515,976 $ 28,741,002 2,261,738 $ 42,562,412 ================================================================================================ Class Y Shares sold 94,425,176 $ 1,855,605,990 55,314,333 $1,052,078,724 Reinvestment of distributions 3,046,171 59,086,477 3,422,765 66,710,786 Less shares repurchased (49,292,166) (971,095,782) (20,079,685) (381,189,190) ------------------------------------------------------------------------------------------------ Net increase 48,179,181 $ 943,596,685 38,657,413 $ 737,600,320 ================================================================================================ Class Z* Shares sold or exchanged -- $ -- 136,232 $ 2,627,203 Reinvestment of distributions -- -- -- -- Less shares repurchased -- -- (320,712) (6,338,181) ------------------------------------------------------------------------------------------------ Net decrease -- $ -- (184,480) $ (3,710,978) ================================================================================================ * Class Z shares converted to Class Y shares on August 7, 2015. The accompanying notes are an integral part of these financial statements. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 27 Financial Highlights --------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 --------------------------------------------------------------------------------------------------------------------------- Class A Net asset value, beginning of period $ 19.00 $ 19.06 $ 16.66 $ 14.33 $ 13.23 --------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.08(a) $ 0.07(a) $ 0.06 $ 0.06 $ 0.07 Net realized and unrealized gain (loss) on investments 2.13 0.70 2.86 2.95 1.20 --------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 2.21 $ 0.77 $ 2.92 $ 3.01 $ 1.27 --------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.06) $ (0.05) $ (0.05) $ (0.06) $ (0.06) Net realized gain (0.37) (0.78) (0.47) (0.62) (0.11) --------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.43) $ (0.83) $ (0.52) $ (0.68) $ (0.17) --------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 1.78 $ (0.06) $ 2.40 $ 2.33 $ 1.10 --------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 20.78 $ 19.00 $ 19.06 $ 16.66 $ 14.33 =========================================================================================================================== Total return* 11.78% 4.00% 17.60% 21.16% 9.64% Ratio of net expenses to average net assets 1.09% 1.09% 1.09% 1.08% 1.09% Ratio of net investment income (loss) to average net assets 0.39% 0.38% 0.38% 0.46% 0.54% Portfolio turnover rate 23% 13% 12% 21% 28% Net assets, end of period (in thousands) $1,205,124 $992,927 $796,689 $644,527 $436,682 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 1.09% 1.11% 1.13% 1.13% 1.20% Net investment income (loss) to average net assets 0.39% 0.36% 0.34% 0.41% 0.43% =========================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. (a) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 28 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------------------------------ Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 ------------------------------------------------------------------------------------------------------------------------------------ Class C Net asset value, beginning of period $ 17.63 $ 17.81 $ 15.66 $ 13.55 $ 12.57 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ (0.05)(a)(b) $ (0.05)(a)(b) $ (0.03) $ (0.04) $ (0.02)(a) Net realized and unrealized gain (loss) on investments 1.96 0.65 2.65 2.77 1.12 ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 1.91 $ 0.60 $ 2.62 $ 2.73 $ 1.10 ------------------------------------------------------------------------------------------------------------------------------------ Distribution to shareowners: Net investment income $ -- $ -- $ -- $ -- $ (0.01) Net realized gain (0.37) (0.78) (0.47) (0.62) (0.11) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.37) $ (0.78) $ (0.47) $ (0.62) $ (0.12) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ 1.54 $ (0.18) $ 2.15 $ 2.11 $ 0.98 ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 19.17 $ 17.63 $ 17.81 $ 15.66 $ 13.55 ==================================================================================================================================== Total return* 10.98% 3.29% 16.81% 20.29% 8.77% Ratio of net expenses to average net assets 1.77% 1.77% 1.79% 1.83% 1.91% Ratio of net investment income (loss) to average net assets (0.30)% (0.29)% (0.32)% (0.28)% (0.23)% Portfolio turnover rate 23% 13% 12% 21% 28% Net assets, end of period (in thousands) $ 465,545 $ 356,675 $ 246,593 $ 174,565 $89,299 ==================================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. (a) The amount shown for a share outstanding does not correspond with net investment income on the Statement of Operations for the period due to timing of the sales and repurchase of shares. (b) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 29 Financial Highlights (continued) ------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Ended Ended Ended Ended 12/20/12 to 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 ------------------------------------------------------------------------------------------------------------------------- Class K Net asset value, beginning of period $ 19.00 $ 19.05 $ 16.64 $ 14.30 $ 13.37 ------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.16(c) $ 0.15(c) $ 0.16 $ 0.06 $ 0.03 Net realized and unrealized gain (loss) on investments 2.13 0.70 2.84 3.01 1.00 ------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 2.29 $ 0.85 $ 3.00 $ 3.07 $ 1.03 ------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.13) $ (0.12) $ (0.12) $ (0.11) $ (0.10) Net realized gain (0.37) (0.78) (0.47) (0.62) -- ------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.50) $ (0.90) $ (0.59) $ (0.73) $ (0.10) ------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 1.79 $ (0.05) $ 2.41 $ 2.34 $ 0.93 ------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 20.79 $ 19.00 $ 19.05 $ 16.64 $ 14.30 ========================================================================================================================= Total return* 12.24% 4.43% 18.11% 21.61% 7.77%(a)(b) Ratio of net expenses to average net assets 0.67% 0.67% 0.69% 0.71% 0.77%** Ratio of net investment income (loss) to average net assets 0.81% 0.80% 0.81% 0.85% 0.77%** Portfolio turnover rate 23% 13% 12% 21% 28% Net assets, end of period (in thousands) $376,708 $131,813 $97,063 $31,501 $ 11 ========================================================================================================================= * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. ** Annualized. (a) If the Fund had not recognized gains in settlement of class action lawsuits during the year ended March 31, 2013, the total return would have been 7.74%. (b) Not annualized. (c) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 30 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 ---------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Ended Ended Ended Ended 4/2/12 to 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 ---------------------------------------------------------------------------------------------------------------------------- Class R Net asset value, beginning of period $ 18.76 $ 18.86 $ 16.50 $ 14.25 $ 13.34 ---------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.01(d) $ 0.02(d) $ (0.00)(c) $ 0.01 $ 0.06 Net realized and unrealized gain (loss) on investments 2.10 0.69 2.83 2.94 1.05 ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 2.11 $ 0.71 $ 2.83 $ 2.95 $ 1.11 ---------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.01) $ (0.03) $ -- $ (0.08) $ (0.09) Net realized gain (0.37) (0.78) (0.47) (0.62) (0.11) ---------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.38) $ (0.81) $ (0.47) $ (0.70) $ (0.20) ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 1.73 $ (0.10) $ 2.36 $ 2.25 $ 0.91 ---------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 20.49 $ 18.76 $ 18.86 $ 16.50 $ 14.25 ============================================================================================================================ Total return* 11.41% 3.70% 17.23% 20.84% 8.42%(a)(b) Ratio of net expenses to average net assets 1.40% 1.40% 1.40% 1.39% 1.40%** Ratio of net investment income (loss) to average net assets 0.08% 0.10% 0.05% 0.18% 0.27%** Portfolio turnover rate 23% 13% 12% 21% 28% Net assets, end of period (in thousands) $117,931 $79,519 $ 37,285 $40,703 $ 2,437 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 1.41% 1.43% 1.52% 1.39% 1.45%** Net investment income (loss) to average net assets 0.07% 0.07% (0.07)% 0.18% 0.21%** ============================================================================================================================ * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. ** Annualized. (a) If the Fund had not recognized gains in settlement of class action lawsuits during the year ended March 31, 2013, the total return would have been 8.41%. (b) Not annualized. (c) Amount rounds to less than $0.01 or $(0.01) per share. (d) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 31 Financial Highlights (continued) ------------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 ------------------------------------------------------------------------------------------------------------------------------- Class Y Net asset value, beginning of period $ 19.15 $ 19.20 $ 16.77 $ 14.41 $ 13.30 ------------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.14(b) $ 0.13(b) $ 0.10 $ 0.10 $ 0.10 Net realized and unrealized gain (loss) on investments 2.14 0.71 2.90 2.97 1.22 ------------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 2.28 $ 0.84 $ 3.00 $ 3.07 $ 1.32 ------------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.11) $ (0.11) $ (0.10) $ (0.09) $ (0.10) Net realized gain (0.37) (0.78) (0.47) (0.62) (0.11) ------------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.48) $ (0.89) $ (0.57) $ (0.71) $ (0.21) ------------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 1.80 $ (0.05) $ 2.43 $ 2.36 $ 1.11 ------------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 20.95 $ 19.15 $ 19.20 $ 16.77 $ 14.41 =============================================================================================================================== Total return* 12.11% 4.29% 17.98% 21.44% 9.99%(a) Ratio of net expenses to average net assets 0.77% 0.79% 0.80% 0.82% 0.81% Ratio of net investment income (loss) to average net assets 0.71% 0.70% 0.68% 0.72% 0.85% Portfolio turnover rate 23% 13% 12% 21% 28% Net assets, end of period (in thousands) $3,198,861 $2,001,002 $1,263,594 $842,680 $558,383 =============================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. (a) If the Fund had not recognized gains in settlement of class action lawsuits during the year ended March 31, 2013, the total return would have been 9.96%. (b) The per-share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 32 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Notes to Financial Statements | 3/31/17 1. Organization and Significant Accounting Policies Pioneer Fundamental Growth Fund (the Fund) is a series of Pioneer Series Trust X, a Delaware statutory trust. The Fund is registered under the Investment Company Act of 1940 as a diversified, open-end management investment company. The Fund's investment objective is to seek long-term capital growth. The Fund offers five classes of shares designated as Class A, Class C, Class K, Class R and Class Y shares. Class Z shares were converted to Class Y shares as of the close of business on August 7, 2015. Each class of shares represents an interest in the same portfolio of investments of the Fund and has identical rights (based on relative net asset values) to assets and liquidation proceeds. Share classes can bear different rates of class-specific fees and expenses such as transfer agent and distribution fees. Differences in class-specific fees and expenses will result in differences in net investment income and, therefore, the payment of different dividends from net investment income earned by each class. The Amended and Restated Declaration of Trust of the Fund gives the Board of Trustees the flexibility to specify either per share voting or dollar-weighted voting when submitting matters for shareholder approval. Under per share voting, each share of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a shareholder's voting power is determined not by the number of shares owned, but by the dollar value of the shares on the record date. Each share class has exclusive voting rights with respect to matters affecting only that class, including with respect to the distribution plan for that class. There is no distribution plan for Class K or Class Y shares. The Fund's financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) that require the management of the Fund to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of income, expenses and gains and losses on investments during the reporting period. Actual results could differ from those estimates. The Fund is an investment company and follows investment company accounting and reporting guidance under U.S. GAAP. The following is a summary of significant accounting policies followed by the Fund in the preparation of its financial statements: Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 33 A. Security Valuation The net asset value of the Fund is computed once daily, on each day the New York Stock Exchange (NYSE) is open, as of the close of regular trading on the NYSE. Equity securities that have traded on an exchange are valued by using the last sale price on the principal exchange where they are traded. Equity securities that have not traded on the date of valuation, or securities for which sale prices are not available, generally are valued using the mean between the last bid and asked prices or, if both last bid and asked prices are not available, at the last quoted bid price. Last sale and bid and asked prices are provided by independent third party pricing services. In the case of equity securities not traded on an exchange, prices are typically determined by independent third party pricing services using a variety of techniques and methods. The value of foreign securities is translated into U.S. dollars based on foreign currency exchange rate quotations supplied by a third party pricing source. Trading in non-U.S. equity securities is substantially completed each day at various times prior to the close of the NYSE. The values of such securities used in computing the net asset value of the Fund's shares are determined as of such times. The fund may use a fair value model developed by an independent pricing service to value non-U.S. equity securities. Fixed-income securities are valued by using prices supplied by independent pricing services, which consider such factors as market prices, market events, quotations from one or more brokers, Treasury spreads, yields, maturities and ratings, or may use a pricing matrix or other fair value methods or techniques to provide an estimated value of the security or instrument. A pricing matrix is a means of valuing a debt security on the basis of current market prices for other debt securities, historical trading patterns in the market for Fixed-income securities and/or other factors. Non-U.S. debt securities that are listed on an exchange will be valued at the bid price obtained from an independent third party pricing service. When independent third party pricing services are unable to supply prices, or when prices market quotations are considered to be unreliable, the value of that security may be determined using quotations from one or more broker-dealers. Securities for which independent pricing services or broker-dealers are unable to supply prices or for which market prices and/or quotations are not readily available or are considered to be unreliable are valued by a fair valuation team comprised of certain personnel of Pioneer Investment Management, Inc. (PIM), the Fund's investment adviser and a wholly owned indirect subsidiary of UniCredit S.p.A. (UniCredit), pursuant to procedures adopted by the Board of Trustees. PIM's fair valuation team uses fair value 34 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 methods approved by the Valuation Committee of the Board of Trustees. PIM's fair valuation team is responsible for monitoring developments that may impact fair valued securities and for discussing and assessing fair values on an ongoing basis, and at least quarterly, with the Valuation Committee of the Board of Trustees. Inputs used when applying fair value methods to value a security may include credit ratings, the financial condition of the company, current market conditions and comparable securities. The Fund may use fair value methods if it is determined that a significant event has occurred after the close of the exchange or market on which the security trades and prior to the determination of the Fund's net asset value. Examples of a significant event might include political or economic news, corporate restructurings, natural disasters, terrorist activity or trading halts. Thus, the valuation of the Fund's securities may differ significantly from exchange prices, and such differences could be material. At March 31, 2017, there were no securities that were valued using fair value methods (other than securities valued using prices supplied by independent pricing services). B. Investment Income and Transactions Dividend income is recorded on the ex-dividend date, except that certain dividends from foreign securities where the ex-dividend date may have passed are recorded as soon as the Fund becomes aware of the ex-dividend data in the exercise of reasonable diligence. Interest income, including interest on income-bearing cash accounts, is recorded on the accrual basis. Dividend and interest income are reported net of unrecoverable foreign taxes withheld at the applicable country rates. Security transactions are recorded as of trade date. Gains and losses on sales of investments are calculated on the identified cost method for both financial reporting and federal income tax purposes. C. Federal Income Taxes It is the Fund's policy to comply with the requirements of the Internal Revenue Code applicable to regulated investment companies and to distribute all of its net taxable income and net realized capital gains, if any, to its shareowners. Therefore, no provision for federal income taxes is required. As of March 31, 2017, the Fund did not accrue any interest or penalties with respect to uncertain tax positions, which, if applicable, would be recorded as an income tax expense in the Statement of Operations. Tax returns filed within the prior three years remain subject to examination by federal and state tax authorities. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 35 The amount and character of income and capital gain distributions to shareowners are determined in accordance with federal income tax rules, which may differ from U.S. GAAP. Distributions in excess of net investment income or net realized gains are temporary overdistributions for financial statement purposes resulting from differences in the recognition or classification of income or distributions for financial statement and tax purposes. Capital accounts within the financial statements are adjusted for permanent book/tax differences to reflect tax character, but are not adjusted for temporary differences. At March 31, 2017, the Fund reclassified $18,694 to decrease undistributed net investment income and $18,694 to increase accumulated net realized gain on investments to reflect permanent book/tax differences. These adjustments have no impact on net assets or the results of operations. The tax character of distributions during the years ended March 31, 2017 and March 31, 2016 were as follows: --------------------------------------------------------------------------- 2017 2016 --------------------------------------------------------------------------- Distributions paid from: Ordinary income $ 22,408,405 $ 14,574,901 Long-term capital gain 90,517,680 116,386,891 --------------------------------------------------------------------------- Total $112,926,085 $130,961,792 =========================================================================== The following shows the components of distributable earnings on a federal income tax basis at March 31, 2017: --------------------------------------------------------------------------- 2017 --------------------------------------------------------------------------- Distributable earnings: Undistributed ordinary income $ 13,497,760 Undistributed long-term capital gain 55,326,435 Unrealized appreciation 1,094,857,369 --------------------------------------------------------------------------- Total $1,163,681,564 =========================================================================== The difference between book-basis and tax-basis net unrealized appreciation is attributable to the tax deferral of losses on wash sales and tax basis adjustments on common stock. D. Fund Shares The Fund records sales and repurchases of its shares as of trade date. Pioneer Funds Distributor, Inc. (PFD), the principal underwriter for the Fund and a wholly owned indirect subsidiary of UniCredit, earned $358,299 in underwriting commissions on the sale of Class A shares during the year ended March 31, 2017. 36 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 E. Class Allocations Income, common expenses and realized and unrealized gains and losses are calculated at the Fund level and allocated daily to each class of shares based on its respective percentage of adjusted net assets at the beginning of the day. Distribution fees are calculated based on the average daily net asset value attributable to Class A, Class C and Class R shares of the Fund, respectively (see Note 4). Class K and Class Y shares do not pay distribution fees. All expenses and fees paid to the Fund's transfer agent for its services are allocated among the classes of shares based on the number of accounts in each class and the ratable allocation of related out-of-pocket expenses (see Note 3). Distributions to shareowners are recorded as of the ex-dividend date. Distributions paid by the Fund with respect to each class of shares are calculated in the same manner and at the same time, except that net investment income dividends to Class A, Class C, Class K, Class R and Class Y shares can reflect different transfer agent and distribution expense rates. F. Risks The value of securities held by the fund may go up or down, sometimes rapidly or unpredictably, due to general market conditions, such as real or perceived adverse economic, political or regulatory conditions, inflation, changes in interest rates, lack of liquidity in the bond markets or adverse investor sentiment. In the past several years, financial markets have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty. These conditions may continue, recur, worsen or spread. At times, the Fund's investments may represent industries or industry sectors that are interrelated or have common risks, making the Fund more susceptible to any economic, political, or regulatory developments or other risks affecting those industries and sectors. The Fund's prospectus contains unaudited information regarding the Fund's principal risks. Please refer to that document when considering the Fund's principal risks. G. Repurchase Agreements Repurchase agreements are arrangements under which the Fund purchases securities from a broker-dealer or a bank, called the counterparty, upon the agreement of the counterparty to repurchase the securities from the Fund at a later date, and at a specific price, which is typically higher than the purchase price paid by the Fund. The securities purchased serve as the Fund's collateral for the obligation of the counterparty to repurchase the securities. The value of the collateral, including accrued interest, is required to be equal to or in excess of the repurchase price. The collateral for all repurchase agreements is Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 37 held in safekeeping in the customer-only account of the Fund's custodian or a subcustodian of the Fund. PIM is responsible for determining that the value of the collateral remains at least equal to the repurchase price. In the event of a default by the counterparty, the Fund is entitled to sell the securities, but the Fund may not be able to sell them for the price at which they were purchased, thus causing a loss to the Fund. Additionally, if the counterparty becomes insolvent, there is some risk that the Fund will not have a right to the securities, or the immediate right to sell the securities. 2. Management Agreement PIM manages the Fund's portfolio. Management fees are calculated daily at the annual rate of 0.65% of the Fund's average daily net assets up to $1 billion and 0.60% on assets over $1 billion. For the year ended March 31, 2017, the effective management fee (excluding waivers and/or assumption of expenses) was equivalent to 0.61% of the Fund's average daily net assets. PIM has contractually agreed to limit ordinary operating expenses (ordinary operating expenses means all fund expenses other than extraordinary expenses, such as litigation, taxes, brokerage commissions and acquired fund fees and expenses) of the Fund to the extent required to reduce Fund expenses to 1.09%, 1.40% and 0.83% of the average daily net assets attributable to Class A, Class R, and Class Y shares, respectively. Class C and Class K shares do not have an expense limitation. Fees waived and expenses reimbursed during the year ended March 31, 2017 are reflected on the Statement of Operations. These expense limitations are in effect through August 1, 2018. There can be no assurance that PIM will extend the expense limitation agreement for a class of shares beyond the date referred to above. In addition, under the management and administration agreements, certain other services and costs, including accounting, regulatory reporting and insurance premiums, are paid by the Fund as administrative reimbursements. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $186,268 in management fees, administrative costs and certain other reimbursements payable to PIM at March 31, 2017. 3. Transfer Agent Boston Financial Data Services, Inc. serves as the transfer agent to the Fund at negotiated rates. Transfer agent fees and payables shown on the Statement of Operations and the Statement of Assets and Liabilities, respectively, include sub-transfer agent expenses incurred through the Fund's omnibus relationship contracts. In addition, the Fund reimbursed the transfer agent for out-of-pocket expenses incurred by the transfer agent related to shareholder communications activities such as proxy and statement mailings and outgoing 38 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 phone calls. For the year ended March 31, 2017, such out-of-pocket expenses by class of shares were as follows: -------------------------------------------------------------------------------- Shareholder Communications: -------------------------------------------------------------------------------- Class A $ 474,909 Class C 76,255 Class K 5,785 Class R 17,461 Class Y 630,005 -------------------------------------------------------------------------------- Total $1,204,415 ================================================================================ 4. Distribution and Service Plans The Fund has adopted a distribution plan pursuant to Rule 12b-1 of the Investment Company Act of 1940 with respect to its Class A, Class C and Class R shares (the Plan). Pursuant to the Plan, the Fund pays PFD 0.25% of the average daily net assets attributable to Class A shares as compensation for personal services and/or account maintenance services or distribution services with regard to Class A shares. Pursuant to the Plan, the Fund also pays PFD 1.00% of the average daily net assets attributable to Class C shares. The fee for Class C shares consists of a 0.25% service fee and a 0.75% distribution fee paid as compensation for personal services and/or account maintenance services or distribution services with regard to Class C shares. Pursuant to the Plan, the Fund further pays PFD 0.50% of the average daily net assets attributable to Class R shares for distribution services. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $45,325 in distribution fees payable to PFD at March 31, 2017. The Fund also has adopted a separate service plan for Class R shares (Service Plan). The Service Plan authorizes the Fund to pay securities dealers, plan administrators or other service organizations that agree to provide certain services to retirement plans or plan participants holding shares of the Fund a service fee of up to 0.25% of the Fund's average daily net assets attributable to Class R shares held by such plans. In addition, redemptions of each class of shares (except Class K, Class R and Class Y shares) may be subject to a contingent deferred sales charge (CDSC). A CDSC of 1.00% may be imposed on redemptions of certain net asset value purchases of Class A shares within 12 months of purchase. Redemptions of Class C shares within 12 months of purchase are subject to a CDSC of 1.00%, based on the lower of cost or market value of shares being redeemed. Shares purchased as part of an exchange remain subject to any CDSC that applied to the original purchase of those shares. There is no CDSC for Class K, Class R or Class Y shares. Proceeds from the CDSCs are paid to PFD. For the year ended March 31, 2017, CDSCs in the amount of $136,628 were paid to PFD. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 39 5. Line of Credit Facility The Fund, along with certain other funds in the Pioneer Family of Funds (the Funds), participates in a committed, unsecured revolving line of credit facility. Borrowings are used solely for temporary or emergency purposes. The Fund may borrow up to the lesser of the amount available under the facility or the limits set for borrowing by the Fund's prospectus and the 1940 Act. The credit facility in which the Fund participated until February 9, 2016 was in the amount of $240 million. The credit facility in which the fund participated until February 7, 2017 was in the amount of $220 million. Effective February 8, 2017, the Fund participated in a facility that is in the amount of $195 million. Under such facility, depending on the type of loan, interest on borrowings is payable at the London Interbank Offered Rate (LIBOR) plus 0.85% on an annualized basis, or the Alternate Base Rate, which is the greater of (a) the facility's administrative agent's daily announced prime rate on the borrowing date, (b) 2% plus the Federal Funds Rate on the borrowing date and (c) 2% plus the overnight Eurodollar rate on the borrowing date. The Funds pay an annual commitment fee to participate in a credit facility. The commitment fee is allocated among participating Funds based on an allocation schedule set forth in the credit agreement. For the year ended March 31, 2017, the Fund had no borrowings under the credit facility. 40 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Report of Independent Registered Public Accounting Firm To the Board of Trustees of Pioneer Series Trust X and the Shareowners of Pioneer Fundamental Growth Fund: -------------------------------------------------------------------------------- We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Pioneer Fundamental Growth Fund (the "Fund") (one of the funds constituting Pioneer Series Trust X), as of March 31, 2017, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the two years in the period then ended and the financial highlights for each of the three years in the period then ended. These financial statements and the financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits. The financial highlights for the years ended March 31, 2014, and 2013, were audited by other auditors. Those auditors expressed an unqualified opinion on those financial statements and financial highlights in their report dated May 22, 2014. We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of March 31, 2017, by correspondence with the custodian and brokers; where replies were not received from brokers, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion. In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Pioneer Fundamental Growth Fund as of March 31, 2017, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended and the financial highlights for each of the three years in the period then ended, in conformity with accounting principles generally accepted in the United States of America. /s/ Deloitte & Touche LLP Boston, Massachusetts May 26, 2017 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 41 Additional Information (unaudited) For the year ended March 31, 2017, certain dividends paid by the Fund may be subject to a maximum tax rate of 15%, as provided for by the Jobs and Growth Tax Relief Reconciliation Act (the Act) of 2003. The Fund intends to designate up to the maximum amount of such dividends allowable under the Act, as taxed at a maximum rate of 15%. Complete information will be computed and reported in conjunction with your 2015 form 1099-DIV. The qualifying percentage of the Fund's ordinary income dividends for the purpose of the corporate dividends received deduction was 100.00%. Pioneer Investment Management, Inc. (the "Adviser"), the Fund's investment adviser, is currently an indirect, wholly owned subsidiary of UniCredit S.p.A. ("UniCredit"). On December 12, 2016, UniCredit announced that it has entered into a binding agreement for the sale of its Pioneer Investments business, which includes the Adviser, to Amundi (the "Transaction"). Amundi is headquartered in Paris, France, and, as of September 30, 2016, had more than $1.1 trillion in assets under management worldwide. The closing of the Transaction is expected to happen in 2017, subject to certain regulatory and antitrust approvals, and other conditions. Under the Investment Company Act of 1940, the closing of the Transaction will cause the Fund's current investment advisory agreement with the Adviser to terminate. Accordingly, the Fund's Board of Trustees has approved a new investment advisory agreement for the Fund, which will be submitted to the shareholders of the Fund for their approval. Change in Independent Registered Public Accounting Firm Deloitte & Touche LLP, the Fund's independent registered public accounting firm, has informed the Board that it will no longer be independent with respect to the Fund upon the completion of the Transaction and, accordingly, that it intends to resign as the Fund's independent registered public accounting firm upon the completion of the Transaction. The Board will engage a new independent registered public accounting firm for the Fund upon the completion of the Transaction. During the periods that Deloitte & Touche LLP has served as the Fund's independent registered public accounting firm, including the Fund's two most recent fiscal years, Deloitte & Touche LLP's reports on the Fund's financial statements have not contained an adverse opinion or disclaimer of opinion and have not been qualified or modified as to uncertainty, audit scope or 42 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 accounting principles. Further, there have been no disagreements with Deloitte & Touche LLP on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which, if not resolved to the satisfaction of Deloitte & Touche LLP, would have caused Deloitte & Touche LLP to make reference to the subject matter of the disagreement in connection with its report on the financial statements. In addition, there have been no reportable events of the kind described in Item 304(a)(1)(v) of Regulation S-K under the Securities Exchange Act of 1934. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 43 Approval of New and Interim Management Agreements Pioneer Investment Management, Inc. (PIM) serves as the investment adviser to Pioneer Fundamental Growth Fund (the Fund) pursuant to an investment management agreement between PIM and the Fund. PIM is the principal U.S. asset management business of Pioneer Investments, a group of companies owned by Pioneer Global Asset Management S.p.A. ("PGAM"). PGAM is a wholly-owned subsidiary of UniCredit S.p.A. ("UniCredit"). UniCredit and PGAM have entered into a binding agreement to sell Pioneer Investments, including PIM, to Amundi (the "Transaction"). Upon the consummation of the transaction, PIM will become an indirect wholly-owned subsidiary of Amundi and Amundi's wholly-owned subsidiary, Amundi USA, Inc. The closing of the Transaction is expected to happen in 2017. Under the Investment Company Act of 1940, the Fund's current investment management agreement (the "Current Management Agreement") will terminate automatically upon the consummation of the Transaction. In order for PIM to continue to manage the Fund after the consummation of the Transaction, the Trustees and shareholders of the Fund must approve a new investment management agreement for the Fund (the "New Management Agreement"). As discussed below, the Board of Trustees of the Fund approved the New Management Agreement at a meeting held on March 6-7, 2017. The New Management Agreement has been submitted to the shareholders of the Fund for their approval at a meeting to be held on June 13, 2017. If the shareholders of the Fund do not approve the New Management Agreement and the Transaction is completed, an interim investment management agreement between PIM and the Fund (the "Interim Management Agreement") will take effect upon the closing of the Transaction. The Board of Trustees of the Fund also approved the Interim Management Agreement at the March 6-7, 2017 meeting. Board Evaluation of the New and Interim Management Agreements The Board evaluated the Transaction and the New Management Agreement and Interim Management Agreement for the Fund. In connection with their evaluation of the Transaction and the New Management Agreement for the Fund, the Trustees requested such information as they deemed reasonably necessary, including: (a) the structure of the Transaction and the strategy underlying the Transaction; (b) the anticipated benefits of the Transaction to the Fund and its shareholders; (c) the post-Transaction plans for PIM, including Amundi's plans for integration of Pioneer Investments and PIM with 44 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 its existing asset management businesses and plans for the future development of PIM; (d) the effect of the Transaction on the ongoing services provided to the Fund, including the need to select a new independent registered public accounting firm for the Fund, and any plans to modify the operations of the Fund; (e) the stability and continuity of PIM's management and key employees, including compensation and benefits to PIM's key employees, and retention plans and incentive plan structure; (f) the post-Transaction indebtedness and financial resources of PIM; (g) Amundi's legal and operational structure, its principal shareholders and senior management, its investment management, risk management, administrative, legal and compliance functions; (h) certain regulatory matters relating to Amundi's affiliates; and (i) Amundi's commitment to the United States, including the role of PIM in the larger Amundi business. The Trustees also requested and obtained the following information in connection with their evaluation of the Transaction and the New Management Agreement for the Fund: (i) memoranda provided by Fund counsel that summarized the legal standards and other considerations that are relevant to the Trustees in their deliberations regarding the New Management Agreement; (ii) the qualifications of the investment management teams for the Fund, as well as the level of investment by the Fund's portfolio managers in the Fund; (iii) the Fund's management fees and total expense ratios, the financial statements of PIM and its pre- and post-Transaction parent companies, profitability analyses from PIM, and analyses from PIM as to possible economies of scale; (iv) the profitability of the institutional business of PIM and PIM's affiliate, Pioneer Institutional Asset Management, Inc. ("PIAM") as compared to that of PIM's fund management business; and (v) the differences between the fees and expenses of the Fund and the fees and expenses of PIM's and PIAM's institutional accounts, as well as the different services provided by Adviser to the Fund and by PIM and PIAM to the institutional accounts. In addition, the Trustees considered the information provided at regularly scheduled meetings throughout the year regarding the Fund's performance and risk attributes, including through meetings with investment management personnel, and took into account other information related to the Fund provided to the Trustees at regularly scheduled meetings. The Trustees also considered information they had received in their review of the continuance of the Current Management Agreement for the Fund in September 2016. At meetings held on January 9, 2017 and January 10, 2017, the Trustees met with representatives of Amundi and PGAM, including separate meetings of the Trustees who are not "interested persons" of the Fund Complex ("Independent Trustees") and counsel with representatives of Amundi and PGAM, and subsequently with representatives of Amundi. In those meetings, Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 45 they received an extensive presentation from the representatives of Amundi, including the chief executive officer of Amundi, describing Amundi's background and history, its global asset management activities, the growth of its business, and its status as the largest asset management firm in Europe and one of the largest globally; its capital structure and financial resources, including information as to the financing of the Transaction; its principal investors, including its majority investor Credit Agricole S.A., and Credit Agricole's long-term commitment to the asset management business; the philosophy and strategy underlying the Transaction and the complementarity of Amundi's and Pioneer Investments' respective asset management businesses; Amundi's various operating and investment committees and how they would likely interact with PIM; the proposed integration process, including the progress to date and the establishment of various integration work streams; Amundi's plans for management of PIM; Amundi's philosophy as to compensation of key employees and its general intentions with respect to incentive plans for key employees of PIM; Amundi's preliminary plans to achieve cost and other synergies; and opportunities to further develop the business of PIM and PIAM, including in the area of institutional asset management, and how that would benefit shareholders of the Pioneer Funds. In those meetings, the representatives of Amundi confirmed their intention that the Chief Executive Officer and Chief Investment Officer of PIM would remain in their current positions, and confirmed that they do not currently foresee major changes in the day-to-day investment management operations of PIM with respect to the Fund as a direct result of the Transaction. They discussed incentive arrangements for key personnel that would continue after the closing of the Transaction and their plans to establish a new long-term incentive plan following the closing. They also generally discussed ways in which PIM could potentially draw on the expanded global resources of Amundi post-Transaction. At those meetings, the Independent Trustees identified certain areas to which they requested further information, including as to trading and execution of securities transactions, research and portfolio management and potential changes in investment process, particularly where asset classes managed by PIM would overlap with asset classes managed by Amundi, the continued availability of resources currently at Pioneer Investments or elsewhere within Amundi to assist in management of certain Funds, and any anticipated significant changes in operations. The Independent Trustees considered the uncertainty as to whether the Fund's independent registered public accounting firm could continue to act in that capacity after the closing of the Transaction. The Independent Trustees also met with counsel to review the information they had received to date and to discuss next steps. 46 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Subsequently, the Trustees received further information from Amundi, including written responses to questions raised by the Independent Trustees, and received from PIM the information requested of it. The Independent Trustees reviewed the information provided with counsel at telephonic meetings held on February 16, 2017 and February 27, 2017. The Trustees held a special in-person Board meeting on March 6-7, 2017 for further consideration of the New Management Agreements, the Interim Management Agreements and the Transaction. The Trustees met again with senior executives of Amundi at the March 6-7, 2017 meeting. At the March 6-7, 2017 meeting, based on their evaluation of the information provided by PIM and Amundi, the Trustees including the Independent Trustees voting separately, approved the New Management Agreement and the Interim Management Agreement for the Fund. In considering the New Management Agreement for the Fund, the Trustees considered various factors that they determined were relevant, including the factors described below. The Trustees did not identify any single factor as the controlling factor in their determinations. The Trustees considered the same factors with respect to the Interim Management Agreement for the Fund. Nature, Extent and Quality of Services The Trustees considered the nature, extent and quality of the services that had been provided by PIM to the Fund and that are expected to be provided by PIM to the Fund following the consummation of the Transaction. The Trustees reviewed the terms of the New Management Agreement, and noted that such terms are substantially similar to the terms of the Current Management Agreement, except for different execution dates, effective dates and termination dates. The Trustees reviewed PIM's investment approach for the Fund and its research process. The Trustees considered the resources of PIM and the personnel of PIM who provide investment management services to the Fund. They also reviewed the amount of non-investment resources and personnel of PIM that are involved in PIM's services to the Fund, including PIM's compliance and legal resources and personnel. The Trustees noted the substantial attention and high priority given by PIM's senior management to the Pioneer Fund complex. The Trustees considered that PIM supervises and monitors the performance of the Fund's service providers and provides the Fund with personnel (including Fund officers) and other resources that are necessary for the Fund's business management and operations and that PIM would continue to provide those investment management and research services and resources to the Fund following the consummation of the Transaction. The Trustees also considered that, as administrator, PIM would continue to be responsible for the Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 47 administration of the Fund's business and other affairs. The Trustees considered the fees to be paid to PIM for the provision of administration services. The Trustees considered that Deloitte & Touche LLP has informed the Board that it will no longer be independent with respect to the Fund upon the completion of the Transaction and, accordingly, that it will be necessary for the Board to engage a new independent registered public accounting firm for the Fund. The Trustees considered that the Transaction is not expected to have a material adverse impact on the nature, scope and overall quality of services provided to the Fund and its shareholders, including investment management, risk management, administrative, compliance, legal and other services, as a result of the Transaction. In that regard, the Trustees considered that Amundi is one of the largest asset managers globally, and that PIM may have access to additional research and portfolio management capabilities as a result of the Transaction and that PIM, as part of Amundi, is expected to have an enhanced global presence that may contribute to an increase in the overall scale and resources of PIM. Furthermore, in considering whether the Transaction would be expected to have a material adverse impact on the nature, scope and overall quality of services provided to the Fund and its shareholders, the Trustees considered the statements by representatives of Amundi that they expect the Chief Executive Officer and Chief Investment Officer of PIM to remain in their current positions and that they do not currently foresee major changes in the day-to-day investment management operations of PIM as a direct result of the Transaction, or the risk management, legal or compliance services provided by PIM, with respect to the Fund. They further considered the current incentive arrangements for key personnel of PIM that would continue after the closing of the Transaction. They also noted Amundi's stated intention to establish a new long-term incentive plan following the closing. The Trustees also took into account their experience in evaluating the proposed combination of Pioneer Investments and Santander Asset Management, which was announced in September, 2014 and abandoned in July, 2016. In light of, among other things, this experience, the Trustees determined that they were not able to identify any realistic alternatives to approving the New Management Agreement that would provide the level of services to the Fund and its shareholders that are expected to be provided by PIM after the closing of the Transaction. 48 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Based on these considerations, the Trustees concluded that the nature, extent and quality of services that PIM would continue to provide to the Fund under the New Management Agreement would be satisfactory and consistent with the terms of the New Management Agreement. Performance of the Fund. In considering the Fund's performance, the Trustees regularly reviewed and discussed throughout the year data prepared by PIM and information comparing the Fund's performance with the performance of its peer group of funds, as classified by each of Morningstar, Inc. (Morningstar) and Lipper, and the performance of the Fund's benchmark index. They also discussed the Fund's performance with PIM on a regular basis. The Trustees' regular reviews and discussions were factored into the Trustees' deliberations concerning the approval of the New Management Agreement. Management Fee and Expenses The Trustees noted that the stated management fees to be paid by the Fund are identical under the Current Management Agreement and the New Management Agreement. The Trustees considered information showing the fees and expenses of the Fund in comparison to the management fees and expense ratios of its peer group of funds as classified by Morningstar and also to the expense ratios of a peer group of funds selected on the basis of criteria determined by the Independent Trustees for this purpose using data provided by Strategic Insight Mutual Fund Research and Consulting, LLC (Strategic Insight), an independent third party. In all quintile rankings referred to below, first quintile is most favorable to the Fund's shareowners. To the extent applicable, the Trustees also considered the impact of transfer agency, sub-transfer agency, and other non-management fee expenses on the expense ratios of the Fund. The Trustees noted that they separately review the Fund's transfer agency, sub-transfer agency and intermediary arrangements and that the results of the most recent such review were considered in the consideration of the Fund's expense ratio. The Trustees considered that the Fund's management fee as of September 30, 2016 was in the second quintile relative to the management fees paid by other funds in its Morningstar category for the comparable period. The Trustees also considered the breakpoint in the management fee schedule and the reduced fee rate above a certain asset level. The Trustees considered that the expense ratio of the Fund's Class A shares as of September 30, 2016 was in the second quintile relative to its Morningstar category and in the fourth quintile relative to its Strategic Insight peer group, in each case for the comparable period. The Trustees considered that the expense ratio of the Fund's Class Y shares as of Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 49 September 30, 2016 was in the third quintile relative to its Morningstar category and in the third quintile relative to its Strategic Insight peer group, in each case for the comparable period. The Trustees noted that PIM had agreed to waive fees and/or reimburse expenses in order to limit the ordinary operating expenses of the Fund. The Trustees reviewed management fees charged by PIM and PIAM to institutional and other clients, including publicly offered European funds sponsored by PIM's affiliates, unaffiliated U.S. registered investment companies (in a sub-advisory capacity), and unaffiliated foreign and domestic separate accounts. The Trustees also considered PIM's costs in providing services to the Fund and PIM's and PIAM's costs in providing services to the other clients and considered the differences in management fees and profit margins for fund and non-fund services. In evaluating the fees associated with PIM's and PIAM's client accounts, the Trustees took into account the respective demands, resources and complexity associated with the Fund and other client accounts. The Trustees noted that in some instances the fee rates for those clients were lower than the management fee for the Fund and considered that, under both the Current Management Agreement and the New Management Agreement, PIM would perform additional services for the Fund that it does not provide to those other clients or services that are broader in scope, including oversight of the Fund's other service providers and activities related to compliance and the extensive regulatory and tax regimes to which the Fund is subject. The Trustees also considered the different risks associated with PIM's management of the Fund and PIM's and PIAM's management of the other client accounts. The Trustees concluded that the management fee payable by the Fund to PIM was reasonable in relation to the nature and quality of the services to be provided by PIM. Profitability The Trustees considered information provided by PIM regarding the profitability of PIM with respect to the advisory services provided by PIM to the Fund, including the methodology used by PIM in allocating certain of its costs to the management of the Fund. The Trustees also considered PIM's profit margin in connection with the overall operation of the Fund. They further reviewed the financial results, including the profit margins, realized by PIM and PIAM from non-fund businesses. The Trustees considered PIM's profit margins with respect to the Fund in comparison to the limited industry data available and noted that the profitability of any adviser was affected by numerous factors, including its organizational structure and method for allocating expenses. The Trustees concluded that PIM's profitability with respect to the management of the Fund was not unreasonable. 50 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Economies of Scale The Trustees considered PIM's views relating to economies of scale in connection with the Pioneer Funds as fund assets grow and the extent to which any such economies of scale are shared with the Fund and Fund shareholders. The Trustees recognize that economies of scale are difficult to identify and quantify, and that, among other factors that may be relevant, are the following: fee levels, expense subsidization, investment by PIM in research and analytical capabilities and PIM's commitment and resource allocation to the Fund. The Trustees noted that profitability also may be an indicator of the availability of any economies of scale, although profitability may vary for other reasons including due to reductions in expenses. The Trustees concluded that economies of scale, if any, were being appropriately shared with the Fund. Other Benefits The Trustees considered the other benefits that PIM enjoys from its relationship with the Fund. The Trustees considered the character and amount of fees paid or to be paid by the Fund, other than under the Current Management Agreement or the New Management Agreement, for services provided by PIM and its affiliates. The Trustees further considered the revenues and profitability of PIM's businesses other than the Fund business. To the extent applicable, the Trustees also considered the benefits to the Fund and to PIM and its affiliates from the use of "soft" commission dollars generated by the Fund to pay for research and brokerage services. The Trustees considered that following the completion of the Transaction, PIM will be the principal U.S. asset management business of Amundi, and that Amundi's worldwide asset management business will manage over $1.38 trillion in assets (including the Pioneer Funds). This may create opportunities for PIM, PIAM and Amundi that derive from PIM's relationships with the Fund, including Amundi's ability to market the services of PIM globally. The Trustees noted that PIM may have access to additional research capabilities as a result of the Transaction and Amundi's enhanced global presence that may contribute to an increase of the overall scale of PIM. The Trustees considered that PIM and the Fund are expected to receive reciprocal intangible benefits from the relationship, including mutual brand recognition and, for the Fund, direct and indirect access to the resources of a large global asset manager. The Trustees concluded that any such benefits received by PIM as a result of its relationship with the Fund were reasonable. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 51 Conclusion After consideration of the factors described above as well as other factors, the Trustees, including the Independent Trustees, concluded that the New Management Agreement and the Interim Management Agreement for the Fund, including the fees payable thereunder, were fair and reasonable and voted to approve the New Management Agreement and the Interim Management Agreement, and to recommend that shareholders approve the New Management Agreement. 52 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Trustees, Officers and Service Providers Investment Adviser Pioneer Investment Management, Inc. Custodian and Sub-Administrator Brown Brothers Harriman & Co. Independent Registered Public Accounting Firm Deloitte & Touche LLP Principal Underwriter Pioneer Funds Distributor, Inc. Legal Counsel Morgan, Lewis & Bockius LLP Shareowner Services and Transfer Agent Boston Financial Data Services, Inc. Proxy Voting Policies and Procedures of the Fund are available without charge, upon request, by calling our toll free number (1-800-225-6292). Information regarding how the Fund voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is publicly available to shareowners at us.pioneerinvestments.com. This information is also available on the Securities and Exchange Commission's web site at www.sec.gov. Trustees and Officers The Fund's Trustees and officers are listed below, together with their principal occupations during at least the past five years. Trustees who are interested persons of the Fund within the meaning of the 1940 Act are referred to as Interested Trustees. Trustees who are not interested persons of the Fund are referred to as Independent Trustees. Each of the Trustees serves as a Trustee of each of the 46 U.S. registered investment portfolios for which Pioneer serves as investment adviser (the "Pioneer Funds"). The address for all Trustees and all officers of the Fund is 60 State Street, Boston, Massachusetts 02109. The Statement of Additional Information of the Fund includes additional information about the Trustees and is available, without charge, upon request, by calling 1-800-225-6292. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 53 Independent Trustees ----------------------------------------------------------------------------------------------------------------------------------- Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ----------------------------------------------------------------------------------------------------------------------------------- Thomas J. Perna (66) Trustee since 2006. Private investor (2004 - 2008 and 2013 - Director, Broadridge Chairman of the Board Serves until a successor present); Chairman (2008 - 2013) and Chief Financial Solutions, Inc. and Trustee trustee is elected or earlier Executive Officer (2008 - 2012), Quadriserv, (investor communications retirement or removal. Inc. (technology products for securities and securities processing lending industry); and Senior Executive Vice provider for financial President, The Bank of New York (financial services industry) (2009 and securities services) (1986 - 2004) - present); Director, Quadriserv, Inc. (2005 - 2013); and Commissioner, New Jersey State Civil Service Commission (2011 - 2015) ----------------------------------------------------------------------------------------------------------------------------------- David R. Bock (73) Trustee since 2005. Managing Partner, Federal City Capital Director of New York Trustee Serves until a successor Advisors (corporate advisory services Mortgage Trust trustee is elected or earlier company) (1997 - 2004 and 2008 - present); (publicly-traded mortgage retirement or removal. Interim Chief Executive Officer, Oxford REIT) (2004 - 2009, 2012 Analytica, Inc. (privately-held research and - present); Director of consulting company) (2010); Executive Vice The Swiss Helvetia Fund, President and Chief Financial Officer, Inc. (closed-end fund) I-trax, Inc. (publicly traded health care (2010 - present); services company) (2004 - 2007); and Director of Oxford Executive Vice President and Chief Financial Analytica, Inc. (2008 - Officer, Pedestal Inc. (internet-based present); and Director of mortgage trading company) (2000 - 2002); Enterprise Community Private consultant (1995-1997), Managing Investment, Inc. Director, Lehman Brothers (investment (privately-held banking firm) (1992-1995); and Executive, The affordable housing finance World Bank (1979-1992) company) (1985 - 2010) ----------------------------------------------------------------------------------------------------------------------------------- Benjamin M. Friedman (72) Trustee since 2008. William Joseph Maier Professor of Political Trustee, Mellon Trustee Serves until a successor Economy, Harvard University (1972 - present) Institutional Funds trustee is elected or earlier Investment Trust and retirement or removal. Mellon Institutional Funds Master Portfolio (oversaw 17 portfolios in fund complex) (1989-2008) ----------------------------------------------------------------------------------------------------------------------------------- 54 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Margaret B.W. Graham (69) Trustee since 2002. Founding Director, Vice President and None Trustee Serves until a successor Corporate Secretary, The Winthrop Group, trustee is elected or earlier Inc. (consulting firm) (1982 - present); retirement or removal. Desautels Faculty of Management, McGill University (1999 - present); and Manager of Research Operations and Organizational Learning, Xerox PARC, Xerox's advance research center (1990-1994) ------------------------------------------------------------------------------------------------------------------------------------ Marguerite A. Piret (68) Trustee since 2002. President and Chief Executive Officer, Director of New America Trustee Serves until a successor Newbury Piret Company (investment banking High Income Fund, Inc. trustee is elected or earlier firm) (1981 - present) (closed-end investment retirement or removal. company) (2004 - present); and Member, Board of Governors, Investment Company Institute (2000 - 2006) ------------------------------------------------------------------------------------------------------------------------------------ Fred J. Ricciardi (70) Trustee since 2014. Consultant (investment company services) None Trustee Serves until a successor (2012 - present); Executive Vice President, trustee is elected or earlier BNY Mellon (financial and investment company retirement or removal. services) (1969 - 2012); Director, BNY International Financing Corp. (financial services) (2002 - 2012); and Director, Mellon Overseas Investment Corp. (financial services) (2009 - 2012) ------------------------------------------------------------------------------------------------------------------------------------ Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 55 Interested Trustee ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Kenneth J. Taubes (58)* Trustee since 2014. Director and Executive Vice President (since None Trustee Serves until a successor 2008) and Chief Investment Officer, U.S. trustee is elected or earlier (since 2010) of Pioneer Investment retirement or removal. Management-USA (PIM-USA); Executive Vice President of Pioneer (since 2008); Executive Vice President of Pioneer Institutional Asset Management, Inc. (since 2009); and Portfolio Manager of Pioneer (since 1999) ------------------------------------------------------------------------------------------------------------------------------------ * Mr. Taubes is an Interested Trustee because he is an officer of the Fund's investment adviser and certain of its affiliates. 56 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 Advisory Trustee ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Lorraine Monchak (60)** Advisory Trustee since 2014. Chief Investment Officer, 1199 SEIU Funds Trustee of Pioneer Advisory Trustee (healthcare workers union pension funds) closed-end investment (2001 - present); Vice President - companies (5 portfolios) International Investments Group, American (Sept. 2015 - present) International Group, Inc. (insurance company) (1993 - 2001); Vice President, Corporate Finance and Treasury Group, Citibank, N.A. (1980 - 1986 and 1990 - 1993); Vice President - Asset/Liability Management Group, Federal Farm Funding Corporation (government-sponsored issuer of debt securities) (1988 - 1990); Mortgage Strategies Group, Shearson Lehman Hutton, Inc. (investment bank) (1987 - 1988); and Mortgage Strategies Group, Drexel Burnham Lambert, Ltd. (investment bank) (1986 - 1987) ------------------------------------------------------------------------------------------------------------------------------------ ** Ms. Monchak is a non-voting advisory trustee. Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 57 Fund Officers ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Officer ------------------------------------------------------------------------------------------------------------------------------------ Lisa M. Jones (55) Since 2014. Serves at Chair, Director, CEO and President of Trustee of Pioneer President and Chief the discretion of the Board. PIM-USA (since September 2014); Chair, closed-end investment Executive Officer Director, CEO and President of Pioneer companies (5 portfolios) Investment Management, Inc. (since September (Sept. 2015 - present) 2014); Chair, Director, CEO and President of Pioneer Funds Distributor, Inc. (since September 2014); Chair, Director, CEO and President of Pioneer Institutional Asset Management, Inc. (since September 2014); and Chair, Director, and CEO of Pioneer Investment Management Shareholder Services, Inc. (since September 2014); Managing Director, Morgan Stanley Investment Management (2010 - 2013); and Director of Institutional Business, CEO of International, Eaton Vance Management (2005 - 2010) ------------------------------------------------------------------------------------------------------------------------------------ Christopher J. Kelley (52) Since 2003. Serves at Vice President and Associate General Counsel None Secretary and the discretion of the Board. of Pioneer since January 2008; Secretary and Chief Legal Officer Chief Legal Officer of all of the Pioneer Funds since June 2010; Assistant Secretary of all of the Pioneer Funds from September 2003 to May 2010; and Vice President and Senior Counsel of Pioneer from July 2002 to December 2007 ------------------------------------------------------------------------------------------------------------------------------------ Carol B. Hannigan (56) Since 2010. Serves at Fund Governance Director of Pioneer since None Assistant Secretary the discretion of the Board. December 2006 and Assistant Secretary of all the Pioneer Funds since June 2010; Manager - Fund Governance of Pioneer from December 2003 to November 2006; and Senior Paralegal of Pioneer from January 2000 to November 2003 ------------------------------------------------------------------------------------------------------------------------------------ Thomas Reyes (54) Since 2010. Serves at Senior Counsel of Pioneer since May 2013 and None Assistant Secretary the discretion of the Board. Assistant Secretary of all the Pioneer Funds since June 2010; and Counsel of Pioneer from June 2007 to May 2013 ------------------------------------------------------------------------------------------------------------------------------------ Mark E. Bradley (57) Since 2008. Serves at Vice President - Fund Treasury of Pioneer; None Treasurer and Chief the discretion of the Board. Treasurer of all of the Pioneer Funds since Financial March 2008; Deputy Treasurer of Pioneer from and Accounting Officer March 2004 to February 2008; and Assistant Treasurer of all of the Pioneer Funds from March 2004 to February 2008 ------------------------------------------------------------------------------------------------------------------------------------ 58 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Officer ------------------------------------------------------------------------------------------------------------------------------------ Luis I. Presutti (51) Since 2002. Serves at Director - Fund Treasury of Pioneer; and None Assistant Treasurer the discretion of the Board. Assistant Treasurer of all of the Pioneer Funds ------------------------------------------------------------------------------------------------------------------------------------ Gary Sullivan (58) Since 2002. Serves at Fund Accounting Manager - Fund Treasury of None Assistant Treasurer the discretion of the Board. Pioneer; and Assistant Treasurer of all of the Pioneer Funds ------------------------------------------------------------------------------------------------------------------------------------ David F. Johnson (37) Since 2009. Serves at Fund Administration Manager - Fund Treasury None Assistant Treasurer the discretion of the Board. of Pioneer since November 2008; Assistant Treasurer of all of the Pioneer Funds since January 2009; and Client Service Manager - Institutional Investor Services at State Street Bank from March 2003 to March 2007 ------------------------------------------------------------------------------------------------------------------------------------ Jean M. Bradley (64) Since 2010. Serves at Chief Compliance Officer of Pioneer and of None Chief Compliance Officer the discretion of the Board. all the Pioneer Funds since March 2010; Chief Compliance Officer of Pioneer Institutional Asset Management, Inc. since January 2012; Chief Compliance Officer of Vanderbilt Capital Advisors, LLC since July 2012: Director of Adviser and Portfolio Compliance at Pioneer since October 2005; and Senior Compliance Officer for Columbia Management Advisers, Inc. from October 2003 to October 2005 ------------------------------------------------------------------------------------------------------------------------------------ Kelly O'Donnell (46) Since 2006. Serves at Director - Transfer Agency Compliance of None Anti-Money the discretion of the Board. Pioneer and Anti-Money Laundering Officer of Laundering Officer all the Pioneer Funds since 2006 ------------------------------------------------------------------------------------------------------------------------------------ Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 59 This page is for your notes. 60 Pioneer Fundamental Growth Fund | Annual Report | 3/31/17 How to Contact Pioneer We are pleased to offer a variety of convenient ways for you to contact us for assistance or information. Call us for: -------------------------------------------------------------------------------- Account Information, including existing accounts, new accounts, prospectuses, applications and service forms 1-800-225-6292 FactFone(SM) for automated fund yields, prices, account information and transactions 1-800-225-4321 Retirement plans information 1-800-622-0176 Write to us: -------------------------------------------------------------------------------- Pioneer Funds P.O. Box 55014 Boston, Massachusetts 02205-5014 Our toll-free fax 1-800-225-4240 Our internet e-mail address ask.pioneer@pioneerinvestments.com (for general questions about Pioneer only) Visit our web site: us.pioneerinvestments.com This report must be preceded or accompanied by a prospectus. The Fund files a complete schedule of investments with the Securities and Exchange Commission for the first and third quarters for each fiscal year on Form N-Q. Shareholders may view the filed Form N-Q by visiting the Commission's web site at http://www.sec.gov. The filed form may also be viewed and copied at the Commission's Public Reference Room in Washington, DC. Information regarding the operations of the Public Reference Room may be obtained by calling 1-800-SEC-0330. [LOGO] PIONEER Investments(R) Pioneer Investment Management, Inc. 60 State Street Boston, MA 02109 us.pioneerinvestments.com Securities offered through Pioneer Funds Distributor, Inc. 60 State Street, Boston, MA 02109 Underwriter of Pioneer Mutual Funds, Member SIPC (C) 2017 Pioneer Investments 19341-11-0517 Pioneer Multi-Asset Ultrashort Income Fund -------------------------------------------------------------------------------- Annual Report | March 31, 2017 -------------------------------------------------------------------------------- Ticker Symbols: Class A MAFRX Class C MCFRX Class C2 MAUCX Class K MAUKX Class Y MYFRX [LOGO] PIONEER Investments(R) visit us: us.pioneerinvestments.com Table of Contents President's Letter 2 Portfolio Management Discussion 4 Portfolio Summary 12 Prices and Distributions 13 Performance Update 14 Comparing Ongoing Fund Expenses 19 Schedule of Investments 21 Financial Statements 94 Notes to Financial Statements 103 Report of Independent Registered Public Accounting Firm 113 Approval of New and Interim Management Agreements 115 Trustees, Officers and Service Providers 124 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 1 President's Letter After an overall strong year for leading market indices in 2016, U.S. markets continued to generate positive returns over the first calendar quarter of 2017, with so-called "risk" assets, such as equities and credit-sensitive bonds, posting solid gains. In the first quarter, U.S. equities, as measured by the Standard & Poor's 500 Index, returned slightly more than 6%, while high-yield securities dominated bond market performance. The transfer of power in Washington, D.C. in January had little or no effect on the markets in the first quarter, as the post-election momentum we witnessed late in the fourth quarter of 2016 slowed only when oil prices slumped in March, due to both higher-than-expected inventories and concerns over whether OPEC (Organization of Petroleum Exporting Countries) would continue its supply cuts in June. Not even the Federal Reserve System's (the Fed's) highly anticipated rate hike during the month of March, its second in three months, nor Britain's trigger of Article 50 to begin the "Brexit" process caused any dramatic sell-off of risk assets. While U.S. gross domestic product (GDP) did slow in the first quarter, the expectation is for GDP to accelerate in the second quarter, with a strong consumer leading the way. Pioneer believes the U.S. economy may lead all developed nations in 2017, with GDP growth in excess of 2% for the year. President Trump has proposed decidedly pro-business policies, such as lower taxes, higher infrastructure spending, and less regulation, though we believe the economy may realize the benefits of those policies, if enacted, more so in 2018 than in 2017. Conversely, the effects of the President's potentially restrictive trade policies could offset some of the benefits of the pro-growth fiscal policies. Even so, we believe solid domestic employment figures should continue to support consumption and the housing market, and that stronger corporate profits and increased government spending may contribute to economic growth in 2018 and beyond. Increasing global Purchasing Manager Indices (PMIs) suggest that growth in global economies is also improving. (PMIs are used to measure the economic health of the manufacturing sector.) There are, as always, some risks to our outlook. First, the market already has priced in a good deal of the Trump economic reform platform, and that could lead to near-term disappointment if Congressional follow-through does not happen this year. The future of the Affordable Care Act is another potential concern. The first attempt to repeal/replace it failed, but any new proposed 2 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 legislation will undoubtedly have an effect on the health care sector, one of the largest segments of the US economy. Geopolitical risks, of course, remain a potential headwind, given ongoing strife in the Middle East and renewed tensions on the Korean Peninsula. While our current outlook is generally optimistic, conditions can and often do change, and while passive investment strategies may have a place in one's overall portfolio, it is our view that all investment decisions are active choices. Throughout Pioneer's history, we have believed in the importance of active management. The active decisions to invest in equities or fixed-income securities are made by a team of experienced investment professionals focusing on identifying value across global markets using proprietary research, careful risk management, and a long-term perspective. We believe our shareowners can benefit from the experience and tenure of our investment teams as well as the insights generated from our extensive research process. As always, and particularly during times of market uncertainty, we encourage you to work with your financial advisor to develop an overall investment plan that addresses both your short- and long-term goals, and to implement such a plan in a disciplined manner. We greatly appreciate the trust you have placed in us and look forward to continuing to serve you in the future. Sincerely, /s/ Lisa M. Jones Lisa M. Jones President and CEO Pioneer Investment Management USA Inc. March 31, 2017 Any information in this shareowner report regarding market or economic trends or the factors influencing the Fund's historical or future performance are statements of opinion as of the date of this report. Past performance is no guarantee of future results. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 3 Portfolio Management Discussion | 3/31/17 In the following interview, portfolio managers Charles Melchreit, Seth Roman, and Jonathan Sharkey discuss the factors that influenced Pioneer Multi-Asset Ultrashort Income Fund's performance during the 12-month period ended March 31, 2017. Mr. Melchreit, Director of Investment-Grade Management, a senior vice president and a portfolio manager at Pioneer, Mr. Roman, a vice president and a portfolio manager at Pioneer, and Mr. Sharkey, a senior vice president and a portfolio manager at Pioneer, are responsible for the day-to-day management of the Fund. Q How did the Fund perform during the 12-month period ended March 31, 2017? A Pioneer Multi-Asset Ultrashort Income Fund's Class A shares returned 2.33% at net asset value during the 12-month period ended March 31, 2017, while the Fund's benchmark, the Bank of America Merrill Lynch 3-Month U.S. Dollar LIBOR Index (the BofA ML Index), returned 0.74%. During the same period, the average return of the 125 mutual funds in Lipper's Ultrashort Obligations Funds category was 1.35%, and the average return of the 157 mutual funds in Morningstar's Ultrashort Bond category was 1.61%. Q How would you describe the market environment for fixed-income investors over the 12-month period ended March 31, 2017? A The period began in April 2016 against a backdrop of disappointing global economic growth. In the U.S., credit markets received support from the domestic economy's continued, modest progress, and from expectations that the U.S. Federal Reserve (the Fed), after increasing interest rates in December 2015 for the first time in several years, would follow a more elongated trajectory than originally anticipated with respect to rate normalization. U.S. interest rates, in fact, began the period near historical lows and traded within a relatively narrow band over most of the period's first three months. In June 2016, the result of a referendum in the United Kingdom, in which citizens voted to exit the European Union, caught the markets off guard. The uncertainty about the ultimate implications of the so-called "Brexit" vote spurred a brief flight-to-safety trade and drove U.S. Treasury yields down even further, while temporarily shaking up the credit-sensitive areas of the market. Markets recovered in a matter of days, however, as investors 4 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 began to put the likely impact of Brexit on global economic growth into perspective. The supportive actions taken by global central banks, as exemplified by moves to negative interest rates in both Europe and Japan, also provided investors with a reason to look past Brexit and re-enter the "risk" trade. In addition, July 2016 saw oil prices stabilize into a range substantially higher than the lows seen at the beginning of 2016, reflecting in part improved sentiment about the Chinese economy and the global demand backdrop. In December 2016, the Fed once again raised the benchmark overnight lending (Federal funds) rate by 25 basis points (bps), to the 0.50% - 0.75% range. (A basis point is equal to 1/100th of a percentage point.) The market had a muted response to the rate hike, though, having anticipated the Fed's move long in advance. Credit sentiment and interest rates rose notably after the November 8, 2016, U.S. elections. Investors appeared to anticipate higher levels of both economic growth and inflation going forward in the wake of the election results, which put the Republicans in control of the White House and both houses of Congress. Moreover, the victor in the Presidential race, Donald Trump, had campaigned on a pro-growth economic platform featuring proposals to cut corporate and individual tax rates, increase infrastructure spending, and ease regulatory oversight on the business community. U.S. Treasury yields trended higher across the maturity spectrum over November and December, and economically sensitive, credit-oriented segments of the bond market outperformed. Those trends held up well into 2017, before a dip in oil prices and inflation expectations in March led to a decline in Treasury yields. In addition, the failure of President Trump and the Republican-controlled Congress to pass a plan to replace the Affordable Care Act brought into question the outlook for passage of the rest of the administration's pro-growth economic platform. March 2017 also saw the Fed implement another 25 bps hike in the Federal funds rate, increasing it to the 0.75% - 1.00% target range. The rate increase initially caught the markets off guard, but ultimately came to be seen as the Fed's verifying the favorable economic growth outlook. U.S. Treasury rates rose notably over the 12-month period ended March 31, 2017. To illustrate, the two-year Treasury yield rose from 0.73% to 1.27%, the five-year yield rose from 1.21% to 1.93%, and the 10-year yield rose from 1.78% to 2.40%. Over the same period, the three-month London Interbank Offered Rate (LIBOR), a commonly used baseline for loans and securities globally, rose from 0.63% to 1.15%. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 5 Q Can you review your principal strategies in managing the Fund during the 12-month period ended March 31, 2017, and their effects on performance? A During the period, we continued to maintain a portfolio of investments that seeks to provide income, while also striving to protect shareholders' principal against a rise in market interest rates. Our strategy entailed investing the portfolio in a wide range of mostly high-quality floating-rate securities, and fixed-rate instruments with very short remaining maturities. At period end, well over 90% of the Fund's total investment portfolio was allocated either to floating-rate issues with interest rates tied to a short-term reference rate such as LIBOR, or to fixed-rate issues with less than one-year duration. (Duration is a measure of the sensitivity of the price, or the value of principal, of a fixed-income investment to a change in interest rates, expressed as a number of years.) Unlike many other floating-rate vehicles, we typically invest the Fund's assets with a primary focus on investment-grade asset classes. At the same time, we did seek to have the Fund's performance benefit from credit spreads during the period. In doing so, we sought at all times to maintain the portfolio's broadly diversified* exposure to a number of different spread sectors. (Spread sectors represent non-governmental fixed-income investments with higher yields - at greater risk - than governmental investments.) The Fund's net asset value (NAV) rose from $9.92 to $9.99 over the period, supported by a strengthening in prices within the credit-sensitive sectors. During the 12-month period, the Fund's outperformance relative to its benchmark, the BofA ML 3-Month U.S. Dollar LIBOR Index, received support from the portfolio's allocations to credit-based areas of the fixed-income market. More specifically, the leading contributor to the Fund's benchmark-relative performance during the period was the portfolio's allocation to floating-rate commercial mortgage-backed securities (CMBS), as improvements in the employment backdrop and consumer sentiment, as well as declining airfares, bolstered the fundamentals for hotels and other leisure properties. While the Fund mainly focuses on the investment-grade sectors, we also include below-investment-grade assets in the portfolio in areas where we believe the incremental income available provides an attractive tradeoff between risk and reward. In that vein, the portfolio's allocation to * Diversification does not assure a profit nor protect against loss. 6 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 floating-rate, leveraged bank loans was another leading contributor to positive benchmark-relative returns, as credit spreads narrowed over the 12 months and the recovery and stabilization in oil prices aided that segment of the market. We reduced the Fund's loan positions as the period progressed, as new loan issuance is unfavorable from a quality perspective, in our opinion. In addition, many higher-rated loans are trading above par (face value), without call protection. That said, with the recent rise in LIBOR rates, most loans have reset to at least their floor rates, meaning that yields and valuations in the loan market are poised to benefit from any further interest-rate increases. (LIBOR floors ensure that investors in the loans receive some minimum base level of compensation in addition to the credit spread the loan pays.) Another positive contributor to the Fund's benchmark-relative returns during the period was a portfolio allocation to event-linked securities ("catastrophe," or cat bonds), which are used by property/casualty insurers and reinsurers looking to mitigate the risk of having to pay claims after a natural disaster. In addition to providing the Fund with incremental income, cat bonds have a very low correlation to other areas of the bond market; therefore, we view the issues as a valuable source of portfolio diversification. (Correlation represents the degree to which assets or asset class prices have moved in relation to one another.) We are careful to extensively diversify the Fund's holdings within the cat bond sector by both the type of peril (for example, hurricanes, floods, and earthquakes), and geographic region. The performance of the cat bonds benefited the Fund's returns as the period saw relatively modest claims activity. The portfolio held no positions that detracted materially from the Fund's benchmark-relative performance during the period. While we manage the Fund with a focus on total return, we are mindful that many investors also view the Fund as a source of liquidity in their portfolios. As such, we make sure to maintain significant portfolio liquidity in an effort to help reduce fluctuations in the Fund's NAV. Q Can you discuss the factors that affected the Fund's income-generation, or yield, during the 12-month period ended March 31, 2017? A The Fund's income benefited over the period from the increase in short-term LIBOR rates. As noted earlier, throughout the period the bulk of the Fund's investments were in floating-rate issues with interest rates tied to LIBOR, or another short-term reference rate. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 7 U.S. regulators, increasingly focused on the "shadow banking system," set October 14, 2016, as a deadline for non-government money market funds to meet new guidelines regarding floating net asset values and redemption gates. The impending change caused many money market fund complexes to transform prime money market funds into government funds. That activity sparked an increase in LIBOR rates beginning in mid-June 2016, thus benefiting holders of floating-rate securities, given that the payouts for a majority of floating-rate instruments have benchmarks to the one-month or three-month LIBOR. LIBOR rates also rose over the course of the period due to anticipation of the Fed ramping-up its monetary tightening process by increasing the overnight lending rate. Q Did you use any derivative strategies in managing the Fund during the 12-month period ended March 31, 2017? A No. The Fund had no exposure to derivatives during the period. Q What is your assessment of the current investment climate for the Fund, and how have you positioned the Fund's portfolio based on that view? A We believe that conditions remain supportive of credit-sector fundamentals, as reflected in strong economic data releases around such areas as manufacturing and employment. Measures of business and consumer confidence have moved higher as well. The Fund's fiscal year ended amidst significant uncertainty regarding the prospects for the implementation of some aspects of President Trump's pro-growth agenda. However, in our view, the ongoing environment of moderate growth and contained inflation underpinned the recent rally in risk assets as much or more than the market's anticipation of the new administration's economic proposals. Of course, there are reasons for caution with respect to the credit market outlook. Upcoming elections in Europe, most imminently in France, feature populist parties running on anti-globalization, anti-trade platforms. The degree to which these parties achieve electoral success would represent a threat to the stability of the world's largest trading block, and to sentiment among global risk investors. Geopolitics aside, market valuations are notably higher and spreads notably tighter following the extended period of outperformance by credit-oriented assets. 8 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Given current conditions, we have increased the Fund's liquidity and are maintaining relatively low exposure to changing spreads within the portfolio's core, credit-oriented allocation. As always, we are taking care not to assume any risk for which the Fund is not seeking adequate compensation. While the portfolio's sector allocations will shift around the margins to reflect our view of relative risk and reward, the Fund's portfolio continues to be broadly diversified with respect to its allocation across asset categories. In all investment environments, however, we will continue to seek to provide shareholders with higher income than cash vehicles, albeit with additional risk, while striving to provide protection against any future rise in market interest rates. (Please note that the Fund is not a money market fund.) Please refer to the Schedule of Investments on pages 21-93 for a full listing of Fund securities. All investments are subject to risk, including the possible loss of principal. In the past several years, financial markets have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty. These conditions may continue, recur, worsen or spread. Pioneer Multi-Asset Ultrashort Income Fund ("The Fund") has the ability to invest in a wide variety of debt securities. The Fund may invest in underlying funds (including ETFs). In addition to the Fund's operating expenses, you will indirectly bear the operating expenses of investments in any underlying funds. The Fund and some of the underlying funds may utilize strategies that have a leveraging effect on the Fund, which increases the volatility of investment returns and subjects the Fund to magnified losses if the Fund's or an underlying fund's investments decline in value. The Fund and some of the underlying funds may use derivatives, such as options and futures, which can be illiquid, may disproportionately increase losses, and have a potentially large impact on Fund performance. The Fund may invest in inflation-linked securities. As inflationary expectations increase, inflation-linked securities may become more attractive, because they protect future interest payments against inflation. Conversely, as inflationary concerns decrease, inflation-linked securities will become less attractive and less valuable. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 9 The Fund may invest in credit default swaps, which may in some cases be illiquid, and they increase credit risk since the Fund has exposure to both the issuer of the referenced obligation and the counterparty to the credit default swap. The Fund may invest in subordinated securities which may be disproportionately adversely affected by a default or even a perceived decline in creditworthiness of the issuer. The Fund may invest in floating-rate loans. The value of collateral, if any, securing a floating-rate loan can decline or may be insufficient to meet the issuer's obligations or may be difficult to liquidate. The Fund may invest in event-linked bonds. The return of principal and the payment of interest on event-linked bonds are contingent on the non-occurrence of a pre-defined "trigger" event, such as a hurricane or an earthquake of a specific magnitude. The Fund may invest in zero-coupon bonds and payment-in-kind securities, which may be more speculative and fluctuate more in value than other fixed income securities. The accrual of income from these securities are payable as taxable annual dividends to shareholders. Investments in equity securities are subject to price fluctuation. International investments are subject to special risks including currency fluctuations, social, economic and political uncertainties, which could increase volatility. These risks are magnified in emerging markets. Investments in fixed-income securities involve interest rate, credit, inflation, and reinvestment risks. As interest rates rise, the value of fixed income securities generally falls. The Fund may invest in mortgage-backed securities, which during times of fluctu- ating interest rates may increase or decrease more than other fixed-income securities. Mortgage-backed securities are also subject to pre-payments. Prepayment risk is the chance that an issuer may exercise its right to prepay its security, if falling interest rates prompt the issuer to do so. Forced to reinvest the unanticipated proceeds at lower interest rates, the Fund would experience a decline in income and lose the opportunity for additional price appreciation. High yield bonds possess greater price volatility, illiquidity, and possibility of default. 10 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 There may be insufficient or illiquid collateral securing the floating rate loans held within the Fund. This may reduce the future redemption or recovery value of such loans. The Fund may have disadvantaged access to confidential information that could be used to assess a loan issuer, as Pioneer normally seeks to avoid receiving material, non-public information. Pioneer Multi-Asset Ultrashort Income Fund is not a money market fund. These risks may increase share price volatility. There is no assurance that these and other strategies used by the Fund or underlying funds will be successful. Please see the prospectus for a more complete discussion of the Fund's risks. Before investing, consider the product's investment objectives, risks, charges and expenses. Contact your advisor or Pioneer Investments for a prospectus or summary prospectus containing this information. Read it carefully. Any information in this shareholder report regarding market or economic trends or the factors influencing the Fund's historical or future performance are statements of opinion as of the date of this report. Past performance is no guarantee of future results. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 11 Portfolio Summary | 3/31/17 Portfolio Diversification* -------------------------------------------------------------------------------- (As a percentage of total investment portfolio) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] Asset Backed Securities 27.8% Collateralized Mortgage Obligations 24.5% U.S. Corporate Bonds 19.2% U.S. Government Securities 9.2% International Corporate Bonds 9.1% Senior Secured Loans 5.0% Temporary Cash Investments 4.8% Municipal Bonds 0.4% * Includes investments in Insurance Linked Securities totaling 5.6% of total investment portfolio. 10 Largest Holdings -------------------------------------------------------------------------------- (As a percentage of total long-term holdings)** 1. U.S. Treasury Notes, Floating Rate Note, 10/31/17 1.54% ----------------------------------------------------------------------------------------- 2. U.S. Treasury Notes, Floating Rate Note, 1/31/19 1.51 ----------------------------------------------------------------------------------------- 3. U.S. Treasury Notes, Floating Rate Note, 7/31/18 1.48 ----------------------------------------------------------------------------------------- 4. U.S. Treasury Notes, Floating Rate Note, 10/31/18 1.47 ----------------------------------------------------------------------------------------- 5. U.S. Treasury Notes, Floating Rate Note, 1/31/18 1.47 ----------------------------------------------------------------------------------------- 6. U.S. Treasury Notes, Floating Rate Note, 4/30/18 1.46 ----------------------------------------------------------------------------------------- 7. Everglades Re, Ltd., Floating Rate Note, 4/28/17 (Cat Bond) (144A) 0.57 ----------------------------------------------------------------------------------------- 8. U.S. Treasury Bill, 4/13/17 0.50 ----------------------------------------------------------------------------------------- 9. Government National Mortgage Association REMICS, Floating Rate Note, 1/20/47 0.45 ----------------------------------------------------------------------------------------- 10. Federal National Mortgage Association, Floating Rate Note, 2/25/38 0.33 ----------------------------------------------------------------------------------------- ** This list excludes temporary cash investments and derivative instruments. The portfolio is actively managed and current holdings may be different. The holdings listed should not be considered recommendations to buy or sell any security listed. 12 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Prices and Distributions | 3/31/17 Net Asset Value per Share -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Class 3/31/17 3/31/16 -------------------------------------------------------------------------------- A $9.99 $9.92 -------------------------------------------------------------------------------- C $9.97 $9.91 -------------------------------------------------------------------------------- C2 $9.97 $9.91 -------------------------------------------------------------------------------- K $9.99 $9.93 -------------------------------------------------------------------------------- Y $9.99 $9.93 -------------------------------------------------------------------------------- Distributions per Share: 4/1/16-3/31/17 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Short-Term Long-Term Class Dividends Capital Gains Capital Gains -------------------------------------------------------------------------------- A $0.1699 $ -- $ -- -------------------------------------------------------------------------------- C $0.1379 $ -- $ -- -------------------------------------------------------------------------------- C2 $0.1376 $ -- $ -- -------------------------------------------------------------------------------- K $0.1913 $ -- $ -- -------------------------------------------------------------------------------- Y $0.1821 $ -- $ -- -------------------------------------------------------------------------------- The Bank of America Merrill Lynch U.S. Dollar 3-Month LIBOR Index is an unmanaged index that tracks the performance of a synthetic asset paying the London Interbank Offered Rate (LIBOR), with a constant 3-month average maturity. The index is based on the assumed purchase at par value of a synthetic instrument having exactly its stated maturity and with a coupon equal to that day's 3-month LIBOR rate. Index returns assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. It is not possible to invest directly in an index. The index defined here pertains to the "Value of $10,000 Investment" and "Value of $5 Million Investment" charts on pages 14-18. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 13 Performance Update | 3/31/17 Class A Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class A shares of Pioneer Multi-Asset Ultrashort Income Fund at public offering price during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML Net Public U.S. Dollar Asset Offering 3-Month Value Price LIBOR Period (NAV) (POP) Index -------------------------------------------------------------------------------- Life-of-Class (4/29/11) 1.34% 0.90% 0.39% 5 Years 1.29 0.77 0.40 1 Year 2.43 (0.08) 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.63% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Multi-Asset BofA ML U.S. Ultrashort Income Dollar 3-Month Fund LIBOR Index 4/11 $ 9,750 $10,000 3/12 $ 9,891 $10,032 3/13 $10,103 $10,075 3/14 $10,196 $10,103 3/15 $10,252 $10,126 3/16 $10,294 $10,159 3/17 $10,544 $10,234 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. NAV results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. POP returns reflect deduction of maximum 2.50% sales charge. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 14 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Performance Update | 3/31/17 Class C Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class C shares of Pioneer Multi-Asset Ultrashort Income Fund during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML U.S. Dollar 3-Month If If LIBOR Period Held Redeemed Index -------------------------------------------------------------------------------- Life-of-Class (4/29/11) 0.91% 0.91% 0.39% 5 Years 0.92 0.92 0.40 1 Year 2.00 2.00 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.94% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Multi-Asset BofA ML U.S. Ultrashort Income Dollar 3-Month Fund LIBOR Index 4/11 $10,000 $10,000 3/12 $10,082 $10,032 3/13 $10,243 $10,075 3/14 $10,298 $10,103 3/15 $10,333 $10,126 3/16 $10,345 $10,159 3/17 $10,552 $10,234 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. "If Held" results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 15 Performance Update | 3/31/17 Class C2 Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Class C2 shares of Pioneer Multi-Asset Ultrashort Income Fund during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML U.S. Dollar 3-Month If If LIBOR Period Held Redeemed Index -------------------------------------------------------------------------------- Life-of-Fund (4/29/11) 0.91% 0.91% 0.39% 5 Years 0.91 0.91 0.40 1 Year 2.00 2.00 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.94% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Multi-Asset BofA ML U.S. Ultrashort Income Dollar 3-Month Fund LIBOR Index 4/11 $10,000 $10,000 3/12 $10,082 $10,032 3/13 $10,243 $10,075 3/14 $10,297 $10,103 3/15 $10,331 $10,126 3/16 $10,342 $10,159 3/17 $10,549 $10,234 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class C2 shares held for less than 1 year are subject to a 1% contingent deferred sales charge (CDSC). "If Held" results represent the percentage change in net asset value per share. Returns would have been lower had sales charges been reflected. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. The performance shown for periods prior to the commencement of operations of Class C2 shares on August 1, 2013, is the net asset value performance of the Fund's Class C shares, which has not been restated to reflect any differences in expenses. For the period beginning August 1, 2013, the actual performance of Class C2 shares is reflected. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 16 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Performance Update | 3/31/17 Class K Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $5 million investment made in Class K shares of Pioneer Multi-Asset Ultrashort Income Fund during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML Net U.S. Dollar Asset 3-Month Value LIBOR Period (NAV) Index -------------------------------------------------------------------------------- Life-of-Fund (4/29/11) 1.50% 0.39% 5 Years 1.47 0.40 1 Year 2.55 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.42% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Pioneer Multi-Asset BofA ML U.S. Ultrashort Income Dollar 3-Month Fund LIBOR Index 4/11 $5,000,000 $5,000,000 3/12 $5,074,193 $5,016,143 3/13 $5,185,973 $5,037,507 3/14 $5,246,391 $5,051,252 3/15 $5,290,155 $5,063,025 3/16 $5,323,885 $5,079,487 3/17 $5,459,537 $5,116,913 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. The performance shown for Class K shares for the period prior to the commencement of operations of Class K shares on December 20, 2012, is the net asset value performance of the Fund's Class A shares, which has not been restated to reflect any differences in expenses, including Rule 12b-1 fees applicable to Class A shares. Since fees for Class A shares generally are higher than those of Class K shares, the performance of Class K shares prior to their inception would have been higher than the performance shown. For the period beginning on December 20, 2012, the actual performance of Class K shares is reflected. Class K shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 17 Performance Update | 3/31/17 Class Y Shares Investment Returns -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $5 million investment made in Class Y shares of Pioneer Multi-Asset Ultrashort Income Fund during the periods shown, compared to that of the Bank of America (BofA) Merrill Lynch (ML) U.S. Dollar 3-Month LIBOR Index. Average Annual Total Returns (As of March 31, 2017) -------------------------------------------------------------------------------- BofA ML Net U.S. Dollar Asset 3-Month Value LIBOR Period (NAV) Index -------------------------------------------------------------------------------- Life-of-Class (4/29/11) 1.50% 0.39% 5 Years 1.42 0.40 1 Year 2.46 0.74 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated August 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.51% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Pioneer Multi-Asset BofA ML U.S. Ultrashort Income Dollar 3-Month Fund LIBOR Index 4/11 $5,000,000 $5,000,000 3/12 $5,089,498 $5,016,143 3/13 $5,208,889 $5,037,507 3/14 $5,260,398 $5,051,252 3/15 $5,302,158 $5,063,025 3/16 $5,331,017 $5,079,487 3/17 $5,461,860 $5,116,913 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class Y shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 18 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Comparing Ongoing Fund Expenses As a shareowner in the Fund, you incur two types of costs: (1) ongoing costs, including management fees, distribution and/or service (12b-1) fees, and other Fund expenses; and (2) transaction costs, including sales charges (loads) on purchase payments. This example is intended to help you understand your ongoing expenses (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. The example is based on an investment of $1,000 at the beginning of the Fund's latest six-month period and held throughout the six months. Using the Tables -------------------------------------------------------------------------------- Actual Expenses The first table below provides information about actual account values and actual expenses. You may use the information in this table, together with the amount you invested, to estimate the expenses that you paid over the period as follows: (1) Divide your account value by $1,000 Example: an $8,600 account value (divided by) $1,000 = 8.6 (2) Multiply the result in (1) above by the corresponding share class's number in the third row under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period. Expenses Paid on a $1,000 Investment in Pioneer Multi-Asset Ultrashort Income Fund Based on actual returns from October 1, 2016, through March 31, 2017. ---------------------------------------------------------------------------------------- Share Class A C C2 K Y ---------------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 $1,000.00 $1,000.00 Value on 10/1/16 ---------------------------------------------------------------------------------------- Ending Account Value $1,010.36 $1,007.71 $1,007.71 $1,010.44 $1,009.86 (after expenses) on 3/31/17 ---------------------------------------------------------------------------------------- Expenses Paid $ 3.06 $ 4.66 $ 4.66 $ 2.11 $ 2.51 During Period* ---------------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.61%, 0.93%, 0.93%, 0.42% and 0.50% for Class A, Class C, Class C2, Class K, and Class Y respectively, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half year period). Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 19 Hypothetical Example for Comparison Purposes The table below provides information about hypothetical account values and hypothetical expenses based on the Fund's actual expense ratio and an assumed rate of return of 5% per year before expenses, which is not the Fund's actual return. The hypothetical account values and expenses may not be used to estimate the actual ending account balance or expenses you paid for the period. You may use this information to compare the ongoing costs of investing in the Fund and other funds. To do so, compare this 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of the other funds. Please note that the expenses shown in the tables are meant to highlight your ongoing costs only and do not reflect any transaction costs, such as sales charges (loads) that are charged at the time of the transaction. Therefore, the table below is useful in comparing ongoing costs only and will not help you determine the relative total costs of owning different funds. In addition, if these transaction costs were included, your costs would have been higher. Expenses Paid on a $1,000 Investment in Pioneer Multi-Asset Ultrashort Income Fund Based on a hypothetical 5% return per year before expenses, reflecting the period from October 1, 2016, through March 31, 2017. ---------------------------------------------------------------------------------------- Share Class A C C2 K Y ---------------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 $1,000.00 $1,000.00 Value on 10/1/16 ---------------------------------------------------------------------------------------- Ending Account Value $1,021.89 $1,020.29 $1,020.29 $1,022.84 $1,022.44 (after expenses) on 3/31/17 ---------------------------------------------------------------------------------------- Expenses Paid $ 3.07 $ 4.68 $ 4.68 $ 2.12 $ 2.52 During Period* ---------------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.61%, 0.93%, 0.93%, 0.42% and 0.50% for Class A, Class C, Class C2, Class K, and Class Y respectively, multiplied by the average account value over the period, multiplied by 182/365 (to reflect the one-half year period). 20 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Schedule of Investments | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- 28.4% ENERGY -- 0.7% Oil & Gas Exploration & Production -- 0.7% 4,543,471 AXIS Equipment Finance Receivables IV LLC, 2.21%, 11/20/21 (144A) $ 4,517,972 686,700 DT Auto Owner Trust 2016-2, 1.73%, 8/15/19 (144A) 686,908 2,737,424 GCAT 2015-2, 3.75%, 7/25/20 (Step) (144A) 2,739,157 6,800,000 1.73 Master Credit Card Trust II Series 2016-1, Floating Rate Note, 9/23/19 (144A) 6,825,876 3,000,000 2.48 NCF Dealer Floorplan Master Trust, Floating Rate Note, 10/20/20 (144A) 2,974,760 3,088,437 PRPM 2016-1 LLC, 4.0%, 9/27/21 (Step) (144A) 3,074,803 2,551,666 WVUE 2015-1, 4.5%, 9/25/20 (Step) (144A) 2,561,803 ------------- $ 23,381,279 ------------- Total Energy $ 23,381,279 ----------------------------------------------------------------------------------------------------------- MATERIALS -- 0.6% Steel -- 0.6% 1,662,889 1.70 First NLC Trust 2005-2, Floating Rate Note, 9/25/35 $ 1,631,317 6,000,000 1.27 Home Equity Asset Trust 2005-6, Floating Rate Note, 12/25/35 5,902,770 195,396 1.70 Mastr Asset Backed Securities Trust 2005-WMC1, Floating Rate Note, 3/25/35 191,869 124,298 1.63 New Century Home Equity Loan Trust 2005-2 REMICS, Floating Rate Note, 6/25/35 124,202 575,000 1.66 New Century Home Equity Loan Trust 2005-2 Series 2005-2 Cl M2, Floating Rate Note, 6/25/35 564,136 889,596 1.64 Option One Mortgage Loan Trust 2005-1, Floating Rate Note, 2/25/35 880,641 3,946,000 1.42 Option One Mortgage Loan Trust 2005-4 Asset-Backed Certificates Series 2005-4, Floating Rate Note, 11/25/35 3,874,832 603,449 1.22 RASC Series 2005-AHL3 Trust, Floating Rate Note, 9/25/35 601,164 5,100,000 1.44 Wells Fargo Home Equity Asset-Backed Securities 2005-2 Trust, Floating Rate Note, 11/25/35 5,089,183 ------------- $ 18,860,114 ------------- Total Materials $ 18,860,114 ----------------------------------------------------------------------------------------------------------- TRANSPORTATION -- 0.1% Trucking -- 0.1% 231,664 1.26 Hertz Fleet Lease Funding LP, Floating Rate Note, 4/10/28 (144A) $ 231,625 3,600,000 4.21 Hertz Fleet Lease Funding LP, Floating Rate Note, 4/10/30 (144A) 3,735,061 ------------- $ 3,966,686 ------------- Total Transportation $ 3,966,686 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 21 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.1% Hotels, Resorts & Cruise Lines -- 0.1% 1,068,902 Westgate Resorts 2014-1 LLC, 2.15%, 12/20/26 (144A) $ 1,058,426 ------------- Total Consumer Services $ 1,058,426 ----------------------------------------------------------------------------------------------------------- RETAILING -- 0.0%+ Automotive Retail -- 0.0%+ 550,000 2.36 Hertz Fleet Lease Funding LP Series 2014-1 Cl D, Floating Rate Note, 4/10/28 (144A) $ 549,257 ------------- Total Retailing $ 549,257 ----------------------------------------------------------------------------------------------------------- BANKS -- 24.5% Diversified Banks -- 0.0%+ 5,143 1.34 KeyCorp Student Loan Trust 2004-A, Floating Rate Note, 10/28/41 $ 5,138 ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- 24.5% 4,241,270 1.14 321 Henderson Receivables I LLC, Floating Rate Note, 11/15/40 (144A) $ 4,027,235 3,884,033 1.11 321 Henderson Receivables I LLC, Floating Rate Note, 12/15/41 (144A) 3,783,139 744,810 1.11 321 Henderson Receivables I LLC, Floating Rate Note, 3/15/41 (144A) 724,056 555,638 1.26 321 Henderson Receivables I LLC, Floating Rate Note, 9/15/45 (144A) 539,257 2,333,378 1.11 321 Henderson Receivables II LLC, Floating Rate Note, 9/15/41 (144A) 2,197,982 706,952 1.73 ABFC 2005-HE2 Trust, Floating Rate Note, 6/25/35 702,641 169,498 1.60 ABFC 2005-WF1 Trust, Floating Rate Note, 12/25/34 169,504 2,289,223 1.66 ABFC 2005-WMC1 Trust, Floating Rate Note, 6/25/35 2,235,753 63,789 1.38 Accredited Mortgage Loan Trust 2005-2, Floating Rate Note, 7/25/35 63,736 2,265,041 1.18 ACE Securities Corp Home Equity Loan Trust Series 2006-ASAP2, Floating Rate Note, 3/25/36 2,220,222 395,574 1.45 Aegis Asset Backed Securities Trust 2005-3, Floating Rate Note, 8/25/35 392,155 136,164 2.08 Aegis Asset Backed Securities Trust Mortgage Pass- Through Certificates Series 2004-3, Floating Rate Note, 9/25/34 136,085 597,355 2.08 Aegis Asset Backed Securities Trust Mortgage Pass-Through Certificates Series 2004-4, Floating Rate Note, 10/25/34 594,606 112,657 1.35 Aegis Asset Backed Securities Trust Mortgage Pass-Through Certificates Series 2005-4, Floating Rate Note, 10/25/35 111,912 4,600,000 1.31 Ally Master Owner Trust, Floating Rate Note, 2/15/21 4,609,492 1,463,418 3.20 Alterna Funding II LLC, Series 2015-1A Class B, Floating Rate Note, 2/15/24 (144A) 1,452,442 The accompanying notes are an integral part of these financial statements. 22 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 553,839 American Credit Acceptance Receivables Trust 2015-3, 1.95%, 9/12/19 (144A) $ 553,870 365,358 American Credit Acceptance Receivables Trust 2016-1A, 2.37%, 5/12/20 (144A) 365,661 4,100,000 American Credit Acceptance Receivables Trust 2017-1, 2.39%, 2/16/21 (144A) 4,099,391 235,000 2.17 American Express Credit Account Master Trust Series 2008-2 Class A, Floating Rate Note, 9/15/20 237,422 2,600,000 1.20 American Express Credit Account Master Trust, Floating Rate Note, 1/15/20 2,601,362 475,000 1.01 American Express Credit Account Secured Note Trust 2012-4, Floating Rate Note, 5/15/20 475,446 2,000,000 2.26 American Homes 4 Rent 2014-SFR1, Floating Rate Note, 6/17/31 1,995,896 812,810 1.60 AmeriCredit Automobile Receivables 2015-4, Floating Rate Note, 4/8/19 813,326 2,204,832 1.60 AmeriCredit Automobile Receivables 2016-1, Floating Rate Note, 6/10/19 2,207,772 1,575,454 1.41 Americredit Automobile Receivables Trust 2016-3 Series 2016-3 Class A2B, Floating Rate Note, 11/8/19 1,578,217 2,700,000 1.28 AmeriCredit Automobile Receivables Trust, Floating Rate Note, 5/18/20 2,700,544 1,147,042 1.47 Ameriquest Mortgage Securities, Inc., Asset-Backed Pass-Through Ctfs Ser 2005-R5, Floating Rate Note, 7/25/35 1,144,167 237,562 1.31 Ameriquest Mortgage Securities, Inc., Asset Backed Pass-Through Ctfs Series 2005-R11, Floating Rate Note, 1/25/36 235,254 8,866 4.73 Ameriquest Mortgage Securities, Inc., Asset-Backed Pass-Through Ctfs Series 03-AR3, Floating Rate Note, 6/25/33 8,865 220,163 1.59 Ameriquest Mortgage Securities, Inc., Asset-Backed Pass-Through Ctfs Series 2004-R11, Floating Rate Note, 11/25/34 220,083 183,925 1.66 Ameriquest Mortgage Securities, Inc., Asset-Backed Pass-Through Ctfs Series 2005-R1, Floating Rate Note, 3/25/35 184,025 305,711 1.32 Argent Securities Inc Asset-Backed Pass-Through Certificates Series 2005-W3, Floating Rate Note, 11/25/35 299,109 36,269 ARI Fleet Lease Trust 2014-A, 0.81%, 11/15/22 (144A) 36,259 410,000 Ascentium Equipment Receivables 2015-1 LLC, 5.92%, 6/12/23 (144A) 422,573 2,818,000 Ascentium Equipment Receivables 2016-2 Trust, 1.46%, 4/10/19 (144A) 2,813,551 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 23 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 30,082 1.69 Asset Backed Securities Corp., Home Equity Loan Trust Series 2005-HE3, Floating Rate Note, 4/25/35 $ 30,054 559,903 1.18 Asset Backed Securities Corp., Home Equity Loan Trust Series AEG 2006-HE1, Floating Rate Note, 1/25/36 549,400 1,274,330 1.93 Asset Backed Securities Corp., Home Equity Loan Trust Series NC 2005-HE4, Floating Rate Note, 5/25/35 1,249,126 1,254,863 1.41 Asset Backed Securities Corp., Home Equity Loan Trust Series NC 2005-HE8, Floating Rate Note, 11/25/35 1,238,947 309,513 1.75 Asset Backed Securities Corp., Home Equity Loan Trust Series OOMC 2005-HE6, Floating Rate Note, 7/25/35 310,017 72,222 1.67 Asset-Backed Pass-Through Certificates Series 2004-R2, Floating Rate Note, 4/25/34 71,443 664,110 1.60 Asset-Backed Pass-Through Certificates Series 2004-R2, Floating Rate Note, 4/25/34 656,100 270,000 1.30 BA Credit Card Trust, Floating Rate Note, 10/15/21 271,766 1,800,000 1.11 Barclays Dryrock Issuance Trust, Floating Rate Note, 3/16/20 1,800,496 30,154 Bayview Financial Acquisition Trust, 6.205%, 5/28/37 (Step) 31,096 327,539 1.96 Bayview Financial Acquisition Trust, Floating Rate Note, 5/28/44 327,765 239,221 1.99 Bayview Financial Acquisition Trust, Floating Rate Note, 8/28/44 239,050 1,167,025 1.73 Bayview Financial Mortgage Pass-Through Trust 2005-C, Floating Rate Note, 6/28/44 1,163,693 73,394 1.28 Bayview Financial Mortgage Pass-Through Trust 2006-B, Floating Rate Note, 4/28/36 73,247 57,379 1.25 Bayview Financial Mortgage Pass-Through Trust 2006-B, Floating Rate Note, 4/28/36 57,263 111,462 2.22 Bcc Funding Corp., X Series 2015-1 Class A2, Floating Rate Note, 10/20/20 (144A) 111,372 1,544,123 1.73 Bear Stearns Asset Backed Securities I Trust 2005-FR1, Floating Rate Note, 6/25/35 1,535,392 226,721 1.46 Bear Stearns Asset Backed Securities I Trust 2005-HE12, Floating Rate Note, 12/25/35 223,220 1,751,533 1.44 Bear Stearns Asset Backed Securities I Trust 2005-TC1, Floating Rate Note, 5/25/35 1,729,521 2,887,334 1.38 Bear Stearns Asset Backed Securities I Trust 2006-EC2, Floating Rate Note, 2/25/36 2,788,857 252,298 2.18 Bear Stearns Asset Backed Securities Trust 2004-2, Floating Rate Note, 8/25/34 252,656 212,683 1.55 Bear Stearns Asset Backed Securities Trust 2004-SD3, Floating Rate Note, 9/25/34 210,865 22,283 1.38 Bear Stearns Asset Backed Securities Trust 2005-SD1, Floating Rate Note, 8/25/43 22,132 493,418 1.45 Bear Stearns Asset Backed Securities Trust 2005-SD2, Floating Rate Note, 3/25/35 491,545 The accompanying notes are an integral part of these financial statements. 24 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 507,360 1.38 Bear Stearns Asset Backed Securities Trust 2005-SD2, Floating Rate Note, 3/25/35 $ 505,144 981,164 1.35 Bear Stearns Asset Backed Securities Trust 2006-SD1, Floating Rate Note, 4/25/36 956,014 2,429,731 1.36 Bear Stearns Asset Backed Securities Trust 2006-SD2, Floating Rate Note, 6/25/36 2,384,620 391,048 1.47 Bear Stearns Asset Backed Securities Trust 2006-SD2, Floating Rate Note, 6/25/36 384,336 402,087 1.98 Bear Stearns Structured Products Trust 2007-EMX1, Floating Rate Note, 3/25/37 (144A) 399,274 2,895,000 1.25 Cabela's Credit Card Master Note Trust, Floating Rate Note, 6/15/20 (144A) 2,896,463 2,700,000 1.62 Cabela's Credit Card Master Note Trust, Floating Rate Note, 6/15/22 2,732,278 2,289,293 California Republic Auto Receivables Trust 2016-2, 1.34%, 3/15/19 2,288,562 1,050,000 California Republic Auto Receivables Trust 2016-2, 1.56%, 7/15/20 1,047,923 2,100,000 California Republic Auto Receivables Trust 2017-1, 1.55%, 11/15/19 2,097,172 4,157,907 CAM Mortgage Trust 2016-2, 3.25%, 6/15/57 (Step) (144A) 4,127,304 1,095,015 1.68 Capital Auto Receivables Asset Trust 2016-1, Floating Rate Note, 11/20/18 1,096,430 19,000 CarMax Auto Owner Trust 2013-1, 1.99%, 8/15/19 19,001 750,757 1.51 CarMax Auto Owner Trust 2015-4, Floating Rate Note, 4/15/19 751,429 1,054,764 1.44 CarMax Auto Owner Trust 2016-1, Floating Rate Note, 4/15/19 1,056,215 2,185,422 1.16 Carrington Mortgage Loan Trust Series 2006-OPT1, Floating Rate Note, 12/26/35 2,145,728 926,453 Cazenovia Creek Funding I LLC, 2.0%, 12/10/23 (144A) 920,084 564,990 Cazenovia Creek Funding I LLC, 2.773%, 12/10/23 (144A) 558,815 1,058,997 CCG Receivables Trust 2014-1, 1.06%, 11/15/21 (144A) 1,058,516 2,006,602 CCG Receivables Trust 2016-1, 1.69%, 9/14/22 (144A) 2,004,995 5,028,456 2.14 Cent CLO, Floating Rate Note, 8/1/24 (144A) 5,020,712 280,579 3.65 Centex Home Equity Loan Trust 2003-A, Floating Rate Note, 3/25/33 280,040 2,700,000 1.08 Chase Issuance Trust, Floating Rate Note, 1/18/22 2,706,751 200,000 1.17 Chase Issuance Trust, Floating Rate Note, 12/16/19 200,288 2,420,000 1.19 Chase Issuance Trust, Floating Rate Note, 4/15/20 2,424,326 7,750,000 1.02 Chase Issuance Trust, Floating Rate Note, 5/15/19 7,751,613 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 25 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 4,500,000 1.29 Chase Issuance Trust, Series 2017-A2 Class A, Floating Rate Note, 3/15/24 $ 4,510,899 2,401,593 2.06 Chesapeake Funding II LLC, Floating Rate Note, 3/15/28 (144A) 2,413,585 2,600,000 1.91 Chesapeake Funding II LLC, Floating Rate Note, 6/15/28 (144A) 2,612,970 1,250,000 Citibank Credit Card Issuance Trust, 1.23%, 4/24/19 1,250,074 4,700,000 1.19 Citibank Credit Card Issuance Trust, Floating Rate Note, 1/19/21 4,705,912 7,984,000 2.13 Citibank Credit Card Issuance Trust, Floating Rate Note, 1/23/20 8,053,177 4,050,000 2.35 Citibank Credit Card Issuance Trust, Floating Rate Note, 5/20/20 4,109,219 2,980,000 1.26 Citibank Credit Card Issuance Trust, Floating Rate Note, 5/26/20 2,985,959 1,050,000 1.29 Citibank Credit Card Issuance Trust, Floating Rate Note, 9/10/20 1,054,291 1,673,076 Citicorp Residential Mortgage Trust Series 2006-1, 5.54836%, 7/25/36 (Step) 1,690,152 211,944 1.18 Citigroup Mortgage Loan Trust 2006-SHL1, Floating Rate Note, 11/27/45 (144A) 211,644 37,122 1.16 Citigroup Mortgage Loan Trust 2007-WFHE2, Floating Rate Note, 3/25/37 37,091 744,983 1.66 Citigroup Mortgage Loan Trust Series 2005-Opt3 Asset B Series 2005-Opt3 Class M2, Floating Rate Note, 5/25/35 741,144 176,825 2.00 Citigroup Mortgage Loan Trust, Inc., Floating Rate Note, 11/25/34 171,553 1,181,100 1.73 Citigroup Mortgage Loan Trust, Inc., Floating Rate Note, 5/25/35 (144A) 1,177,348 583,704 CNH Equipment Trust 2013-B, 0.99%, 11/15/18 583,549 3,700,000 2.76 Colony American Homes 2014-1, Floating Rate Note, 5/19/31 (144A) 3,699,995 2,000,000 4.11 Colony American Homes 2014-2 REMICS, Floating Rate Note, 7/17/31 (144A) 1,999,994 1,150,000 3.56 Colony Starwood Homes 2016-1 Trust, Floating Rate Note, 7/17/33 (144A) 1,172,372 829,203 2.43 Commonbond Student Loan Trust 2016-B, Floating Rate Note, 10/25/40 (144A) 839,342 204,119 Conn's Receivables Funding 2016-A LLC, 4.68%, 4/16/18 (144A) 204,339 1,996,393 Conn's Receivables Funding 2016-B LLC, 3.73%, 10/15/18 (144A) 2,001,939 314,224 3.27 Conseco Finance Home Equity Loan Trust 2002-B, Floating Rate Note, 6/15/32 305,311 158,562 2.27 Conseco Finance Home Equity Loan Trust 2002-C, Floating Rate Note, 4/15/32 155,577 328 Conseco Financial Corp., 7.05%, 1/15/19 328 The accompanying notes are an integral part of these financial statements. 26 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 18,198 Consumer Credit Origination Loan Trust 2015-1, 2.82%, 3/15/21 (144A) $ 18,198 616,997 1.04 Countrywide Asset-Backed Certificates Series 2006-4 Class 1A1M, Floating Rate Note, 7/25/36 608,312 41,464 1.72 Countrywide Asset-Backed Certificates, Floating Rate Note, 12/25/35 41,478 1,656,429 1.88 Countrywide Asset-Backed Certificates, Floating Rate Note, 3/25/35 1,642,088 156,863 1.66 Countrywide Asset-Backed Certificates, Floating Rate Note, 6/25/33 (144A) 153,094 33,536 1.88 Countrywide Asset-Backed Certificates, Floating Rate Note, 6/25/33 (144A) 32,663 578,764 CPS Auto Receivables Trust 2015-B, 1.65%, 11/15/19 (144A) 578,669 1,247,170 CPS Auto Receivables Trust 2016-A, 2.25%, 10/15/19 (144A) 1,251,206 400,000 CPS Auto Receivables Trust 2016-C, 2.48%, 9/15/20 (144A) 399,817 1,893,933 CPS Auto Trust, 1.5%, 6/15/20 (144A) 1,889,697 1,962,679 CPS Auto Trust, 1.68%, 8/17/20 (144A) 1,960,354 1,312,302 1.63 Credit Suisse First Boston Mortgage Securities Corp., Floating Rate Note, 2/25/32 1,284,574 1,084,959 1.05 Credit Suisse Mortgage Capital Certificates, Floating Rate Note, 10/27/36 (144A) 1,076,774 204,533 1.09 Credit-Based Asset Servicing & Securitization LLC, Floating Rate Note, 10/25/36 202,263 83,627 1.25 Credit-Based Asset Servicing & Securitization LLC, Floating Rate Note, 5/25/36 (144A) 83,293 235,197 1.64 Credit-Based Asset Servicing & Securitization LLC, Floating Rate Note, 7/25/34 234,722 848,815 1.08 Credit-Based Asset Servicing & Securitization LLC, Floating Rate Note, 7/25/36 849,487 58,181 1.99 CWABS Asset-Backed Certificates Trust 2004-10, Floating Rate Note, 1/25/35 58,301 3,360,458 2.03 CWABS Asset-Backed Certificates Trust 2004-7, Floating Rate Note, 12/25/34 3,358,735 5,898,788 1.21 CWABS Asset-Backed Certificates Trust 2005-14, Floating Rate Note, 4/25/36 5,861,462 7,104 1.33 CWABS Asset-Backed Certificates Trust 2005-14, Floating Rate Note, 4/25/36 7,105 498,093 1.88 Dell Equipment Finance Trust 2015-2, Floating Rate Note, 12/22/17 (144A) 498,514 277 Delta Funding Home Equity Loan Trust 1997-2, 7.04%, 6/25/27 275 5,915,000 1.12 Discover Card Execution Note Trust, Floating Rate Note, 8/17/20 5,928,047 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 27 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 2,796,270 2.78 DRB Prime Student Loan Trust 2016-B, Floating Rate Note, 6/25/40 (144A) $ 2,854,760 1,306,945 Drive Auto Receivables Trust 2015-D, 2.59%, 12/16/19 (144A) 1,309,788 2,998,706 Drive Auto Receivables Trust 2016-C, 1.41%, 1/15/19 (144A) 2,998,809 2,800,000 Drive Auto Receivables Trust 2017-A, 1.48%, 3/15/19 (144A) 2,799,130 2,000,000 2.20 Drive Auto Receivables Trust, 2017-B Series 2017-Ba Class B, Floating Rate Note, 5/15/20 (144A) 1,999,795 2,027,918 3.87 Drug Royalty II LP 2, Floating Rate Note, 7/15/23 (144A) 2,040,759 133,663 DT Auto Owner Trust 2015-3, 1.66%, 3/15/19 (144A) 133,662 259,774 DT Auto Owner Trust 2016-1, 2.0%, 9/16/19 (144A) 259,940 4,500,000 DT Auto Owner Trust 2017-1, 2.26%, 2/15/21 (144A) 4,493,110 2,469,351 2.83 Earnest Student Loan Program 2016-C LLC, Floating Rate Note, 10/27/36 (144A) 2,506,169 2,069,700 2.38 Earnest Student Loan Program 2016-D LLC, Floating Rate Note, 1/25/41 (144A) 2,103,665 348,199 1.88 Ellington Loan Acquisition Trust 2007-1, Floating Rate Note, 5/26/37 (144A) 348,073 88,836 Engs Commercial Finance Trust 2016-1, 1.25%, 11/22/17 (144A) 88,738 5,700,000 Engs Commercial Finance Trust 2016-1, 2.63%, 2/22/22 (144A) 5,688,114 1,464,867 Enterprise Fleet Financing LLC, 1.59%, 2/22/21 (144A) 1,464,924 2,000,000 Enterprise Fleet Financing LLC, 1.74%, 2/22/22 (144A) 1,995,702 3,550,000 1.41 Evergreen Credit Card Trust Series 2016-3, Floating Rate Note, 11/16/20 (144A) 3,563,802 615,832 Exeter Automobile Receivables Trust 2015-1, 1.6%, 6/17/19 (144A) 615,701 482,601 Exeter Automobile Receivables Trust 2015-2, 1.54%, 11/15/19 (144A) 482,352 3,437,643 Exeter Automobile Receivables Trust 2017-1, 1.96%, 3/15/21 (144A) 3,434,477 5,963,058 1.50 FBR Securitization Trust, Floating Rate Note, 10/25/35 5,796,124 296,426 1.72 FBR Securitization Trust, Floating Rate Note, 11/25/35 294,193 1,608,513 1.50 FFMLT Trust 2005-FF2, Floating Rate Note, 3/25/35 1,599,418 173,458 2.71 Fieldstone Mortgage Investment Trust Series 2004-5, Floating Rate Note, 2/25/35 172,795 5,852,105 1.23 Fieldstone Mortgage Investment Trust Series 2005-3, Floating Rate Note, 2/25/36 5,752,069 109,169 2.28 First Franklin Mortgage Loan Trust 2003-FFC, Floating Rate Note, 11/25/32 107,727 631,862 1.81 First Franklin Mortgage Loan Trust 2004-FF8, Floating Rate Note, 10/25/34 630,754 The accompanying notes are an integral part of these financial statements. 28 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 211,905 2.26 First Franklin Mortgage Loan Trust 2004-FFH4, Floating Rate Note, 1/25/35 $ 211,872 925,537 1.59 First Franklin Mortgage Loan Trust 2005-FFH2, Floating Rate Note, 4/25/35 (144A) 884,544 152,403 1.75 First Franklin Mortgage Loan Trust 2005-FFH3, Floating Rate Note, 9/25/35 152,381 3,382,320 1.20 First Franklin Mortgage Loan Trust 2006-FF1, Floating Rate Note, 1/25/36 3,359,470 685,748 1.22 First Franklin Mortgage Loan Trust 2006-FF1, Floating Rate Note, 1/25/36 682,761 625,265 1.24 First Franklin Mortgage Loan Trust Series 2005-FF12, Floating Rate Note, 11/25/36 620,956 1,733,404 First Investors Auto Owner Trust 2017-1, 1.69%, 4/15/21 (144A) 1,732,304 1,950,000 Flagship Credit Auto Trust 2013-1, 5.38%, 7/15/20 (144A) 1,966,322 1,375,224 Flagship Credit Auto Trust 2015-2, 1.98%, 10/15/20 (144A) 1,377,440 1,612,264 Flagship Credit Auto Trust 2015-3, 2.38%, 10/15/20 (144A) 1,615,519 967,328 Flagship Credit Auto Trust 2016-3, 1.61%, 12/15/19 (144A) 966,627 3,658,566 Flagship Credit Auto Trust 2017-1, 1.93%, 12/15/21 (144A) 3,657,827 1,124,400 FNA 2015-1 Trust, 3.24%, 12/10/23 (144A) 1,117,654 563,639 1.31 Ford Credit Auto Owner Trust 2016-A, Floating Rate Note, 12/15/18 564,000 1,862,767 1.22 Ford Credit Auto Owner Trust 2016-B, Floating Rate Note, 3/15/19 1,863,132 3,700,000 1.03 Ford Credit Auto Owner Trust 2017-A, Floating Rate Note, 12/15/19 3,701,432 4,900,000 1.37 Ford Credit Floorplan Master Owner Trust A, Floating Rate Note, 11/15/21 4,925,601 4,000,000 1.81 Ford Credit Floorplan Master Owner Trust A, Floating Rate Note, 2/15/21 4,042,422 3,500,000 1.53 Ford Credit Floorplan Master Owner Trust, A Series 2016-3 Class A2, Floating Rate Note, 7/15/21 3,528,778 553,000 2.88 Four Corners CLO II, Ltd., Floating Rate Note, 1/26/20 (144A) 550,627 3,048,683 Foursight Capital Automobile Receivables Trust 2016-1, 2.87%, 10/15/21 (144A) 3,057,776 538,919 1.50 Fremont Home Loan Trust 2005-2, Floating Rate Note, 6/25/35 530,179 7,612,540 1.21 Fremont Home Loan Trust 2005-E, Floating Rate Note, 1/25/36 7,519,340 10,709 1.26 Gale Force 3 CLO, Ltd., Floating Rate Note, 4/19/21 (144A) 10,693 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 29 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 939,712 GCAT 2015-1 LLC, 3.625%, 5/26/20 (Step) (144A) $ 939,807 6,400,000 3.38 Gcat Series 17-1 Class A1, Floating Rate Note, 3/25/47 (144A) 6,390,400 7,642,633 1.21 Ge-Wmc Asset-Backed Pass-Through Certificates, Series 2005-2 Class A1, Floating Rate Note, 12/25/35 7,578,782 238,884 GLC Trust 2013-1, 3.0%, 7/15/21 (144A) 235,778 1,253,568 GLS Auto Receivables Trust 2016-1, 2.73%, 10/15/20 (144A) 1,255,030 444,324 1.56 GM Financial Automobile Leasing Trust 2015-3, Floating Rate Note, 6/20/18 444,874 853,864 4.54 GMACM Home Equity Loan Trust 2002-He4 Series 2002-He4 Class A2, Floating Rate Note, 10/25/32 850,244 1,589,207 GMAT 2013-1 Trust, 6.9669%, 8/25/53 (Step) 1,591,523 2,696,488 GMAT 2015-1 Trust, 4.25%, 9/25/20 (Step) (144A) 2,696,714 4,700,000 1.48 GMF Floorplan Owner Revolving Trust, Floating Rate Note, 1/18/22 (144A) 4,715,401 1,300,000 1.41 GMF Floorplan Owner Revolving Trust, Floating Rate Note, 5/15/20 (144A) 1,303,606 2,100,000 1.62 GMF Floorplan Owner Revolving Trust, Floating Rate Note, 5/17/21 (144A) 2,120,569 321,576 GO Financial Auto Securitization Trust 2015-2, 3.27%, 11/15/18 (144A) 321,772 4,000,000 1.37 Golden Credit Card Trust, Floating Rate Note, 1/15/20 (144A) 4,008,229 150,000 1.21 Golden Credit Card Trust, Floating Rate Note, 2/15/20 (144A) 150,212 590,000 1.22 Golden Credit Card Trust, Floating Rate Note, 3/15/21 (144A) 591,459 5,000,000 Green Tree Agency Advance Funding Trust I, 3.1216%, 10/15/48 (144A) 4,960,850 1,202,033 1.68 Green Tree Mortgage Loan Trust 2005-HE1, Floating Rate Note, 12/25/32 (144A) 1,182,824 356,126 1.44 GSAA Home Equity Trust 2004-11, Floating Rate Note, 12/25/34 355,947 1,147,568 1.60 GSAA Trust, Floating Rate Note, 6/25/35 1,124,161 3,035,958 1.75 GSAMP Trust 2004-HE2, Floating Rate Note, 9/25/34 2,966,147 945,918 1.75 GSAMP Trust 2004-SEA2, Floating Rate Note, 3/25/34 946,227 848,968 1.73 GSAMP Trust 2005-HE1, Floating Rate Note, 12/25/34 845,220 1,843,364 1.16 GSAMP Trust 2006-HE2, Floating Rate Note, 3/25/46 1,832,742 486 1.28 GSAMP Trust 2006-SEA1, Floating Rate Note, 5/25/36 (144A) 486 812,720 2.33 GSRPM Mortgage Loan Trust 2003-2, Floating Rate Note, 6/25/33 787,866 634,821 1.28 GSRPM Mortgage Loan Trust 2006-1, Floating Rate Note, 3/25/35 (144A) 625,052 1,293,098 1.28 GSRPM Mortgage Loan Trust 2006-2, Floating Rate Note, 9/25/36 (144A) 1,279,445 The accompanying notes are an integral part of these financial statements. 30 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,570,000 1.35 Hasc 2006-Opt2 M1, Floating Rate Note, 1/25/36 $ 1,549,794 1,115,317 Hero Residual Funding 2016-1R, 4.5%, 9/21/42 (144A) 1,105,210 3,200,000 2.36 Hertz Fleet Lease Funding LP, Floating Rate Note, 7/10/29 (144A) 3,214,361 2,600,000 3.16 Hertz Fleet Lease Funding LP, Floating Rate Note, 7/10/29 (144A) 2,587,081 180,320 1.25 Home Equity Asset Trust 2005-6, Floating Rate Note, 12/25/35 180,372 699,499 1.36 Home Equity Asset Trust 2005-7, Floating Rate Note, 1/25/36 699,184 42,272 1.15 Home Equity Asset Trust 2006-4, Floating Rate Note, 8/25/36 42,152 4,176,623 1.35 Home Equity Mortgage Loan Asset-Backed Trust Series INABS 2005-C, Floating Rate Note, 10/25/35 4,124,218 234,522 2.88 Home Equity Mortgage Trust, Floating Rate Note, 10/25/34 230,036 5,099,470 2.56 Home Partners of America 2016-1 Trust, Floating Rate Note, 3/17/33 (144A) 5,137,897 1,799,000 4.21 Home Partners of America 2016-1 Trust, Floating Rate Note, 3/18/33 (144A) 1,815,412 1,250,000 3.31 Home Partners of America 2016-2 Trust, Floating Rate Note, 10/17/33 (144A) 1,255,246 1,856,031 1.52 HomeBanc Mortgage Trust 2004-2, Floating Rate Note, 12/25/34 1,798,801 2,063,765 Honor Automobile Trust Securitization 2016-1A, 2.94%, 11/15/19 (144A) 2,070,900 1,757,007 1.18 HSBC Home Equity Loan Trust USA 2007-1, Floating Rate Note, 3/20/36 1,755,058 244,098 1.28 HSBC Home Equity Loan Trust USA 2007-2, Floating Rate Note, 7/20/36 243,168 3,031,560 1.17 HSBC Home Equity Loan Trust USA 2007-2, Floating Rate Note, 7/20/36 3,017,119 1,193,346 1.46 Hyundai Auto Lease Securitization Trust 2016-A, Floating Rate Note, 7/16/18 (144A) 1,195,231 1,612,966 1.84 Impac Secured Assets CMN Owner Trust, Floating Rate Note, 2/25/35 1,615,001 1,448,581 3.01 Invitation Homes 2014-SFR1 Trust REMICS, Floating Rate Note, 6/19/31 (144A) 1,448,578 6,600,000 2.51 Invitation Homes 2014-SFR2 Trust, Floating Rate Note, 9/19/31 (144A) 6,606,565 1,955,085 2.11 Invitation Homes 2014-SFR3 Trust, Floating Rate Note, 12/17/31 (144A) 1,955,781 2,887,000 2.91 Invitation Homes 2015-SFR2 Trust, Floating Rate Note, 6/17/32 (144A) 2,895,876 3,500,000 2.66 Invitation Homes 2015-SFR3 Trust, Floating Rate Note, 8/17/32 (144A) 3,511,332 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 31 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,400,000 Invitation Homes Trust 2014-SFR3 Class D, 3.51%, 12/17/31 $ 1,399,996 509,354 2.48 Irwin Whole Loan Home Equity Trust 2003-C, Floating Rate Note, 6/25/28 504,459 986,150 1.48 Irwin Whole Loan Home Equity Trust 2005-B, Floating Rate Note, 12/25/29 978,209 638 1.56 IXIS Real Estate Capital Trust 2005-HE1, Floating Rate Note, 6/25/35 648 13,971 1.46 IXIS Real Estate Capital Trust 2005-HE4, Floating Rate Note, 2/25/36 13,958 1,570,704 1.76 JP Morgan Mortgage Acquisition Corp., 2005-FLD1, Floating Rate Note, 7/25/35 1,560,936 466,389 1.20 JP Morgan Mortgage Acquisition Corp., 2005-FRE1, Floating Rate Note, 10/25/35 463,745 262,775 1.13 JP Morgan Mortgage Acquisition Trust 2006-ACC1, Floating Rate Note, 5/25/36 262,704 7,490,073 1.68 Lake Country Mortgage Loan Trust 2006-HE1, Floating Rate Note, 7/25/34 (144A) 7,383,413 38,098 1.36 Lehman ABS Manufactured Housing Contract Trust 2002-A, Floating Rate Note, 6/15/33 37,691 2,029,476 1.78 Lehman XS Trust Series 2005-4, Floating Rate Note, 10/25/35 1,972,124 6,199,362 1.21 Long Beach Mortgage Loan Trust, 2006-Wl1 Series 2006-Wl1 Class 1A1, Floating Rate Note, 1/25/46 6,099,451 253,100 2.12 MASTR Adjustable Rate Mortgages Trust 2004-11, Floating Rate Note, 11/25/34 253,198 5,850,000 1.03 MBNA Credit Card Master Note Trust, Floating Rate Note, 8/16/21 5,862,590 2,500,000 1.23 Mercedes-Benz Master Owner Trust 2015-A, Floating Rate Note, 4/15/19 (144A) 2,500,202 4,122,416 1.20 Merrill Lynch Mortgage Investors Trust Series 2006-FF1, Floating Rate Note, 8/25/36 4,107,259 1,834,755 1.78 Morgan Stanley ABS Capital I Inc Trust 2005-HE3, Floating Rate Note, 7/25/35 1,825,476 1,380,766 1.72 Morgan Stanley ABS Capital I Inc Trust 2005-WMC1, Floating Rate Note, 1/25/35 1,359,966 15,476 1.69 Morgan Stanley ABS Capital I Inc Trust 2005-WMC3, Floating Rate Note, 3/25/35 15,432 64,293 1.73 Morgan Stanley ABS Capital I Inc Trust 2005-WMC6, Floating Rate Note, 7/25/35 64,209 350,320 1.41 Morgan Stanley ABS Capital I, Inc. Trust 2005-NC2, Floating Rate Note, 3/25/35 350,003 221,092 1.76 Morgan Stanley Home Equity Loan Trust 2005-1, Floating Rate Note, 12/25/34 218,507 1,046,178 1.26 Morgan Stanley Home Equity Loan Trust 2006-2, Floating Rate Note, 2/25/36 991,067 The accompanying notes are an integral part of these financial statements. 32 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 13,123 1.06 Morgan Stanley Structured Trust, Floating Rate Note, 6/25/37 $ 13,291 490,000 1.17 Morgan Stanley Structured Trust, Floating Rate Note, 6/25/37 480,203 966,781 1.38 MOTOR 2015-1 Plc, Floating Rate Note, 6/27/22 (144A) 966,979 216,563 Nations Equipment Finance Funding II LLC, 1.558%, 7/20/18 (144A) 216,353 759,212 Nations Equipment Finance Funding II LLC, 3.276%, 1/22/19 (144A) 759,929 1,089,239 Nations Equipment Finance Funding III LLC, 3.61%, 2/22/21 (144A) 1,095,137 592,281 1.26 Nationstar Home Equity Loan Trust 2006-B REMICS, Floating Rate Note, 9/25/36 574,893 2,771,503 1.13 Nationstar Home Equity Loan Trust 2007-A, Floating Rate Note, 3/25/37 2,769,412 2,750,000 Navitas Equipment Receivables LLC 2016-1, 2.2%, 6/15/21 (144A) 2,746,633 4,600,000 3.22 Navitas Equipment Receivables LLC, 2016-1 Series 2016-1 Class B, Floating Rate Note, 10/15/21 (144A) 4,608,758 2,750,000 4.23 NCF Dealer Floorplan Master Trust, Floating Rate Note, 3/21/22 (144A) 2,732,380 500,000 6.48 NCF Dealer Floorplan Master Trust, Floating Rate Note, 3/21/22 (144A) 490,564 777,805 1.48 New Century Home Equity Loan Trust 2005-1, Floating Rate Note, 3/25/35 774,339 594,677 1.47 New Century Home Equity Loan Trust 2005-3 REMICS, Floating Rate Note, 7/25/35 586,870 200,000 New Residential Advance Receivables Trust Advance Receivables Backed Notes, 2.5751%, 10/15/49 (144A) 197,875 4,300,000 2.61 NextGear Floorplan Master Owner Trust, Floating Rate Note, 4/15/21 (144A) 4,380,112 2,600,000 2.52 NextGear Floorplan Master Owner Trust, Floating Rate Note, 7/15/19 (144A) 2,600,772 5,000,000 2.01 NextGear Floorplan Master Owner Trust, Floating Rate Note, 9/15/21 (144A) 5,005,348 571,705 1.26 Nissan Auto Receivables 2015-C Owner Trust, Floating Rate Note, 11/15/18 572,112 1,642,126 1.26 Nissan Auto Receivables 2016-A Owner Trust, Floating Rate Note, 2/15/19 1,643,812 1,082,896 1.21 Nissan Auto Receivables 2016-B Owner Trust, Floating Rate Note, 4/15/19 1,084,222 2,700,000 1.04 Nissan Auto Receivables, 2017-A Owner Trust Series 2017-A Class A2B, Floating Rate Note, 1/15/20 2,700,000 280,031 1.76 NovaStar Mortgage Funding Trust Series 2003-1, Floating Rate Note, 5/25/33 262,509 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 33 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 981,694 2.43 NovaStar Mortgage Funding Trust Series 2004-4, Floating Rate Note, 3/25/35 $ 976,836 72,390 1.72 NovaStar Mortgage Funding Trust Series 2005-3, Floating Rate Note, 1/25/36 72,265 7,200,000 1.66 NovaStar Mortgage Funding Trust Series 2005-3, Floating Rate Note, 1/25/36 7,125,646 8,582,464 1.14 Novastar Mortgage Funding Trust, Series 2006-1 Series 2006-1 Class A1A, Floating Rate Note, 5/25/36 8,288,945 1,290,725 NYCTL 2016-A Trust, 1.47%, 11/10/29 (144A) 1,281,763 4,452,000 Ocwen Master Advance Receivables Trust, 2.5207%, 8/17/48 (144A) 4,431,158 1,659,778 OneMain Financial Issuance Trust 2014-2, 2.47%, 9/18/24 (144A) 1,662,454 3,000,000 Oportun Funding III LLC, 3.69%, 7/8/21 (144A) 3,006,502 613,678 1.75 Opteum Mortgage Acceptance Corp., Asset Backed Pass-Through Certificates 2005-1, Floating Rate Note, 2/25/35 614,120 1,222,526 1.78 Option One Mortgage Loan Trust 2005-1, Floating Rate Note, 2/25/35 1,220,115 31,529 Option One Mortgage Loan Trust 2007-FXD2, 5.9%, 3/25/37 (Step) 29,033 111,806 Orange Lake Timeshare Trust 2012-A, 4.87%, 3/10/27 (144A) 113,693 5,908,783 OSAT 2016-NPL1 Trust, 3.75%, 7/25/56 (Step) (144A) 5,928,456 3,731,724 Oscar US Funding Trust II, 1.86%, 10/15/19 (144A) 3,709,699 2,824,635 Oscar US Funding Trust IV, 2.53%, 7/15/20 (144A) 2,821,274 1,329,240 2.47 Oscar US Funding Trust IV, Floating Rate Note, 7/15/20 (144A) 1,329,828 4,150,000 Oscar US Funding Trust V, 2.31%, 11/15/19 (144A) 4,145,369 3,300,000 1.80 Oscar US Funding Trust, Vi LLC Series 2017-1A Class A2B, Floating Rate Note, 5/11/20 (144A) 3,300,000 57,955 1.24 Park Place Securities Inc Asset-Backed Pass-Through Certificates Series 2005-WHQ4, Floating Rate Note, 9/25/35 57,834 498,420 1.35 Park Place Securities, Inc. Asset-Backed Pass-Through Certificates Series 2005-WHQ4, Floating Rate Note, 9/25/35 497,025 652,344 1.88 People's Choice Home Loan Securities Trust Series 2004-2, Floating Rate Note, 10/25/34 650,271 2,290,000 1.37 PFS Financing Corp., Floating Rate Note, 10/15/19 (144A) 2,287,979 1,700,000 1.62 PFS Financing Corp., Floating Rate Note, 10/15/19 (144A) 1,697,749 4,000,000 2.11 PFS Financing Corp., Floating Rate Note, 2/18/20 (144A) 4,017,309 1,250,000 2.66 PFS Financing Corp., Floating Rate Note, 2/18/20 (144A) 1,257,696 The accompanying notes are an integral part of these financial statements. 34 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,250,000 1.39 PFS Financing Corp., Floating Rate Note, 4/15/20 (144A) $ 1,249,610 1,962,912 1.43 Popular ABS Mortgage Pass-Through Trust 2005-C, Floating Rate Note, 11/25/35 1,943,361 205,644 1.30 Popular ABS Mortgage Pass-Through Trust 2006-A, Floating Rate Note, 2/25/36 203,337 1,500,000 Prestige Auto Receivables Trust 2013-1, 3.04%, 7/15/20 (144A) 1,503,771 2,300,000 Prestige Auto Receivables Trust 2016-2, 1.46%, 7/15/20 (144A) 2,294,133 2,492,007 Pretium Mortgage Credit Partners I 2016-NPL1, 4.375%, 2/27/31 (Step) (144A) 2,516,661 1,540,417 Pretium Mortgage Credit Partners I 2016-NPL4 LLC, 4.0%, 7/25/31 (Step) (144A) 1,542,783 3,286,290 Pretium Mortgage Credit Partners I 2016-NPL6 LLC, 3.5%, 10/27/31 (Step) (144A) 3,295,381 1,700,000 Progreso Receivables Funding IV LLC, 3.0%, 7/8/20 (144A) 1,699,707 1,944,000 3.41 Progress Residential 2016-SFR1 Trust, Floating Rate Note, 9/17/33 (144A) 1,968,132 6,030,169 PRPM 2017-1 LLC, 4.25%, 1/25/22 (Step) (144A) 6,047,497 262,858 Purchasing Power Funding 2015-A LLC, 3.5%, 12/15/19 (144A) 263,022 1,493,806 1.64 Quest Trust REMICS, Floating Rate Note, 3/25/34 (144A) 1,467,071 144,813 1.93 RAAC Series 2005-RP1 Trust, Floating Rate Note, 7/25/37 (144A) 144,452 575,395 1.78 RAAC Series 2005-RP3 Trust, Floating Rate Note, 5/25/39 (144A) 564,013 1,201,644 1.23 RAAC Series 2006-RP2 Trust, Floating Rate Note, 2/25/37 (144A) 1,193,777 174,095 1.71 RAMP Series 2004-RS11 Trust, Floating Rate Note, 11/25/34 174,211 538,325 1.14 RAMP Series 2006-Efc2 Trust Series 2006-Efc2 Class A3, Floating Rate Note, 12/25/36 526,339 41,896 0.94 RAMP Series 2006-RZ3 Trust, Floating Rate Note, 10/25/35 41,870 2,687,275 1.44 RASC Series 2001-Ks3 Trust, Series 2001-Ks3 Class AII, Floating Rate Note, 9/25/31 2,578,709 2,711,028 1.19 RASC Series 2005-KS10 Trust, Floating Rate Note, 11/25/35 2,689,652 900,000 1.38 RASC Series 2005-KS11 Trust, Floating Rate Note, 12/25/35 887,455 1,349,119 1.63 RASC Series 2005-Ks2 Trust Series 2005-Ks2 Class M1, Floating Rate Note, 3/25/35 1,320,413 361,872 1.41 RASC Series 2005-KS9 Trust, Floating Rate Note, 10/25/35 360,043 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 35 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,005,102 RBSHD 2013-1 Trust, 7.6853%, 10/25/47 (Step) (144A) $ 1,004,988 3,057,695 2.25 Resimac Premier Series 2016-1, Floating Rate Note, 10/10/47 (144A) 3,059,618 70,338 1.88 Salomon Mortgage Loan Trust Series 2001-CB4, Floating Rate Note, 11/25/33 68,924 625,000 Santander Drive Auto Receivables Trust 2015-3, 2.74%, 1/15/21 631,636 561,769 1.60 SASCO Mortgage Loan Trust 2005-GEL1, Floating Rate Note, 12/25/34 551,849 994,205 1.44 Saxon Asset Securities Trust 2005-3, Floating Rate Note, 11/25/35 988,736 1,182,183 1.14 Saxon Asset Securities Trust 2006-1, Floating Rate Note, 3/25/36 1,168,020 4,967,069 SCF Equipment Trust 2016-1 LLC, 3.62%, 11/20/21 (144A) 4,952,173 171,683 1.26 Securitized Asset Backed Receivables LLC Trust Series 2006-Wm1 Class A1B, Floating Rate Note, 12/25/35 169,679 3,600,000 1.33 Securitized Term Auto Receivables Trust 2016-1, Floating Rate Note, 11/26/18 (144A) 3,601,534 5,600,000 1.28 Securitized Term Auto Receivables Trust 2017-1, Floating Rate Note, 4/25/19 (144A) 5,600,174 1,082,379 Sierra Auto Receivables Securitization Trust 2016-1, 2.85%, 1/18/22 (144A) 1,083,542 3,778,000 2.96 Silver Bay Realty 2014-1 Trust, Floating Rate Note, 9/18/31 (144A) 3,773,485 2,700,000 Skopos Auto Receivables Trust 2015-1, 5.43%, 12/15/23 (144A) 2,715,516 667,864 Skopos Auto Receivables Trust 2015-2, 3.55%, 2/17/20 (144A) 668,730 740,237 1.64 SMART ABS Series 2015-3US Trust, Floating Rate Note, 4/16/18 742,525 1,577,626 SNAAC Auto Receivables Trust 2013-1, 4.56%, 4/15/20 (144A) 1,579,055 2,816,051 Sofi Consumer Loan Program 2017-1 LLC, 3.28%, 1/26/26 (144A) 2,829,509 2,230,020 2.23 SoFi Professional Loan Program 2014-B LLC, Floating Rate Note, 8/25/32 (144A) 2,261,142 3,466,179 1.83 SoFi Professional Loan Program 2015-B LLC, Floating Rate Note, 4/25/35 (144A) 3,503,958 1,336,425 2.53 Sofi Professional Loan Program 2016-A LLC, Floating Rate Note, 8/25/36 (144A) 1,381,453 1,264,176 1.98 Sofi Professional Loan Program 2016-B LLC, Floating Rate Note, 6/25/33 (144A) 1,283,328 617,469 1.88 SoFi Professional Loan Program 2016-C LLC, Floating Rate Note, 10/25/36 (144A) 625,328 The accompanying notes are an integral part of these financial statements. 36 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 3,629,969 1.73 SoFi Professional Loan Program 2016-D LLC, Floating Rate Note, 1/25/39 (144A) $ 3,658,030 1,836,774 1.63 Sofi Professional Loan Program 2016-E LLC, Floating Rate Note, 7/25/39 (144A) 1,845,343 2,750,000 1.48 SoFi Professional Loan Program 2017-A LLC, Floating Rate Note, 3/26/40 (144A) 2,751,367 3,000,000 1.83 Sofi Professional Loan Program, 2017-B LLC Series 2017-B Class A1 Fx, Floating Rate Note, 5/25/40 (144A) 2,999,773 336,987 1.50 Soundview Home Loan Trust 2005-DO1, Floating Rate Note, 5/25/35 336,322 291,734 1.24 Soundview Home Loan Trust 2005-OPT4, Floating Rate Note, 12/25/35 290,183 46,318 1.37 Specialty Underwriting & Residential Finance Trust Series 2005-AB2, Floating Rate Note, 6/25/36 46,321 76,336 1.31 Specialty Underwriting & Residential Finance Trust Series 2005-AB2, Floating Rate Note, 6/25/36 76,336 3,418,205 1.28 Specialty Underwriting & Residential Finance Trust Series 2006-BC1, Floating Rate Note, 12/25/36 3,381,438 4,250,000 SPS Servicer Advance Receivables Trust Advance Receivables Backed Notes 2015-T3, 3.41%, 7/15/47 (144A) 4,261,892 4,700,000 SPS Servicer Advance Receivables Trust Advance Receivables Backed Notes 2016-T1, 2.53%, 11/16/48 (144A) 4,684,632 1,285,000 SPS Servicer Advance Receivables Trust Advance Receivables Backed Notes 2016-T1, 3.32%, 11/16/48 (144A) 1,279,837 420,319 1.84 Structured Asset Investment Loan Trust 2004-10, Floating Rate Note, 11/25/34 416,843 362,407 1.68 Structured Asset Investment Loan Trust 2004-11, Floating Rate Note, 1/25/35 359,437 2,228,126 2.02 Structured Asset Investment Loan Trust 2004-BNC2, Floating Rate Note, 12/25/34 2,222,566 1,096,241 1.70 Structured Asset Investment Loan Trust 2005-6, Floating Rate Note, 7/25/35 1,094,026 853,533 1.48 Structured Asset Investment Loan Trust 2005-HE1, Floating Rate Note, 7/25/35 839,194 663,449 1.18 Structured Asset Investment Loan Trust 2006-1, Floating Rate Note, 1/25/36 658,309 3,870,882 1.74 Structured Asset Investment Loan Trust, 2003-Bc1 Series 2003-Bc1 Class A1, Floating Rate Note, 1/25/33 3,795,633 849,907 1.44 Structured Asset Securities Corp., 2005-WF1, Floating Rate Note, 2/25/35 834,713 1,235,591 1.13 Structured Asset Securities Corp., Mortgage Loan Trust 2006-EQ1, Floating Rate Note, 7/25/36 (144A) 1,215,102 1,173,957 1.12 Structured Asset Securities Corp., Mortgage Loan Trust 2007-BC3, Floating Rate Note, 5/25/47 1,156,363 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 37 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 4,508,550 1.08 Structured Asset Securities Corp., Mortgage Loan Trust 2007-TC1, Floating Rate Note, 4/25/31 (144A) $ 4,316,686 1,078,462 2.48 Structured Asset Securities Corp., Mortgage Pass-Through Ctfs Ser 2003-BC2, Floating Rate Note, 3/25/33 1,069,599 435,668 Sunset Mortgage Loan Co., 2014-NPL2 LLC, 3.721%, 11/16/44 (Step) (144A) 435,611 1,760,862 Sunset Mortgage Loan Co., 2015-NPL1 LLC, 4.4586%, 9/16/45 (Step) (144A) 1,762,238 216,846 SVO 2012-A VOI Mortgage LLC, 2.0%, 9/20/29 (144A) 214,633 4,459,941 2.21 SWAY Residential 2014-1 Trust, Floating Rate Note, 1/20/32 (144A) 4,469,677 1,770,550 Tax Ease Funding LLC Series 16-1A, 3.13%, 6/15/28 1,771,691 4,252,955 TCF Auto Receivables Owner Trust 2016-PT1, 1.93%, 6/15/22 (144A) 4,247,446 386,346 2.56 Terwin Mortgage Trust 2005-1SL, Floating Rate Note, 2/25/35 (144A) 379,659 1,088,290 1.36 Terwin Mortgage Trust 2006-1, Floating Rate Note, 1/25/37 (144A) 1,078,380 4,758,005 1.21 Terwin Mortgage Trust 2006-3, Floating Rate Note, 4/25/37 (144A) 4,688,159 661,096 1.29 Terwin Mortgage Trust Series TMTS 2005-12ALT, Floating Rate Note, 7/25/36 655,321 630,375 Tidewater Auto Receivables Trust 2016-A, 2.3%, 9/15/19 (144A) 630,186 2,150,000 0.84 Toyota Auto Receivables, 2017-A Owner Trust Series 2017-A Class A2B, Floating Rate Note, 9/16/19 2,150,000 2,000,000 5.16 Trade MAPS 1, Ltd., Floating Rate Note, 12/10/18 (144A) 2,000,000 5,423,000 1.86 Trafigura Securitisation Finance Plc., 2014-1, Floating Rate Note, 4/16/18 (144A) 5,414,583 1,750,000 3.02 Trafigura Securitisation Finance Plc., 2014-1, Floating Rate Note, 4/16/18 (144A) 1,748,123 4,150,000 2.56 Tricon American Homes 2015-SFR1 Trust REMICS, Floating Rate Note, 5/19/32 (144A) 4,149,995 8,000,000 1.70 Trillium Credit Card Trust II, Floating Rate Note, 5/26/21 (144A) 8,037,253 861,578 2.68 Truman Capital Mortgage Loan Trust, Floating Rate Note, 1/25/34 849,820 745,559 1.04 Truman Capital Mortgage Loan Trust, Floating Rate Note, 3/25/36 (144A) 686,438 763,488 United Auto Credit Securitization Trust 2016-2, 1.67%, 9/10/18 (144A) 763,972 5,000,000 United Auto Credit Securitization Trust 2016-2, 2.2%, 5/10/19 (144A) 5,000,754 5,038,593 3.47 US Residential Opportunity Fund, IV Trust 2 Series 2016-1IV Class A, Floating Rate Note, 7/27/36 (144A) 5,051,843 7,217,000 VOLT LIV LLC, 3.5%, 2/25/47 (Step) (144A) 7,191,676 The accompanying notes are an integral part of these financial statements. 38 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 138,612 VOLT XIX LLC, 3.875%, 4/26/55 (Step) (144A) $ 138,835 6,200,321 VOLT XLVII LLC, 3.75%, 6/25/46 (Step) (144A) 6,192,983 2,688,245 VOLT XLVIII LLC, 3.5%, 7/25/46 (Step) (144A) 2,702,761 3,636,188 VOLT XXV LLC, 3.5%, 6/26/45 (Step) (144A) 3,649,526 1,208,686 VOLT XXXI LLC, 3.375%, 2/25/55 (Step) (144A) 1,204,864 1,246,060 VOLT XXXIII LLC, 3.5%, 3/25/55 (Step) (144A) 1,250,701 4,397,188 VOLT XXXIX LLC, 4.125%, 10/25/45 (Step) (144A) 4,406,742 5,276,380 VOLT XXXV, 3.5%, 9/25/46 (Step) (144A) 5,275,181 1,643,491 VOLT XXXVI LLC, 3.625%, 7/25/45 (Step) (144A) 1,647,465 2,044,639 VOLT XXXVII LLC, 3.625%, 7/25/45 (Step) (144A) 2,053,807 2,616,801 VOLT XXXVIII LLC, 3.875%, 9/25/45 (Step) (144A) 2,635,233 1,517,758 1.23 Wells Fargo Home Equity Asset-Backed Securities 2006-1 Trust REMICS, Floating Rate Note, 7/25/36 1,488,238 484,654 Westgate Resorts 2016-1 LLC, 3.5%, 12/20/28 (144A) 487,009 8,600,000 3.05 Westgate Resorts 2017-1 LLC, Series 2017-1A Class A, 12/20/30 (144A) 8,589,250 2,500,000 Westlake Automobile Receivables Trust 2014-2, 2.86%, 7/15/21 2,510,651 223,945 1.66 Westlake Automobile Receivables Trust 2015-2, Floating Rate Note, 7/16/18 (144A) 223,975 2,456,993 1.84 Westlake Automobile Receivables Trust 2015-3, Floating Rate Note, 5/17/21 (144A) 2,459,322 2,699,485 1.96 Westlake Automobile Receivables Trust 2016-1, Floating Rate Note, 1/15/19 (144A) 2,706,174 2,550,000 Westlake Automobile Receivables Trust 2016-3, 1.42%, 10/15/19 (144A) 2,547,653 4,770,000 4.55 Westlake Automobile Receivables Trust, 2016-1 Series 2016-1A Class D, Floating Rate Note, 9/15/21 (144A) 4,877,830 3,550,000 1.78 Westlake Automobile Receivables Trust, 2017-1 Series 2017-1A Class A2, Floating Rate Note, 4/15/20 (144A) 3,552,145 8,738 Wheels SPV 2 LLC, 0.84%, 3/20/23 (144A) 8,736 21,361 1.26 Wilshire Mortgage Loan Trust, Floating Rate Note, 5/25/28 21,065 3,000,000 World Financial Network Credit Card Master Trust, 1.26%, 3/15/21 2,999,922 1,725,000 1.39 World Financial Network Credit Card Master Trust, Floating Rate Note, 2/15/22 1,729,990 1,011,634 1.31 World Omni Auto Receivables Trust 2015-B, Floating Rate Note, 7/15/19 1,012,332 ------------- $ 781,309,765 ------------- Total Banks $ 781,314,903 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 39 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 2.3% Other Diversified Financial Services -- 0.6% 1,699,750 1.11 321 Henderson Receivables I LLC, Floating Rate Note, 6/15/41 (144A) $ 1,656,298 1,300,000 American Credit Acceptance Receivables Trust 2014-1, 5.2%, 4/12/21 (144A) 1,308,562 3,400,000 American Credit Acceptance Receivables Trust 2014-2, 4.96%, 5/10/21 (144A) 3,426,087 543,680 BCC Funding VIII LLC, 1.794%, 6/22/20 (144A) 543,000 2,000,000 3.06 Colony American Homes 2014-1 REMICS, Floating Rate Note, 5/17/31 (144A) 1,999,997 2,100,000 2.81 Colony American Homes 2014-2, Floating Rate Note, 7/19/31 (144A) 2,099,997 2,303,047 1.76 Countrywide Asset-Backed Certificates, Floating Rate Note, 5/25/36 2,300,272 1,300,000 1.62 Gracechurch Card Funding Plc, Floating Rate Note, 5/15/19 (144A) 1,300,546 272,490 1.21 Mastr Asset Backed Securities Trust 2006-AB1 REMICS, Floating Rate Note, 2/25/36 272,065 2,051,310 1.28 Mastr Specialized Loan Trust, Floating Rate Note, 1/25/36 (144A) 2,017,089 1,112,630 PFS Tax Lien Trust 2014-1, 1.44%, 5/15/29 (144A) 1,105,497 980,736 Sierra Timeshare 2013-1 Receivables Funding LLC, 2.39%, 11/20/29 (144A) 980,853 387,540 TAL Advantage V LLC, 1.7%, 5/20/39 (144A) 384,037 ------------- $ 19,394,300 ----------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.3% 2,600,000 1.31 Ally Master Owner Trust, Floating Rate Note, 6/17/19 $ 2,601,508 453,556 Alterna Funding I LLC, 1.639%, 2/15/21 (144A) 444,485 48,424 2.12 Conseco Finance Corp., Floating Rate Note, 11/17/31 48,197 3,255,000 1.43 Wells Fargo Dealer Floorplan Master Note Trust, Floating Rate Note, 10/21/19 3,257,192 2,670,000 1.36 Wells Fargo Dealer Floorplan Master Note Trust, Floating Rate Note, 7/22/19 2,674,196 ------------- $ 9,025,578 ----------------------------------------------------------------------------------------------------------- Consumer Finance -- 1.2% 3,600,000 American Credit Acceptance Receivables Trust 2013-1, 4.94%, 6/15/20 (144A) $ 3,603,717 350,000 1.04 American Express Credit Account Master Trust, Floating Rate Note, 1/15/20 350,155 3,300,000 1.06 American Express Credit Account Master Trust, Floating Rate Note, 5/15/20 3,304,246 2,770,000 1.33 American Express Credit Account Master Trust, Floating Rate Note, 5/17/21 2,782,035 2,100,000 1.57 American Express Credit Account Secured Note Trust 2012-4, Floating Rate Note, 5/15/20 (144A) 2,105,201 The accompanying notes are an integral part of these financial statements. 40 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Consumer Finance -- (continued) 7,250,000 1.06 BA Credit Card Trust, Floating Rate Note, 1/15/20 $ 7,256,660 6,400,000 1.04 BA Credit Card Trust, Floating Rate Note, 9/16/19 6,399,999 2,822 California Republic Auto Receivables Trust 2013-1, 1.41%, 9/17/18 (144A) 2,821 883,061 1.36 CarMax Auto Owner Trust 2015-3, Floating Rate Note, 11/15/18 883,443 2,510,000 Chase Issuance Trust, 1.26%, 7/15/19 2,510,721 169,826 CPS Auto Receivables Trust 2013-B, 1.82%, 9/15/20 (144A) 169,821 235,670 CPS Auto Receivables Trust 2014-C, 1.31%, 2/15/19 (144A) 235,549 95,238 CPS Auto Trust, 1.48%, 3/16/20 (144A) 95,220 4,175,000 First Investors Auto Owner Trust 2013-1, 2.53%, 1/15/20 (144A) 4,176,009 4,400,000 1.54 First National Master Note Trust 2015-1, Floating Rate Note, 9/15/20 4,409,291 ------------- $ 38,284,888 ----------------------------------------------------------------------------------------------------------- Asset Management & Custody Banks -- 0.0%+ 786,168 Engs Commercial Finance Trust 2015-1, 2.31%, 10/22/21 (144A) $ 784,421 1,472,548 RMAT 2015-1 LLC, 4.09%, 7/27/20 (Step) (144A) 1,480,843 ------------- $ 2,265,264 ----------------------------------------------------------------------------------------------------------- Investment Banking & Brokerage -- 0.2% 1,906,844 1.33 Chesapeake Funding LLC, Floating Rate Note, 2/8/27 (144A) $ 1,905,769 1,750,000 2.58 Chesapeake Funding LLC, Floating Rate Note, 2/8/27 (144A) 1,719,022 2,014,486 1.25 Chesapeake Funding LLC, Floating Rate Note, 3/9/26 (144A) 2,012,354 ------------- $ 5,637,145 ------------- Total Diversified Financials $ 74,607,175 ----------------------------------------------------------------------------------------------------------- REAL ESTATE -- 0.1% Residential REIT -- 0.1% 2,500,000 2.66 American Homes 4 Rent 2014-SFR1 REMICS, Floating Rate Note, 6/17/31 (144A) $ 2,497,295 ----------------------------------------------------------------------------------------------------------- Specialized REIT -- 0.0%+ 162,932 1.17 HSI Asset Securitization Corp., Trust 2006-OPT1, Floating Rate Note, 12/25/35 $ 162,386 ------------- Total Real Estate $ 2,659,681 ----------------------------------------------------------------------------------------------------------- TOTAL ASSET BACKED SECURITIES (Cost $905,434,662) $ 906,397,521 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 41 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- 24.9% ENERGY -- 0.1% Oil & Gas Exploration & Production -- 0.1% 2,100,000 2.61 Arbor Realty Commercial Real Estate Notes 2016-FL1, Ltd., Floating Rate Note, 9/15/26 (144A) $ 2,134,938 ------------- Total Energy $ 2,134,938 ----------------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 0.1% Construction & Engineering -- 0.0%+ 1,104,079 3.43 Velocity Commercial Capital Loan Trust 2016-1, Floating Rate Note, 4/25/46 (144A) $ 1,117,259 ----------------------------------------------------------------------------------------------------------- Industrial Conglomerates -- 0.1% 3,600,000 3.95 Vsd 2017-Plt1 LLC, Floating Rate Note, 12/25/43 (144A) $ 3,590,899 ------------- Total Capital Goods $ 4,708,158 ----------------------------------------------------------------------------------------------------------- TRANSPORTATION -- 0.0%+ Trucking -- 0.0%+ 44,459 1.41 Hertz Fleet Lease Funding LP, Floating Rate Note, 12/10/27 (144A) $ 44,458 500,000 1.91 Hertz Fleet Lease Funding LP, Floating Rate Note, 12/10/27 (144A) 500,090 ------------- $ 544,548 ------------- Total Transportation $ 544,548 ----------------------------------------------------------------------------------------------------------- BANKS -- 18.1% Diversified Banks -- 0.2% 1,750,000 3.66 Bancorp Commercial Mortgage 2016-CRE1 Trust, Floating Rate Note, 11/15/33 (144A) $ 1,746,680 2,697,399 5.89 CD 2007-CD5 Mortgage Trust REMICS, Floating Rate Note, 11/15/44 2,714,850 1,100,000 3.42 Primus Clo II, Ltd., Floating Rate Note, 7/15/21 (144A) 1,089,242 ------------- $ 5,550,772 ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- 17.9% 241,397 1.76 Adjustable Rate Mortgage Trust 2005-2, Floating Rate Note, 6/25/35 $ 239,832 624,008 1.54 Adjustable Rate Mortgage Trust 2005-5, Floating Rate Note, 9/25/35 611,894 1,194,582 1.56 Alternative Loan Trust 2004-6CB, Floating Rate Note, 4/25/34 1,185,817 810,555 1.88 Alternative Loan Trust 2004-J13, Floating Rate Note, 2/25/35 796,594 3,300,000 3.16 AMSR 2016-SFR1 Trust, Floating Rate Note, 11/17/33 (144A) 3,322,637 2,382,343 2.32 Apidos CLO IX, Floating Rate Note, 7/17/23 (144A) 2,385,538 The accompanying notes are an integral part of these financial statements. 42 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 5,000,000 2.52 Arbor Realty Collateralized Loan Obligation 2015-FL1, Ltd., Floating Rate Note, 3/17/25 (144A) $ 4,950,402 2,700,000 0.00 Arbor Realty Commercial Real Estate Notes, 20 Series 2017-Fl1 Class A, Floating Rate Note, 4/15/27 (144A) 2,700,000 2,000,000 1.67 Ares Iiir/Ivr Classo, Ltd., Series 2007-3Ra Class C, Floating Rate Note, 4/16/21 (144A) 1,996,220 2,966,868 3.44 Asg Resecuritization Trust, 2012-1 Series 2012-1 Class A64, Floating Rate Note, 4/28/36 (144A) 2,954,424 3,613,000 3.11 BAMLL Commercial Mortgage Securities Trust 2014-FL1, Floating Rate Note, 12/17/31 (144A) 3,624,773 1,920,000 2.01 BAMLL Commercial Mortgage Securities Trust 2014-ICTS, Floating Rate Note, 6/15/28 (144A) 1,886,264 3,490,000 3.51 BAMLL Commercial Mortgage Securities Trust 2014-INLD REMICS, Floating Rate Note, 12/17/29 (144A) 3,534,014 5,500,000 3.77 BAMLL Commercial Mortgage Securities Trust 2016-ASHF, Floating Rate Note, 3/15/28 (144A) 5,587,813 4,700,000 1.22 BAMLL Re-REMIC Trust 2014-FRR5, Floating Rate Note, 3/29/45 (144A) 4,628,678 3,822,922 3.04 BAMLL Re-REMIC Trust 2014-FRR7, Floating Rate Note, 10/26/44 (144A) 3,821,008 3,400,000 5.63 Bank of America Commercial Mortgage Trust 2006-1, Floating Rate Note, 9/10/45 3,394,455 2,739,480 6.19 Bank of America Commercial Mortgage Trust 2008-1, Floating Rate Note, 2/10/51 2,788,056 944,895 1.60 Bank of America Funding 2005-A Trust, Floating Rate Note, 2/20/35 921,271 72,984 3.86 Bank of America Mortgage 2003-A Trust, Floating Rate Note, 2/25/33 71,875 176,164 3.23 Bank of America Mortgage 2004-I Trust, Floating Rate Note, 10/25/34 173,171 4,239,220 2.73 Bayview Opportunity Master Fund IVb Trust 2016-CRT1, Floating Rate Note, 10/27/27 (144A) 4,238,678 3,152,748 3.13 Bayview Opportunity Master Fund IVb Trust 2017-CRT1, Floating Rate Note, 10/25/28 (144A) 3,155,382 3,150,000 2.91 BBCMS Trust 2015-SLP, Floating Rate Note, 2/15/28 (144A) 3,114,133 356,087 3.44 BCAP LLC 2009-RR13-I Trust, Floating Rate Note, 9/26/35 (144A) 357,725 4,800,000 1.01 BCAP LLC, 2012-Rr4 Trust, Series 2012-Rr4 Class 8A4, Floating Rate Note, 6/26/47 (144A) 4,521,415 542,638 1.82 Bear Stearns ALT-A Trust 2004-11, Floating Rate Note, 11/25/34 530,728 1,251,494 1.68 Bear Stearns ALT-A Trust 2004-12, Floating Rate Note, 1/25/35 1,214,871 2,807,985 1.82 Bear Stearns ALT-A Trust 2004-12, Floating Rate Note, 1/25/35 2,663,380 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 43 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,851,706 1.82 Bear Stearns ALT-A Trust 2004-12, Floating Rate Note, 1/25/35 $ 1,782,778 939,346 1.72 Bear Stearns ALT-A Trust 2004-13, Floating Rate Note, 11/25/34 920,586 2,270,294 1.58 Bear Stearns ALT-A Trust 2004-4, Floating Rate Note, 6/25/34 2,233,936 501,684 1.48 Bear Stearns ALT-A Trust 2005-2, Floating Rate Note, 3/25/35 492,282 691,216 3.11 Bear Stearns ARM Trust 2003-3, Floating Rate Note, 5/25/33 689,274 244,968 3.34 Bear Stearns ARM Trust 2004-3, Floating Rate Note, 7/25/34 237,307 4,965,461 5.71 Bear Stearns Commercial Mortgage Securities Trust 2007-TOP28, Floating Rate Note, 9/11/42 5,038,228 230,360 3.39 Bear Stearns Mortgage Securities, Inc., Floating Rate Note, 6/25/30 233,104 1,725,448 5.48 Bellemeade Re II, Ltd., Floating Rate Note, 4/25/26 (144A) 1,730,373 4,100,000 2.74 BHMS 2014-ATLS Mortgage Trust REMICS, Floating Rate Note, 7/8/33 (144A) 4,036,673 4,976,381 1.43 Black Diamond CLO 2006-1 Luxembourg SA, Floating Rate Note, 4/29/19 (144A) 4,971,597 4,750,000 2.39 Black Diamond CLO 2006-1 Luxembourg SA, Floating Rate Note, 4/29/19 (144A) 4,750,499 2,490,000 2.26 BLCP Hotel Trust, Floating Rate Note, 8/15/29 (144A) 2,478,396 3,823,000 3.76 BXHTL 2015-JWRZ Mortgage Trust, Floating Rate Note, 5/15/29 (144A) 3,840,990 1,102,335 1.30 Callidus Debt Partners Clo Fund VI, Ltd., Floating Rate Note, 10/23/21 (144A) 1,101,992 880,000 2.32 Cathedral Lake CLO 2015-3, Ltd., Floating Rate Note, 1/15/26 (144A) 879,857 6,445,000 3.41 CDGJ Commercial Mortgage Trust 2014-BXCH, Floating Rate Note, 12/15/27 (144A) 6,472,153 3,500,000 1.72 Cent CDO 14, Ltd., Floating Rate Note, 4/15/21 (144A) 3,288,854 7,200,000 3.06 CFCRE 2015-RUM Mortgage Trust, Floating Rate Note, 7/15/30 (144A) 7,083,207 1,000,000 5.51 CFCRE 2015-RUM Mortgage Trust, Floating Rate Note, 7/15/30 (144A) 977,527 4,270,629 1.86 CG-CCRE Commercial Mortgage Trust 2014-FL1, Floating Rate Note, 6/16/31 (144A) 4,269,760 2,000,000 4.01 CGWF Commercial Mortgage Trust 2013-RKWH REMICS, Floating Rate Note, 11/15/30 (144A) 1,995,182 94,216 1.31 Chevy Chase Funding LLC Mortgage-Backed Certificates Series 2004-1, Floating Rate Note, 1/25/35 (144A) 85,295 39,617 1.28 Chevy Chase Funding LLC Mortgage-Backed Certificates Series 2004-3, Floating Rate Note, 8/25/35 (144A) 36,861 The accompanying notes are an integral part of these financial statements. 44 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 289,357 1.48 CHL Mortgage Pass-Through Trust 2003-15 REMICS, Floating Rate Note, 6/25/18 $ 284,084 2,049,689 2.78 CIM Trust 2015-4AG, Floating Rate Note, 11/25/57 (144A) 2,036,227 4,257 Citicorp Mortgage Securities REMIC Pass-Through Certificates Trust Series 2005-4, 5.0%, 7/25/20 4,368 250,191 Citicorp Mortgage Securities REMIC Pass-Through Certificates Trust Series 2005-7, 5.0%, 10/25/35 251,434 1,661,611 6.04 Citigroup Commercial Mortgage Trust 2008-C7, Floating Rate Note, 12/10/49 1,679,118 1,500,000 4.21 Citigroup Commercial Mortgage Trust 2015-SHP2, Floating Rate Note, 7/15/27 (144A) 1,509,582 5,400,000 3.01 Citigroup Commercial Mortgage Trust 2015-SSHP REMICS, Floating Rate Note, 9/15/27 (144A) 5,358,839 465,463 Citigroup Mortgage Loan Trust 2010-4 REMICS, 5.0%, 10/25/35 (144A) 471,126 1,700,000 3.26 Colony American Homes 2014-2 REMICS, Floating Rate Note, 7/17/31 (144A) 1,705,320 1,247,958 2.78 Colony Mortgage Capital Series 2015-FL3, Ltd., Floating Rate Note, 9/5/32 (144A) 1,247,583 4,840,000 2.66 Colony Starwood Homes 2016-2 Trust, Floating Rate Note, 12/19/33 (144A) 4,855,324 6,400,000 1.71 Comm 2014-BBG Mortgage Trust REMICS, Floating Rate Note, 3/15/29 (144A) 6,404,001 5,600,000 3.36 COMM 2014-FL4 Mortgage Trust REMICS, Floating Rate Note, 7/15/31 (144A) 5,476,210 5,470,000 3.06 COMM 2014-FL5 Mortgage Trust, Floating Rate Note, 10/15/31 (144A) 5,433,695 6,980,000 1.71 COMM 2014-PAT Mortgage Trust REMICS, Floating Rate Note, 8/13/27 (144A) 6,977,812 2,722,000 2.51 COMM 2014-PAT Mortgage Trust, Floating Rate Note, 8/13/27 (144A) 2,674,165 7,340,000 2.48 COMM 2014-TWC Mortgage Trust, Floating Rate Note, 2/13/32 (144A) 7,376,795 4,500,000 3.21 COMM 2016-SAVA Mortgage Trust, Floating Rate Note, 10/15/34 (144A) 4,523,946 4,000,000 3.56 Cosmopolitan Hotel Trust 2016-COSMO, Floating Rate Note, 11/15/33 (144A) 4,054,930 321,182 1.72 Credit Suisse First Boston Mortgage Securities Corp., Floating Rate Note, 6/25/34 309,926 1,283,908 2.56 Crown Point CLO, Ltd., Floating Rate Note, 11/21/22 (144A) 1,287,901 2,300,000 3.16 CSMC 2015-TWNI Trust, Floating Rate Note, 3/15/28 (144A) 2,297,825 3,946,668 2.50 CSMC Series 2013-14R REMICS, Floating Rate Note, 10/27/37 (144A) 4,042,722 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 45 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 3,887,589 3.00 CSMC Trust 2014-OAK1, Floating Rate Note, 11/25/44 (144A) $ 3,876,411 1,965,847 4.00 CSMC Trust 2014-Saf1, Series 2014-Saf1 Class A12, Floating Rate Note, 3/25/44 (144A) 1,995,102 3,500,000 2.76 CSMC Trust 2015-DEAL, Floating Rate Note, 4/16/29 (144A) 3,506,557 3,750,000 3.76 CSMC Trust 2015-SAND, Floating Rate Note, 8/15/30 (144A) 3,758,165 6,681,463 3.00 CSMC Trust, Series 2014-Win2 Class A5, Floating Rate Note, 10/25/44 (144A) 6,677,160 1,650,000 4.46 Eaton Vance CDO VIII, Ltd., Floating Rate Note, 8/15/22 (144A) 1,641,861 1,850,000 2.45 EQTY 2014-INNS Mortgage Trust REMICS, Floating Rate Note, 5/8/31 (144A) 1,840,766 3,530,000 2.05 EQTY 2014-INNS Mortgage Trust, Floating Rate Note, 5/8/31 (144A) 3,521,190 3,498,606 3.00 FirstKey Mortgage Trust 2014-1 REMICS, Floating Rate Note, 11/25/44 (144A) 3,496,421 6,078,969 2.28 FORT CRE 2016-1 LLC, Floating Rate Note, 5/21/36 (144A) 6,081,400 356,026 2.21 GAHR Commercial Mortgage Trust 2015-NRF, Floating Rate Note, 12/15/34 (144A) 357,431 4,450,000 2.42 Gale Force 3 Clo, Ltd., Floating Rate Note, 4/19/21 (144A) 4,374,079 461,033 Global Mortgage Securitization, Ltd., 5.25%, 4/25/32 (144A) 451,065 189,583 1.30 Global Mortgage Securitization, Ltd., Floating Rate Note, 11/25/32 (144A) 175,493 2,009,623 1.25 Global Mortgage Securitization, Ltd., Floating Rate Note, 4/25/32 (144A) 1,902,751 1,773,542 1.74 Gosforth Funding 2016-1 Plc, Floating Rate Note, 2/15/58 (144A) 1,777,914 3,350,000 2.21 GP Portfolio Trust 2014-GGP, Floating Rate Note, 2/15/27 (144A) 3,354,619 3,500,000 4.16 GS Mortgage Securities Corp Trust 2016-ICE2, Floating Rate Note, 2/15/33 (144A) 3,550,198 3,200,000 6.66 GS Mortgage Securities Corp Trust 2016-ICE2, Floating Rate Note, 2/15/33 (144A) 3,302,131 2,811,090 5.95 GS Mortgage Securities Trust 2007-GG10 REMICS, Floating Rate Note, 8/10/45 2,808,184 2,885,000 2.52 GS Mortgage Securities Trust 2014-GSFL, Floating Rate Note, 7/15/31 (144A) 2,857,186 2,000,000 3.68 GS Mortgage Securities Trust 2014-GSFL, Floating Rate Note, 7/15/31 (144A) 2,009,752 316,289 1.76 GSAA Home Equity Trust 2004-6, Floating Rate Note, 6/25/34 317,129 The accompanying notes are an integral part of these financial statements. 46 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 382,187 1.72 GSAA Home Equity Trust 2004-8, Floating Rate Note, 9/25/34 $ 377,297 208,611 1.91 HarborView Mortgage Loan Trust 2004-4, Floating Rate Note, 6/19/34 200,341 6,846,298 1.22 HomeBanc Mortgage Trust 2005-3, Floating Rate Note, 7/25/35 6,748,237 1,151,675 2.08 Homestar Mortgage Acceptance Corp. REMICS, Floating Rate Note, 9/25/34 1,127,272 4,469,109 1.62 Homestar Mortgage Acceptance Corp., Floating Rate Note, 3/25/34 4,273,299 555,622 1.68 Homestar Mortgage Acceptance Corp., Floating Rate Note, 6/25/34 548,457 875,940 1.88 Homestar Mortgage Acceptance Corp., Floating Rate Note, 7/25/34 866,642 903,358 2.14 Homestar Mortgage Acceptance Corp., Floating Rate Note, 7/25/34 897,044 3,500,000 2.41 Hudsons Bay Simon JV Trust 2015-HBS, Floating Rate Note, 8/7/34 (144A) 3,503,365 2,480,000 2.61 Hyatt Hotel Portfolio Trust 2015-HYT, Floating Rate Note, 11/15/29 (144A) 2,486,203 641,563 1.68 Impac CMB Trust Series 2003-8, Floating Rate Note, 10/25/33 614,452 457,385 1.62 Impac CMB Trust Series 2004-5, Floating Rate Note, 8/25/34 445,179 208,958 3.40 Impac CMB Trust Series 2004-8, Floating Rate Note, 8/25/34 200,353 8,150,000 1.88 Impac Secured Assets Cmn Owner Trust, Series 2004-3 Class M1, Floating Rate Note, 11/25/34 7,982,374 1,007,067 4.16 Invitation Homes 2014-SFR1 Trust REMICS, Floating Rate Note, 6/17/31 (144A) 1,007,064 7,900,000 2.41 JP Morgan Chase Commercial Mortgage Securities Trust 2016-ASH, Floating Rate Note, 10/15/34 (144A) 7,925,201 3,600,000 3.01 JP Morgan Chase Commercial Mortgage Securities Trust 2016-WPT, Floating Rate Note, 10/15/33 (144A) 3,631,466 4,400,000 2.26 JP Morgan Chase Commercial Mortgage Securities Trust 2016-WSP, Floating Rate Note, 8/15/33 (144A) 4,403,564 24,584 6.45 JP Morgan Chase Commercial Mortgage Securities Corp., Pass-Through Certificates Series 2002 CIBC4, Floating Rate Note, 5/12/34 24,787 219,555 4.84 JP Morgan Chase Commercial Mortgage Securities Trust 2004-LN2, Floating Rate Note, 7/15/41 (144A) 219,061 60,170 1.07 JP Morgan Chase Commercial Mortgage Securities Trust 2006-LDP9, Floating Rate Note, 5/15/47 59,779 2,270,752 5.79 JP Morgan Chase Commercial Mortgage Securities Trust 2007-CIBC20, Floating Rate Note, 2/12/51 2,288,527 6,722,731 5.88 JP Morgan Chase Commercial Mortgage Securities Trust 2007-LDP12, Floating Rate Note, 2/15/51 6,756,777 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 47 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 2,448,190 3.50 JP Morgan Chase Commercial Mortgage Securities Trust 2013-A5, Floating Rate Note, 7/25/20 $ 2,474,011 5,600,000 2.16 JP Morgan Chase Commercial Mortgage Securities Trust 2014-BXH, Floating Rate Note, 4/15/27 (144A) 5,553,191 4,280,000 2.31 JP Morgan Chase Commercial Mortgage Securities Trust 2014-CBM, Floating Rate Note, 10/15/29 (144A) 4,290,688 3,470,000 2.86 JP Morgan Chase Commercial Mortgage Securities Trust 2014-CBM, Floating Rate Note, 10/15/29 (144A) 3,487,325 1,250,000 3.11 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL4 REMICS, Floating Rate Note, 12/16/30 (144A) 1,238,537 450,476 2.66 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL4, Floating Rate Note, 12/16/30 (144A) 450,616 2,500,000 3.01 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL5 REMICS, Floating Rate Note, 7/15/31 (144A) 2,472,313 400,000 2.26 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL5, Floating Rate Note, 7/15/31 (144A) 401,439 3,436,661 2.31 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL6, Floating Rate Note, 11/17/31 (144A) 3,442,050 3,750,000 1.83 JP Morgan Chase Commercial Mortgage Securities Trust 2014-INN, Floating Rate Note, 6/15/29 (144A) 3,754,672 3,500,000 2.61 JP Morgan Chase Commercial Mortgage Securities Trust 2014-INN, Floating Rate Note, 6/15/29 (144A) 3,500,003 3,770,000 2.51 JP Morgan Chase Commercial Mortgage Securities Trust 2014-PHH, Floating Rate Note, 8/16/27 (144A) 3,778,261 989,837 2.16 JP Morgan Chase Commercial Mortgage Securities Trust 2015-FL7 REMICS, Floating Rate Note, 5/15/28 (144A) 988,033 3,600,000 2.71 JP Morgan Chase Commercial Mortgage Securities Trust 2015-FL7, Floating Rate Note, 5/15/28 (144A) 3,579,008 4,500,000 3.66 JP Morgan Chase Commercial Mortgage Securities Trust 2015-SGP, Floating Rate Note, 7/15/36 (144A) 4,528,094 1,758,748 5.86 LB-UBS Commercial Mortgage Trust 2007-C6, Floating Rate Note, 7/15/40 1,762,876 3,247,537 5.87 LB-UBS Commercial Mortgage Trust 2007-C7 REMICS, Floating Rate Note, 9/15/45 3,296,251 191,424 1.20 Lehman Brothers Small Balance Commercial Mortgage Trust 2006-1, Floating Rate Note, 4/25/31 (144A) 184,190 373,445 1.21 Lehman Brothers Small Balance Commercial Mortgage Trust 2006-1, Floating Rate Note, 4/25/31 (144A) 360,787 155,890 1.93 Lehman Brothers Small Balance Commercial Mortgage Trust 2007-3 Class 1A4, Floating Rate Note, 10/25/37 (144A) 153,941 235,133 2.03 Lehman Brothers Small Balance Commercial Mortgage Trust 2007-3, Floating Rate Note, 10/25/37 (144A) 233,928 1,269,753 1.48 Lehman XS Trust Series 2005-2, Floating Rate Note, 8/25/35 1,219,370 The accompanying notes are an integral part of these financial statements. 48 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 7,861,418 2.78 LSTAR Commercial Mortgage Trust 2016-7, Floating Rate Note, 12/1/21 (144A) $ 7,792,630 6,115,293 2.78 LSTAR Securities Investment Trust 2016-5, Floating Rate Note, 11/1/21 (144A) 6,097,726 267,148 2.78 LSTAR Securities Investment, Ltd., 2015-10, Floating Rate Note, 11/1/20 (144A) 267,065 2,724,966 2.78 LSTAR Securities Investment, Ltd., 2015-7, Floating Rate Note, 7/1/17 (144A) 2,717,303 1,525,266 2.78 LSTAR Securities Investment, Ltd., 2015-8, Floating Rate Note, 8/3/20 (144A) 1,527,113 4,172,921 2.78 LSTAR Securities Investment, Ltd., 2015-9, Floating Rate Note, 10/1/20 (144A) 4,157,272 2,241,582 2.78 LSTAR Securities Investment, Ltd., 2016-1, Floating Rate Note, 1/1/21 (144A) 2,214,353 3,766,067 2.78 LSTAR Securities Investment, Ltd., 2016-2 REMICS, Floating Rate Note, 3/1/21 (144A) 3,766,067 4,144,237 2.78 LSTAR Securities Investment, Ltd., 2016-3, Floating Rate Note, 9/1/21 (144A) 4,115,746 4,748,530 2.78 LSTAR Securities Investment, Ltd., 2016-4, Floating Rate Note, 10/1/21 (144A) 4,716,589 6,438,181 2.78 LSTAR Securities Investment, Ltd., 2017-1, Floating Rate Note, 1/1/22 (144A) 6,422,085 4,926,159 2.78 LSTAR Securities Investment, Ltd., 2017-2, Floating Rate Note, 2/1/22 (144A) 4,871,232 1,961,194 4.50 Marketplace Loan Trust, 2016-Bs1 Series 2016-Bs1 Class A, Floating Rate Note, 1/15/21 (144A) 1,971,000 293,808 1.33 MASTR Alternative Loan Trust 2005-1, Floating Rate Note, 2/25/35 291,717 1,202,864 1.35 Mellon Residential Funding Corp., Mortgage Pass-Through Trust Series 2000-TBC3, Floating Rate Note, 12/15/30 1,147,136 817,142 2.18 Merrill Lynch Mortgage Investors Trust Series MLCC 2003-A, Floating Rate Note, 3/25/28 763,687 1,744,173 1.64 Merrill Lynch Mortgage Investors Trust Series MLCC 2003-C REMICS, Floating Rate Note, 6/25/28 1,657,954 1,887,715 2.02 Merrill Lynch Mortgage Investors Trust Series MLCC 2003-C, Floating Rate Note, 6/25/28 1,858,275 562,942 1.62 Merrill Lynch Mortgage Investors Trust Series MLCC 2003-G, Floating Rate Note, 1/25/29 538,106 143,504 2.67 Merrill Lynch Mortgage Investors Trust Series MLCC 2003-G, Floating Rate Note, 1/25/29 141,961 1,093,651 1.62 Merrill Lynch Mortgage Investors Trust Series MLCC 2003-H, Floating Rate Note, 1/25/29 1,072,364 276,012 1.82 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-B, Floating Rate Note, 5/25/29 271,520 1,637,768 1.54 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-C, Floating Rate Note, 7/25/29 1,521,305 83,067 2.32 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-C, Floating Rate Note, 7/25/29 79,761 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 49 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 304,620 2.96 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-D, Floating Rate Note, 9/25/29 $ 302,957 1,765,582 2.15 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-E, Floating Rate Note, 11/25/29 1,706,106 1,713,142 1.54 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-G, Floating Rate Note, 1/25/30 1,615,392 573,689 1.92 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-G, Floating Rate Note, 1/25/30 553,577 1,551,702 1.44 Merrill Lynch Mortgage Investors Trust Series MLCC 2005-A, Floating Rate Note, 3/25/30 1,502,358 523,345 5.52 ML-CFC Commercial Mortgage Trust 2006-3, Floating Rate Note, 7/12/46 522,719 8,036,023 Morgan Stanley Capital I Trust 2007-HQ13, 5.569%, 12/15/44 8,116,891 2,639,002 5.57 Morgan Stanley Capital I Trust 2007-TOP25, Floating Rate Note, 11/12/49 2,675,262 3,860,000 2.66 Morgan Stanley Capital I Trust 2015-XLF1, Floating Rate Note, 8/14/31 (144A) 3,864,215 2,870,000 3.11 Morgan Stanley Capital I Trust 2015-XLF1, Floating Rate Note, 8/14/31 (144A) 2,874,127 3,000,000 3.66 Morgan Stanley Capital I Trust 2015-XLF1, Floating Rate Note, 8/17/26 (144A) 3,000,000 3,500,000 2.26 Morgan Stanley Capital I Trust 2017-PRME, Floating Rate Note, 2/15/34 (144A) 3,478,222 1,861,680 1.52 Morgan Stanley Mortgage Loan Trust 2005-5AR, Floating Rate Note, 9/25/35 1,860,616 1,389,218 1.26 Morgan Stanley Mortgage Loan Trust 2005-6AR, Floating Rate Note, 11/25/35 1,362,312 26,005 1.25 Morgan Stanley Mortgage Loan Trust 2005-6AR, Floating Rate Note, 11/25/35 25,986 2,527,459 1.76 MortgageIT Trust 2004-1, Floating Rate Note, 11/25/34 2,464,035 2,250,000 2.00 Nelder Grove CLO, Ltd., Floating Rate Note, 8/28/26 (144A) 2,249,667 2,645,434 2.93 Newstar Trust, Floating Rate Note, 1/20/23 (144A) 2,645,285 890,498 0.93 Nomura Resecuritization Trust 2014-1R, Floating Rate Note, 10/26/36 (144A) 873,093 7,942,260 2.37 NorthStar 2016-1, Floating Rate Note, 9/25/31 (144A) 7,928,441 3,351,502 1.37 Opteum Mortgage Acceptance Corp., Asset Backed Pass-Through Certificates 2005-4, Floating Rate Note, 11/25/35 3,183,847 3,223,241 2.39 Palmer Square Loan Funding 2016-2, Ltd., Floating Rate Note, 6/21/24 (144A) 3,223,073 500,000 3.14 Palmer Square Loan Funding 2016-2, Ltd., Floating Rate Note, 6/21/24 (144A) 499,972 3,500,000 1.59 Pepper Residential Securities Trust No 14, Floating Rate Note, 6/13/17 3,501,424 The accompanying notes are an integral part of these financial statements. 50 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 2,811,647 2.89 Pepper Residential Securities Trust, Floating Rate Note, 3/10/58 (144A) $ 2,812,459 3,500,000 0.00 Pepper Residential Securities Trust, No. 16 Series 16A Class A1U2, Floating Rate Note, 3/13/18 3,500,000 8,000,000 1.95 Pepper Residential Securities Trust, Series 18A Class A1Ua, Floating Rate Note, 8/12/58 8,000,000 2,564,134 2.36 PFP 2015-2, Ltd., Floating Rate Note, 7/14/34 (144A) 2,562,880 2,600,000 1.83 Pfp 2017-3, Ltd., Series 2017-3 Class A, Floating Rate Note, 1/14/35 (144A) 2,606,214 2,998,945 3.50 Pmt Loan Trust, 2013-J1 Series 2013-J1 Class A6, Floating Rate Note, 9/25/43 (144A) 3,002,485 4,089,468 Pretium Mortgage Credit Partners I 2016-NPL5 LLC, 3.875%, 9/27/31 (Step) (144A) 4,089,538 1,700,000 2.31 Progress Residential 2016-SFR2 Trust, Floating Rate Note, 1/17/34 (144A) 1,715,375 2,400,000 2.66 Progress Residential 2016-SFR2 Trust, Floating Rate Note, 1/17/34 (144A) 2,402,140 3,374,658 2.33 RAIT 2016-FL6 Trust, Floating Rate Note, 11/13/31 (144A) 3,374,658 11,058 1.33 RALI Series 2002-QS16 Trust, Floating Rate Note, 10/25/17 11,009 181,295 1.23 RALI Series 2003-QS5 Trust, Floating Rate Note, 3/25/18 179,655 1,873,625 1.38 RALI Series 2005-QA1 Trust, Floating Rate Note, 1/25/35 1,851,750 2,495,904 Readycap Mortgage Trust 2016-3, 2.93997%, 11/20/38 (144A) 2,472,399 3,864,052 2.31 RESI Finance LP 2003-CB1, Floating Rate Note, 7/9/35 3,670,850 1,399,080 1.82 RESI MAC, 2014-1A, Floating Rate Note, 6/12/19 1,390,088 364,693 1.23 Residential Asset Securitization Trust 2003-A15, Floating Rate Note, 2/25/34 329,071 1,246,851 1.99 Resource Capital Corp., 2014-CRE2, Ltd., Floating Rate Note, 4/15/32 (144A) 1,246,434 840,617 2.17 Resource Capital Corp., 2015-CRE4, Ltd., Floating Rate Note, 8/15/32 (144A) 837,171 337,731 RREF 2015-LT7 LLC, 3.0%, 12/27/32 (144A) 337,805 368,623 1.94 Sequoia Mortgage Trust 2003-2, Floating Rate Note, 6/20/33 358,058 141,060 1.62 Sequoia Mortgage Trust 2003-8, Floating Rate Note, 1/20/34 134,294 207,472 2.65 Sequoia Mortgage Trust 2004-7, Floating Rate Note, 8/20/34 208,616 2,300,194 1.91 Silver Bay Realty 2014-1 Trust, Floating Rate Note, 9/17/31 (144A) 2,301,635 438,090 1.78 Springleaf Mortgage Loan Trust 2013-2, Floating Rate Note, 12/28/65 (144A) 438,460 2,000,000 2.37 Stone Tower CLO VI, Ltd., Floating Rate Note, 4/17/21 (144A) 1,999,909 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 51 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,262,590 3.29 Structured Adjustable Rate Mortgage Loan Trust, Floating Rate Note, 3/25/34 $ 1,264,538 1,173,026 1.88 Structured Asset Mortgage Investments Trust 2002-AR5, Floating Rate Note, 5/19/33 1,150,515 251,865 1.92 Structured Asset Securities Corp., Mortgage Pass-Through Certificates Series 1998-8, Floating Rate Note, 8/25/28 250,596 40,395 1.48 Structured Asset Securities Corp., Mortgage Pass-Through Certificates Series 2003-35, Floating Rate Note, 12/25/33 40,315 241,605 1.08 Structured Asset Securities Corp., Trust 2005-14, Floating Rate Note, 7/25/35 191,538 4,500,000 2.51 Symphony CLO VIII LP, Floating Rate Note, 1/9/23 (144A) 4,502,286 467,180 2.74 Thornburg Mortgage Securities Trust 2004-4, Floating Rate Note, 12/25/44 461,015 961,479 2.98 Velocity Commercial Capital Loan Trust 2014-1, Floating Rate Note, 9/25/44 (144A) 967,489 5,001,594 VOLT LI LLC, 3.5%, 10/25/46 (Step) (144A) 5,038,307 660,580 VOLT NPL X LLC, 3.375%, 10/26/54 (Step) (144A) 662,242 2,929,590 2.34 Voya CLO 2012-3, Ltd., Floating Rate Note, 10/15/22 (144A) 2,929,993 574,195 6.05 Wachovia Bank Commercial Mortgage Trust Series 2007-C33 REMICS, Floating Rate Note, 2/15/51 573,550 2,600,000 5.82 Wachovia Bank Commercial Mortgage Trust Series 2007-C34 REMICS, Floating Rate Note, 5/15/46 2,641,946 2,500,000 2.76 Wells Fargo Commercial Mortgage Trust 2014-TISH REMICS, Floating Rate Note, 2/15/27 (144A) 2,501,097 1,500,000 4.41 Wells Fargo Commercial Mortgage Trust 2014-TISH, Floating Rate Note, 1/15/27 (144A) 1,452,942 1,211,076 3.73 Wells Fargo Credit Risk Transfer Securities Trust 2015, Floating Rate Note, 11/25/25 (144A) 1,216,847 1,162,882 3.83 Wells Fargo Credit Risk Transfer Securities Trust 2015, Floating Rate Note, 11/25/25 (144A) 1,168,689 1,664,897 3.06 Wells Fargo Mortgage Backed Securities 2005-AR13 Trust, Floating Rate Note, 5/25/35 1,667,879 31,223 1.26 Westwood CDO II, Ltd., Floating Rate Note, 4/25/22 (144A) 31,211 ------------- $ 573,185,474 ------------- Total Banks $ 578,736,246 ----------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 0.8% Other Diversified Financial Services -- 0.7% 3,600,000 5.76 Bank of America Commercial Mortgage Trust 2007-3, Floating Rate Note, 6/10/49 $ 3,608,785 836,778 5.72 Credit Suisse Commercial Mortgage Trust Series 2007-C3, Floating Rate Note, 6/15/39 836,340 The accompanying notes are an integral part of these financial statements. 52 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Other Diversified Financial Services -- (continued) 887,539 5.96 Credit Suisse Commercial Mortgage Trust Series 2007-C4 REMICS, Floating Rate Note, 9/15/39 $ 891,809 5,000,000 5.96 Credit Suisse Commercial Mortgage Trust Series 2007-C4, Floating Rate Note, 9/15/39 5,032,018 1,878,408 1.08 Crusade Global Trust No 1 of 2007, Floating Rate Note, 4/19/38 1,868,310 1,857,631 5.79 Morgan Stanley Capital I Trust 2007-TOP27 REMICS, Floating Rate Note, 6/11/42 1,860,023 7,074,919 6.30 Morgan Stanley Capital I Trust 2008-TOP29 REMICS, Floating Rate Note, 1/11/43 7,248,155 ------------- $ 21,345,440 ----------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.1% 3,500,000 2.91 BAMLL Commercial Mortgage Securities Trust 2015-ASHF REMICS, Floating Rate Note, 1/15/28 (144A) $ 3,471,300 ------------- Total Diversified Financials $ 24,816,740 ----------------------------------------------------------------------------------------------------------- REAL ESTATE -- 0.0%+ Residential REIT -- 0.0%+ 125,000 3.41 American Homes 4 Rent 2014-SFR1 REMICS, Floating Rate Note, 6/17/31 (144A) $ 125,000 ------------- Total Real Estate $ 125,000 ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- 5.8% 1,158,094 2.78 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 10/25/23 $ 1,170,478 834,957 2.38 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 4/25/28 836,997 1,947,693 2.28 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 4/25/29 1,957,599 1,312,179 1.73 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 5/25/24 1,317,265 5,548,893 1.98 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 7/25/24 5,562,915 4,156,433 2.08 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 7/25/29 4,176,502 1,899,763 2.73 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 8/25/28 1,922,535 1,744,818 2.93 Fannie Mae Connecticut Avenue Securities, Floating Rate Note, 9/25/28 1,768,591 3,480,000 2.13 Fannie Mae Connecticut Avenue Securities, Series 2017-C02 Class 2M1, Floating Rate Note, 9/15/29 3,483,290 2,616,128 1.13 Fannie Mae Trust 2003-W6, Floating Rate Note, 9/25/42 2,600,491 159,993 2.72 Fannie Mae Trust 2005-W4, Floating Rate Note, 6/26/45 170,685 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 53 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 1,286,597 1.04 Fannie Mae Whole Loan, Floating Rate Note, 11/25/46 $ 1,288,665 1,034,488 Fannie Mae, 2.5%, 6/25/24 1,043,560 953,474 Fannie Mae, 3.0%, 1/25/29 962,121 970,651 Fannie Mae, 3.0%, 11/25/18 977,919 175,616 Fannie Mae, 3.0%, 8/25/25 176,739 199,300 Fannie Mae, 3.5%, 10/25/23 199,758 525,444 Fannie Mae, 3.5%, 6/25/21 534,433 1,315,411 Fannie Mae, 4.5%, 9/25/18 1,335,559 308,199 Fannie Mae, 4.5%, 9/25/35 309,735 416,535 Federal Home Loan Banks, 2.9%, 4/20/17 416,920 705,711 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 1/15/33 706,027 180,521 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 1/15/36 180,110 1,747,005 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 1/15/37 1,738,278 29,145 0.92 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 10/15/20 29,119 48,187 1.72 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 10/15/31 48,941 712,080 1.35 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 10/15/37 717,208 281,006 1.39 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 10/15/37 284,981 70,253 1.37 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 11/15/31 71,343 162,613 1.77 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 11/15/33 166,795 114,054 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 11/15/35 113,772 527,324 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 11/15/36 526,435 284,344 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 11/15/36 283,766 198,108 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 11/15/40 198,234 69,858 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/20 70,188 309,313 1.22 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/28 310,033 97,808 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/32 97,709 18,020 1.27 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/32 18,095 224,092 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/32 224,870 The accompanying notes are an integral part of these financial statements. 54 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 240,469 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/32 $ 241,435 600,605 1.47 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/39 603,166 388,133 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/41 385,848 41,507 1.00 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/19 41,503 99,731 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/25 99,836 167,575 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/29 167,355 428,323 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/30 428,911 395,069 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/33 395,349 220,236 1.32 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/33 222,825 543,945 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/36 541,332 196,101 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/36 195,348 318,991 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 2/15/39 320,028 855,918 1.82 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 3/15/24 875,357 419,745 1.77 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 3/15/32 430,184 129,101 1.47 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 3/15/32 130,281 593,008 1.77 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 3/15/32 611,151 573,091 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 3/15/36 571,765 63,823 1.22 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 3/15/39 64,078 1,313,041 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 3/15/41 1,318,241 348,527 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 4/15/36 347,757 75,167 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/29 75,625 248,862 2.28 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/33 258,074 585,115 1.11 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/35 583,370 171,430 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/35 171,778 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 55 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 284,899 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/36 $ 284,408 133,846 1.11 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/37 133,221 75,502 2.02 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/37 76,510 59,679 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 5/15/41 59,425 20,702 1.22 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 6/15/23 20,740 320,565 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 6/15/33 320,910 350,468 1.19 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 6/15/36 350,378 1,265,825 1.08 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 6/15/36 1,261,065 25,887 1.16 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 7/15/21 25,935 319,578 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 7/15/23 321,009 356,684 1.01 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 7/15/34 353,498 690,164 1.27 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 7/15/36 692,255 29,162 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 7/15/36 29,149 274,735 0.97 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 7/15/36 274,883 293,028 1.12 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 7/15/40 292,111 255,167 0.97 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 8/15/26 255,177 456,611 1.02 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 8/15/35 456,494 255,620 1.02 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 8/15/35 254,424 443,051 1.02 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 8/15/36 440,005 490,509 1.07 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 9/15/26 491,476 91,055 1.37 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 9/15/32 92,322 237,776 1.19 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 9/15/36 237,936 161,707 1.17 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 9/15/36 161,624 1,549,934 Federal Home Loan Mortgage Corp., 3.0%, 12/15/24 1,561,425 The accompanying notes are an integral part of these financial statements. 56 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 443,554 1.02 Federal Home Loan Mortgage Corp., Floating Rate Note, 1/15/35 $ 441,286 91,923 1.12 Federal Home Loan Mortgage Corp., Floating Rate Note, 2/15/18 91,873 354,636 1.77 Federal Home Loan Mortgage Corp., Floating Rate Note, 3/15/32 363,456 367,391 1.37 Federal Home Loan Mortgage Corp., Floating Rate Note, 4/15/28 373,463 215,900 1.37 Federal Home Loan Mortgage Corp., Floating Rate Note, 6/15/31 219,246 2,616,428 1.47 Federal Home Loan Mortgage Corp., Floating Rate Note, 8/15/35 2,640,621 146,326 1.43 Federal National Mortgage Association REMICS, Floating Rate Note, 1/18/32 148,701 234,544 1.48 Federal National Mortgage Association REMICS, Floating Rate Note, 1/25/32 238,917 93,867 1.43 Federal National Mortgage Association REMICS, Floating Rate Note, 1/25/33 95,609 257,411 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 1/25/33 257,906 160,046 1.33 Federal National Mortgage Association REMICS, Floating Rate Note, 1/25/40 160,843 383,769 1.08 Federal National Mortgage Association REMICS, Floating Rate Note, 10/25/35 381,721 1,477,081 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 10/25/36 1,474,639 77,968 1.33 Federal National Mortgage Association REMICS, Floating Rate Note, 10/25/37 78,177 481,073 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 10/25/37 485,295 370,222 2.00 Federal National Mortgage Association REMICS, Floating Rate Note, 10/25/38 378,414 5,443 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 10/27/37 5,439 1,191,774 1.78 Federal National Mortgage Association REMICS, Floating Rate Note, 11/18/32 1,220,363 287,774 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 11/25/31 292,361 253,241 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 11/25/31 257,278 434,854 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 11/25/33 435,753 308,397 1.08 Federal National Mortgage Association REMICS, Floating Rate Note, 11/25/34 309,891 217,298 1.10 Federal National Mortgage Association REMICS, Floating Rate Note, 11/25/36 216,306 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 57 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 65,934 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/23 $ 66,083 192,259 1.78 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/23 194,377 63,057 1.33 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/30 64,107 538,860 1.68 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/31 546,337 238,008 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/32 239,382 134,872 1.02 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/36 133,930 286,183 1.40 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/37 287,026 95,562 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 12/25/38 95,812 210,119 1.53 Federal National Mortgage Association REMICS, Floating Rate Note, 2/25/33 214,351 497,561 1.13 Federal National Mortgage Association REMICS, Floating Rate Note, 2/25/33 501,417 529,672 1.09 Federal National Mortgage Association REMICS, Floating Rate Note, 2/25/35 527,695 369,290 1.03 Federal National Mortgage Association REMICS, Floating Rate Note, 2/25/37 366,546 287,882 0.98 Federal National Mortgage Association REMICS, Floating Rate Note, 2/25/37 285,980 138,670 1.48 Federal National Mortgage Association REMICS, Floating Rate Note, 2/25/38 140,385 47,079 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/23 47,088 345,856 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/24 349,658 174,427 1.16 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/28 175,224 944,850 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/34 944,915 79,427 1.08 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/36 78,397 118,345 1.78 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/37 121,693 560,656 1.03 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/37 556,481 273,332 1.03 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/37 271,580 1,213,329 1.20 Federal National Mortgage Association REMICS, Floating Rate Note, 3/25/45 1,182,901 113,822 1.08 Federal National Mortgage Association REMICS, Floating Rate Note, 4/25/25 113,770 The accompanying notes are an integral part of these financial statements. 58 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 1,287,710 1.68 Federal National Mortgage Association REMICS, Floating Rate Note, 4/25/32 $ 1,306,723 643,133 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 4/25/33 646,229 312,749 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 4/25/42 313,642 241,136 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 5/25/33 241,529 244,334 1.13 Federal National Mortgage Association REMICS, Floating Rate Note, 5/25/36 243,468 737,532 1.09 Federal National Mortgage Association REMICS, Floating Rate Note, 5/25/36 736,499 435,105 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 5/25/37 431,551 146,967 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 5/25/40 148,241 384,134 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 5/25/40 385,269 519,292 1.33 Federal National Mortgage Association REMICS, Floating Rate Note, 5/25/40 523,737 151,266 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 6/25/23 151,896 469,034 1.23 Federal National Mortgage Association REMICS, Floating Rate Note, 6/25/36 469,201 540,106 1.02 Federal National Mortgage Association REMICS, Floating Rate Note, 6/25/37 535,230 49,687 1.01 Federal National Mortgage Association REMICS, Floating Rate Note, 6/25/37 49,290 186,738 1.03 Federal National Mortgage Association REMICS, Floating Rate Note, 6/25/37 185,310 53,695 1.23 Federal National Mortgage Association REMICS, Floating Rate Note, 6/25/37 53,786 39,648 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 7/18/27 40,131 278,513 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/31 282,952 199,478 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/31 202,989 121,664 1.78 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/32 123,950 332,063 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/34 332,164 101,507 1.23 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/34 101,538 1,340,679 1.08 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/35 1,334,238 1,284,995 1.03 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/35 1,279,812 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 59 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 176,685 1.07 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/36 $ 175,889 174,867 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 7/25/37 174,937 126,668 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 8/25/31 127,216 54,032 1.38 Federal National Mortgage Association REMICS, Floating Rate Note, 8/25/32 54,847 178,187 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 8/25/32 179,013 4,671 1.18 Federal National Mortgage Association REMICS, Floating Rate Note, 8/25/33 4,685 129,158 1.33 Federal National Mortgage Association REMICS, Floating Rate Note, 8/25/36 129,077 863 1.58 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/20 864 49,075 1.68 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/21 49,822 230,373 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/32 231,227 1,240,469 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/33 1,243,088 234,473 1.35 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/36 234,930 478,917 1.28 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/37 479,497 226,858 1.35 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/37 229,683 125,733 1.33 Federal National Mortgage Association REMICS, Floating Rate Note, 9/25/37 127,299 192,259 2.02 Federal National Mortgage Association, Floating Rate Note, 12/25/23 195,893 4,541,240 1.08 Federal National Mortgage Association, Floating Rate Note, 12/25/33 4,525,812 10,167,381 1.23 Federal National Mortgage Association, Floating Rate Note, 2/25/38 10,188,676 322,440 1.08 Federal National Mortgage Association, Floating Rate Note, 3/25/18 322,428 92,573 3.01 Federal National Mortgage Association, Floating Rate Note, 4/25/35 95,228 320,734 1.12 Freddie Mac Strips, Floating Rate Note, 12/15/36 320,110 245,053 1.02 Freddie Mac Strips, Floating Rate Note, 8/15/36 243,884 1,059,370 1.07 Freddie Mac Strips, Floating Rate Note, 8/15/36 1,056,180 153,507 3.18 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 10/25/24 153,893 1,500,000 2.98 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 10/25/28 1,527,701 The accompanying notes are an integral part of these financial statements. 60 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 479,269 2.23 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 11/25/23 $ 481,054 942,390 1.98 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 11/25/28 945,961 1,689,706 1.78 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 2/25/24 1,690,965 750,000 2.08 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 3/25/29 752,185 1,209,987 1.58 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 4/25/29 1,211,504 1,444,143 2.23 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 7/25/28 1,450,721 300,000 3.68 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 7/25/28 312,569 128,286 3.18 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 8/25/24 128,861 3,974,302 2.13 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 8/25/29 3,988,389 1,452,569 2.53 Freddie Mac Structured Agency Credit Risk Debt Notes, Floating Rate Note, 9/25/28 1,461,758 5,291,965 2.08 Freddie Mac Structured Agency Credit Risk Debt Notes, Series 2015-Hq2 Class M1, Floating Rate Note, 5/25/35 5,304,933 584,233 Freddie Mac, 2.0%, 11/15/20 588,157 664,216 Freddie Mac, 2.0%, 8/15/20 667,440 2,035,628 Freddie Mac, 3.0%, 10/15/25 2,063,325 327,151 Freddie Mac, 3.0%, 4/15/24 328,328 1,481,825 Freddie Mac, 3.0%, 5/15/29 1,506,438 3,072,441 Freddie Mac, 3.1%, 2/15/25 3,104,790 1,028,726 Freddie Mac, 3.5%, 1/15/24 1,039,358 9,292,000 4.77 FREMF Mortgage Trust 2011-K702, Floating Rate Note, 4/25/44 (144A) 9,498,694 250,000 4.88 FREMF Mortgage Trust 2011-K703, Floating Rate Note, 7/25/44 (144A) 257,016 3,897,000 2.90 FREMF Mortgage Trust 2013-K502, Floating Rate Note, 3/27/45 (144A) 3,895,646 1,487,874 3.00 FREMF Mortgage Trust 2014-KF04 REMICS, Floating Rate Note, 6/25/21 (144A) 1,503,183 5,183,551 4.79 FREMF Mortgage Trust 2014-KF05 REMICS, Floating Rate Note, 9/25/21 (144A) 5,030,678 4,186,920 3.36 FREMF Mortgage Trust 2014-KS02 REMICS, Floating Rate Note, 8/25/23 (144A) 4,170,549 9,161,779 2.59 FREMF Mortgage Trust 2015-KLSF REMICS, Floating Rate Note, 11/25/22 (144A) 9,249,894 13,905,688 1.13 Government National Mortgage Association REMICS, Floating Rate Note, 1/20/47 13,946,903 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 61 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- GOVERNMENT -- (continued) 503,112 Government National Mortgage Association, 3.0%, 2/16/24 $ 509,554 450,091 0.97 Government National Mortgage Association, Floating Rate Note, 1/16/33 451,105 786,099 1.02 Government National Mortgage Association, Floating Rate Note, 1/16/35 781,735 205,441 1.45 Government National Mortgage Association, Floating Rate Note, 10/16/39 207,737 249,855 1.18 Government National Mortgage Association, Floating Rate Note, 10/20/38 250,762 749,081 1.03 Government National Mortgage Association, Floating Rate Note, 2/20/35 744,894 775,229 1.27 Government National Mortgage Association, Floating Rate Note, 4/16/30 777,965 162,206 1.32 Government National Mortgage Association, Floating Rate Note, 4/16/32 164,294 170,131 1.17 Government National Mortgage Association, Floating Rate Note, 5/16/38 170,223 154,000 1.27 Government National Mortgage Association, Floating Rate Note, 6/16/31 154,706 281,603 1.77 Government National Mortgage Association, Floating Rate Note, 8/16/39 288,349 260,287 1.28 Government National Mortgage Association, Floating Rate Note, 8/20/38 261,744 700,061 1.31 NCUA Guaranteed Notes Trust REMICS, Floating Rate Note, 3/9/21 698,743 ------------- $ 185,830,695 ------------- Total Government $ 185,830,695 ----------------------------------------------------------------------------------------------------------- TOTAL COLLATERALIZED MORTGAGE OBLIGATIONS (Cost $797,578,446) $ 796,896,325 ----------------------------------------------------------------------------------------------------------- CORPORATE BONDS -- 28.8% ENERGY -- 1.7% Oil & Gas Equipment & Services -- 0.2% 5,985,000 Schlumberger Holdings Corp., 1.9%, 12/21/17 (144A) $ 5,995,546 ----------------------------------------------------------------------------------------------------------- Integrated Oil & Gas -- 1.0% 1,848,000 1.54 Bp Capital Markets Plc, Floating Rate Note, 5/10/18 $ 1,854,389 1,585,000 Chevron Corp., 1.718%, 6/24/18 1,590,089 1,385,000 1.42 Chevron Corp., Floating Rate Note, 11/16/18 1,394,706 2,550,000 1.10 Chevron Corp., Floating Rate Note, 3/2/18 2,552,530 3,115,000 1.30 Chevron Corp., Floating Rate Note, 3/3/20 3,116,330 4,190,000 1.41 Chevron Corp., Floating Rate Note, 5/16/18 4,210,824 2,700,000 1.54 Exxon Mobil Corp., Floating Rate Note, 2/28/18 2,716,035 The accompanying notes are an integral part of these financial statements. 62 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Integrated Oil & Gas -- (continued) 5,590,000 1.46 Shell International Finance BV, Floating Rate Note, 11/10/18 $ 5,629,611 1,390,000 1.20 Shell International Finance BV, Floating Rate Note, 5/10/17 1,390,470 2,650,000 1.30 Shell International Finance BV, Floating Rate Note, 9/12/19 2,659,726 3,280,000 1.09 Statoil ASA, Floating Rate Note, 11/9/17 3,284,061 2,555,000 1.33 Statoil ASA, Floating Rate Note, 5/15/18 2,559,114 ------------- $ 32,957,885 ----------------------------------------------------------------------------------------------------------- Oil & Gas Exploration & Production -- 0.2% 3,120,000 Canadian Natural Resources, Ltd., 1.75%, 1/15/18 $ 3,119,348 3,800,000 Canadian Natural Resources, Ltd., 5.7%, 5/15/17 3,817,522 ------------- $ 6,936,870 ----------------------------------------------------------------------------------------------------------- Oil & Gas Storage & Transportation -- 0.3% 2,650,000 Enterprise Products Operating LLC, 6.3%, 9/15/17 $ 2,704,465 3,190,000 Kinder Morgan Energy Partners LP, 5.95%, 2/15/18 3,298,805 1,280,000 Tennessee Gas Pipeline Co., LLC, 7.5%, 4/1/17 1,280,000 2,895,000 TransCanada PipeLines, Ltd., 1.625%, 11/9/17 2,895,156 ------------- $ 10,178,426 ------------- Total Energy $ 56,068,727 ----------------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 0.4% Aerospace & Defense -- 0.2% 5,155,000 United Technologies Corp., 1.8%, 6/1/17 $ 5,160,036 2,650,000 1.24 United Technologies Corp., Floating Rate Note, 11/1/19 2,667,175 ------------- $ 7,827,211 ----------------------------------------------------------------------------------------------------------- Industrial Conglomerates -- 0.2% 6,015,000 1.32 Honeywell International, Inc., Floating Rate Note, 10/30/19 $ 6,053,568 ------------- Total Capital Goods $ 13,880,779 ----------------------------------------------------------------------------------------------------------- TRANSPORTATION -- 0.1% Railroads -- 0.1% 2,600,000 Burlington Northern Santa Fe LLC, 5.65%, 5/1/17 $ 2,608,333 1,670,000 1.07 Canadian National Railway Co., Floating Rate Note, 11/14/17 1,670,985 ------------- $ 4,279,318 ------------- Total Transportation $ 4,279,318 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 63 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- AUTOMOBILES & COMPONENTS -- 1.9% Automobile Manufacturers -- 1.9% 2,650,000 1.66 Daimler Finance North America LLC, Floating Rate Note, 10/30/19 (144A) $ 2,662,943 1,275,000 1.35 Daimler Finance North America LLC, Floating Rate Note, 3/2/18 (144A) 1,277,128 5,555,000 1.50 Daimler Finance North America LLC, Floating Rate Note, 5/18/18 (144A) 5,572,287 3,761,000 1.37 Daimler Finance North America LLC, Floating Rate Note, 8/1/17 (144A) 3,764,517 3,215,000 1.74 Daimler Finance North America LLC, Floating Rate Note, 8/3/17 (144A) 3,222,211 2,980,000 2.01 Ford Motor Credit Co LLC, Floating Rate Note, 1/9/20 3,011,844 2,600,000 1.82 Ford Motor Credit Co. LLC, Floating Rate Note, 1/9/18 2,609,815 4,360,000 1.47 Ford Motor Credit Co. LLC, Floating Rate Note, 9/8/17 4,362,947 4,795,000 1.95 Ford Motor Credit Co., LLC, Floating Rate Note Series 1, 3/12/19 4,815,014 1,072,000 Nissan Motor Acceptance Corp., 1.95%, 9/12/17 (144A) 1,073,037 1,000,000 2.12 Nissan Motor Acceptance Corp., Floating Rate Note, 3/8/19 (144A) 1,009,748 3,115,000 1.81 Nissan Motor Acceptance Corp., Floating Rate Note, 4/6/18 (144A) 3,131,992 2,650,000 1.48 Nissan Motor Acceptance Corp., Floating Rate Note, 9/13/19 (144A) 2,657,894 3,150,000 Toyota Motor Credit Corp., 1.25%, 10/5/17 3,148,850 2,802,000 Toyota Motor Credit Corp., 1.75%, 5/22/17 2,804,326 2,650,000 1.46 Toyota Motor Credit Corp., Floating Rate Note, 10/18/19 2,661,427 4,400,000 1.73 Toyota Motor Credit Corp., Floating Rate Note, 2/19/19 4,453,099 2,589,000 1.11 Toyota Motor Credit Corp., Floating Rate Note, 5/16/17 2,589,831 2,501,000 1.48 Toyota Motor Credit Corp., Floating Rate Note, 7/13/18 2,509,666 2,500,000 1.35 Volkswagen Group of America Finance LLC, Floating Rate Note, 11/20/17 (144A) 2,501,588 ------------- $ 59,840,164 ------------- Total Automobiles & Components $ 59,840,164 ----------------------------------------------------------------------------------------------------------- MEDIA -- 0.2% Broadcasting -- 0.2% 6,795,000 1.71 NBCUniversal Enterprise, Inc., Floating Rate Note, 4/15/18 (144A) $ 6,836,490 ------------- Total Media $ 6,836,490 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 64 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- RETAILING -- 0.1% Home Improvement Retail -- 0.1% 2,600,000 1.33 The Home Depot, Inc., Floating Rate Note, 9/15/17 $ 2,605,164 ------------- Total Retailing $ 2,605,164 ----------------------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 0.4% Brewers -- 0.1% 2,580,000 Anheuser-Busch InBev Worldwide, Inc., 1.375%, 7/15/17 $ 2,577,405 ----------------------------------------------------------------------------------------------------------- Packaged Foods & Meats -- 0.1% 4,305,000 1.65 Mondelez International Holdings Netherlands BV, Floating Rate Note, 10/28/19 (144A) $ 4,322,797 ----------------------------------------------------------------------------------------------------------- Tobacco -- 0.2% 4,532,000 Reynolds American, Inc., 2.3%, 8/21/17 $ 4,544,726 ------------- Total Food, Beverage & Tobacco $ 11,444,928 ----------------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.7% Health Care Equipment -- 0.2% 2,945,000 Becton Dickinson and Co., 1.8%, 12/15/17 $ 2,947,197 2,680,000 1.76 Medtronic, Inc., Floating Rate Note, 3/15/20 2,728,106 ------------- $ 5,675,303 ----------------------------------------------------------------------------------------------------------- Managed Health Care -- 0.5% 9,700,000 1.76 Aetna, Inc., Floating Rate Note, 12/8/17 $ 9,736,812 2,960,000 UnitedHealth Group, Inc., 1.4%, 12/15/17 2,960,024 3,950,000 UnitedHealth Group, Inc., 1.45%, 7/17/17 3,952,666 ------------- $ 16,649,502 ------------- Total Health Care Equipment & Services $ 22,324,805 ----------------------------------------------------------------------------------------------------------- PHARMACEUTICALS, BIOTECHNOLOGY & LIFE SCIENCES -- 0.9% Biotechnology -- 0.8% 6,335,000 Abbvie, Inc., 1.8%, 5/14/18 $ 6,342,127 2,650,000 Amgen, Inc., 2.125%, 5/15/17 2,652,952 2,725,000 1.30 Amgen, Inc., Floating Rate Note, 5/22/17 2,726,313 3,484,000 1.65 Amgen, Inc., Floating Rate Note, 5/22/19 3,511,684 2,500,000 1.78 Baxalta, Inc., Floating Rate Note, 6/22/18 2,502,460 3,555,000 Biogen Idec, Inc., 6.875%, 3/1/18 3,721,687 2,650,000 Celgene Corp., 1.9%, 8/15/17 2,652,123 ------------- $ 24,109,346 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 65 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Pharmaceuticals -- 0.1% 1,400,000 1.14 Bayer US Finance LLC, Floating Rate Note, 10/6/17 (144A) $ 1,398,859 2,100,000 1.19 Pfizer, Inc., Floating Rate Note, 5/15/17 2,100,416 ------------- $ 3,499,275 ------------- Total Pharmaceuticals, Biotechnology & Life Sciences $ 27,608,621 ----------------------------------------------------------------------------------------------------------- BANKS -- 9.9% Diversified Banks -- 7.2% 5,985,000 1.66 ABN AMRO Bank NV, Floating Rate Note, 1/18/19 (144A) $ 6,000,884 653,260 1.18 American Express Bank FSB, Floating Rate Note, 6/12/17 653,426 3,115,000 Bank of America Corp., 2.0%, 1/11/18 3,122,962 1,350,000 2.06 Bank of America Corp., Floating Rate Note, 1/15/19 1,366,362 3,100,000 2.19 Bank of America Corp., Floating Rate Note, 1/20/23 3,143,028 2,875,000 2.07 Bank of America Corp., Floating Rate Note, 3/22/18 2,894,938 1,300,000 1.87 Bank of America Corp., Floating Rate Note, 4/1/19 1,311,371 3,060,000 1.43 Bank of America Corp., Floating Rate Note, 5/2/17 3,060,401 1,423,000 1.54 Bank of America Corp., Floating Rate Note, 8/25/17 1,425,500 5,135,000 1.39 Bank of America NA, Floating Rate Note, 6/5/17 5,138,677 2,300,000 1.13 Bank of Montreal, Floating Rate Note, 7/14/17 2,301,516 2,540,000 1.53 Bank of Montreal, Floating Rate Note, 7/18/19 2,556,670 2,665,000 1.50 Bank of Montreal, Floating Rate Note, 7/31/18 2,674,343 2,590,000 1.55 Caisse Centrale Desjardins, Floating Rate Note, 1/29/18 (144A) 2,597,664 2,610,000 1.47 Canadian Imperial Bank of Commerce, Floating Rate Note, 9/6/19 2,620,959 3,915,000 1.63 Citigroup, Inc., Floating Rate Note, 11/24/17 3,927,927 7,015,000 1.58 Citigroup, Inc., Floating Rate Note, 4/27/18 7,045,031 4,691,000 2.74 Citigroup, Inc., Floating Rate Note, 5/15/18 4,761,534 1,500,000 2.03 Citigroup, Inc., Floating Rate Note, 6/1/19 1,513,902 3,140,000 1.92 Citigroup, Inc., Floating Rate Note, 7/30/18 3,162,269 3,840,000 1.60 Citizens Bank NA, Floating Rate Note, 3/2/20 3,848,467 4,440,000 1.37 Cooperatieve Rabobank UA New York, Floating Rate Note, 4/28/17 4,441,101 2,525,000 1.55 Cooperatieve Rabobank UA New York, Floating Rate Note, 8/9/19 2,529,121 2,500,000 1.50 Credit Agricole SA London, Floating Rate Note, 6/12/17 (144A) 2,501,680 2,650,000 1.53 Danske Bank AS, Floating Rate Note, 9/6/19 (144A) 2,656,792 4,680,000 Discover Bank, 2.0%, 2/21/18 4,683,941 3,195,000 HSBC USA, Inc., 1.7%, 3/5/18 3,196,601 The accompanying notes are an integral part of these financial statements. 66 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Diversified Banks -- (continued) 2,675,000 2.13 ING Bank NV, Floating Rate Note, 3/22/19 (144A) $ 2,711,503 3,190,000 1.82 ING Bank NV, Floating Rate Note, 8/17/18 (144A) 3,206,795 8,825,000 1.94 JPMorgan Chase & Co., Floating Rate Note, 1/25/18 8,878,074 3,800,000 1.44 JPMorgan Chase & Co., Floating Rate Note, 3/1/18 3,811,571 2,500,000 1.43 JPMorgan Chase & Co., Floating Rate Note, 4/25/18 2,510,332 2,875,000 1.44 JPMorgan Chase Bank NA, Floating Rate Note, 9/21/18 2,883,858 1,548,000 1.49 Lloyds Bank Plc, Floating Rate Note, 3/16/18 1,551,964 6,720,000 1.59 Lloyds Bank Plc, Floating Rate Note, 5/14/18 6,740,758 3,750,000 1.69 Lloyds Bank Plc, Floating Rate Note, 8/17/18 3,765,480 4,941,000 1.67 Macquarie Bank, Ltd., Floating Rate Note, 10/27/17 (144A) 4,955,660 2,800,000 2.07 Mizuho Bank, Ltd., Floating Rate Note, 10/20/18 (144A) 2,827,770 1,670,000 1.64 Mizuho Bank, Ltd., Floating Rate Note, 3/26/18 (144A) 1,673,110 2,370,000 1.45 Mizuho Bank, Ltd., Floating Rate Note, 4/16/17 (144A) 2,370,246 513,000 1.60 Mizuho Bank, Ltd., Floating Rate Note, 9/25/17 513,410 2,425,000 1.46 MUFG Americas Holdings Corp., Floating Rate Note, 2/9/18 2,426,159 275,000 Nordea Bank AB, 1.25%, 4/4/17 (144A) 275,000 3,875,000 1.36 Nordea Bank AB, Floating Rate Note, 4/4/17 3,875,000 3,600,000 1.83 Nordea Bank AB, Floating Rate Note, 9/17/18 (144A) 3,619,429 4,515,000 1.62 Nordea Bank AB, Floating Rate Note, 9/30/19 (144A) 4,534,189 1,300,000 Royal Bank of Canada, 1.25%, 6/16/17 1,299,886 2,500,000 1.14 Royal Bank of Canada, Floating Rate Note, 10/13/17 2,501,852 3,115,000 1.48 Royal Bank of Canada, Floating Rate Note, 3/2/20 3,115,595 2,200,000 1.21 Royal Bank of Canada, Floating Rate Note, 6/16/17 2,200,394 2,500,000 1.37 Royal Bank of Canada, Floating Rate Note, 7/29/19 2,507,602 1,325,000 1.43 Royal Bank of Canada, Floating Rate Note, 7/30/18 1,330,595 6,005,000 1.53 Skandinaviska Enskilda Banken AB, Floating Rate Note, 9/13/19 (144A) 6,013,263 2,980,000 1.56 Sumitomo Mitsui Banking Corp., Floating Rate Note, 1/11/19 2,982,059 2,975,000 1.46 Sumitomo Mitsui Banking Corp., Floating Rate Note, 1/16/18 2,983,149 3,279,000 1.69 Sumitomo Mitsui Banking Corp., Floating Rate Note, 10/19/18 3,287,932 3,115,000 1.61 Sumitomo Mitsui Trust Bank, Ltd., Floating Rate Note, 3/6/19 (144A) 3,119,738 3,750,000 1.44 Svenska Handelsbanken AB, Floating Rate Note, 9/6/19 3,759,401 4,493,000 1.19 The Bank of Nova Scotia, Floating Rate Note, 4/11/17 4,493,297 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 67 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Diversified Banks -- (continued) 2,525,000 1.26 The Bank of Tokyo-Mitsubishi UFJ, Ltd., Floating Rate Note, 9/8/17 (144A) $ 2,524,795 2,000,000 1.31 The Huntington National Bank, Floating Rate Note, 4/24/17 2,000,512 3,000,000 1.46 The Toronto-Dominion Bank, Floating Rate Note, 1/18/19 3,005,856 4,645,000 1.12 The Toronto-Dominion Bank, Floating Rate Note, 5/2/17 4,645,632 3,860,000 1.42 The Toronto-Dominion Bank, Floating Rate Note, 7/23/18 3,875,915 2,600,000 1.55 The Toronto-Dominion Bank, Floating Rate Note, 8/13/19 2,619,864 1,055,000 1.44 U.S. Bank NA Cincinnati, Floating Rate Note, 4/26/19 1,060,254 2,600,000 US Bancorp, 1.65%, 5/15/17 2,600,226 3,650,000 1.44 US Bancorp, Floating Rate Note, 4/25/19 3,658,957 2,600,000 Wells Fargo & Co., 1.15%, 6/2/17 2,599,340 3,125,000 2.15 Wells Fargo & Co., Floating Rate Note, 1/24/23 3,159,909 6,675,000 1.51 Wells Fargo & Co., Floating Rate Note, 4/23/18 6,706,199 2,000,000 1.38 Westpac Banking Corp., Floating Rate Note, 5/19/17 2,000,762 ------------- $ 228,320,359 ----------------------------------------------------------------------------------------------------------- Regional Banks -- 2.7% 3,065,000 1.74 BB&T Corp., Floating Rate Note, 1/15/20 $ 3,088,515 2,500,000 Branch Banking & Trust Co., 1.35%, 10/1/17 2,500,062 3,000,000 1.48 Branch Banking & Trust Co., Floating Rate Note, 1/15/20 3,006,507 500,000 1.22 Branch Banking & Trust Co., Floating Rate Note, 5/23/17 500,062 1,250,000 1.56 Capital One NA, Floating Rate Note, 2/5/18 1,253,694 4,000,000 2.06 Capital One NA, Floating Rate Note, 8/17/18 4,039,156 4,000,000 1.72 Capital One NA, Floating Rate Note, 9/13/19 4,025,732 2,600,000 Fifth Third Bank Cincinnati Ohio, 1.35%, 6/1/17 2,600,380 455,000 1.74 Fifth Third Bank, Floating Rate Note, 9/27/19 455,110 2,112,000 KeyBank NA Cleveland Ohio, 1.65%, 2/1/18 2,113,419 5,350,000 1.57 KeyBank NA Cleveland Ohio, Floating Rate Note, 6/1/18 5,370,095 4,985,000 Manufacturers & Traders Trust Co., 1.4%, 7/25/17 4,981,835 1,725,000 Manufacturers & Traders Trust Co., 1.45%, 3/7/18 1,722,519 2,400,000 1.34 Manufacturers & Traders Trust Co., Floating Rate Note, 7/25/17 2,401,783 5,825,000 1.50 PNC Bank NA, Floating Rate Note, 12/7/18 5,842,254 4,300,000 1.47 PNC Bank NA, Floating Rate Note, 6/1/18 4,313,098 2,500,000 1.33 PNC Bank NA, Floating Rate Note, 8/1/17 2,501,258 2,032,000 SunTrust Bank, 7.25%, 3/15/18 2,133,937 The accompanying notes are an integral part of these financial statements. 68 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Regional Banks -- (continued) 6,215,000 1.56 SunTrust Bank, Floating Rate Note, 1/31/20 $ 6,240,252 800,000 1.70 UBS AG, Floating Rate Note, 3/26/18 803,217 3,000,000 1.61 UBS AG, Floating Rate Note, 6/1/17 3,002,187 2,965,000 1.36 US Bank NA Cincinnati Ohio, Floating Rate Note, 1/24/20 2,967,007 2,600,000 1.33 US Bank NA Cincinnati Ohio, Floating Rate Note, 1/26/18 2,604,017 4,603,000 1.62 US Bank NA Cincinnati Ohio, Floating Rate Note, 1/29/18 4,620,887 2,525,000 1.50 US Bank NA Cincinnati Ohio, Floating Rate Note, 8/23/17 2,528,444 3,169,000 1.23 Wachovia Corp., Floating Rate Note, 6/15/17 3,170,188 550,000 1.36 Wells Fargo & Co., Floating Rate Note, 6/2/17 550,130 6,485,000 1.78 Wells Fargo Bank NA, Floating Rate Note, 1/22/18 6,518,022 450,000 1.65 Wells Fargo Bank NA, Floating Rate Note, 5/24/19 452,964 1,285,000 1.50 Wells Fargo Bank NA, Floating Rate Note, 9/7/17 1,287,709 ------------- $ 87,594,440 ------------- Total Banks $ 315,914,799 ----------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 3.3% Other Diversified Financial Services -- 0.3% 2,750,000 1.30 Bank of America NA, Floating Rate Note, 5/8/17 $ 2,751,196 3,795,000 General Electric Co., 2.3%, 4/27/17 3,797,414 4,600,000 1.32 General Electric Co., Floating Rate Note, 5/15/17 4,600,327 ------------- $ 11,148,937 ----------------------------------------------------------------------------------------------------------- Multi-Sector Holdings -- 0.3% 2,530,000 Berkshire Hathaway Finance Corp., 1.6%, 5/15/17 $ 2,530,536 2,500,000 1.16 Berkshire Hathaway Finance Corp., Floating Rate Note, 8/14/17 2,501,668 3,315,000 1.18 Berkshire Hathaway, Inc., Floating Rate Note, 8/6/18 3,317,844 ------------- $ 8,350,048 ----------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.1% 3,180,000 MassMutual Global Funding II, 2.0%, 4/5/17 (144A) $ 3,180,000 ----------------------------------------------------------------------------------------------------------- Consumer Finance -- 1.3% 2,500,000 American Express Credit Corp., 1.125%, 6/5/17 $ 2,500,098 1,750,000 1.46 American Express Credit Corp., Floating Rate Note, 10/30/19 1,753,787 3,115,000 1.52 American Express Credit Corp., Floating Rate Note, 3/3/20 3,112,116 2,116,000 1.21 American Express Credit Corp., Floating Rate Note, 6/5/17 2,116,548 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 69 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Consumer Finance -- (continued) 2,700,000 1.30 American Express Credit Corp., Floating Rate Note, 9/22/17 $ 2,702,740 2,953,000 American Honda Finance Corp., 1.55%, 12/11/17 2,957,994 2,570,000 1.26 American Honda Finance Corp., Floating Rate Note, 12/11/17 2,574,693 4,004,000 1.45 American Honda Finance Corp., Floating Rate Note, 9/20/17 4,013,413 2,600,000 Capital One Bank USA NA, 1.3%, 6/5/17 2,599,922 3,115,000 Capital One NA, 1.65%, 2/5/18 3,114,477 6,975,000 3.08 General Motors Financial Co., Inc., Floating Rate Note, 1/15/19 7,152,263 2,500,000 2.37 General Motors Financial Co., Inc., Floating Rate Note, 4/10/18 2,524,672 2,323,000 2.34 General Motors Financial Co., Inc., Floating Rate Note, 5/9/19 2,362,533 1,290,000 1.14 PACCAR Financial Corp., Floating Rate Note, 6/6/17 1,290,472 ------------- $ 40,775,728 ----------------------------------------------------------------------------------------------------------- Asset Management & Custody Banks -- 0.5% 3,190,000 State Street Corp., 4.956%, 3/15/18 $ 3,280,277 3,000,000 1.95 State Street Corp., Floating Rate Note, 8/18/20 3,057,042 1,090,000 1.39 The Bank of New York Mellon Corp., Floating Rate Note, 3/6/18 1,093,008 1,047,000 1.45 The Bank of New York Mellon Corp., Floating Rate Note, 8/1/18 1,053,452 1,770,000 The Charles Schwab Corp., 1.5%, 3/10/18 1,769,648 4,460,000 1.72 The Goldman Sachs Group, Inc., Floating Rate Note, 5/22/17 4,463,666 ------------- $ 14,717,093 ----------------------------------------------------------------------------------------------------------- Investment Banking & Brokerage -- 0.8% 3,130,000 1.89 Morgan Stanley, Floating Rate Note, 1/24,19 $ 3,154,358 4,325,000 1.60 Morgan Stanley, Floating Rate Note, 1/5/18 4,339,567 7,360,000 2.26 Morgan Stanley, Floating Rate Note, 2/1/19 7,479,902 2,800,000 1.06 Svensk Exportkredit AB, Floating Rate Note, 11/10/17 2,801,596 1,000,000 The Charles Schwab Corp., 2.2%, 7/25/18 1,006,194 3,115,000 The Charles Schwab Corp., 6.375%, 9/1/17 3,176,901 970,000 1.76 The Goldman Sachs Group, Inc., Floating Rate Note, 12/15/17 973,465 3,470,000 2.24 The Goldman Sachs Group, Inc., Floating Rate Note, 4/30/18 3,500,710 ------------- $ 26,432,693 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 70 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.0%+ 700,000 1.41 Moody's Corp., Floating Rate Note, 9/4/18 $ 701,213 ------------- Total Diversified Financials $ 105,305,712 ----------------------------------------------------------------------------------------------------------- INSURANCE -- 7.1% Life & Health Insurance -- 0.7% 2,600,000 1.46 Jackson National Life Global Funding, Floating Rate Note, 10/13/17 (144A) $ 2,605,444 2,940,000 1.42 Metropolitan Life Global Funding I, Floating Rate Note, 12/19/18 (144A) 2,948,729 2,050,000 Pricoa Global Funding I, 1.35%, 8/18/17 (144A) 2,047,025 2,650,000 Principal Life Global Funding II, 1.5%, 9/11/17 (144A) 2,649,743 7,370,000 1.55 Principal Life Global Funding II, Floating Rate Note, 12/1/17 (144A) 7,393,621 2,481,000 1.35 Principal Life Global Funding II, Floating Rate Note, 5/21/18 (144A) 2,482,727 800,000 1.82 Prudential Financial, Inc., Floating Rate Note, 8/15/18 804,892 ------------- $ 20,932,181 ----------------------------------------------------------------------------------------------------------- Multi-line Insurance -- 0.8% 3,210,000 American International Group, Inc., 5.85%, 1/16/18 $ 3,312,136 1,135,000 Metropolitan Life Global Funding I, 1.3%, 4/10/17 (144A) 1,135,020 6,015,000 1.26 Metropolitan Life Global Funding I, Floating Rate Note, 4/10/17 (144A) 6,015,319 1,695,000 New York Life Global Funding, 1.3%, 10/30/17 (144A) 1,693,956 3,419,000 New York Life Global Funding, Floating Rate Note, 10/24/19 (144A) 3,435,873 8,050,000 1.41 New York Life Global Funding, Floating Rate Note, 12/15/17 (144A) 8,068,499 1,250,000 New York Life Global Funding, Floating Rate Note, 7/6/18 (144A) 1,251,039 ------------- $ 24,911,842 ----------------------------------------------------------------------------------------------------------- Reinsurance -- 5.6% 5,000,000 7.13 Alamo Re, Ltd., Floating Rate Note, 6/7/17 (Cat Bond) (144A) $ 5,015,000 2,500,000 6.13 Alamo Re, Ltd., Floating Rate Note, 6/7/18 (Cat Bond) (144A) 2,580,500 500,000 3.36 Aozora Re, Ltd., Floating Rate Note, 4/7/23 (Cat Bond) (144A) 509,050 1,500,000 4.50 Aozora Re, Ltd., Floating Rate Note, 4/7/21 (Cat Bond) (144A) 1,500,000 500,000 Arlington Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 8/31/16 (d)(e) 24,300 750,000 Arlington Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 8/31/17 (d)(e) 836,250 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 71 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 1,500,000 4.19 Atlas IX Capital DAC, Floating Rate Note, 1/17/19 (Cat Bond) (144A) $ 1,523,100 1,250,000 Berwick 2016-1 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 2/1/18 (d)(e) 59,375 1,250,000 Berwick 2016-1 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 2/1/19 (d)(e) 1,277,375 750,000 14.35 Blue Halo Re, Ltd., Floating Rate Note, 6/21/19 (Cat Bond) (144A) 748,950 3,100,000 4.70 Bonanza Re, Ltd., Floating Rate Note, 12/31/19 (Cat Bond) (144A) 3,098,140 750,000 4.34 Bosphorus, Ltd., Floating Rate Note, 8/17/18 (Cat Bond) (144A) 762,450 2,250,000 5.50 Caelus Re IV, Ltd., Floating Rate Note, 3/6/20 (Cat Bond) (144A) 2,355,075 3,050,000 7.06 Caelus Re, Ltd., Floating Rate Note, 4/7/17 (Cat Bond) (144A) 3,047,560 750,000 Carnoustie 2016-N,Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 11/30/20 (d)(e) 81,150 2,000,000 Carnoustie Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 11/30/21 (d)(e) 2,021,200 7,500,000 5.35 Citrus Re, Ltd., Floating Rate Note, 4/18/17 (Cat Bond) (144A) 7,501,500 6,800,000 4.48 Citrus Re, Ltd., Floating Rate Note, 4/24/17 (Cat Bond) (144A) 6,803,400 1,000,000 4.02 Cranberry Re, Ltd., Floating Rate Note, 7/6/18 (Cat Bond) (144A) 1,019,400 1,000,000 Cypress Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/10/17 (d)(e) 885,300 2,480,000 Denning 2016 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/7/17 (d)(e) 2,459,664 2,000,000 2.75 East Lane Re VI, Ltd., Floating Rate Note, 3/14/18 (Cat Bond) (144A) 2,001,800 1,274,130 0.00 Eden Re II, Ltd., Variable Rate Notes, 3/22/21 (Cat Bond) 1,302,288 1,750,000 0.00 Eden Re II, Ltd., Variable Rate Notes, 3/22/21 (Cat Bond) (144A) 1,788,325 1,131 Eden Re II, Variable Rate Notes, 4/23/19 (d)(e) 91,616 17,450,000 8.12 Everglades Re, Ltd., Floating Rate Note, 4/28/17 (Cat Bond) (144A) 17,493,625 1,250,000 0.00 Galilei Re, Ltd., Floating Rate Note, 1/8/21 (Cat Bond) (144A) 1,243,375 2,500,000 0.00 Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) (144A) 2,499,750 1,900,000 0.00 Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) (144A) 1,891,450 The accompanying notes are an integral part of these financial statements. 72 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 1,500,000 0.00 Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) (144A) $ 1,496,250 2,000,000 0.00 Galilei Re, Ltd., Floating Rate Note, 1/8/21 (Cat Bond) (144A) 2,000,800 1,250,000 0.00 Galilei Re, Ltd., Floating Rate Note, 1/8/21 (Cat Bond) (144A) 1,247,250 175,000 3.37 Gator Re, Ltd., Floating Rate Note, 1/9/20 (Cat Bond) (144A) 26,250 1,300,000 Gleneagles Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 11/30/20 (d)(e) 218,660 2,650,000 2.52 Golden State Re II, Ltd., Floating Rate Note, 1/8/19 (Cat Bond) (144A) 2,642,580 2,600,000 Gullane Segregated Account (Artex SAC Ltd.), Variable Rate Notes 11/30/20 (d)(e) 108,940 3,000,000 Gullane Segregated Account (Artex SAC Ltd.), Variable Rate Notes 11/30/21 (d)(e) 3,039,000 2,350,000 4.24 Kilimanjaro Re, Ltd., Floating Rate Note, 11/25/19 (Cat Bond) (144A) 2,386,895 2,000,000 9.41 Kilimanjaro Re, Ltd., Floating Rate Note, 12/6/19 (Cat Bond) (144A) 2,041,800 2,500,000 6.75 Kilimanjaro Re, Ltd., Floating Rate Note, 12/6/19 (Cat Bond) (144A) 2,551,750 3,300,000 5.24 Kilimanjaro Re, Ltd., Floating Rate Note, 4/30/18 (Cat Bond) (144A) 3,324,420 1,000,000 5.00 Kilimanjaro Re, Ltd., Floating Rate Note, 4/30/18 (Cat Bond) (144A) 1,007,500 1,500,000 Kingsbarns Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 5/15/17 (d)(e) 1,490,100 1,800,000 2.80 Kizuna Re II, Ltd., Floating Rate Note, 4/6/18 (Cat Bond) (144A) 1,800,000 1,250,000 Lahinch Re, Variable Rate Notes, 5/10/21 (d)(e) 22,250 500,000 0.00 Limestone Re, Ltd., Floating Rate Note, 8/31/21 (Cat Bond) 501,550 850,000 0.00 Limestone Re, Ltd., Floating Rate Note, 8/31/21 (Cat Bond) 852,635 4,000,000 4.05 Long Point Re, III, Ltd., Floating Rate Note, 5/23/18 (Cat Bond) (144A) 4,037,200 750,000 Lorenz Re, Ltd., Variable Rate Notes, 3/31/18 (d)(e) 4,350 2,500,000 Lorenz Re, Ltd., Variable Rate Notes, 3/31/19 (d)(e) 2,755,750 2,500,000 Madison Re, Variable Rate Notes, 3/31/19 (d)(e) 2,757,250 2,000,000 2.56 Merna Re V, Ltd., Floating Rate Note, 4/7/17 (Cat Bond) (144A) 1,998,000 2,500,000 3.07 Nakama Re, Ltd., Floating Rate Note, 10/13/21 (Cat Bond) (144A) 2,542,750 2,500,000 Pangaea Re, Series 2015-1, Principal at Risk Notes, 2/1/19 (d)(e) 11,250 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 73 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 2,800,000 Pangaea Re, Series 2015-2, Principal at Risk Notes, 11/30/19 (d)(e) $ 225,960 1,500,000 Pangaea Re, Series 2016-2, Principal at Risk Notes, 11/30/20 (d)(e) 1,714,950 2,000,000 Pangaea Re, Series 2017-1, Principal at Risk Notes, 11/30/21 (d)(e) 2,046,800 2,500,000 Pangaea Re, Variable Rate Notes, 2/1/20 (d)(e) 347,500 3,500,000 6.71 Pelican Re, Ltd., Floating Rate Note, 5/15/17 (Cat Bond) (144A) 3,511,200 3,500,000 4.81 PennUnion Re, Ltd., Floating Rate Note, 12/7/18 (Cat Bond) (144A) 3,512,600 3,000,000 Pinehurst Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 1/16/18 (d)(e) 2,871,000 1,500,000 Port Rush RE, Variable Rate Notes, 6/15/17 (d)(e) 342,450 1,500,000 5.75 Queen Street X Re, Ltd., Floating Rate Note, 6/8/18 (Cat Bond) (144A) 1,508,550 1,750,000 6.49 Queen Street XI Re Dac, Floating Rate Note, 6/7/19 (Cat Bond) (144A) 1,778,875 850,000 9.97 Residential Reinsurance 2013, Ltd., Floating Rate Note, 6/6/17 (Cat Bond) (144A) 854,250 750,000 3.61 Residential Reinsurance 2014, Ltd., Floating Rate Note, 6/6/18 (Cat Bond) (144A) 753,825 1,000,000 7.60 Residential Reinsurance 2015, Ltd., Floating Rate Note, 12/6/19 (Cat Bond) (144A) 1,031,500 250,000 0.00 Residential Reinsurance 2016, Ltd., Floating Rate Note, 12/6/20 (Cat Bond) (144A) 234,950 2,000,000 3.50 Residential Reinsurance 2016, Ltd., Floating Rate Note, 12/6/23 (Cat Bond) (144A) 1,947,000 2,500,000 0.00 Resilience Re, Ltd., Floating Rate Note, 1/12/18 (Cat Bond) 2,361,750 1,500,000 0.00 Resilience Re, Ltd., Floating Rate Note, 1/8/19 (Cat Bond) 1,500,000 2,500,000 3.30 Resilience Re, Ltd., Floating Rate Note, 1/9/19 (Cat Bond) 2,500,000 2,500,000 0.00 Resilience Re, Ltd., Floating Rate Note, 4/7/17 (Cat Bond) 2,533,500 1,250,000 0.00 Resilience Re, Ltd., Floating Rate Note, 6/12/17 (Cat Bond) 1,250,500 3,000,000 3.50 Sanders Re, Ltd., Floating Rate Note, 5/25/18 (Cat Bond) (144A) 3,002,700 1,250,000 4.21 Sanders Re, Ltd., Floating Rate Note, 5/5/17 (Cat Bond) (144A) 1,249,875 2,500,000 4.00 Sanders Re, Ltd., Floating Rate Note, 5/5/17 (Cat Bond) (144A) 2,499,000 The accompanying notes are an integral part of these financial statements. 74 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 3,000,000 3.97 Sanders Re, Ltd., Floating Rate Note, 6/7/17 (Cat Bond) (144A) $ 3,004,800 500,000 Sector Re V, Ltd., Variable Rate Notes, 12/1/21 (144A) (d)(e) 508,000 1,250,000 Sector Re V, Ltd., Variable Rate Notes 3/1/21 (d)(e) 1,410,375 2,369 Sector Re V, Ltd., Variable Rate Notes, 12/1/20 (144A) (d)(e) 28,663 2,500,000 Shenandoah 2017-1 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/7/17 (d)(e) 2,462,750 1,000,000 Silverton Re, Ltd., Variable Rate Notes, 9/18/19 (144A) (d)(e) 1,026,900 1,000,000 Silverton Re, Ltd., Variable Rate Notes, 9/18/18 (144A) (d)(e) 48,800 2,500,000 12.00 Skyline Re, Ltd., Floating Rate Note, 1/6/20 (Cat Bond) 2,490,625 1,250,000 St. Andrews Segregated Account (Artex SAC Ltd.), Variable Rate Note, 2/1/19 (d)(e) 1,270,875 1,250,000 St. Andrews Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 2/1/18 (d)(e) 175,750 1,000,000 Sunningdale Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 1/16/18 (d)(e) 916,600 750,000 5.50 Tradewynd Re, Ltd., Floating Rate Note, 1/8/18 (Cat Bond) (144A) 752,550 250,000 9.94 Tramline Re II, Ltd., Floating Rate Note, 1/4/19 (Cat Bond) (144A) 255,425 1,750,000 3.74 Tramline Re II, Ltd., Floating Rate Note, 7/7/17 (Cat Bond) (144A) 1,747,200 1,800,000 4.00 Ursa Re, Ltd., Floating Rate Note, 12/10/19 (Cat Bond) (144A) 1,816,740 2,500,000 5.22 Ursa Re, Ltd., Floating Rate Note, 9/21/18 (Cat Bond) (144A) 2,544,250 2,700,000 Versutus 2016, Class A-1, Variable Rate Notes, 11/30/20 (d)(e) 110,160 2,600,000 Versutus 2017, Class A-1, Variable Rate Notes, 11/30/21 (d)(e) 2,653,040 3,800,000 2.01 Vitality Re V, Ltd., Floating Rate Note, 1/7/19 (Cat Bond) (144A) 3,783,660 2,000,000 2.47 Vitality Re VII, Ltd., Floating Rate Note, 1/7/20 (Cat Bond) (144A) 2,015,400 1,000,000 2.83 Vitality Re VII, Ltd., Floating Rate Note, 1/7/20 (Cat Bond) (144A) 1,017,900 ------------- $ 182,905,346 ------------- Total Insurance $ 228,749,369 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 75 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- REAL ESTATE -- 0.2% Diversified REIT -- 0.2% 5,960,000 Duke Realty LP, 6.5%, 1/15/18 $ 6,177,790 ------------- Total Real Estate $ 6,177,790 ----------------------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 0.1% Systems Software -- 0.1% 2,910,000 Oracle Corp., 1.2%, 10/15/17 $ 2,909,243 1,937,000 1.07 Oracle Corp., Floating Rate Note, 7/7/17 1,938,786 ------------- $ 4,848,029 ------------- Total Software & Services $ 4,848,029 ----------------------------------------------------------------------------------------------------------- TECHNOLOGY HARDWARE & EQUIPMENT -- 0.1% Computer Hardware Storage & Peripherals -- 0.1% 2,650,000 1.74 Apple, Inc., Floating Rate Note, 2/22/19 $ 2,690,148 ------------- Total Technology Hardware & Equipment $ 2,690,148 ----------------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 0.3% Integrated Telecommunication Services -- 0.3% 2,400,000 1.79 AT&T, Inc., Floating Rate Note, 3/11/19 $ 2,413,841 2,560,000 AT&T, Inc., 1.4%, 12/1/17 2,557,916 2,550,000 1.85 AT&T, Inc., Floating Rate Note, 11/27/18 2,573,297 2,990,000 1.60 Deutsche Telekom International Finance BV, Floating Rate Note, 1/17/20 (144A) 2,990,102 ------------- $ 10,535,156 ------------- Total Telecommunication Services $ 10,535,156 ----------------------------------------------------------------------------------------------------------- UTILITIES -- 1.4% Electric Utilities -- 1.1% 1,840,000 American Electric Power Co., Inc., 1.65%, 12/15/17 $ 1,839,441 1,631,000 Commonwealth Edison Co., 5.8%, 3/15/18 1,695,734 1,147,000 Duke Energy Corp., 2.1%, 6/15/18 1,151,455 8,650,000 1.38 Duke Energy Corp., Floating Rate Note, 4/3/17 8,650,000 7,095,000 1.11 Duke Energy Progress LLC, Floating Rate Note, 11/20/17 7,095,255 2,545,000 Exelon Corp., 1.55%, 6/9/17 2,545,076 2,650,000 NextEra Energy Capital Holdings, Inc., 1.586%, 6/1/17 2,650,705 517,000 NextEra Energy Capital Holdings, Inc., 2.056%, 9/1/17 518,666 6,145,000 PECO Energy Co., 5.35%, 3/1/18 6,354,219 1,440,000 Southern California Edison Co., 1.125%, 5/1/17 1,439,866 ------------- $ 33,940,417 ----------------------------------------------------------------------------------------------------------- Gas Utilities -- 0.1% 3,754,000 Kinder Morgan Finance Co., LLC, 6.0%, 1/15/18 (144A) $ 3,871,275 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 76 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Multi-Utilities -- 0.2% 2,295,000 Dominion Resources, Inc., Virginia, 1.4%, 9/15/17 $ 2,292,753 1,750,000 Dominion Resources, Inc., Virginia, 1.6%, 8/15/19 1,728,099 2,030,000 Sempra Energy, 2.3%, 4/1/17 2,030,000 ------------- $ 6,050,852 ------------- Total Utilities $ 43,862,544 ----------------------------------------------------------------------------------------------------------- TOTAL CORPORATE BONDS (Cost $919,493,490) $ 922,972,543 ----------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- 9.4% 629 Fannie Mae, 7.0%, 10/1/17 $ 631 14,411 3.15 Fannie Mae, Floating Rate Note, 1/1/48 15,196 8,657 2.99 Fannie Mae, Floating Rate Note, 10/1/32 8,848 3,808 2.63 Fannie Mae, Floating Rate Note, 11/1/23 3,933 21,580 2.92 Fannie Mae, Floating Rate Note, 2/1/34 21,726 14,896 2.67 Fannie Mae, Floating Rate Note, 9/1/32 15,749 2,645,000 1.00 Federal Farm Credit Banks, Floating Rate Note, 10/17/17 2,649,026 4,196 2.84 Federal Home Loan Mortgage Corp., Floating Rate Note, 10/1/23 4,297 13,150 3.50 Federal Home Loan Mortgage Corp., Floating Rate Note, 11/1/33 13,651 5,642 3.12 Federal Home Loan Mortgage Corp., Floating Rate Note, 6/1/35 5,649 6,561 2.00 Government National Mortgage Association II, Floating Rate Note, 1/20/22 6,721 15,400,000 U.S. Treasury Bill, 4/13/17 (c) 15,396,905 47,480,000 0.93 U.S. Treasury Notes, Floating Rate Note, 10/31/17 47,529,551 2,550,000 U.S. Treasury Notes, 0.625%, 11/30/17 2,544,023 2,590,000 U.S. Treasury Notes, 0.875%, 5/15/17 2,590,609 45,275,000 1.05 U.S. Treasury Notes, Floating Rate Note, 1/31/18 45,376,869 46,790,000 0.92 U.S. Treasury Notes, Floating Rate Note, 1/31/19 46,824,391 45,510,000 0.95 U.S. Treasury Notes, Floating Rate Note, 10/31/18 45,575,534 45,075,000 0.97 U.S. Treasury Notes, Floating Rate Note, 4/30/18 45,149,915 45,595,000 0.96 U.S. Treasury Notes, Floating Rate Note, 7/31/18 45,671,873 ------------- $ 299,405,097 ----------------------------------------------------------------------------------------------------------- TOTAL U.S. GOVERNMENT AND AGENCY OBLIGATIONS (Cost $299,193,213) $ 299,405,097 ----------------------------------------------------------------------------------------------------------- MUNICIPAL BONDS -- 0.1% (f) Municipal Development -- 0.1% 2,095,000 0.91 Mississippi Business Finance Corp., Floating Rate Note, 12/1/30 $ 2,095,000 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 77 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Municipal Student Loan -- 0.0%+ 553,437 1.78 Louisiana Public Facilities Authority, Floating Rate Note, 4/26/27 $ 554,865 ----------------------------------------------------------------------------------------------------------- TOTAL MUNICIPAL BONDS (Cost $2,650,667) $ 2,649,865 ----------------------------------------------------------------------------------------------------------- SENIOR FLOATING RATE LOAN INTERESTS -- 5.1%** ENERGY -- 0.1% Oil & Gas Refining & Marketing -- 0.0%+ 220,369 5.25 Western Refining, Inc., Term Loan 2013, 11/12/20 $ 220,782 ----------------------------------------------------------------------------------------------------------- Oil & Gas Storage & Transportation -- 0.1% 1,000,000 3.73 Energy Transfer Equity LP, Loan, 2/2/24 $ 998,929 915,400 6.25 Gulf Finance LLC, Tranche B Term Loan, 8/17/23 915,400 ------------- $ 1,914,329 ------------- Total Energy $ 2,135,111 ----------------------------------------------------------------------------------------------------------- MATERIALS -- 0.1% Commodity Chemicals -- 0.0%+ 375,603 4.65 Tronox Pigments Holland BV, New Term Loan, 3/19/20 $ 378,384 ----------------------------------------------------------------------------------------------------------- Diversified Chemicals -- 0.0%+ 472,106 6.00 Chemours Co., LLC, Term Loan (First Lien), 5/12/22 $ 473,139 ----------------------------------------------------------------------------------------------------------- Specialty Chemicals -- 0.1% 728,903 3.65 Axalta Coating Systems US Holdings, Inc., Term B-1 Dollar Loan, 2/1/20 $ 736,136 66,538 4.40 Kloeckner Pentaplast of America, Inc., Initial German Borrower Dollar Term Loan, 4/28/20 67,307 155,699 4.40 Kloeckner Pentaplast of America, Inc., Initial U.S. Dollar Term Loan, 4/28/20 157,499 246,877 3.13 PolyOne Corp., Term B-2 Loan, 11/12/22 249,345 408,072 5.29 PQ Corp., First Amendment Tranche B-1 Term Loan, 11/4/22 412,881 473,757 3.03 WR Grace & Co-Conn, U.S. Term Loan, 1/23/21 475,830 ------------- $ 2,098,998 ----------------------------------------------------------------------------------------------------------- Paper Packaging -- 0.0%+ 132,197 4.25 Multi Packaging Solutions, Inc., Initial Dollar Tranche B Term, 9/30/20 $ 132,941 ----------------------------------------------------------------------------------------------------------- Diversified Metals & Mining -- 0.0%+ 497,500 3.75 Fortescue Metals Group, Ltd., Bank Loan, 6/30/19 $ 165,341 164,253 5.25 Global Brass and Copper, Inc., Initial Term Loan, 6/30/23 504,652 ------------- $ 669,993 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 78 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Steel -- 0.0%+ 142,829 4.56 TMS International Corp., Term B Loan, 10/2/20 $ 144,168 496,256 4.91 Zekelman Industries, Inc., Term Loan, 6/8/21 503,700 ------------- $ 647,868 ------------- Total Materials $ 4,401,323 ----------------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 0.4% Aerospace & Defense -- 0.2% 1,271,998 3.73 DigitalGlobe, Inc., Term Loan, 12/22/23 $ 1,277,828 698,250 3.25 Leidos Innovations Corp., B Term Loan, 6/9/23 706,454 1,214,586 5.65 The SI Organization, Inc., Term Loan (First Lien), 11/19/19 1,233,944 1,260,885 4.12 TransDigm, Inc., Tranche C Term Loan, 2/28/20 1,262,303 1,231,664 3.65 Wesco Aircraft Hardare Corp., Tranche B Term Loan (First Lien), 2/24/21 1,229,610 ------------- $ 5,710,139 ----------------------------------------------------------------------------------------------------------- Building Products -- 0.1% 955,350 3.80 Armstrong World Industries, Inc., Term Loan B, 2/23/23 $ 956,146 689,500 3.67 Beacon Roofing Supply, Inc., Initial Term Loan, 9/25/22 694,815 2,722 4.00 Builders Firstsource, Inc., 1st Lien Term Loan, 3/29/24 2,724 615,271 4.23 Quikrete Holdings, Inc., Initial Loan (First Lien), 11/3/23 622,450 350,000 4.25 Unifrax Corp., New Term B Loan, 12/31/19 765,595 765,834 0.00 Unifrax Holding Co., New Term Dollar Loan, 3/30/24 353,062 ------------- $ 3,394,792 ----------------------------------------------------------------------------------------------------------- Electrical Components & Equipment -- 0.1% 1,296,750 3.49 Dell International LLC, Term Loan, 9/7/23 $ 1,304,560 1,536,873 3.38 Southwire Co., Term Loan, 1/31/21 1,550,640 663,438 6.50 WireCo WorldGroup, Inc., Initial Term Loan (First Lien), 7/22/23 670,625 ------------- $ 3,525,825 ----------------------------------------------------------------------------------------------------------- Industrial Conglomerates -- 0.0%+ 451,862 3.00 Milacron LLC, Term B Loan, 9/25/23 $ 454,686 ----------------------------------------------------------------------------------------------------------- Construction & Farm Machinery & Heavy Trucks -- 0.0%+ 302,591 3.54 Terex Corp., U.S. Term Loan (2017), 1/31/24 $ 304,167 ----------------------------------------------------------------------------------------------------------- Industrial Machinery -- 0.0%+ 229,776 4.56 Gardner Denver, Inc., Initial Dollar Term Loan, 7/30/20 $ 229,596 738,583 5.23 NN, Inc., Tranche B Term Loan, 10/19/22 739,853 ------------- $ 969,449 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 79 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Trading Companies & Distributors -- 0.0%+ 236,330 4.22 WESCO Distribution, Inc., Tranche B-1 Loan, 12/12/19 $ 237,291 ------------- Total Capital Goods $ 14,596,349 ----------------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.2% Environmental & Facilities Services -- 0.1% 147,000 3.73 Waste Industries USA, Inc., Term B Loan, 2/27/20 $ 147,873 2,808,908 5.15 Wheelabrator, Term B Loan, 10/15/21 2,838,168 126,437 5.15 Wheelabrator, Term C Loan, 10/15/21 127,754 ------------- $ 3,113,795 ----------------------------------------------------------------------------------------------------------- Office Services & Supplies -- 0.0%+ 461,518 3.54 West Corp., Refinanced Term B-12 Loan, 6/17/23 $ 463,191 ----------------------------------------------------------------------------------------------------------- Security & Alarm Services -- 0.1% 1,219,998 4.01 Garda World Security Corp., Term B Loan, 11/1/20 $ 1,224,826 312,092 4.01 Garda World Security Corp., Term B Loan, 11/8/20 313,328 ------------- $ 1,538,154 ----------------------------------------------------------------------------------------------------------- Human Resource & Employment Services -- 0.0%+ 1,035,194 3.03 On Assignment, Inc., Tranche B-2 Term Loan, 6/5/22 $ 1,043,390 ------------- Total Commercial Services & Supplies $ 6,158,530 ----------------------------------------------------------------------------------------------------------- TRANSPORTATION -- 0.1% Air Freight & Logistics -- 0.0%+ 193,500 5.25 Syncreon Group BV, Term Loan, 9/26/20 $ 175,359 ----------------------------------------------------------------------------------------------------------- Airlines -- 0.1% 2,474,058 3.38 American Airlines, Inc., 2015 Term Loan, 10/10/21 $ 491,776 240,625 2.98 American Airlines, Inc., 2017 Replacement Term Loan, 6/27/20 2,477,150 490,000 3.48 Delta Air Lines, Inc., Term Loan (First Lien), 8/24/22 298,501 295,500 3.35 Delta Air Lines, Inc., 2014 Term B-1 Loan, 10/18/18 723,904 718,125 0.00 United AirLines, Inc., Term Loan B, 4/1/24 241,753 ------------- $ 4,233,084 ------------- Total Transportation $ 4,408,443 ----------------------------------------------------------------------------------------------------------- AUTOMOBILES & COMPONENTS -- 0.2% Auto Parts & Equipment -- 0.2% 1,155,000 3.00 Allison Transmission, Inc., Term B-3 Loan, 8/23/19 $ 435,357 1,026,759 3.00 American Axle & Manufacturing, Inc., Term Loan B, 3/9/24 1,158,369 430,818 6.00 BBB Industries US, Initial Term Loan, 10/15/21 990,778 982,500 3.75 MPG Holdco I, Inc., Tranche B-1 Term Loan (2015), 10/20/21 1,226,342 The accompanying notes are an integral part of these financial statements. 80 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Auto Parts & Equipment -- (continued) 1,222,521 3.73 TI Group Automotive Systems LLC, Initial US Term Loan, 6/25/22 $ 803,612 798,125 3.62 Tower Automotive Holdings USA LLC, Initial Term Loan, 3/6/24 1,026,118 291,667 4.07 Visteon Corp., Tranche B Loan (First Lien), 4/8/21 293,307 ------------- $ 5,933,883 ----------------------------------------------------------------------------------------------------------- Tires & Rubber -- 0.0%+ 266,667 2.86 The Goodyear Tire & Rubber Co., Term Loan (Second Lien), 3/27/19 $ 268,000 ----------------------------------------------------------------------------------------------------------- Automobile Manufacturers -- 0.0%+ 1,669,364 3.39 Chrysler Group LLC, Tranche B Term Loan, 12/29/18 $ 1,676,533 ------------- Total Automobiles & Components $ 7,878,416 ----------------------------------------------------------------------------------------------------------- CONSUMER DURABLES & APPAREL -- 0.1% Housewares & Specialties -- 0.1% 571,395 3.73 Prestige Brands, Inc., Term B-4 Loan, 1/20/24 $ 577,227 995,006 3.98 Reynolds Group Holdings, Inc., Incremental U.S. Term Loan, 2/5/23 1,000,293 ------------- $ 1,577,520 ----------------------------------------------------------------------------------------------------------- Leisure Products -- 0.0%+ 750,000 5.97 Bass Pro Group LLC, Initial Term Loan, 11/16/23 $ 724,375 ----------------------------------------------------------------------------------------------------------- Apparel, Accessories & Luxury Goods -- 0.0%+ 374,853 3.48 Hanesbrands, Inc., New Term B Loan, 4/15/22 $ 378,365 ------------- Total Consumer Durables & Apparel $ 2,680,260 ----------------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.4% Casinos & Gaming -- 0.0%+ 12,167 4.15 Pinnacle Entertainment, Inc., Term B Facility Loan, 3/30/23 $ 12,307 1,539,098 4.85 Scientific Games International, Inc., Initial Term B-3 Loan, 10/1/21 1,560,101 ------------- $ 1,572,408 ----------------------------------------------------------------------------------------------------------- Hotels, Resorts & Cruise Lines -- 0.1% 374,063 4.15 Four Seasons Holdings, Inc., Term Loan, 6/27/20 $ 378,772 1,286,908 2.98 Hilton Worldwide Finance LLC, Series B-2 Term Loan, 10/25/23 1,298,527 275,289 3.73 Sabre GLBL, Inc., 2017 Incremental Term Loan, 2/16/24 277,594 ------------- $ 1,954,893 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 81 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Leisure Facilities -- 0.0%+ 95,930 3.48 Cedar Fair LP, U.S. Term Facility, 3/6/20 $ 96,574 432,370 6.00 L.A. Fitness International, LLC, Tranche B Term Loan (First Lien), 4/25/20 436,424 986,278 3.24 Six Flags Theme Parks, Inc., Tranche B Term Loan, 6/30/22 997,066 ------------- $ 1,530,064 ----------------------------------------------------------------------------------------------------------- Restaurants -- 0.1% 1,442,750 2.98 KFC Holding Co., Term B Loan, 6/2/23 $ 1,459,695 219,318 4.04 Landry's, Inc., B Term Loan, 9/22/23 221,492 152,000 4.75 NPC International, Inc., Term Loan, 12/28/18 153,235 817,411 4.53 PF Chang's China Bistro, Inc., Term Borrowing, 7/2/19 807,193 ------------- $ 2,641,615 ----------------------------------------------------------------------------------------------------------- Education Services -- 0.1% 1,920,856 3.74 Bright Horizons Family Solutions LLC (f.k.a. Bright Horizons Family Solutions, Inc.), Effective Date Incremental Term Loan, 11/3/23 $ 1,943,426 ----------------------------------------------------------------------------------------------------------- Specialized Consumer Services -- 0.1% 474,874 5.50 Allied Universal Holdco LLC, Incremental Term Loan, 7/28/22 $ 478,288 598,500 4.50 Creative Artists Agency LLC, Term Loan B, 2/9/24 605,981 522,378 4.25 Prime Security Services Borrower LLC, 2016-2 Refinancing Term B-1 Loan (First Lien), 5/2/22 527,789 377,905 4.34 Weight Watchers International, Inc., Initial Tranche B-2 Term Loan, 4/2/20 353,847 ------------- $ 1,965,905 ------------- Total Consumer Services $ 11,608,311 ----------------------------------------------------------------------------------------------------------- MEDIA -- 0.7% Broadcasting -- 0.3% 647,534 4.50 CBS Radio, Inc., Term Loan, 10/7/23 $ 273,861 270,948 3.94 CSC Holdings LLC, 2016 Extended Term Loan, 10/31/24 655,976 656,250 4.55 Entercom Radio LLC, Term B Loan, 11/1/23 214,590 213,124 3.48 Gray Television, Inc., Term B-2 Loan, 2/7/24 1,008,611 999,862 3.35 Nielsen Finance LLC, Class B-3 Term Loan, 9/28/23 503,045 498,750 3.54 Quebecor Media, Inc., Facility B-1 Tranche, 8/17/20 488,172 486,146 3.24 Sinclair Television Group, Inc., Tranche B Term Loan, 1/31/24 2,298,296 2,287,099 3.49 The EW Scripps Co., Tranche B Term Loan, 11/26/20 520,707 514,490 4.60 Tribune Media Co., Term B Loan, 12/27/20 92,857 91,994 3.98 Tribune Media Co., Term C Loan, 1/18/24 1,160,241 The accompanying notes are an integral part of these financial statements. 82 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Broadcasting -- (continued) 1,149,465 3.75 Univision Communications, Inc., 2017 Replacement Repriced First-Lien Term Loan, 3/15/24 $ 643,790 ------------- $ 7,860,146 ----------------------------------------------------------------------------------------------------------- Cable & Satellite -- 0.2% 2,450,000 2.99 Charter Communications Operating LLC, Term F-1 Loan, 1/3/21 $ 1,279,397 1,275,313 3.23 Charter Communications Operating LLC, Term I-1 Loan, 1/15/24 996,119 990,000 3.89 Intelsat Jackson Holdings SA, Tranche B-2 Term Loan, 6/30/19 514,559 521,732 3.45 MCC Iowa LLC, Tranche H Term Loan, 1/29/21 249,926 248,067 3.20 Mediacom Illinois LLC, Tranche K Term Loan, 2/19/24 1,368,875 1,361,500 3.66 UPC Financing Partnership, Facility AP, 4/15/25 803,500 800,000 3.41 Ziggo, Secured Finance PartnershipTerm Loan E Facility, 4/25/25 2,446,938 ------------- $ 7,659,314 ----------------------------------------------------------------------------------------------------------- Movies & Entertainment -- 0.2% 399,000 3.73 AMC Entertainment Holdings, Inc., 2016 Incremental Term Loan, 12/15/23 $ 504,750 500,000 3.66 AMC Entertainment, Inc., Initial Term Loan, 4/30/20 1,442,712 1,428,427 3.63 Kasima LLC, Term Loan, 5/17/21 608,805 603,774 3.50 Live Nation Entertainment, Inc., Term B-2 Loan, 10/27/23 1,269,484 1,258,675 4.65 NVA Holdings, Inc., Term B-2 Loan (First Lien), 8/14/21 403,322 997,813 3.49 Rovi Solutions Corp., Term B Loan, 7/2/21 1,002,595 577,500 3.90 Seminole Hard Rock Entertainment, Inc., Term Loan, 5/14/20 581,711 821,620 3.75 WMG Acquisition Corp., Tranche C Term Loan, 11/1/23 825,986 ------------- $ 6,639,365 ----------------------------------------------------------------------------------------------------------- Publishing -- 0.0%+ 496,894 3.58 MTL Publishing LLC, Term B-4 Loan, 8/20/22 $ 499,864 694,976 0.00 Quincy Media, Inc., Term Loan B, 10/19/22 701,926 ------------- $ 1,201,790 ------------- Total Media $ 23,360,615 ----------------------------------------------------------------------------------------------------------- RETAILING -- 0.2% Home Improvement Retail -- 0.1% 1,195,584 4.50 Apex Tool Group LLC, Term Loan, 2/1/20 $ 1,188,111 ----------------------------------------------------------------------------------------------------------- Specialty Stores -- 0.0%+ 962,193 3.75 Michaels Stores, Inc., 2016 New Replacement Term B-1 Loan, 1/28/23 $ 960,189 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 83 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Automotive Retail -- 0.1% 1,306,602 3.15 Avis Budget Car Rental LLC, Tranche B Term Loan, 3/15/22 $ 1,310,849 199,679 3.90 Cooper-Standard Automotive, Inc., Additional Term B-1 Loan, 10/28/23 201,926 1,059,414 4.61 CWGS Group LLC, Term Loan, 11/3/23 1,067,360 421,284 3.73 The Hertz Corp., Tranche B-1 Term Loan, 6/30/23 422,568 ------------- $ 3,002,703 ----------------------------------------------------------------------------------------------------------- Homefurnishing Retail -- 0.0%+ 572,192 4.54 Serta Simmons Bedding LLC, Initial Term Loan (First Lien), 10/21/23 $ 575,564 ------------- Total Retailing $ 5,726,567 ----------------------------------------------------------------------------------------------------------- FOOD & STAPLES RETAILING -- 0.1% Food Distributors -- 0.0%+ 54,247 4.00 AdvancePierre Foods, Inc., Effective Date Loan, 5/18/23 $ 54,931 ----------------------------------------------------------------------------------------------------------- Food Retail -- 0.1% 1,047,076 4.30 Albertsons LLC, 2016-1 Term B-6 Loan, 6/23/23 $ 1,054,602 496,259 4.40 Albertsons LLC, 2016-2 Term B-5 Loan, 12/23/22 499,749 ------------- $ 1,554,351 ------------- Total Food & Staples Retailing $ 1,609,282 ----------------------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 0.2% Agricultural Products -- 0.0%+ 1,542,300 3.51 Darling International, Inc., Term B USD Loan, 12/19/20 $ 1,563,005 ----------------------------------------------------------------------------------------------------------- Packaged Foods & Meats -- 0.2% 533,425 3.23 B&G Foods, Inc., Tranche B Term Loan, 11/2/22 $ 538,426 2,400,000 3.29 JBS USA Lux SA (f.k.a. JBS USA LLC), Initial Term Loan, 10/30/22 2,408,750 2,153,436 2.81 Pinnacle Foods Finance LLC, Initial Term Loan, 1/30/24 2,165,934 ------------- $ 5,113,110 ------------- Total Food, Beverage & Tobacco $ 6,676,115 ----------------------------------------------------------------------------------------------------------- HOUSEHOLD & PERSONAL PRODUCTS -- 0.1% Household Products -- 0.0%+ 543,262 3.40 Spectrum Brands, Inc., 2016 Replacement USD Term Loan, 6/23/22 $ 547,846 ----------------------------------------------------------------------------------------------------------- Personal Products -- 0.1% 1,004,950 4.48 Revlon Consumer Products Corp., Initial Term B Loan, 7/22/23 $ 1,007,043 235,719 4.65 The Nature's Bounty Co., Dollar Term B-1 Loan, 5/5/23 237,118 ------------- $ 1,244,161 ------------- Total Household & Personal Products $ 1,792,007 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 84 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.5% Health Care Equipment -- 0.0%+ 625,000 3.48 Cidron Healthcare, Ltd., (a..k.a ConvaTec, Inc.), Term B Loan, 10/14/23 $ 631,250 ----------------------------------------------------------------------------------------------------------- Health Care Supplies -- 0.1% 1,145,000 4.25 Kinetic Concepts, Inc., Term Loan B, 2/1/24 $ 1,145,597 985,000 4.40 Sterigenics-Nordion Holdings LLC, Initial Term Loan, 4/27/22 988,694 ------------- $ 2,134,291 ----------------------------------------------------------------------------------------------------------- Health Care Services -- 0.1% 523,299 6.50 BioScrip, Inc., Initial Term B Loan, 7/31/20 $ 517,739 313,980 6.50 BioScrip, Inc., Term Loan, 7/31/20 310,644 593,611 4.00 BSN Medical GmbH & Co. KG, Facility B1A, 8/28/19 595,095 463,144 3.73 DaVita HealthCare Partners, Inc., Tranche B Loan (First Lien), 6/19/21 469,139 1,223,367 4.15 Envision Healthcare Corp., Initial Term Loan, 11/17/23 1,237,130 489,899 4.40 National Mentor Holdings, Inc., Tranche B Term Loan, 1/31/21 491,838 896,531 4.33 Pharmaceutical Product Development LLC, Initial Term Loan, 8/6/22 900,566 ------------- $ 4,522,151 ----------------------------------------------------------------------------------------------------------- Health Care Facilities -- 0.2% 24,025 3.90 CHS, Incremental 2019 Term G Loan, 12/31/19 $ 23,917 44,205 4.05 CHS, Incremental 2021 Term H Loan, 1/27/21 43,630 1,951,967 4.03 HCA, Inc., Tranche B-9 Term Loan, 3/10/23 1,962,490 476,326 4.50 IASIS Healthcare LLC, Term B-2 Loan, 5/3/18 476,368 1,080,565 4.56 Kindred Healthcare, Inc., Tranche B Loan (First Lien), 4/10/21 1,081,916 1,497,635 4.50 Select Medical Corp., Tranche B Term Loan, 2/13/24 1,513,547 439,926 5.00 Vizient, Inc., Term B-2 Loan, 2/11/23 444,692 ------------- $ 5,546,560 ----------------------------------------------------------------------------------------------------------- Managed Health Care -- 0.0%+ 744,375 7.12 Prospect Medical Holdings, Inc., Term Loan, 6/20/22 $ 755,075 ----------------------------------------------------------------------------------------------------------- Health Care Technology -- 0.1% 1,390,108 3.75 Change Healthcare Holdings, Inc. (f.k.a. Emdeon, Inc.), Closing Date Term Loan, 2/3/24 $ 1,394,163 ------------- Total Health Care Equipment & Services $ 14,983,490 ----------------------------------------------------------------------------------------------------------- PHARMACEUTICALS, BIOTECHNOLOGY & LIFE SCIENCES -- 0.3% Biotechnology -- 0.1% 1,099,693 3.58 Alkermes, Inc., 2021 Term Loan, 9/25/19 $ 1,110,690 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 85 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Pharmaceuticals -- 0.2% 397,894 5.25 Concordia Healthcare Corp., Initial Dollar Term Loan, 10/20/21 $ 280,515 296,613 4.25 DPx Holdings BV, 2015 Incremental Dollar Term Loan, 1/23/21 297,434 1,085,582 4.00 Endo Luxembourg Finance I Co., Sarl, 2015 Incremental Term B Loan, 6/24/22 1,087,467 525,000 3.19 Grifols Worldwide Operations USA, Inc., Tranche B Term Loan, 1/23/25 526,923 891,824 3.90 Mallinckrodt International Finance SA, 2017, Term B Loan, 9/24/24 892,938 500,000 0.00 RPI Finance Trust, Initial Term Loan B-6, 3/17/23 502,098 1,308,866 3.65 RPI Finance Trust, Term B-5 Term Loan, 10/5/22 1,314,593 1,395,428 5.57 Valeant Pharmaceuticals, Series F-1, 3/11/22 1,402,564 ------------- $ 6,304,532 ----------------------------------------------------------------------------------------------------------- Life Sciences Tools & Services -- 0.0%+ 496,222 6.01 Albany Molecular Research, Inc., Term Loan, 7/14/21 $ 501,184 ------------- Total Pharmaceuticals, Biotechnology & Life Sciences $ 7,916,406 ----------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 0.3% Other Diversified Financial Services -- 0.2% 717,463 4.50 Altisource Solutions Sarl, Term B Loan, 12/9/20 $ 692,351 303,549 3.78 AWAS Finance Luxembourg 2012 SA, Term Loan, 7/16/18 305,257 1,292,032 3.40 Delos Finance Sarl, Loan, 10/6/23 1,305,625 1,909,107 3.79 Fly Funding II Sarl, Loan, 8/9/19 1,919,449 481,250 5.50 Livingston International, Inc., Initial Term B-1 Loan (First Lien), 4/18/19 477,340 241,938 6.00 Ocwen Loan Servicing LLC, Restatement Effective Date Term Loan, 12/5/20 245,012 ------------- $ 4,945,034 ----------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.0% 462,493 3.31 Restaurant Brands, Inc., 1st Lien Term Loan B, 2/7/24 $ 464,083 831,587 3.24 SBA Senior Finance II LLC, Incremental Tranche B-1 Term Loan, 3/31/21 835,151 ------------- $ 1,299,234 ----------------------------------------------------------------------------------------------------------- Diversified Capital Markets -- 0.1% 1,000,000 3.73 Avolon TLB Borrower 1 (U.S.) LLC, Initial Term B-2 Loan, 1/20/22 $ 1,015,139 The accompanying notes are an integral part of these financial statements. 86 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Diversified Capital Markets -- (continued) 1,594,274 3.18 Outfront Media Capital LLC (Outfront Media Capital Corp.,), Term Loan, 3/10/24 $ 1,606,730 1,000,000 3.25 Restaurant Brands, Inc., 1st Lien Term Loan, 2/7/24 1,000,625 ------------- $ 3,622,494 ------------- Total Diversified Financials $ 9,866,762 ----------------------------------------------------------------------------------------------------------- INSURANCE -- 0.1% Insurance Brokers -- 0.0%+ 793,077 4.25 USI Insurance Services LLC, Term B Loan, 12/30/19 $ 795,224 ----------------------------------------------------------------------------------------------------------- Life & Health Insurance -- 0.0%+ 740,839 6.79 Integro, Ltd., Initial Term Loan (First Lien), 10/9/22 $ 744,543 ----------------------------------------------------------------------------------------------------------- Multi-line Insurance -- 0.0%+ 71,219 4.39 Alliant Holdings Intermediate LLC, Initial Term Loan, 7/28/22 $ 71,805 ----------------------------------------------------------------------------------------------------------- Property & Casualty Insurance -- 0.1% 1,000,000 5.89 Acrisure LLC, Term B Loan (First Lien), 11/3/23 $ 1,016,563 576,385 5.75 Confie Seguros Holding II Co., Term B Loan, 4/13/22 579,411 ------------- $ 1,595,974 ------------- Total Insurance $ 3,207,546 ----------------------------------------------------------------------------------------------------------- REAL ESTATE -- 0.1% Hotel & Resort REIT -- 0.0%+ 1,123,650 3.48 MGM Growth Properties Operating Partnership LP, Term B Loan, 4/7/23 $ 1,130,954 ----------------------------------------------------------------------------------------------------------- Retail REIT -- 0.1% 1,676,354 4.30 DTZ US Borrower LLC, 2015-1 Additional Term Loan (First Lien), 11/4/21 $ 1,688,927 ----------------------------------------------------------------------------------------------------------- Specialized REIT -- 0.0%+ 393,027 4.00 Uniti Group, Inc., Shortfall Term Loan, 10/24/22 $ 392,780 ------------- Total Real Estate $ 3,212,661 ----------------------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 0.2% Internet Software & Services -- 0.1% 1,995,000 4.53 Rackspace Hosting, Inc., Term B Loan (First Lien), 10/26/23 $ 2,012,664 997,500 3.41 Vantiv LLC, Term B Loan, 6/12/21 1,007,920 ------------- $ 3,020,584 ----------------------------------------------------------------------------------------------------------- IT Consulting & Other Services -- 0.0%+ 1,132,598 3.15 CDW LLC, Term Loan, 8/16/23 $ 1,140,385 390,000 5.75 Evergreen Skills Lux Sarl, Initial Term Loan (First Lien), 4/23/21 359,531 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 87 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- IT Consulting & Other Services -- (continued) 223,100 4.54 PSAV Presentation Services, Tranche B Term Loan (First Lien), 1/24/21 $ 223,937 ------------- $ 1,723,853 ----------------------------------------------------------------------------------------------------------- Data Processing & Outsourced Services -- 0.0%+ 496,250 4.48 WEX, Inc., Term B Loan, 6/24/23 $ 502,852 ----------------------------------------------------------------------------------------------------------- Application Software -- 0.1% 497,500 6.29 DTI HoldCo, Inc., Term Loan (First Lien), 9/23/23 $ 490,659 201,799 4.79 MA FinanceCo LLC, Initial Tranche B-2 Term Loan, 11/20/21 203,655 1,000,000 4.08 Synchronoss Technologies, Inc., Initial Term Loan, 1/19/24 998,250 323,233 3.76 Verint Systems, Inc., Tranche B-2 Term Loan (First Lien), 9/6/19 325,132 ------------- $ 2,017,696 ------------- Total Software & Services $ 7,264,985 ----------------------------------------------------------------------------------------------------------- TECHNOLOGY HARDWARE & EQUIPMENT -- 0.1% Communications Equipment -- 0.1% 1,216,730 3.48 Ciena Corp., Refinancing Term Loan, 2/25/22 $ 1,225,856 1,754,000 3.48 CommScope, Inc., Tranche 5 Term Loan (2015), 12/29/22 1,767,141 ------------- $ 2,992,997 ----------------------------------------------------------------------------------------------------------- Computer Hardware -- 0.0%+ 795,000 5.38 Diebold Nixdorf, Inc., Dollar Term B Loan, 3/18/23 $ 808,416 ----------------------------------------------------------------------------------------------------------- Electronic Equipment Manufacturers -- 0.0%+ 715,000 3.60 Zebra Technologies Corp., Refinancing Term Loan, 12/27/21 $ 721,927 ------------- Total Technology Hardware & Equipment $ 4,523,340 ----------------------------------------------------------------------------------------------------------- SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT -- 0.1% Semiconductor Equipment -- 0.1% 1,968,692 3.40 Sensata Technologies BV, Sixth Amendment Term Loan, 10/14/21 $ 1,984,226 ----------------------------------------------------------------------------------------------------------- Semiconductors -- 0.0%+ 643,856 3.86 M/A-COM Technology, Initial Term Loan, 5/7/21 $ 403,389 396,939 3.23 Microsemi Corp., Closing Date Term B Loan, 12/17/22 55,636 55,279 3.23 ON Semiconductor Corp., 2016 New Replacement Term Loan, 3/31/23 646,718 ------------- $ 1,105,743 ------------- Total Semiconductors & Semiconductor Equipment $ 3,089,969 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 88 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 0.2% Integrated Telecommunication Services -- 0.1% 1,000,000 4.00 Cincinnati Bell, Inc., Tranche B Term Loan, 9/10/20 $ 736,044 692,723 3.78 GCI Holdings, Inc., New Term B Loan (2016), 2/2/22 653,333 731,019 3.23 Level 3 Financing, Inc., Tranche B 2024 Term Loan, 2/17/24 1,002,250 646,464 4.20 Windstream Services LLC (fka Windstream Corp.,), Tranche B-7 Term Loan, 2/8/24 693,156 ------------- $ 3,084,783 ----------------------------------------------------------------------------------------------------------- Wireless Telecommunication Services -- 0.1% 2,000,000 3.98 Altice US Finance I Corp., 2016 Refinancing Term Loan, 10/25/24 $ 1,099,272 1,095,165 3.50 Sprint Communications, Inc., Initial Term Loan, 2/2/24 2,002,916 1,484,673 3.66 Virgin Media Bristol LLC, I Facility, 1/31/25 1,490,241 ------------- $ 4,592,429 ------------- Total Telecommunication Services $ 7,677,212 ----------------------------------------------------------------------------------------------------------- UTILITIES -- 0.3% Electric Utilities -- 0.2% 1,496,250 6.15 APLP Holdings LP, Term Loan, 4/12/23 $ 2,082,525 2,065,315 3.03 Calpine Construction Finance Co. LP, Term B-1 Loan, 5/3/20 1,159,693 1,155,000 6.06 Talen Energy Supply LLC, Initial Term Loan, 10/18/23 1,521,499 ------------- 498,750 4.24 The Dayton Power & Light Co., Loan, 8/18/22 502,175 ------------- $ 5,265,892 ----------------------------------------------------------------------------------------------------------- Independent Power Producers & Energy Traders -- 0.1% 543,125 0.00 Calpine Corp., Term Loan (2015), 1/15/23 $ 546,293 284,925 3.90 Calpine Corp., Term Loan, 5/28/22 286,483 200,000 4.25 Dynegy, Inc., Tranche C-1 Term Loan, 2/27/24 201,038 1,639,351 3.23 NRG Energy, Inc., Term Loan, 6/30/23 1,647,958 918,428 5.65 TerraForm AP Acquisition Holdings LLC, Term Loan, 6/26/22 927,612 ------------- $ 3,609,384 ------------- Total Utilities $ 8,875,276 ----------------------------------------------------------------------------------------------------------- TOTAL SENIOR FLOATING RATE LOAN INTERESTS (Cost $163,166,885) $ 163,648,976 ----------------------------------------------------------------------------------------------------------- TEMPORARY CASH INVESTMENTS -- 4.9% Commercial Paper -- 2.9% 3,200,000 Agrium, Inc., Commercial Paper, 4/25/17 (c) $ 3,197,318 8,300,000 Amphenol Corp., Commercial Paper, 4/3/17 (c) 8,299,238 3,190,000 Autozone, Inc., Commercial Paper, 4/3/17 (c) 3,189,707 The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 89 Schedule of Investments | 3/31/17 (continued) ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Commercial Paper -- (continued) 3,175,000 Autozone, Inc., Commercial Paper, 4/6/17 (c) $ 3,174,410 3,070,000 Bell Canada, Commercial Paper, 5/16/17 (c) 3,065,422 3,170,000 Candian Natural Resources, Inc., Commercial Paper, 4/13/17 (c) 3,168,509 6,500,000 CVS Corp., Commercial Paper, 4/3/17 (c) 6,499,403 3,100,000 Dominion Resources, Inc., Commercial Paper, 4/17/17 (c) 3,098,295 15,995,000 Federation, Commercial Paper, 4/3/17 (c) 15,993,893 3,150,000 ING U.S. Funding, Inc., Commercial Paper, 9/1/17 (c) 3,132,321 8,970,000 Mitsubishi Bank and Trust, Inc., Commercial Paper, 6/22/17 (c) 8,972,102 3,150,000 National Grid, Commercial Paper, 4/12/17 (c) 3,148,800 3,380,000 Oneok, Inc., Commercial Paper, 4/12/17 (c) 3,378,712 3,195,000 PPL Electric Co., Commercial Paper, 4/13/17 (c) 3,193,675 8,510,000 PPL Electric Corp., Commercial Paper, 4/6/17 (c) 8,508,419 7,920,000 Rockwell Colliers International, Inc., Commercial Paper, 4/6/17 (c) 7,918,528 3,890,000 1.50 Sumitomo Mitsui Banking Corp., Commercial Paper, 7/20/17 (c) 3,893,676 ------------- $ 91,832,428 ----------------------------------------------------------------------------------------------------------- Certificates of Deposit -- 0.8% 3,060,000 1.50 Bank of Montreal, Floating Rate Note, 12/11/17 $ 3,068,822 2,600,000 1.67 Bank of Montreal, Floating Rate Note, 3/16/18 2,599,366 2,500,000 1.46 Bank of Nova Scotia Houston, Floating Rate Note, 5/2/17 2,500,050 151,000 BMO Harris Bank NA, 1.0%, 4/24/17 151,018 1,460,000 1.30 Credit Agricole Corp., Floating Rate Note, 7/12/17 1,460,718 1,492,000 2.25 Credit Suisse AG New York NY, Floating Rate Note, 3/8/18 1,495,684 2,500,000 1.10 Mizuho Bank, Ltd., Floating Rate Note, 7/12/17 2,500,559 3,000,000 1.28 Nordea Bank AB New York NY, Floating Rate Note, 4/26/17 3,001,035 1,715,000 1.25 Sumitomo Mitsui Banking Corp. New York, Floating Rate Note, 5/2/17 1,715,592 2,695,000 1.26 Sumitomo Mitsui, Floating Rate Note, 11/1/16 2,695,089 2,480,000 1.36 Svenska Handelsbanken New York NY, Floating Rate Note, 5/26/17 2,480,248 3,000,000 1.53 UBS AG, Floating Rate Note, 5/25/17 3,002,357 ------------- $ 26,670,538 ----------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 90 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------- Floating Principal Rate (b) Amount ($) (unaudited) Value ----------------------------------------------------------------------------------------------------------- Repurchase Agreements -- 1.2% 7,995,000 $7,995,000 Scotia Bank, 0.81%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by the following: $9,031 Freddie Mac Giant, 4.5%, 8/1/42 $12,387 Federal Home Loan Mortgage Corp., 2.814%, 5/1/44 $27,931 Federal National Mortgage Association (ARM), 2.557% - 3.026%, 1/1/39-5/1/44 $8,095,903 Federal National Mortgage Association, 3.0% - 4.0%, 2/1/30-1/1/47 $10,200 Government National Mortgage Association, 4.0%, 5/20/46 $ 7,995,000 14,870,000 $14,870,000 RBC Capital Markets LLC, 0.79%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by the following: $366,411 Federal National Mortgage Association (ARM), 2.521-3.055%, 9/1/41-9/1/42 $13,613,273 Federal National Mortgage Association, 2.5% - 4.0%, 2/1/29-3/1/47 $1,187,716 Government National Mortgage Association, 3.0% - 4.0%, 3/20/46-2/20/47 14,870,000 7,995,000 $7,995,000 TD Securities USA LLC, 0.80%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by $8,154,900 Federal National Mortgage Association, 4.0%, 2/1/47 7,995,000 7,995,000 $7,995,000 TD Securities USA LLC, 0.81%, dated 3/31/17 plus accrued interest on 4/3/17 collateralized by $8,154,900 Federal National Mortgage Association, 4.0%, 2/1/47 7,995,000 ---------------- $ 38,855,000 ------------------------------------------------------------------------------------------------------------ TOTAL TEMPORARY CASH INVESTMENTS (Cost $157,360,959) $ 157,357,966 ------------------------------------------------------------------------------------------------------------ TOTAL INVESTMENT IN SECURITIES -- 101.6% (Cost $3,244,878,322) (a) $ 3,249,328,293 ------------------------------------------------------------------------------------------------------------ OTHER ASSETS & LIABILITIES -- (1.6)% $ (51,030,775) ------------------------------------------------------------------------------------------------------------ NET ASSETS -- 100.0% $ 3,198,297,518 ============================================================================================================ + Amount rounds to less than 0.1%. (Cat Bond) Catastrophe or Event Linked Bond. At March 31, 2017, the value of these securities amounted to $146,600,993, or 4.6% of net assets. See Notes to Financial Statements -- Note 1H. (144A) Security is exempt from registration under Rule 144A of the Securities Act of 1933. Such securities may be resold normally to qualified institutional buyers in a transaction exempt from registration. At March 31, 2017, the value of these securities amounted to $1,300,680,496 or 40.7% of net assets. REIT Real Estate Investment Trust. The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 91 Schedule of Investments | 3/31/17 (continued) REMICS Real Estate Mortgage Investment Conduits. ARM Adjustable Rate Mortgage. Strips Separate trading of registered interest and principal of securities. (Step) Bond issued with an initial coupon rate which converts to a higher rate at a later date. ** Senior floating rate loan interests in which the Fund invests generally pay interest at rates that are periodically redetermined by reference to a base lending rate plus a premium. These base lending rates are generally (i) the lending rate offered by one or more major European banks, such as LIBOR (London InterBank Offered Rate), (ii) the prime rate offered by one or more major United States banks, (iii) the certificate of deposit rate or (iv) other base lending rates used by commercial lenders. The rate shown is the coupon rate at period end. (a) At March 31, 2017, the net unrealized depreciation on investments based on cost for federal income tax purposes of $3,250,453,180 was as follows: Aggregate gross unrealized appreciation for all investments in which there is an excess of value over tax cost $ 6,385,166 Aggregate gross unrealized depreciation for all investments in which there is an excess of tax cost over value (7,510,053) ----------- Net unrealized depreciation $(1,124,887) =========== (b) Debt obligation with a variable interest rate. Rate shown is rate at end of period. (c) Security issued with a zero coupon. Income is recognized through accretion of discount. (d) Rate to be determined. (e) Structured reinsurance investment. At March 31, 2017, the value of these securities amounted to $36,304,353 or 1.1% of net assets. See Notes to Financial Statements -- Note 1H. (f) Consists of Revenue Bonds unless otherwise indicated. Purchases and sales of securities (excluding temporary cash investments) for the year ended March 31, 2017 were as follows: -------------------------------------------------------------------------------------------- Purchases Sales -------------------------------------------------------------------------------------------- Long-Term U.S. Government Securities $ 413,229,223 $ 224,702,606 Other Long-Term Securities $ 1,707,808,334 $ 1,632,992,919 The Fund is permitted to engage in purchase and sale transactions ("cross trades") with certain Funds and accounts for which Pioneer Investment Management, Inc. (PIM), serves as the Fund's investment adviser, as set forth in Rule 17a-7 under the Investment Company Act of 1940, pursuant to procedures adopted by the Board of Trustees. Under these procedures, cross trades are effected at current market prices. During the year ended March 31, 2017, the Fund engaged in purchases and sales pursuant to these procedures amounting to $21,346,150 and $8,208,644, respectively, which resulted in a net realized loss of $321,179. Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below. Level 1 - quoted prices in active markets for identical securities. Level 2 - other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.) See Notes to Financial Statements -- Note 1A. Level 3 - significant unobservable inputs (including the Fund's own assumptions in determining fair value of investments) See Notes to Financial Statements -- Note 1A. The accompanying notes are an integral part of these financial statements. 92 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 The following is a summary of the inputs used as of March 31, 2017, in valuing the Fund's assets: ---------------------------------------------------------------------------------------------------- Level 1 Level 2 Level 3 Total ---------------------------------------------------------------------------------------------------- Asset Backed Securities $ -- $ 906,397,521 $ -- $ 906,397,521 Collateralized Mortgage Obligations -- 796,896,325 -- 796,896,325 Corporate Bonds Insurance Reinsurance -- 132,010,445 50,894,901 182,905,346 All Other Corporate bonds -- 740,067,197 -- 740,067,197 U.S. Government and Agency Obligations -- 299,405,097 -- 299,405,097 Municipal Bonds -- 2,649,865 -- 2,649,865 Senior Floating Rate Loan Interests -- 163,648,976 -- 163,648,976 Repurchase Agreements -- 38,855,000 -- 38,855,000 Commercial Paper -- 91,832,428 -- 91,832,428 Certificates of Deposit -- 26,670,538 -- 26,670,538 ---------------------------------------------------------------------------------------------------- Total $ -- $ 3,198,433,392 $ 50,894,901 $ 3,249,328,293 ==================================================================================================== The following is a reconciliation of assets valued using significant unobservable inputs (Level 3): ----------------------------------------------------------------------------------------------------- Corporate Bonds ----------------------------------------------------------------------------------------------------- Balance as of 3/31/16 $ 25,387,932 Realized gain (loss)(1) 8,784 Change in unrealized appreciation (depreciation)(2) 2,355,391 Purchases 47,090,058 Sales (23,947,264) Changes between Level 3* -- ----------------------------------------------------------------------------------------------------- Balance as of 3/31/17 $ 50,894,901 ===================================================================================================== (1) Realized gain (loss) on these securities is included in the net realized gain (loss) from investments in the Statement of Operations. (2) Unrealized appreciation (depreciation) on these securities is included in the change in unrealized appreciation (depreciation) on investments in the Statement of Operations. * Transfers are calculated on the beginning of period values. During the year ended March 31, 2017, there were no transfers between Levels 1, 2 and 3. Net change in unrealized appreciation (depreciation) of investments still held as of 3/31/17 $ 2,936,442 -------------- The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 93 Statement of Assets and Liabilities | 3/31/17 ASSETS: Investment in securities (cost $3,244,878,322) $3,249,328,293 Cash 8,585,812 Receivables -- Investment securities sold 770,885 Fund shares sold 32,178,885 Interest 6,568,183 Other assets 180,129 ---------------------------------------------------------------------------------------------------- Total assets $3,297,612,187 ==================================================================================================== LIABILITIES: Payables -- Investment securities purchased $ 74,063,563 Fund shares repurchased 23,697,326 Distributions 493,008 Due to affiliates 83,657 Accrued expenses 977,115 ---------------------------------------------------------------------------------------------------- Total liabilities $ 99,314,669 ==================================================================================================== NET ASSETS: Paid-in capital $3,219,925,902 Distributions in excess of net investment income (2,002,976) Accumulated net realized loss on investments and foreign currency transactions (24,075,379) Net unrealized appreciation on investments 4,449,971 ---------------------------------------------------------------------------------------------------- Net assets $3,198,297,518 ==================================================================================================== NET ASSET VALUE PER SHARE: (No par value, unlimited number of shares authorized) Class A (based on $759,455,322/76,057,565 shares) $ 9.99 Class C (based on $568,840,400/57,043,692 shares) $ 9.97 Class C2 (based on $9,834,058/986,402 shares) $ 9.97 Class K (based on $91,665,979/9,172,214 shares) $ 9.99 Class Y (based on $1,768,501,759/177,062,000 shares) $ 9.99 MAXIMUM OFFERING PRICE: Class A ($9.99 (divided by) 97.5%) $ 10.25 ==================================================================================================== The accompanying notes are an integral part of these financial statements. 94 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Statement of Operations For the Year Ended 3/31/17 INVESTMENT INCOME: Interest $61,117,252 --------------------------------------------------------------------------------------------------- Total investment income $ 61,117,252 =================================================================================================== EXPENSES: Management fees $ 8,818,723 Transfer agent fees Class A 137,980 Class C 194,290 Class C2 3,883 Class K 6 Class Y 1,435,100 Distribution fees Class A 1,360,123 Class C 2,668,303 Class C2 48,374 Shareholder communications expense 248,377 Administrative expense 868,557 Custodian fees 173,158 Registration fees 283,288 Professional fees 134,377 Printing expense 58,558 Fees and expenses of nonaffiliated Trustees 127,081 Miscellaneous 420,669 --------------------------------------------------------------------------------------------------- Total expenses $ 16,980,847 --------------------------------------------------------------------------------------------------- Net investment income $ 44,136,405 --------------------------------------------------------------------------------------------------- REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS AND FOREIGN CURRENCY TRANSACTIONS: Net realized gain (loss) on: Investments $(1,773,190) Other assets and liabilities denominated in foreign currencies 8,996 $ (1,764,194) --------------------------------------------------------------------------------------------------- Change in net unrealized appreciation (depreciation) on investments $ 20,985,712 --------------------------------------------------------------------------------------------------- Net realized and unrealized gain (loss) on investments $ 19,221,518 --------------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 63,357,923 =================================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 95 Statements of Changes in Net Assets ----------------------------------------------------------------------------------------------------- Year Ended Year Ended 3/31/17 3/31/16 ----------------------------------------------------------------------------------------------------- FROM OPERATIONS: Net investment income (loss) $ 44,136,405 $ 26,863,081 Net realized gain (loss) on investments and foreign currency transactions (1,764,194) (2,690,112) Change in net unrealized appreciation (depreciation) on investments 20,985,712 (13,516,703) ----------------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 63,357,923 $ 10,656,266 ----------------------------------------------------------------------------------------------------- DISTRIBUTIONS TO SHAREOWNERS: Net investment income: Class A ($0.17 and $0.12 per share, respectively) $ (11,645,585) $ (8,586,311) Class C ($0.14 and $0.09 per share, respectively) (7,377,025) (5,163,777) Class C2 ($0.14 and $0.09 per share, respectively) (133,252) (101,540) Class K ($0.19 and $0.14 per share, respectively) (314,128) (73,029) Class Y ($0.18 and $0.13 per share, respectively) (28,545,808) (18,130,486) Class Z* ($0.00 and $0.04 per share, respectively) -- (7,120) ----------------------------------------------------------------------------------------------------- Total distributions to shareowners $ (48,015,798) $ (32,062,263) ----------------------------------------------------------------------------------------------------- FROM FUND SHARE TRANSACTIONS: Net proceeds from sale or exchange of shares $ 2,635,780,672 $ 2,214,104,786 Reinvestment of distributions 42,037,618 28,171,903 Cost of shares repurchased (2,126,031,078) (2,084,487,736) ----------------------------------------------------------------------------------------------------- Net increase in net assets resulting from Fund share transactions $ 551,787,212 $ 157,788,953 ----------------------------------------------------------------------------------------------------- Net increase in net assets $ 567,129,337 $ 136,382,956 NET ASSETS: Beginning of year $ 2,631,168,181 $ 2,494,785,225 ----------------------------------------------------------------------------------------------------- End of year $ 3,198,297,518 $ 2,631,168,181 ----------------------------------------------------------------------------------------------------- Distributions in excess of net investment income $ (2,002,976) $ (926,302) ===================================================================================================== * Class Z shares converted to Class Y shares on August 7, 2015. The accompanying notes are an integral part of these financial statements. 96 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 --------------------------------------------------------------------------------------------------- Year Ended Year Ended Year Ended Year Ended 3/31/17 3/31/17 3/31/16 3/31/16 Shares Amount Shares Amount --------------------------------------------------------------------------------------------------- Class A Shares sold 54,032,493 $ 539,264,584 51,394,899 $ 512,589,367 Reinvestment of distributions 1,052,187 10,498,392 790,234 7,870,694 Less shares repurchased (46,879,123) (467,598,705) (53,732,161) (535,574,030) --------------------------------------------------------------------------------------------------- Net increase (decrease) 8,205,557 $ 82,164,271 (1,547,028) $ (15,113,969) =================================================================================================== Class C Shares sold 28,880,632 $ 287,826,009 26,952,712 $ 268,378,600 Reinvestment of distributions 731,519 7,288,620 512,978 5,102,845 Less shares repurchased (25,444,875) (253,536,832) (34,073,846) (339,162,010) --------------------------------------------------------------------------------------------------- Net increase (decrease) 4,167,276 $ 41,577,797 (6,608,156) $ (65,680,565) =================================================================================================== Class C2 Shares sold 296,871 $ 2,958,188 480,794 $ 4,784,862 Reinvestment of distributions 6,343 63,187 5,430 54,011 Less shares repurchased (355,622) (3,541,422) (574,432) (5,713,727) --------------------------------------------------------------------------------------------------- Net decrease (52,408) $ (520,047) (88,208) $ (874,854) =================================================================================================== Class K Shares sold 9,699,288 $ 96,908,050 55,702 $ 556,671 Reinvestment of distributions 31,438 314,013 7,329 73,038 Less shares repurchased (1,064,634) (10,642,480) (65,441) (652,957) --------------------------------------------------------------------------------------------------- Net increase (decrease) 8,666,092 $ 86,579,583 (2,410) $ (23,248) =================================================================================================== Class Y Shares sold 171,158,865 $ 1,708,823,841 143,234,574 $ 1,427,512,361 Reinvestment of distributions 2,391,859 23,873,406 1,512,571 15,066,282 Less shares repurchased (139,378,771) (1,390,711,639) (120,600,180) (1,201,274,155) --------------------------------------------------------------------------------------------------- Net increase 34,171,953 $ 341,985,608 24,146,965 $ 241,304,488 =================================================================================================== Class Z* Shares sold or exchanged -- $ -- 28,442 $ 282,925 Reinvestment of distributions -- -- 506 5,033 Less shares repurchased -- -- (212,381) (2,110,857) --------------------------------------------------------------------------------------------------- Net decrease -- $ -- (183,433) $ (1,822,899) =================================================================================================== * Class Z shares converted to Class Y shares on August 7, 2015. The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 97 Financial Highlights ---------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 ---------------------------------------------------------------------------------------------------------------------------- Class A Net asset value, beginning of period $ 9.92 $ 10.00 $ 10.07 $ 10.08 $ 10.02 ---------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.16(a) $ 0.10(a) $ 0.10 $ 0.10 $ 0.13 Net realized and unrealized gain (loss) on investments 0.08 (0.06) (0.05) (0.01) 0.08 ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.24 $ 0.04 $ 0.05 $ 0.09 $ 0.21 ---------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.17) $ (0.12) $ (0.12) $ (0.10) $ (0.15) ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.07 $ (0.08) $ (0.07) $ (0.01) $ 0.06 ---------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.99 $ 9.92 $ 10.00 $ 10.07 $ 10.08 ============================================================================================================================ Total return* 2.43% 0.41% 0.54% 0.92% 2.14% Ratio of net expenses to average net assets 0.61% 0.63% 0.63% 0.66% 0.72% Ratio of net investment income (loss) to average net assets 1.59% 1.01% 0.95% 0.93% 0.94% Portfolio turnover rate 69% 58% 45% 47% 101% Net assets, end of period (in thousands) $759,455 $673,352 $694,221 $570,468 $381,267 ============================================================================================================================ * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. (a) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 98 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ---------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 ---------------------------------------------------------------------------------------------------------------------------- Class C Net asset value, beginning of period $ 9.91 $ 9.99 $ 10.05 $ 10.07 $ 10.02 ---------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.13(a) $ 0.07(a) $ 0.07 $ 0.08 $ 0.09 Net realized and unrealized gain (loss) on investments 0.07 (0.06) (0.04) (0.03) 0.07 ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.20 $ 0.01 $ 0.03 $ 0.05 $ 0.16 ---------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.14) $ (0.09) $ (0.09) $ (0.07) $ (0.11) ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.06 $ (0.08) $ (0.06) $ (0.02) $ 0.05 ---------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.97 $ 9.91 $ 9.99 $ 10.05 $ 10.07 ============================================================================================================================ Total return* 2.00% 0.11% 0.34% 0.54% 1.61% Ratio of net expenses to average net assets 0.93% 0.94% 0.94% 0.97% 1.03% Ratio of net investment income (loss) to average net assets 1.27% 0.70% 0.66% 0.62% 0.63% Portfolio turnover rate 69% 58% 45% 47% 101% Net assets, end of period (in thousands) $568,840 $524,030 $594,283 $575,457 $330,828 ============================================================================================================================ * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. (a) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 99 Financial Highlights (continued) ------------------------------------------------------------------------------------------------------------------ Year Year Year Ended Ended Ended 8/1/13 3/31/17 3/31/16 3/31/15 to 3/31/14 ------------------------------------------------------------------------------------------------------------------ Class C2 Net asset value, beginning of period $ 9.91 $ 9.99 $ 10.05 $ 10.04 ------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.13(b) $ 0.07(b) $ 0.06 $ 0.07 Net realized and unrealized gain (loss) on investments 0.07 (0.06) (0.03) (0.01) ------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.20 $ 0.01 $ 0.03 $ 0.06 ------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.14) $ (0.09) $ (0.09) $ (0.05) ------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.06 $ (0.08) $ (0.06) $ 0.01 ------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.97 $ 9.91 $ 9.99 $ 10.05 =================================================================================================================== Total return* 2.00% 0.11% 0.33% 0.56%(a) Ratio of net expenses to average net assets 0.93% 0.94% 0.95% 0.99%** Ratio of net investment income (loss) to average net assets 1.27% 0.69% 0.66% 0.68%** Portfolio turnover rate 69% 58% 45% 47% Net assets, end of period (in thousands) $ 9,834 $10,292 $11,258 $ 3,699 =================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. ** Annualized. (a) Not Annualized. (b) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 100 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 ----------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Ended Ended Ended Ended 12/20/12 3/31/17 3/31/16 3/31/15 3/31/14 to 3/31/13 ----------------------------------------------------------------------------------------------------------------------------- Class K Net asset value, beginning of period $ 9.93 $10.01 $ 10.07 $10.08 $10.09 ----------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.19(c) $ 0.12(c) $ 0.14 $ 0.12 $ 0.03 Net realized and unrealized gain (loss) on investments 0.06 (0.06) (0.06) (0.00)(a) 0.01 ----------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.25 $ 0.06 $ 0.08 $ 0.12 $ 0.04 ----------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.19) $(0.14) $ (0.14) $(0.13) $(0.05) ----------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.06 $(0.08) $ (0.06) $(0.01) $(0.01) ----------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.99 $ 9.93 $ 10.01 $10.07 $10.08 ============================================================================================================================= Total return* 2.55% 0.64% 0.83% 1.16% 0.43%(b) Ratio of net expenses to average net assets 0.42% 0.42% 0.41% 0.41% 0.53%** Ratio of net investment income (loss) to average net assets 1.92% 1.24% 1.28% 1.19% 1.25%** Portfolio turnover rate 69% 58% 45% 47% 101% Net assets, end of period (in thousands) $91,666 $5,026 $ 5,091 $ 10 $ 10 ============================================================================================================================= * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. ** Annualized. (a) Amount rounds to less than $0.01 or $(0.01) per share. (b) Not Annualized. (c) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 101 Financial Highlights (continued) ---------------------------------------------------------------------------------------------------------------------------- Year Year Year Year Year Ended Ended Ended Ended Ended 3/31/17 3/31/16 3/31/15 3/31/14 3/31/13 ---------------------------------------------------------------------------------------------------------------------------- Class Y Net asset value, beginning of period $ 9.93 $ 10.01 $ 10.07 $ 10.09 $ 10.03 ---------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.17(a) $ 0.11(a) $ 0.11 $ 0.12 $ 0.14 Net realized and unrealized gain (loss) on investments 0.07 (0.06) (0.03) (0.02) 0.09 ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.24 $ 0.05 $ 0.08 $ 0.10 $ 0.23 ---------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.18) $ (0.13) $ (0.14) $ (0.12) $ (0.17) ---------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.06 $ (0.08) $ (0.06) $ (0.02) $ 0.06 ---------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.99 $ 9.93 $ 10.01 $ 10.07 $ 10.09 ============================================================================================================================ Total return* 2.46% 0.54% 0.79% 0.99% 2.35% Ratio of net expenses to average net assets 0.50% 0.51% 0.51% 0.54% 0.55% Ratio of net investment income (loss) to average net assets 1.70% 1.15% 1.08% 1.05% 1.11% Portfolio turnover rate 69% 58% 45% 47% 101% Net assets, end of period (in thousands) $1,768,502 $1,418,468 $1,188,107 $912,810 $608,818 ============================================================================================================================ * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. (a) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 102 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Notes to Financial Statements | 3/31/17 1. Organization and Significant Accounting Policies Pioneer Multi-Asset Ultrashort Income Fund (the Fund) is one of three portfolios comprising Pioneer Series Trust X, a Delaware statutory trust. The Fund is registered under the Investment Company Act of 1940 as a diversified, open-end management investment company. The investment objective of the Fund is to seek a high level of current income to the extent consistent with a relatively high level of stability of principal. The Fund offers five classes of shares designated as Class A, Class C, Class C2, Class K and Class Y shares. Class Z shares were converted to Class Y shares as of the close of business on August 7, 2015. Each class of shares represents an interest in the same portfolio of investments of the Fund and has identical rights (based on relative net asset values) to assets and liquidation proceeds. Share classes can bear different rates of class-specific fees and expenses, such as transfer agent and distribution fees. Differences in class-specific fees and expenses will result in differences in net investment income and, therefore, the payment of different dividends from net investment income earned by each class. The Amended and Restated Declaration of Trust of the Fund gives the Board of Trustees the flexibility to specify either per-share voting or dollar-weighted voting when submitting matters for shareholder approval. Under per-share voting, each share of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a shareholder's voting power is determined not by the number of shares owned, but by the dollar value of the shares on the record date. Each share class has exclusive voting rights with respect to matters affecting only that class, including with respect to the distribution plan for that class. There is no distribution plan for Class K or Class Y shares. The Fund's financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) that require the management of the Fund to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of income, expenses and gains and losses on investments during the reporting period. Actual results could differ from those estimates. The Fund is an investment company and follows investment company accounting and reporting guidance under U.S. GAAP. The following is a summary of significant accounting policies followed by the Fund in the preparation of its financial statements: Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 103 A. Security Valuation The net asset value of the Fund is computed once daily, on each day the New York Stock Exchange (NYSE) is open, as of the close of regular trading on the NYSE. Fixed income securities are valued by using prices supplied by independent pricing services, which consider such factors as market prices, market events, quotations from one or more brokers, Treasury spreads, yields, maturities and ratings, or may use a pricing matrix or other fair value methods or techniques to provide an estimated value of the security or instrument. A pricing matrix is a means of valuing a debt security on the basis of current market prices for other debt securities, historical trading patterns in the market for fixed income securities and/or other factors. Non-U.S. debt securities that are listed on an exchange will be valued at the bid price obtained from an independent third party pricing service. When independent third party pricing services are unable to supply prices, or when prices or market quotations are considered to be unreliable, the value of that security may be determined using quotations from one or more broker-dealers. Loan interests are valued in accordance with guidelines established by the Board of Trustees at the mean between the last available bid and asked prices from one or more brokers or dealers as obtained from Loan Pricing Corporation, an independent third party pricing service. If price information is not available from Loan Pricing Corporation, or if the price information is deemed to be unreliable, price information will be obtained from an alternative loan interest pricing service. If no reliable price quotes are available from either the primary or alternative pricing service, broker quotes will be solicited. Event-linked bonds or catastrophe bonds are valued at the bid price obtained from an independent third party pricing service. Other insurance linked securities (including sidecars, collateralized reinsurance and industry loss warranties) may be valued at the bid price obtained from an independent pricing service, or through a third party using a pricing matrix, insurance industry valuation models, or other fair value methods or techniques to provide an estimated value of the instrument. The value of foreign securities is translated into U.S. dollars based on foreign currency exchange rate quotations supplied by a third party pricing source. Trading in non-U.S. equity securities is substantially completed each day at various times prior to the close of the NYSE. The values of such securities used in computing the net asset value of the Fund's shares are determined as of such times. The fund may use a fair value model developed by an independent pricing service to value non-U.S. equity securities. 104 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Shares of open-end registered investment companies (including money market mutual funds) are valued at such funds' net asset value. Repurchase agreements are valued at par. Cash may include overnight time deposits at approved financial institutions. Securities or loan interests for which independent pricing services or broker-dealers are unable to supply prices or for which market prices and/or quotations are not readily available or are considered to be unreliable are valued by a fair valuation team comprised of certain personnel of Pioneer Investment Management, Inc. (PIM), the Fund's investment adviser and a wholly owned indirect subsidiary of UniCredit S.p.A. (UniCredit), pursuant to procedures adopted by the Board of Trustees. PIM's fair valuation team uses fair value methods approved by the Valuation Committee of the Board of Trustees. PIM's fair valuation team is responsible for monitoring developments that may impact fair valued securities and for discussing and assessing fair values on an ongoing basis, and at least quarterly, with the Valuation Committee of the Board of Trustees. Inputs used when applying fair value methods to value a security may include credit ratings, the financial condition of the company, current market conditions and comparable securities. The Fund may use fair value methods if it is determined that a significant event has occurred after the close of the exchange or market on which the security trades and prior to the determination of the Fund's net asset value. Examples of a significant event might include political or economic news, corporate restructurings, natural disasters, terrorist activity or trading halts. Thus, the valuation of the Fund's securities may differ significantly from exchange prices and such differences could be material. At March 31, 2017, no securities were valued using fair value methods (other than securities valued using prices supplied by independent pricing services, broker-dealers or using a third party insurance industry pricing model). B. Investment Income and Transactions Principal amounts of mortgage-backed securities are adjusted for monthly paydowns. Premiums and discounts related to certain mortgage-backed securities are amortized or accreted in proportion to the monthly paydowns. All discounts/premiums on purchase prices of debt securities are accreted/amortized for financial reporting purposes over the life of the respective securities, and such accretion/amortization is included in interest income. Interest income, including interest on income bearing cash accounts, is recorded on the accrual basis, net of unrecoverable foreign taxes withheld at the applicable country rates. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 105 Security transactions are recorded as of trade date. Gains and losses on sales of investments are calculated on the identified cost method for both financial reporting and federal income tax purposes. C. Foreign Currency Translation The books and records of the Fund are maintained in U.S. dollars. Amounts denominated in foreign currencies are translated into U.S. dollars using current exchange rates. Net realized gains and losses on foreign currency transactions, if any, represent, among other things, the net realized gains and losses on foreign currency contracts, disposition of foreign currencies and the difference between the amount of income accrued and the U.S. dollars actually received. Further, the effects of changes in foreign currency exchange rates on investments are not segregated in the Statement of Operations from the effects of changes in the market prices of those securities but are included with the net realized and unrealized appreciation or depreciation on investments. D. Federal Income Taxes It is the Fund's policy to comply with the requirements of the Internal Revenue Code applicable to regulated investment companies and to distribute all of its net taxable income and net realized capital gains, if any, to its shareowners. Therefore, no provision for federal income taxes is required. As of March 31, 2017, the Fund had not accrued any interest or penalties with respect to uncertain tax positions, which, if applicable, would be recorded as an income tax expense in the Statement of Operations. Tax returns filed within the prior three years are subject to examination by Federal and State tax authorities. The amount and character of income and capital gain distributions to shareowners are determined in accordance with federal income tax rules, which may differ from U.S. GAAP. Distributions in excess of net investment income or net realized gains are temporary overdistributions for financial statement purposes resulting from differences in the recognition or classification of income or distributions for financial statement and tax purposes. Capital accounts within the financial statements are adjusted for permanent book/tax differences to reflect tax character, but are not adjusted for temporary differences. At March 31, 2017, the Fund reclassified $2,802,719 to decrease distributions in excess of net investment income and $2,802,719 to increase accumulated net realized loss on investments and foreign currency transactions to reflect permanent book/tax differences. These adjustments have no impact on net assets or the results of operations. 106 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 At March 31, 2017, the Fund was permitted to carry forward indefinitely $17,542,086 of short-term losses and $6,518,166 of long-term losses under the Regulated Investment Company Modernization Act of 2010 without limitation. The tax character of distributions paid during the years ended March 31, 2017 and March 31, 2016 were as follows: ---------------------------------------------------------------------------- 2017 2016 ---------------------------------------------------------------------------- Distributions paid from: Ordinary income $48,015,798 $32,062,263 ---------------------------------------------------------------------------- Total $48,015,798 $32,062,263 ============================================================================ The following shows the components of distributable earnings on a federal income tax basis at March 31, 2017: ---------------------------------------------------------------------------- 2017 ---------------------------------------------------------------------------- Distributable earnings: Undistributed ordinary income $ 4,049,763 Capital loss carryforward (24,060,252) Current year dividend payable (493,008) Unrealized depreciation (1,124,887) ---------------------------------------------------------------------------- Total $(21,628,384) ============================================================================ The difference between book-basis and tax-basis unrealized depreciation is attributable to the tax deferral of losses on wash sales, adjustments relating to catastrophe bonds and the tax treatment of premium and amortization. E. Fund Shares The Fund records sales and repurchases of its shares as of trade date. Pioneer Funds Distributor, Inc. (PFD), the principal underwriter for the Fund and a wholly owned indirect subsidiary of UniCredit, earned $7,621 in underwriting commissions on the sale of Class A shares during the year ended March 31, 2017. F. Class Allocations Income, common expenses, and realized and unrealized appreciation and depreciation are calculated at the Fund level and allocated daily to each class of shares based on its respective percentage of adjusted net assets at the beginning of the day. Distribution fees are calculated based on the average daily net asset value attributable to Class A, Class C and Class C2 shares of the Fund, respectively (see Note 4). Class K and Class Y shares do not pay distribution fees. All expenses and fees paid to the Fund's transfer agent, for its services are Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 107 allocated among the classes of shares based on the number of accounts in each class and the ratable allocation of related out-of-pocket expenses (see Note 3). The Fund declares as daily dividends substantially all of its net investment income. All dividends are paid on a monthly basis. Short-term capital gain distributions, if any, may be declared with the daily dividends. Distributions to shareowners are recorded as of the ex-dividend date. Distributions paid by the Fund with respect to each class of shares are calculated in the same manner and at the same time except that net investment income dividends to Class A, Class C, Class C2, Class K and Class Y shares can reflect different transfer agent and distribution expense rates. G. Risks The value of securities held by the Fund may go up or down, sometimes rapidly or unpredictably, due to general market conditions, such as real or perceived adverse economic, political or regulatory conditions, inflation, changes in interest rates, lack of liquidity in the bond markets or adverse investor sentiment. In the past several years, financial markets have experienced increased volatility, depressed valuations, decreased liquidity and heightened uncertainty. These conditions may continue, recur, worsen or spread. When interest rates rise, the prices of fixed-income securities in the Fund will generally fall. Conversely, when interest rates fall, the prices of fixed-income securities in the Fund will generally rise. Interest rates in the U.S. recently have been historically low, so the Fund faces a heightened risk that interest rates may rise. A general rise in interest rates may cause investors to move out of fixed income securities on a large scale, which could adversely affect the price and liquidity of fixed income securities and could also result in increased redemptions from the Fund. Investments in the Fund are subject to possible loss due to the financial failure of issuers of underlying securities and the issuers' inability to meet their debt obligations. Certain securities in which the Fund invests, including floating rate loans, once sold, may not settle for an extended period (for example, several weeks or even longer). The Fund will not receive its sale proceeds until that time, which may constrain the Fund's ability to meet its obligations (including obligations to redeeming shareholders). The Fund's prospectus contains unaudited information regarding the Fund's principal risks. Please refer to that document when considering the Fund's principal risks. H. Insurance-Linked Securities (ILS) The Fund invests in event-linked bonds. Event-linked bonds are floating rate debt obligations for which the return of principal and the payment of interest are contingent on the non-occurrence of a pre-defined "trigger" event, such 108 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 as a hurricane or an earthquake of a specific magnitude. The trigger event's magnitude may be based on losses to a company or industry, industry indexes or readings of scientific instruments, or may be based on specified actual losses. If a trigger event, as defined within the terms of an event-linked bond occurs, the Fund may lose a portion or all of its accrued interest and/or principal invested in such event-linked bond. The Fund is entitled to receive principal and interest payments so long as no trigger event occurs of the description and magnitude specified by the instrument. In addition to the specified trigger events, event-linked bonds may expose the Fund to other risks, including but not limited to issuer (credit) default, adverse regulatory or jurisdictional interpretations and adverse tax consequences. The Fund's investments in ILS may include special purpose vehicles ("SPVs") or similar instruments structured to comprise a portion of a reinsurer's catastrophe-oriented business, known as quota share instruments (sometimes referred to as reinsurance sidecars), or to provide reinsurance relating to specific risks to insurance or reinsurance companies through a collateralized instrument, known as collateralized reinsurance. Structured reinsurance investments also may include industry loss warranties ("ILWs"). A traditional ILW takes the form of a bilateral reinsurance contract, but there are also products that take the form of derivatives, collateralized structures, or exchange traded instruments. Structured reinsurance investments, including quota share instruments, collateralized reinsurance investments and ILWs, are generally subject to the same risks as event-linked bonds. In addition, where the instruments are based on the performance of underlying reinsurance contracts, the Fund has limited transparency into the individual underlying contracts and therefore must rely upon the risk assessment and sound underwriting practices of the issuer. Accordingly, it may be more difficult for PIM to fully evaluate the underlying risk profile of the Fund's structured reinsurance investments and therefore the Fund's assets are placed at greater risk of loss than if PIM had more complete information. Structured reinsurance instruments generally will be considered illiquid securities by the Fund. These securities may be difficult to purchase, sell or unwind. Illiquid securities also may be difficult to value. If the Fund is forced to sell an illiquid asset, the Fund may be forced to sell at a loss. I. Repurchase Agreements Repurchase agreements are arrangements under which the Fund purchases securities from a broker-dealer or a bank, called the counterparty, upon the agreement of the counterparty to repurchase the securities from the Fund at a later date, and at a specific price, which is typically higher than the purchase Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 109 price paid by the Fund. The securities purchased serve as the Fund's collateral for the obligation of the counterparty to repurchase the securities. The value of the collateral, including accrued interest, is required to be equal to or in excess of the repurchase price. The collateral for all repurchase agreements is held in safekeeping in the customer-only account of the Fund's custodian or a subcustodian of the Fund. PIM is responsible for determining that the value of the collateral remains at least equal to the repurchase price. In the event of a default by the counterparty, the Fund is entitled to sell the securities, but the Fund may not be able to sell them for the price at which they were purchased, thus causing a loss to the Fund. Additionally, if the counterparty becomes insolvent, there is some risk that the Fund will not have a right to the securities, or the immediate right to sell the securities. Open repurchase agreements as of March 31, 2017 are disclosed in the Fund's Schedule of Investments. 2. Management Agreement PIM manages the Fund's portfolio. Management fees are calculated daily at the annual rate equal to 0.35% of the Fund's average daily net assets up to $1 billion and 0.30% on assets over $1 billion. For the year ended March 31, 2017, the effective management fee (excluding waivers and/or assumption of expenses) was equivalent to 0.32% of the Fund's average daily net assets. In addition, under the management and administration agreements, certain other services and costs, including accounting, regulatory reporting, and insurance premiums, are paid by the Fund as administrative reimbursements. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $59,416 in management fees, administrative costs and certain other reimbursements payable to PIM at March 31, 2017. 3. Transfer Agent Boston Financial Data Services, Inc. serves as the transfer agent to the Fund at negotiated rates. Transfer agent fees and payables shown on the Statement of Operations and the Statement of Assets and Liabilities, respectively, include sub-transfer agent expenses incurred through the Fund's omnibus relationship contracts. 110 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 In addition, the Fund reimbursed the transfer agent for out-of-pocket expenses incurred by the transfer agent related to shareholder communications activities such as proxy and statement mailings and outgoing phone calls. For the year ended March 31, 2017, such out-of-pocket expenses by class of shares were as follows: -------------------------------------------------------------------------------- Shareholder Communications: -------------------------------------------------------------------------------- Class A $ 13,574 Class C 25,940 Class C2 222 Class K 228 Class Y 208,413 -------------------------------------------------------------------------------- Total $248,377 ================================================================================ 4. Distribution Plan The Fund has adopted a distribution plan (the Plan) pursuant to Rule 12b-1 of the Investment Company Act of 1940 with respect to its Class A, Class C and Class C2 shares. Pursuant to the Plan, the Fund pays PFD 0.20% of the average daily net assets attributable to Class A shares as compensation for personal services and/or account maintenance services or distribution services with regard to Class A shares. Pursuant to the Plan, the Fund also pays PFD 0.50% of the average daily net assets attributable to Class C and Class C2 shares. The fee for Class C and Class C2 shares consists of a 0.25% service fee and a 0.25% distribution fee paid as compensation for personal services and/or account maintenance services or distribution services with regard to Class C and Class C2 shares. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $24,241 in distribution fees payable to PFD at March 31, 2017. In addition, redemptions of each class of shares (except Class K and Class Y shares) may be subject to a contingent deferred sales charge (CDSC). A CDSC of 1.00% may be imposed on redemptions of certain net asset value purchases of Class A shares within 12 months of purchase. For Class C2 shares redemptions of shares within 12 months of purchase are subject to a CDSC of 1.00%, based on the lower of cost or market value of shares being redeemed. Shares purchased as part of an exchange remain subject to any CDSC that applied to the original purchase of those shares. There is no CDSC for Class K and Class Y shares. Proceeds from the CDSCs are paid to PFD. For the year ended March 31, 2017, CDSCs of $71,185 were paid to PFD. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 111 5. Line of Credit Facility The Fund, along with certain other funds in the Pioneer Family of Funds (the Funds), participates in a committed, unsecured revolving line of credit facility. Borrowings are used solely for temporary or emergency purposes. The Fund may borrow up to the lesser of the amount available under the facility or the limits set for borrowing by the Fund's prospectus and the 1940 Act. The credit facility in which the Fund participated until February 9, 2016 was in the amount of $240 million. The credit facility in which the Fund participated until February 7, 2017 was in the amount of $220 million. Effective February 8, 2017, the Fund participated in a facility that is in the amount of $195 million. Under such facility, depending on the type of loan, interest on borrowings is payable at the London Interbank Offered Rate (LIBOR) plus 0.85% on an annualized basis, or the Alternate Base Rate, which is the greater of (a) the facility's administrative agent's daily announced prime rate on the borrowing date, (b) 2% plus the Federal Funds Rate on the borrowing date and (c) 2% plus the overnight Eurodollar rate on the borrowing date. The Funds pay an annual commitment fee to participate in a credit facility. The commitment fee is allocated among participating Funds based on an allocation schedule set forth in the credit agreement. For the year ended March 31, 2017, the Fund had no borrowings under the credit facility. 112 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Report of Independent Registered Public Accounting Firm To the Board of Trustees of Pioneer Series Trust X and the Shareowners of Pioneer Multi-Asset Ultrashort Income Fund: -------------------------------------------------------------------------------- We have audited the accompanying statement of assets and liabilities, including the schedule of investments, of Pioneer Multi-Asset Ultrashort Income Fund (the "Fund") (one of the funds constituting Pioneer Series Trust X), as of March 31, 2017, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the two years in the period then ended and the financial highlights for each of the three years in the period then ended. These financial statements and the financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits. The financial highlights for the years ended March 31, 2014, and 2013, were audited by other auditors. Those auditors expressed an unqualified opinion on those financial statements and financial highlights in their report dated May 22, 2014. We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. The Fund is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, as well as evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of March 31, 2017, by correspondence with the custodian, brokers and agent banks; where replies were not received from brokers and agent banks, we performed other auditing procedures. We believe that our audits provide a reasonable basis for our opinion. In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Pioneer Multi-Asset Ultrashort Income Fund as of March 31, 2017, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended and the financial highlights for each of the three years in the period then ended, in conformity with accounting principles generally accepted in the United States of America. /s/ Deloitte & Touche LLP Boston, Massachusetts May 26, 2017 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 113 ADDITIONAL INFORMATION (unaudited) The percentages of the Fund's ordinary income distributions that are exempt from nonresident alien (NRA) tax withholding resulting from qualified interest income was 74.07%. Pioneer Investment Management, Inc. (the "Adviser"), the Fund's investment adviser, is currently an indirect, wholly owned subsidiary of UniCredit S.p.A. ("UniCredit"). On December 12, 2016, UniCredit announced that it has entered into a binding agreement for the sale of its Pioneer Investments business, which includes the Adviser, to Amundi (the "Transaction"). Amundi is headquartered in Paris, France, and, as of September 30, 2016, had more than $1.1 trillion in assets under management worldwide. The closing of the Transaction is expected to happen in 2017, subject to certain regulatory and antitrust approvals, and other conditions. Under the Investment Company Act of 1940, the closing of the Transaction will cause the Fund's current investment advisory agreement with the Adviser to terminate. Accordingly, the Fund's Board of Trustees has approved a new investment advisory agreement for the Fund, which will be submitted to the shareholders of the Fund for their approval. Change in Independent Registered Public Accounting Firm Deloitte & Touche LLP, the Fund's independent registered public accounting firm, has informed the Board that it will no longer be independent with respect to the Fund upon the completion of the Transaction and, accordingly, that it intends to resign as the Fund's independent registered public accounting firm upon the completion of the Transaction. The Board will engage a new independent registered public accounting firm for the Fund upon the completion of the Transaction. During the periods that Deloitte & Touche LLP has served as the Fund's independent registered public accounting firm, including the Fund's two most recent fiscal years, Deloitte & Touche LLP's reports on the Fund's financial statements have not contained an adverse opinion or disclaimer of opinion and have not been qualified or modified as to uncertainty, audit scope or accounting principles. Further, there have been no disagreements with Deloitte & Touche LLP on any matter of accounting principles or practices, financial statement disclosure, or auditing scope or procedure, which, if not resolved to the satisfaction of Deloitte & Touche LLP, would have caused Deloitte & Touche LLP to make reference to the subject matter of the disagreement in connection with its report on the financial statements. In addition, there have been no reportable events of the kind described in Item 304(a)(1)(v) of Regulation S-K under the Securities Exchange Act of 1934. 114 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Approval of New and Interim Management Agreements Pioneer Investment Management, Inc. (PIM) serves as the investment adviser to Pioneer Multi-Asset Ultrashort Income Fund (the Fund) pursuant to an investment management agreement between PIM and the Fund. PIM is the principal U.S. asset management business of Pioneer Investments, a group of companies owned by Pioneer Global Asset Management S.p.A. ("PGAM"). PGAM is a wholly-owned subsidiary of UniCredit S.p.A. ("UniCredit"). UniCredit and PGAM have entered into a binding agreement to sell Pioneer Investments, including PIM, to Amundi (the "Transaction"). Upon the consummation of the transaction, PIM will become an indirect wholly-owned subsidiary of Amundi and Amundi's wholly-owned subsidiary, Amundi USA, Inc. The closing of the Transaction is expected to happen in 2017. Under the Investment Company Act of 1940, the Fund's current investment management agreement (the "Current Management Agreement") will terminate automatically upon the consummation of the Transaction. In order for PIM to continue to manage the Fund after the consummation of the Transaction, the Trustees and shareholders of the Fund must approve a new investment management agreement for the Fund (the "New Management Agreement"). As discussed below, the Board of Trustees of the Fund approved the New Management Agreement at a meeting held on March 6-7, 2017. The New Management Agreement has been submitted to the shareholders of the Fund for their approval at a meeting to be held on June 13, 2017. If the shareholders of the Fund do not approve the New Management Agreement and the Transaction is completed, an interim investment management agreement between PIM and the Fund (the "Interim Management Agreement") will take effect upon the closing of the Transaction. The Board of Trustees of the Fund also approved the Interim Management Agreement at the March 6-7, 2017 meeting. Board Evaluation of the New and Interim Management Agreements The Board evaluated the Transaction and the New Management Agreement and Interim Management Agreement for the Fund. In connection with their evaluation of the Transaction and the New Management Agreement for the Fund, the Trustees requested such information as they deemed reasonably necessary, including: (a) the structure of the Transaction and the strategy underlying the Transaction; (b) the anticipated benefits of the Transaction to the Fund and its shareholders; (c) the post-Transaction plans for PIM, including Amundi's plans for integration of Pioneer Investments and PIM with its existing asset management businesses and plans for the future development Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 115 of PIM; (d) the effect of the Transaction on the ongoing services provided to the Fund, including the need to select a new independent registered public accounting firm for the Fund, and any plans to modify the operations of the Fund; (e) the stability and continuity of PIM's management and key employees, including compensation and benefits to PIM's key employees, and retention plans and incentive plan structure; (f) the post-Transaction indebtedness and financial resources of PIM; (g) Amundi's legal and operational structure, its principal shareholders and senior management, its investment management, risk management, administrative, legal and compliance functions; (h) certain regulatory matters relating to Amundi's affiliates; and (i) Amundi's commitment to the United States, including the role of PIM in the larger Amundi business. The Trustees also requested and obtained the following information in connection with their evaluation of the Transaction and the New Management Agreement for the Fund: (i) memoranda provided by Fund counsel that summarized the legal standards and other considerations that are relevant to the Trustees in their deliberations regarding the New Management Agreement; (ii) the qualifications of the investment management teams for the Fund, as well as the level of investment by the Fund's portfolio managers in the Fund; (iii) the Fund's management fees and total expense ratios, the financial statements of PIM and its pre- and post-Transaction parent companies, profitability analyses from PIM, and analyses from PIM as to possible economies of scale; (iv) the profitability of the institutional business of PIM and PIM's affiliate, Pioneer Institutional Asset Management, Inc. ("PIAM") as compared to that of PIM's fund management business; and (v) the differences between the fees and expenses of the Fund and the fees and expenses of PIM's and PIAM's institutional accounts, as well as the different services provided by Adviser to the Fund and by PIM and PIAM to the institutional accounts. In addition, the Trustees considered the information provided at regularly scheduled meetings throughout the year regarding the Fund's performance and risk attributes, including through meetings with investment management personnel, and took into account other information related to the Fund provided to the Trustees at regularly scheduled meetings. The Trustees also considered information they had received in their review of the continuance of the Current Management Agreement for the Fund in September 2016. At meetings held on January 9, 2017 and January 10, 2017, the Trustees met with representatives of Amundi and PGAM, including separate meetings of the Trustees who are not "interested persons" of the Fund Complex ("Independent Trustees") and counsel with representatives of Amundi and PGAM, and subsequently with representatives of Amundi. In those meetings, 116 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 they received an extensive presentation from the representatives of Amundi, including the chief executive officer of Amundi, describing Amundi's background and history, its global asset management activities, the growth of its business, and its status as the largest asset management firm in Europe and one of the largest globally; its capital structure and financial resources, including information as to the financing of the Transaction; its principal investors, including its majority investor Credit Agricole S.A., and Credit Agricole's long-term commitment to the asset management business; the philosophy and strategy underlying the Transaction and the complementarity of Amundi's and Pioneer Investments' respective asset management businesses; Amundi's various operating and investment committees and how they would likely interact with PIM; the proposed integration process, including the progress to date and the establishment of various integration work streams; Amundi's plans for management of PIM; Amundi's philosophy as to compensation of key employees and its general intentions with respect to incentive plans for key employees of PIM; Amundi's preliminary plans to achieve cost and other synergies; and opportunities to further develop the business of PIM and PIAM, including in the area of institutional asset management, and how that would benefit shareholders of the Pioneer Funds. In those meetings, the representatives of Amundi confirmed their intention that the Chief Executive Officer and Chief Investment Officer of PIM would remain in their current positions, and confirmed that they do not currently foresee major changes in the day-to-day investment management operations of PIM with respect to the Fund as a direct result of the Transaction. They discussed incentive arrangements for key personnel that would continue after the closing of the Transaction and their plans to establish a new long-term incentive plan following the closing. They also generally discussed ways in which PIM could potentially draw on the expanded global resources of Amundi post-Transaction. At those meetings, the Independent Trustees identified certain areas to which they requested further information, including as to trading and execution of securities transactions, research and portfolio management and potential changes in investment process, particularly where asset classes managed by PIM would overlap with asset classes managed by Amundi, the continued availability of resources currently at Pioneer Investments or elsewhere within Amundi to assist in management of certain Funds, and any anticipated significant changes in operations. The Independent Trustees considered the uncertainty as to whether the Fund's independent registered public accounting firm could continue to act in that capacity after the closing of the Transaction. The Independent Trustees also met with counsel to review the information they had received to date and to discuss next steps. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 117 Subsequently, the Trustees received further information from Amundi, including written responses to questions raised by the Independent Trustees, and received from PIM the information requested of it. The Independent Trustees reviewed the information provided with counsel at telephonic meetings held on February 16, 2017 and February 27, 2017. The Trustees held a special in-person Board meeting on March 6-7, 2017 for further consideration of the New Management Agreements, the Interim Management Agreements and the Transaction. The Trustees met again with senior executives of Amundi at the March 6-7, 2017 meeting. At the March 6-7, 2017 meeting, based on their evaluation of the information provided by PIM and Amundi, the Trustees including the Independent Trustees voting separately, approved the New Management Agreement and the Interim Management Agreement for the Fund. In considering the New Management Agreement for the Fund, the Trustees considered various factors that they determined were relevant, including the factors described below. The Trustees did not identify any single factor as the controlling factor in their determinations. The Trustees considered the same factors with respect to the Interim Management Agreement for the Fund. Nature, Extent and Quality of Services The Trustees considered the nature, extent and quality of the services that had been provided by PIM to the Fund and that are expected to be provided by PIM to the Fund following the consummation of the Transaction. The Trustees reviewed the terms of the New Management Agreement, and noted that such terms are substantially similar to the terms of the Current Management Agreement, except for different execution dates, effective dates and termination dates. The Trustees reviewed PIM's investment approach for the Fund and its research process. The Trustees considered the resources of PIM and the personnel of PIM who provide investment management services to the Fund. They also reviewed the amount of non-investment resources and personnel of PIM that are involved in PIM's services to the Fund, including PIM's compliance and legal resources and personnel. The Trustees noted the substantial attention and high priority given by PIM's senior management to the Pioneer Fund complex. The Trustees considered that PIM supervises and monitors the performance of the Fund's service providers and provides the Fund with personnel (including Fund officers) and other resources that are necessary for the Fund's business management and operations and that PIM would continue to provide those investment management and research services and resources to the Fund following the consummation of the Transaction. The Trustees also considered that, as administrator, PIM would continue to be responsible for the 118 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 administration of the Fund's business and other affairs. The Trustees considered the fees to be paid to PIM for the provision of administration services. The Trustees considered that Deloitte & Touche LLP has informed the Board that it will no longer be independent with respect to the Fund upon the completion of the Transaction and, accordingly, that it will be necessary for the Board to engage a new independent registered public accounting firm for the Fund. The Trustees considered that the Transaction is not expected to have a material adverse impact on the nature, scope and overall quality of services provided to the Fund and its shareholders, including investment management, risk management, administrative, compliance, legal and other services, as a result of the Transaction. In that regard, the Trustees considered that Amundi is one of the largest asset managers globally, and that PIM may have access to additional research and portfolio management capabilities as a result of the Transaction and that PIM, as part of Amundi, is expected to have an enhanced global presence that may contribute to an increase in the overall scale and resources of PIM. Furthermore, in considering whether the Transaction would be expected to have a material adverse impact on the nature, scope and overall quality of services provided to the Fund and its shareholders, the Trustees considered the statements by representatives of Amundi that they expect the Chief Executive Officer and Chief Investment Officer of PIM to remain in their current positions and that they do not currently foresee major changes in the day-to-day investment management operations of PIM as a direct result of the Transaction, or the risk management, legal or compliance services provided by PIM, with respect to the Fund. They further considered the current incentive arrangements for key personnel of PIM that would continue after the closing of the Transaction. They also noted Amundi's stated intention to establish a new long-term incentive plan following the closing. The Trustees also took into account their experience in evaluating the proposed combination of Pioneer Investments and Santander Asset Management, which was announced in September, 2014 and abandoned in July, 2016. In light of, among other things, this experience, the Trustees determined that they were not able to identify any realistic alternatives to approving the New Management Agreement that would provide the level of services to the Fund and its shareholders that are expected to be provided by PIM after the closing of the Transaction. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 119 Based on these considerations, the Trustees concluded that the nature, extent and quality of services that PIM would continue to provide to the Fund under the New Management Agreement would be satisfactory and consistent with the terms of the New Management Agreement. Performance of the Fund In considering the Fund's performance, the Trustees regularly reviewed and discussed throughout the year data prepared by PIM and information comparing the Fund's performance with the performance of its peer group of funds, as classified by each of Morningstar, Inc. (Morningstar) and Lipper, and the performance of the Fund's benchmark index. They also discussed the Fund's performance with PIM on a regular basis. The Trustees' regular reviews and discussions were factored into the Trustees' deliberations concerning the approval of the New Management Agreement. Management Fee and Expenses The Trustees noted that the stated management fees to be paid by the Fund are identical under the Current Management Agreement and the New Management Agreement. The Trustees considered information showing the fees and expenses of the Fund in comparison to the management fees and expense ratios of its peer group of funds as classified by Morningstar and also to the expense ratios of a peer group of funds selected on the basis of criteria determined by the Independent Trustees for this purpose using data provided by Strategic Insight Mutual Fund Research and Consulting, LLC (Strategic Insight), an independent third party. In all quintile rankings referred to below, first quintile is most favorable to the Fund's shareowners. To the extent applicable, the Trustees also considered the impact of transfer agency, sub-transfer agency, and other non-management fee expenses on the expense ratios of the Fund. The Trustees noted that they separately review the Fund's transfer agency, sub-transfer agency and intermediary arrangements and that the results of the most recent such review were considered in the consideration of the Fund's expense ratio. The Trustees considered that the Fund's management fee as of September 30, 2016 was in the third quintile relative to the management fees paid by other funds in its Morningstar category for the comparable period. The Trustees also considered the breakpoint in the management fee schedule and the reduced fee rate above a certain asset level. The Trustees considered that the expense ratio of the Fund's Class A shares as of September 30, 2016 was in the second quintile relative to its Morningstar category and in the fourth quintile relative 120 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 to its Strategic Insight peer group, in each case for the comparable period. The Trustees considered that the expense ratio of the Fund's Class Y shares as of September 30, 2016 was in the fifth quintile relative to its Morningstar category and in the fifth quintile relative to its Strategic Insight peer group, in each case for the comparable period. The Trustees noted the impact of expenses relating to small accounts and omnibus accounts on transfer and sub-transfer agency expenses generally. The Trustees also considered information showing significant expense reimbursements by the sponsors of the other funds in the peer groups. The Trustees reviewed management fees charged by PIM and PIAM to institutional and other clients, including publicly offered European funds sponsored by PIM's affiliates, unaffiliated U.S. registered investment companies (in a sub-advisory capacity), and unaffiliated foreign and domestic separate accounts. The Trustees also considered PIM's costs in providing services to the Fund and PIM's and PIAM's costs in providing services to the other clients and considered the differences in management fees and profit margins for fund and non-fund services. In evaluating the fees associated with PIM's and PIAM's client accounts, the Trustees took into account the respective demands, resources and complexity associated with the Fund and other client accounts. The Trustees noted that in some instances the fee rates for those clients were lower than the management fee for the Fund and considered that, under both the Current Management Agreement and the New Management Agreement, PIM would perform additional services for the Fund that it does not provide to those other clients or services that are broader in scope, including oversight of the Fund's other service providers and activities related to compliance and the extensive regulatory and tax regimes to which the Fund is subject. The Trustees also considered the different risks associated with PIM's management of the Fund and PIM's and PIAM's management of the other client accounts. The Trustees concluded that the management fee payable by the Fund to PIM was reasonable in relation to the nature and quality of the services to be provided by PIM. Profitability The Trustees considered information provided by PIM regarding the profitability of PIM with respect to the advisory services provided by PIM to the Fund, including the methodology used by PIM in allocating certain of its costs to the management of the Fund. The Trustees also considered PIM's profit margin in connection with the overall operation of the Fund. They further reviewed the financial results, including the profit margins, realized by Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 121 PIM and PIAM from non-fund businesses. The Trustees considered PIM's profit margins with respect to the Fund in comparison to the limited industry data available and noted that the profitability of any adviser was affected by numerous factors, including its organizational structure and method for allocating expenses. The Trustees concluded that PIM's profitability with respect to the management of the Fund was not unreasonable. Economies of Scale The Trustees considered PIM's views relating to economies of scale in connection with the Pioneer Funds as fund assets grow and the extent to which any such economies of scale are shared with the Fund and Fund shareholders. The Trustees recognize that economies of scale are difficult to identify and quantify, and that, among other factors that may be relevant, are the following: fee levels, expense subsidization, investment by PIM in research and analytical capabilities and PIM's commitment and resource allocation to the Fund. The Trustees noted that profitability also may be an indicator of the availability of any economies of scale, although profitability may vary for other reasons including due to reductions in expenses. The Trustees concluded that economies of scale, if any, were being appropriately shared with the Fund. Other Benefits The Trustees considered the other benefits that PIM enjoys from its relationship with the Fund. The Trustees considered the character and amount of fees paid or to be paid by the Fund, other than under the Current Management Agreement or the New Management Agreement, for services provided by PIM and its affiliates. The Trustees further considered the revenues and profitability of PIM's businesses other than the Fund business. To the extent applicable, the Trustees also considered the benefits to the Fund and to PIM and its affiliates from the use of "soft" commission dollars generated by the Fund to pay for research and brokerage services. The Trustees considered that following the completion of the Transaction, PIM will be the principal U.S. asset management business of Amundi, and that Amundi's worldwide asset management business will manage over $1.38 trillion in assets (including the Pioneer Funds). This may create opportunities for PIM, PIAM and Amundi that derive from PIM's relationships with the Fund, including Amundi's ability to market the services of PIM globally. The Trustees noted that PIM may have access to additional research capabilities as a result of the Transaction and Amundi's enhanced global presence that may contribute to an increase of the overall scale of PIM. 122 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 The Trustees considered that PIM and the Fund are expected to receive reciprocal intangible benefits from the relationship, including mutual brand recognition and, for the Fund, direct and indirect access to the resources of a large global asset manager. The Trustees concluded that any such benefits received by PIM as a result of its relationship with the Fund were reasonable. Conclusion After consideration of the factors described above as well as other factors, the Trustees, including the Independent Trustees, concluded that the New Management Agreement and the Interim Management Agreement for the Fund, including the fees payable thereunder, were fair and reasonable and voted to approve the New Management Agreement and the Interim Management Agreement, and to recommend that shareholders approve the New Management Agreement. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 123 Trustees, Officers and Service Providers Investment Adviser Pioneer Investment Management, Inc. Custodian and Sub-Administrator Brown Brothers Harriman & Co. Independent Registered Public Accounting Firm Deloitte & Touche LLP Principal Underwriter Pioneer Funds Distributor, Inc. Legal Counsel Morgan, Lewis & Bockius LLP Shareowner Services and Transfer Agent Boston Financial Data Services, Inc. Proxy Voting Policies and Procedures of the Fund are available without charge, upon request, by calling our toll free number (1-800-225-6292). Information regarding how the Fund voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is publicly available to shareowners at us.pioneerinvestments.com. This information is also available on the Securities and Exchange Commission's web site at www.sec.gov. Trustees and Officers The Fund's Trustees and officers are listed below, together with their principal occupations during at least the past five years. Trustees who are interested persons of the Fund within the meaning of the 1940 Act are referred to as Interested Trustees. Trustees who are not interested persons of the Fund are referred to as Independent Trustees. Each of the Trustees serves as a Trustee of each of the 46 U.S. registered investment portfolios for which Pioneer serves as investment adviser (the "Pioneer Funds"). The address for all Trustees and all officers of the Fund is 60 State Street, Boston, Massachusetts 02109. The Statement of Additional Information of the Fund includes additional information about the Trustees and is available, without charge, upon request, by calling 1-800-225-6292. 124 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Independent Trustees ----------------------------------------------------------------------------------------------------------------------------------- Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ----------------------------------------------------------------------------------------------------------------------------------- Thomas J. Perna (66) Trustee since 2011. Private investor (2004 - 2008 and 2013 - Director, Broadridge Chairman of the Board Serves until a successor present); Chairman (2008 - 2013) and Chief Financial Solutions, Inc. and Trustee trustee is elected or earlier Executive Officer (2008 - 2012), Quadriserv, (investor communications retirement or removal. Inc. (technology products for securities and securities processing lending industry); and Senior Executive Vice provider for financial President, The Bank of New York (financial services industry) (2009 and securities services) (1986 - 2004) - present); Director, Quadriserv, Inc. (2005 - 2013); and Commissioner, New Jersey State Civil Service Commission (2011 - 2015) ----------------------------------------------------------------------------------------------------------------------------------- David R. Bock (73) Trustee since 2011. Managing Partner, Federal City Capital Director of New York Trustee Serves until a successor Advisors (corporate advisory services Mortgage Trust trustee is elected or earlier company) (1997 - 2004 and 2008 - present); (publicly-traded mortgage retirement or removal. Interim Chief Executive Officer, Oxford REIT) (2004 - 2009, 2012 Analytica, Inc. (privately-held research and - present); Director of consulting company) (2010); Executive Vice The Swiss Helvetia Fund, President and Chief Financial Officer, Inc. (closed-end fund) I-trax, Inc. (publicly traded health care (2010 - present); services company) (2004 - 2007); and Director of Oxford Executive Vice President and Chief Financial Analytica, Inc. (2008 - Officer, Pedestal Inc. (internet-based present); and Director of mortgage trading company) (2000 - 2002); Enterprise Community Private consultant (1995-1997), Managing Investment, Inc. Director, Lehman Brothers (investment (privately-held banking firm) (1992-1995); and Executive, The affordable housing finance World Bank (1979-1992) company) (1985 - 2010) ----------------------------------------------------------------------------------------------------------------------------------- Benjamin M. Friedman (72) Trustee since 2011. William Joseph Maier Professor of Political Trustee, Mellon Trustee Serves until a successor Economy, Harvard University (1972 - present) Institutional Funds trustee is elected or earlier Investment Trust and retirement or removal. Mellon Institutional Funds Master Portfolio (oversaw 17 portfolios in fund complex) (1989-2008) ----------------------------------------------------------------------------------------------------------------------------------- Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 125 Independent Trustees continued ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Margaret B.W. Graham (69) Trustee since 2011. Founding Director, Vice President and None Trustee Serves until a successor Corporate Secretary, The Winthrop Group, trustee is elected or earlier Inc. (consulting firm) (1982 - present); retirement or removal. Desautels Faculty of Management, McGill University (1999 - present); and Manager of Research Operations and Organizational Learning, Xerox PARC, Xerox's advance research center (1990-1994) ------------------------------------------------------------------------------------------------------------------------------------ Marguerite A. Piret (68) Trustee since 2011. President and Chief Executive Officer, Director of New America Trustee Serves until a successor Newbury Piret Company (investment banking High Income Fund, Inc. trustee is elected or earlier firm) (1981 - present) (closed-end investment retirement or removal. company) (2004 - present); and Member, Board of Governors, Investment Company Institute (2000 - 2006) ------------------------------------------------------------------------------------------------------------------------------------ Fred J. Ricciardi (70) Trustee since 2014. Consultant (investment company services) None Trustee Serves until a successor (2012 - present); Executive Vice President, trustee is elected or earlier BNY Mellon (financial and investment company retirement or removal. services) (1969 - 2012); Director, BNY International Financing Corp. (financial services) (2002 - 2012); and Director, Mellon Overseas Investment Corp. (financial services) (2009 - 2012) ------------------------------------------------------------------------------------------------------------------------------------ 126 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Interested Trustee ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Kenneth J. Taubes (58)* Trustee since 2014. Director and Executive Vice President (since None Trustee Serves until a successor 2008) and Chief Investment Officer, U.S. trustee is elected or earlier (since 2010) of Pioneer Investment retirement or removal. Management-USA (PIM-USA); Executive Vice President of Pioneer (since 2008); Executive Vice President of Pioneer Institutional Asset Management, Inc. (since 2009); and Portfolio Manager of Pioneer (since 1999) ------------------------------------------------------------------------------------------------------------------------------------ * Mr. Taubes is an Interested Trustee because he is an officer of the Fund's investment adviser and certain of its affiliates. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 127 Advisory Trustee ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Trustee ------------------------------------------------------------------------------------------------------------------------------------ Lorraine Monchak (60)** Advisory Trustee since 2014. Chief Investment Officer, 1199 SEIU Funds Trustee of Pioneer Advisory Trustee (healthcare workers union pension funds) closed-end investment (2001 - present); Vice President - companies (5 portfolios) International Investments Group, American (Sept. 2015 - present) International Group, Inc. (insurance company) (1993 - 2001); Vice President, Corporate Finance and Treasury Group, Citibank, N.A. (1980 - 1986 and 1990 - 1993); Vice President - Asset/Liability Management Group, Federal Farm Funding Corporation (government-sponsored issuer of debt securities) (1988 - 1990); Mortgage Strategies Group, Shearson Lehman Hutton, Inc. (investment bank) (1987 - 1988); and Mortgage Strategies Group, Drexel Burnham Lambert, Ltd. (investment bank) (1986 - 1987) ------------------------------------------------------------------------------------------------------------------------------------ ** Ms. Monchak is a non-voting advisory trustee. 128 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 Fund Officers ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Officer ------------------------------------------------------------------------------------------------------------------------------------ Lisa M. Jones (55) Since 2014. Serves at Chair, Director, CEO and President of Trustee of Pioneer President and Chief the discretion of the Board. PIM-USA (since September 2014); Chair, closed-end investment Executive Officer Director, CEO and President of Pioneer companies (5 portfolios) Investment Management, Inc. (since September (Sept. 2015 - present) 2014); Chair, Director, CEO and President of Pioneer Funds Distributor, Inc. (since September 2014); Chair, Director, CEO and President of Pioneer Institutional Asset Management, Inc. (since September 2014); and Chair, Director, and CEO of Pioneer Investment Management Shareholder Services, Inc. (since September 2014); Managing Director, Morgan Stanley Investment Management (2010 - 2013); and Director of Institutional Business, CEO of International, Eaton Vance Management (2005 - 2010) ------------------------------------------------------------------------------------------------------------------------------------ Christopher J. Kelley (52) Since 2011. Serves at Vice President and Associate General Counsel None Secretary and the discretion of the Board. of Pioneer since January 2008; Secretary and Chief Legal Officer Chief Legal Officer of all of the Pioneer Funds since June 2010; Assistant Secretary of all of the Pioneer Funds from September 2003 to May 2010; and Vice President and Senior Counsel of Pioneer from July 2002 to December 2007 ------------------------------------------------------------------------------------------------------------------------------------ Carol B. Hannigan (56) Since 2011. Serves at Fund Governance Director of Pioneer since None Assistant Secretary the discretion of the Board. December 2006 and Assistant Secretary of all the Pioneer Funds since June 2010; Manager - Fund Governance of Pioneer from December 2003 to November 2006; and Senior Paralegal of Pioneer from January 2000 to November 2003 ------------------------------------------------------------------------------------------------------------------------------------ Thomas Reyes (54) Since 2011. Serves at Senior Counsel of Pioneer since May 2013 and None Assistant Secretary the discretion of the Board. Assistant Secretary of all the Pioneer Funds since June 2010; and Counsel of Pioneer from June 2007 to May 2013 ------------------------------------------------------------------------------------------------------------------------------------ Mark E. Bradley (57) Since 2011. Serves at Vice President - Fund Treasury of Pioneer; None Treasurer and Chief the discretion of the Board. Treasurer of all of the Pioneer Funds since Financial March 2008; Deputy Treasurer of Pioneer from and Accounting Officer March 2004 to February 2008; and Assistant Treasurer of all of the Pioneer Funds from March 2004 to February 2008 ------------------------------------------------------------------------------------------------------------------------------------ Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 129 Fund Officers continued ------------------------------------------------------------------------------------------------------------------------------------ Name, Age and Term of Office and Other Directorships Position Held With the Fund Length of Service Principal Occupation Held by Officer ------------------------------------------------------------------------------------------------------------------------------------ Luis I. Presutti (51) Since 2011. Serves at Director - Fund Treasury of Pioneer; and None Assistant Treasurer the discretion of the Board. Assistant Treasurer of all of the Pioneer Funds ------------------------------------------------------------------------------------------------------------------------------------ Gary Sullivan (58) Since 2011. Serves at Fund Accounting Manager - Fund Treasury of None Assistant Treasurer the discretion of the Board. Pioneer; and Assistant Treasurer of all of the Pioneer Funds ------------------------------------------------------------------------------------------------------------------------------------ David F. Johnson (37) Since 2011. Serves at Fund Administration Manager - Fund Treasury None Assistant Treasurer the discretion of the Board. of Pioneer since November 2008; Assistant Treasurer of all of the Pioneer Funds since January 2009; and Client Service Manager - Institutional Investor Services at State Street Bank from March 2003 to March 2007 ------------------------------------------------------------------------------------------------------------------------------------ Jean M. Bradley (64) Since 2011. Serves at Chief Compliance Officer of Pioneer and of None Chief Compliance Officer the discretion of the Board. all the Pioneer Funds since March 2010; Chief Compliance Officer of Pioneer Institutional Asset Management, Inc. since January 2012; Chief Compliance Officer of Vanderbilt Capital Advisors, LLC since July 2012: Director of Adviser and Portfolio Compliance at Pioneer since October 2005; and Senior Compliance Officer for Columbia Management Advisers, Inc. from October 2003 to October 2005 ------------------------------------------------------------------------------------------------------------------------------------ Kelly O'Donnell (46) Since 2011. Serves at Director - Transfer Agency Compliance of None Anti-Money the discretion of the Board. Pioneer and Anti-Money Laundering Officer of Laundering Officer all the Pioneer Funds since 2006 ------------------------------------------------------------------------------------------------------------------------------------ 130 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 This page is for your notes. Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 131 This page is for your notes. 132 Pioneer Multi-Asset Ultrashort Income Fund | Annual Report | 3/31/17 How to Contact Pioneer We are pleased to offer a variety of convenient ways for you to contact us for assistance or information. Call us for: -------------------------------------------------------------------------------- Account Information, including existing accounts, new accounts, prospectuses, applications and service forms 1-800-225-6292 FactFone(SM) for automated fund yields, prices, account information and transactions 1-800-225-4321 Retirement plans information 1-800-622-0176 Write to us: -------------------------------------------------------------------------------- Pioneer Funds P.O. Box 55014 Boston, Massachusetts 02205-5014 Our toll-free fax 1-800-225-4240 Our internet e-mail address ask.pioneer@pioneerinvestments.com (for general questions about Pioneer only) Visit our web site: us.pioneerinvestments.com This report must be preceded or accompanied by a prospectus. The Fund files a complete schedule of investments with the Securities and Exchange Commission for the first and third quarters for each fiscal year on Form N-Q. Shareholders may view the filed Form N-Q by visiting the Commission's web site at http://www.sec.gov. The filed form may also be viewed and copied at the Commission's Public Reference Room in Washington, DC. Information regarding the operations of the Public Reference Room may be obtained by calling 1-800-SEC-0330. [LOGO] PIONEER Investments(R) Pioneer Investment Management, Inc. 60 State Street Boston, MA 02109 us.pioneerinvestments.com Securities offered through Pioneer Funds Distributor, Inc. 60 State Street, Boston, MA 02109 Underwriter of Pioneer Mutual Funds, Member SIPC (C) 2017 Pioneer Investments 25671-05-0517 ITEM 2. CODE OF ETHICS. (a) Disclose whether, as of the end of the period covered by the report, the registrant has adopted a code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party. If the registrant has not adopted such a code of ethics, explain why it has not done so. The registrant has adopted, as of the end of the period covered by this report, a code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer and controller. (b) For purposes of this Item, the term "code of ethics" means written standards that are reasonably designed to deter wrongdoing and to promote: (1) Honest and ethical conduct, including the ethical handling of actual or apparent conflicts of interest between personal and professional relationships; (2) Full, fair, accurate, timely, and understandable disclosure in reports and documents that a registrant files with, or submits to, the Commission and in other public communications made by the registrant; (3) Compliance with applicable governmental laws, rules, and regulations; (4) The prompt internal reporting of violations of the code to an appropriate person or persons identified in the code; and (5) Accountability for adherence to the code. (c) The registrant must briefly describe the nature of any amendment, during the period covered by the report, to a provision of its code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party, and that relates to any element of the code of ethics definition enumerated in paragraph (b) of this Item. The registrant must file a copy of any such amendment as an exhibit pursuant to Item 10(a), unless the registrant has elected to satisfy paragraph (f) of this Item by posting its code of ethics on its website pursuant to paragraph (f)(2) of this Item, or by undertaking to provide its code of ethics to any person without charge, upon request, pursuant to paragraph (f)(3) of this Item. The registrant has made no amendments to the code of ethics during the period covered by this report. (d) If the registrant has, during the period covered by the report, granted a waiver, including an implicit waiver, from a provision of the code of ethics to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party, that relates to one or more of the items set forth in paragraph (b) of this Item, the registrant must briefly describe the nature of the waiver, the name of the person to whom the waiver was granted, and the date of the waiver. Not applicable. (e) If the registrant intends to satisfy the disclosure requirement under paragraph (c) or (d) of this Item regarding an amendment to, or a waiver from, a provision of its code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions and that relates to any element of the code of ethics definition enumerated in paragraph (b) of this Item by posting such information on its Internet website, disclose the registrant's Internet address and such intention. Not applicable. (f) The registrant must: (1) File with the Commission, pursuant to Item 12(a)(1), a copy of its code of ethics that applies to the registrant's principal executive officer,principal financial officer, principal accounting officer or controller, or persons performing similar functions, as an exhibit to its annual report on this Form N-CSR (see attachment); (2) Post the text of such code of ethics on its Internet website and disclose, in its most recent report on this Form N-CSR, its Internet address and the fact that it has posted such code of ethics on its Internet website; or (3) Undertake in its most recent report on this Form N-CSR to provide to any person without charge, upon request, a copy of such code of ethics and explain the manner in which such request may be made. 	See Item 10(2) ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT. (a) (1) Disclose that the registrant's board of trustees has determined that the registrant either: (i) Has at least one audit committee financial expert serving on its audit committee; or (ii) Does not have an audit committee financial expert serving on its audit committee. The registrant's Board of Trustees has determined that the registrant has at least one audit committee financial expert. (2) If the registrant provides the disclosure required by paragraph (a)(1)(i) of this Item, it must disclose the name of the audit committee financial expert and whether that person is "independent." In order to be considered "independent" for purposes of this Item, a member of an audit committee may not, other than in his or her capacity as a member of the audit committee, the board of trustees, or any other board committee: (i) Accept directly or indirectly any consulting, advisory, or other compensatory fee from the issuer; or (ii) Be an "interested person" of the investment company as defined in Section 2(a)(19) of the Act (15 U.S.C. 80a-2(a)(19)). Ms. Marguerite A. Piret, an independent trustee, is such an audit committee financial expert. (3) If the registrant provides the disclosure required by paragraph (a)(1) (ii) of this Item, it must explain why it does not have an audit committee financial expert. Not applicable. ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES. (a) Disclose, under the caption AUDIT FEES, the aggregate fees billed for each of the last two fiscal years for professional services rendered by the principal accountant for the audit of the registrant's annual financial statements or services that are normally provided by the accountant in connection with statutory and regulatory filings or engagements for those fiscal years. The audit fees for the Trust were $128,294 payable to Deloitte & Touche LLP for the year ended March 31, 2017 and $122,474 for the year ended March 31, 2016. (b) Disclose, under the caption AUDIT-RELATED FEES, the aggregate fees billed in each of the last two fiscal years for assurance and related services by the principal accountant that are reasonably related to the performance of the audit of the registrant's financial statements and are not reported under paragraph (a) of this Item. Registrants shall describe the nature of the services comprising the fees disclosed under this category. Audit-Related Fees There were no fees for audit-related or other services provided to the Fund during the fiscal years ended March 31, 2017 and 2016. (c) Disclose, under the caption TAX FEES, the aggregate fees billed in each of the last two fiscal years for professional services rendered by the principal accountant for tax compliance, tax advice, and tax planning. Registrants shall describe the nature of the services comprising the fees disclosed under this category. The tax fees for the Trust were $23,034 payable to Deloitte & Touche LLP for the year ended March 31, 2017 and $22,950 for the year ended March 31, 2016. (d) Disclose, under the caption ALL OTHER FEES, the aggregate fees billed in each of the last two fiscal years for products and services provided by the principal accountant, other than the services reported in paragraphs (a) through (c) of this Item. Registrants shall describe the nature of the services comprising the fees disclosed under this category. Other Fees There were no fees for audit-related or other services provided to the Fund during the fiscal years ended March 31, 2017 and 2016. (e) (1) Disclose the audit committee's pre-approval policies and procedures described in paragraph (c)(7) of Rule 2-01 of Regulation S-X. PIONEER FUNDS APPROVAL OF AUDIT, AUDIT-RELATED, TAX AND OTHER SERVICES PROVIDED BY THE INDEPENDENT AUDITOR SECTION I - POLICY PURPOSE AND APPLICABILITY The Pioneer Funds recognize the importance of maintaining the independence of their outside auditors. Maintaining independence is a shared responsibility involving Pioneer Investment Management, Inc ("PIM"), the audit committee and the independent auditors. The Funds recognize that a Fund's independent auditors: 1) possess knowledge of the Funds, 2) are able to incorporate certain services into the scope of the audit, thereby avoiding redundant work, cost and disruption of Fund personnel and processes, and 3) have expertise that has value to the Funds. As a result, there are situations where it is desirable to use the Fund's independent auditors for services in addition to the annual audit and where the potential for conflicts of interests are minimal. Consequently, this policy, which is intended to comply with Rule 210.2-01(C)(7), sets forth guidelines and procedures to be followed by the Funds when retaining the independent audit firm to perform audit, audit-related tax and other services under those circumstances, while also maintaining independence. Approval of a service in accordance with this policy for a Fund shall also constitute approval for any other Fund whose pre-approval is required pursuant to Rule 210.2-01(c)(7)(ii). In addition to the procedures set forth in this policy, any non-audit services that may be provided consistently with Rule 210.2-01 may be approved by the Audit Committee itself and any pre-approval that may be waived in accordance with Rule 210.2-01(c)(7)(i)(C) is hereby waived. Selection of a Fund's independent auditors and their compensation shall be determined by the Audit Committee and shall not be subject to this policy. SECTION II - POLICY ---------------- -------------------------------- ------------------------------------------------- SERVICE SERVICE CATEGORY DESCRIPTION SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES CATEGORY ---------------- -------------------------------- ------------------------------------------------- I. AUDIT Services that are directly o Accounting research assistance SERVICES related to performing the o SEC consultation, registration independent audit of the Funds statements, and reporting o Tax accrual related matters o Implementation of new accounting standards o Compliance letters (e.g. rating agency letters) o Regulatory reviews and assistance regarding financial matters o Semi-annual reviews (if requested) o Comfort letters for closed end offerings ---------------- -------------------------------- ------------------------------------------------- II. Services which are not o AICPA attest and agreed-upon procedures AUDIT-RELATED prohibited under Rule o Technology control assessments SERVICES 210.2-01(C)(4) (the "Rule") o Financial reporting control assessments and are related extensions of o Enterprise security architecture the audit services support the assessment audit, or use the knowledge/expertise gained from the audit procedures as a foundation to complete the project. In most cases, if the Audit-Related Services are not performed by the Audit firm, the scope of the Audit Services would likely increase. The Services are typically well-defined and governed by accounting professional standards (AICPA, SEC, etc.) ---------------- -------------------------------- ------------------------------------------------- ------------------------------------- ------------------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------- ------------------------------------ o "One-time" pre-approval o A summary of all such for the audit period for all services and related fees pre-approved specific service reported at each regularly subcategories. Approval of the scheduled Audit Committee independent auditors as meeting. auditors for a Fund shall constitute pre approval for these services. ------------------------------------- ------------------------------------ o "One-time" pre-approval o A summary of all such for the fund fiscal year within services and related fees a specified dollar limit (including comparison to for all pre-approved specified dollar limits) specific service subcategories reported quarterly. o Specific approval is needed to exceed the pre-approved dollar limit for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for Audit-Related Services not denoted as "pre-approved", or to add a specific service subcategory as "pre-approved" ------------------------------------- ------------------------------------ SECTION III - POLICY DETAIL, CONTINUED ----------------------- --------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES DESCRIPTION ----------------------- --------------------------- ----------------------------------------------- III. TAX SERVICES Services which are not o Tax planning and support prohibited by the Rule, o Tax controversy assistance if an officer of the Fund o Tax compliance, tax returns, excise determines that using the tax returns and support Fund's auditor to provide o Tax opinions these services creates significant synergy in the form of efficiency, minimized disruption, or the ability to maintain a desired level of confidentiality. ----------------------- --------------------------- ----------------------------------------------- ------------------------------------- ------------------------- AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------- ------------------------- ------------------------------------- ------------------------- o "One-time" pre-approval o A summary of for the fund fiscal year all such services and within a specified dollar limit related fees 				 (including comparison 			 to specified dollar 			 limits) reported 			 quarterly. o Specific approval is needed to exceed the pre-approved dollar limits for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for tax services not denoted as pre-approved, or to add a specific service subcategory as "pre-approved" ------------------------------------- ------------------------- SECTION III - POLICY DETAIL, CONTINUED ----------------------- --------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES DESCRIPTION ----------------------- --------------------------- ----------------------------------------------- IV. OTHER SERVICES Services which are not o Business Risk Management support prohibited by the Rule, o Other control and regulatory A. SYNERGISTIC, if an officer of the Fund compliance projects UNIQUE QUALIFICATIONS determines that using the Fund's auditor to provide these services creates significant synergy in the form of efficiency, minimized disruption, the ability to maintain a desired level of confidentiality, or where the Fund's auditors posses unique or superior qualifications to provide these services, resulting in superior value and results for the Fund. ----------------------- --------------------------- ----------------------------------------------- --------------------------------------- ------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------- -------------------------- o "One-time" pre-approval o A summary of for the fund fiscal year within all such services and a specified dollar limit related fees 			 (including comparison 			 to specified dollar 				 limits) reported quarterly. o Specific approval is needed to exceed the pre-approved dollar limits for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for "Synergistic" or "Unique Qualifications" Other Services not denoted as pre-approved to the left, or to add a specific service subcategory as "pre-approved" ------------------------------------- -------------------------- SECTION III - POLICY DETAIL, CONTINUED ----------------------- ------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PROHIBITED SERVICE SUBCATEGORIES DESCRIPTION ----------------------- ------------------------- ----------------------------------------------- PROHIBITED SERVICES Services which result 1. Bookkeeping or other services in the auditors losing related to the accounting records or independence status financial statements of the audit under the Rule. client* 2. Financial information systems design and implementation* 3. Appraisal or valuation services, fairness* opinions, or contribution-in-kind reports 4. Actuarial services (i.e., setting actuarial reserves versus actuarial audit work)* 5. Internal audit outsourcing services* 6. Management functions or human resources 7. Broker or dealer, investment advisor, or investment banking services 8. Legal services and expert services unrelated to the audit 9. Any other service that the Public Company Accounting Oversight Board determines, by regulation, is impermissible ----------------------- ------------------------- ----------------------------------------------- ------------------------------------------- ------------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------------- ------------------------------ o These services are not to be o A summary of all performed with the exception of the(*) services and related services that may be permitted fees reported at each if they would not be subject to audit regularly scheduled procedures at the audit client (as Audit Committee meeting defined in rule 2-01(f)(4)) level will serve as continual the firm providing the service. confirmation that has 				 not provided any restricted services. ------------------------------------------- ------------------------------ -------------------------------------------------------------------------------- GENERAL AUDIT COMMITTEE APPROVAL POLICY: o For all projects, the officers of the Funds and the Fund's auditors will each make an assessment to determine that any proposed projects will not impair independence. o Potential services will be classified into the four non-restricted service categories and the "Approval of Audit, Audit-Related, Tax and Other Services" Policy above will be applied. Any services outside the specific pre-approved service subcategories set forth above must be specifically approved by the Audit Committee. o At least quarterly, the Audit Committee shall review a report summarizing the services by service category, including fees, provided by the Audit firm as set forth in the above policy. -------------------------------------------------------------------------------- (2) Disclose the percentage of services described in each of paragraphs (b) through (d) of this Item that were approved by the audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X. Non-Audit Services Beginning with non-audit service contracts entered into on or after May 6, 2003, the effective date of the new SEC pre-approval rules, the Trust's audit committee is required to pre-approve services to affiliates defined by SEC rules to the extent that the services are determined to have a direct impact on the operations or financial reporting of the Trust. For the years ended March 31 2017 and 2016, there were no services provided to an affiliate that required the Trust's audit committee pre-approval. (f) If greater than 50 percent, disclose the percentage of hours expended on the principal accountants engagement to audit the registrant's financial statements for the most recent fiscal year that were attributed to work performed by persons other than the principal accountant's full-time, permanent employees. N/A (g) Disclose the aggregate non-audit fees billed by the registrants accountant for services rendered to the registrant, and rendered to the registrants investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant for each of the last two fiscal years of the registrant. The aggregate non-audit fees for the Fund and affiliates, as previously defined, totaled approximately $23,034 in 2017 and $22,950 in 2016. (h) Disclose whether the registrants audit committee of the board of trustees has considered whether the provision of non-audit services that were rendered to the registrants investment adviser (not including any subadviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant's independence. The Fund's audit committee of the Board of Trustees has considered whether the provision of non-audit services that were rendered to the Affiliates (as defined) that were not pre- approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X is compatible with maintaining the principal accountant's independence. ITEM 5. AUDIT COMMITTEE OF LISTED REGISTRANTS (a) If the registrant is a listed issuer as defined in Rule 10A-3 under the Exchange Act (17 CFR 240.10A-3), state whether or not the registrant has a separately-designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Exchange Act (15 U.S.C. 78c(a)(58)(A)). If the registrant has such a committee, however designated, identify each committee member. If the entire board of directors is acting as the registrant's audit committee as specified in Section 3(a)(58)(B) of the Exchange Act (15 U.S.C. 78c(a)(58)(B)), so state. N/A (b) If applicable, provide the disclosure required by Rule 10A-3(d) under the Exchange Act (17 CFR 240.10A-3(d)) regarding an exemption from the listing standards for audit committees. N/A ITEM 6. SCHEDULE OF INVESTMENTS. File Schedule of Investments in securities of unaffiliated issuers as of the close of the reporting period as set forth in 210.1212 of Regulation S-X [17 CFR 210.12-12], unless the schedule is included as part of the report to shareholders filed under Item 1 of this Form. Included in Item 1 ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR CLOSED-END MANAGEMENT INVESTMENT COMPANIES. A closed-end management investment company that is filing an annual report on this Form N-CSR must, unless it invests exclusively in non-voting securities, describe the policies and procedures that it uses to determine how to vote proxies relating to portfolio securities, including the procedures that the company uses when a vote presents a conflict between the interests of its shareholders, on the one hand, and those of the company's investment adviser; principal underwriter; or any affiliated person (as defined in Section 2(a)(3) of the Investment Company Act of 1940 (15 U.S.C. 80a-2(a)(3)) and the rules thereunder) of the company, its investment adviser, or its principal underwriter, on the other. Include any policies and procedures of the company's investment adviser, or any other third party, that the company uses, or that are used on the company's behalf, to determine how to vote proxies relating to portfolio securities. Not applicable to open-end management investment companies. ITEM 8. PORTFOLIO MANAGERS OF CLOSED-END MANAGEMENT INVESTMENT COMPANIES. (a) If the registrant is a closed-end management investment company that is filing an annual report on this Form N-CSR,provide the following information: (1) State the name, title, and length of service of the person or persons employed by or associated with the registrant or an investment adviser of the registrant who are primarily responsible for the day-to-day management of the registrant's portfolio ("Portfolio Manager"). Also state each Portfolio Manager's business experience during the past 5 years. Not applicable to open-end management investment companies. ITEM 9. PURCHASES OF EQUITY SECURITIES BY CLOSED-END MANAGEMENT INVESTMENT COMPANY AND AFFILIATED PURCHASERS. (a) If the registrant is a closed-end management investment company, in the following tabular format, provide the information specified in paragraph (b) of this Item with respect to any purchase made by or on behalf of the registrant or any affiliated purchaser, as defined in Rule 10b-18(a)(3) under the Exchange Act (17 CFR 240.10b-18(a)(3)), of shares or other units of any class of the registrant's equity securities that is registered by the registrant pursuant to Section 12 of the Exchange Act (15 U.S.C. 781). Not applicable to open-end management investment companies. ITEM 10. SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS. Describe any material changes to the procedures by which shareholders may recommend nominees to the registrant's board of directors, where those changes were implemented after the registrant last provided disclosure in response to the requirements of Item 407(c)(2)(iv) of Regulation S-R(17 CFR 229.407)(as required by Item 22(b)(15)) of Schedule 14A (17 CFR 240.14a-101), or this Item. There have been no material changes to the procedures by which the shareholders may recommend nominees to the registrant's board of directors since the registrant last provided disclosure in response to the requirements of Item 407(c)(2)(iv) of Regulation S-R of Schedule 14(A) in its definitive proxy statement, or this item. ITEM 11. CONTROLS AND PROCEDURES. (a) Disclose the conclusions of the registrant's principal executive and principal financials officers, or persons performing similar functions, regarding the effectiveness of the registrant's disclosure controls and procedures (as defined in Rule 30a-3(c) under the Act (17 CFR 270.30a-3(c))) as of a date within 90 days of the filing date of the report that includes the disclosure required by this paragraph, based on the evaluation of these controls and procedures required by Rule 30a-3(b) under the Act (17 CFR 270.30(a)-3(b) and Rules 13a-15(b) or 15d-15(b) under the Exchange Act (17 CFR 240.13a-15(b) or 240.15d-15(b)). The registrant's principal executive officer and principal financial officer have concluded that the registrant's disclosure controls and procedures are effective based on the evaluation of these controls and procedures as of a date within 90 days of the filing date of this report. (b) Disclose any change in the registrant's internal control over financial reporting (as defined in Rule 30a-3(d) under the Act (17CFR 270.30a-3(d)) that occured during the second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant's internal control over financial reporting. There were no significant changes in the registrant's internal control over financial reporting that occurred during the second fiscal quarter of the period covered by this report that have materially affected, or are reasonably likely to materially affect, the registrant's internal control over financial reporting. The registrant's principal executive officer and principal financial officer, however, voluntarily are reporting the following information: In August of 2006 the registrant's investment adviser enhanced its internal procedures for reporting performance information required to be included in prospectuses. Those enhancements involved additional internal controls over the appropriateness of performance data generated for this purpose. Such enhancements were made following an internal review which identified prospectuses relating to certain classes of shares of a limited number of registrants where, inadvertently, performance information not reflecting the deduction of applicable sales charges was included. Those prospectuses were revised, and the revised prospectuses were distributed to shareholders. ITEM 12. EXHIBITS. (a) File the exhibits listed below as part of this Form. Letter or number the exhibits in the sequence indicated. (1) Any code of ethics, or amendment thereto, that is the subject of the disclosure required by Item 2, to the extent that the registrant intends to satisfy the Item 2 requirements through filing of an exhibit. (2) A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Act (17 CFR 270.30a-2(a)) , exactly as set forth below: Filed herewith. SIGNATURES [See General Instruction F] Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. (Registrant) Pioneer Series Trust X By (Signature and Title)* /s/ Lisa M. Jones Lisa M. Jones, President & Chief Executive Officer Date May 30, 2017 Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated. By (Signature and Title)* /s/ Lisa M. Jones Lisa M. Jones, President & Chief Executive Officer Date May 30, 2017 By (Signature and Title)* /s/ Mark E. Bradley Mark E. Bradley, Treasurer & Chief Accounting & Financial Officer Date May 30, 2017 * Print the name and title of each signing officer under his or her signature.