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 811-02864 Pioneer Bond Fund (Exact name of registrant as specified in charter) 60 State Street, Boston, MA 02109 (Address of principal executive offices) (ZIP code) Terrence J. Cullen, Amundi Pioneer Asset 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: June 30, 2020 Date of reporting period: July 1, 2019 through December 31, 2019 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 Bond Fund -------------------------------------------------------------------------------- Semiannual Report | December 31, 2019 -------------------------------------------------------------------------------- Ticker Symbols: Class A PIOBX Class C PCYBX Class K PBFKX Class R PBFRX Class Y PICYX Beginning in February 2021, as permitted by regulations adopted by the Securities and Exchange Commission, paper copies of the Fund's shareholder reports like this one will no longer be sent by mail, unless you specifically request paper copies of the reports from the Fund or from your financial intermediary, such as a broker-dealer, bank or insurance company. Instead, the reports will be made available on the Fund's website, and you will be notified by mail each time a report is posted and provided with a website link to access the report. If you already elected to receive shareholder reports electronically, you will not be affected by this change and you need not take any action. You may elect to receive shareholder reports and other communications electronically by contacting your financial intermediary or, if you invest directly with the Fund, by calling 1-800-225-6292. You may elect to receive all future reports in paper free of charge. If you invest directly with the Fund, you can inform the Fund that you wish to continue receiving paper copies of your shareholder reports by calling 1-800-225-6292. If you invest through a financial intermediary, you can contact your financial intermediary to request that you continue to receive paper copies of your shareholder reports. Your election to receive reports in paper will apply to all funds held in your account if you invest through your financial intermediary or all funds held within the Pioneer Fund complex if you invest directly. [LOGO] Amundi Pioneer ============== ASSET MANAGEMENT visit us: www.amundipioneer.com/us 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 17 Schedule of Investments 19 Financial Statements 93 Notes to Financial Statements 102 Approval of Investment Management Agreement 118 Trustees, Officers and Service Providers 123 Pioneer Bond Fund | Semiannual Report | 12/31/19 1 President's Letter Dear Shareholders, As we enter 2020 and welcome a new decade, history has taught us the importance of taking a long-term horizon when investing, which has typically proven to be a prudent approach to generating solid returns over time. Since 1928, our investment process has been built on a foundation of fundamental research and active management, principles which have guided our investment decisions for more than 90 years. We believe active management --that is, making active investment decisions -- can help mitigate the potential risks during periods of market volatility. In today's global economy, investment risk can materialize from a number of factors, including a slowing economy, changing U.S. Federal Reserve interest-rate policy, oil price shocks, and political and geopolitical factors. At Amundi Pioneer, active management begins with our own fundamental, bottom-up research process. Our team of dedicated research analysts and portfolio managers analyze each security under consideration, communicating directly with the management teams of the companies issuing the securities and working together to identify those securities that best meet our investment criteria for our family of funds. Our risk management approach begins with each and every security, as we strive to carefully understand the potential opportunity, while considering any and all risk factors. Today, as investors, we have many options. It is our view that active management can serve shareholders well, not only when markets are thriving, but also during periods of market stress. As you consider your long-term investment goals, we encourage you to work with your financial advisor to develop an investment plan that paves the way for you to pursue both your short and long term goals. 2 Pioneer Bond Fund | Semiannual Report | 12/31/19 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 Head of the Americas, President and CEO of U.S. Amundi Pioneer Asset Management USA, Inc. December 31, 2019 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 Bond Fund | Semiannual Report | 12/31/19 3 Portfolio Management Discussion | 12/31/19 In the following interview, Brad Komenda discusses the factors that affected the performance of Pioneer Bond Fund during the six-month period ended December 31, 2019. Mr. Komenda, Senior Vice President, Deputy Director of Investment-Grade Corporates, and a portfolio manager at Amundi Pioneer Asset Management, Inc. (Amundi Pioneer), is responsible for the day-to-day management of the Fund, along with Kenneth J. Taubes, Executive Vice President and Chief Investment Officer, U.S., and a portfolio manager at Amundi Pioneer, and Timothy Rowe, Managing Director, Director of Multisector Fixed Income, and a portfolio manager at Amundi Pioneer. Q How did the Fund perform during the six-month period ended December 31, 2019? A Pioneer Bond Fund's Class A shares returned 2.56% at net asset value during the six-month period ended December 31, 2019, while the Fund's benchmark, the Bloomberg Barclays U.S. Aggregate Bond Index (the Bloomberg Barclays Index), returned 2.45%. During the same period, the average return of the 615 mutual funds in Morningstar's Intermediate Core-Plus Bond Funds Category was 2.33%. Q How would you describe the investment environment in the fixed-income markets during the six-month period ended December 31, 2019? A The period began last summer against the backdrop of an escalating U.S.-China trade war, which threatened an already fragile economic growth backdrop characterized by a global manufacturing recession. However, market sentiment improved on the expectation that the Federal Reserve (Fed) would implement one or more cuts in the benchmark federal funds rate before the end of 2019 to help offset any drag on the economy caused by trade disruptions. During the summer, the Fed implemented quarter-point rate cuts in both July and September. Treasury yields drifted lower through that time period, lending support to the performance of fixed-income assets in general. August and September saw periods when the yield curve became inverted, meaning that along some portion of the curve, yields for securities with longer maturities were lower than those for securities with shorter maturities. An inverted yield curve has often been viewed as foreshadowing a recession, and so that development brought uncertainty to the credit-sensitive markets. 4 Pioneer Bond Fund | Semiannual Report | 12/31/19 The fourth quarter of 2019 (October through December) saw a cooling in bond market returns. The Fed continued its easing approach by implementing a third consecutive quarter-point rate cut at its October 30 meeting, leaving the federal funds target range between 1.50% and 1.75%. After the October rate cut, the Fed signaled that the move likely represented the end of its mid-cycle downward adjustment in rates. The yield curve steepened over the fourth quarter of the year as the Fed's easing of monetary policy appeared to have stabilized investor sentiment. The more credit-sensitive areas of the fixed-income market outperformed interest-rate sensitive investments over the final weeks of the 2019 calendar year on signs of stronger economic growth and an improved tone to the U.S./China trade negotiations. For the six-month period ended December 31, 2019, the investment-grade corporate bond market posted a positive return of 4.27%, while high-yield corporate bonds returned 3.98% (according to the Bloomberg Barclays U.S. Corporate Bond Index and Bloomberg Barclays U.S. Corporate High Yield Index, respectively). The performance of U.S. Treasuries was also positive for the six-month period, but returns trailed the performance of corporate credit. Securitized assets, including mortgage-backed securities (MBS), asset-backed securities (ABS), and commercial-mortgage backed securities (CMBS), delivered positive returns for the six-month period, while lagging the performance of both corporate and Treasury issues. Q What factors influenced the Fund's performance relative to the Bloomberg Barclays Index during the six-month period ended December 31, 2019? A Positive contributions to the Fund's benchmark-relative performance during the six-month period derived primarily from asset allocation, most notably a portfolio underweight to U.S. Treasuries. In addition, security selection was marginally additive to the Fund's returns relative to the Bloomberg Barclays Index. Our tactical shifts in the Fund's credit exposure throughout the six-month period contributed positively to benchmark-relative performance. A portfolio tilt toward lower-quality securities within corporate credit aided the Fund's relative returns; in particular, within investment-grade corporates, the energy issues held in the portfolio outperformed. The Fund's exposure to convertible securities was another positive contributor to benchmark-relative results, as the markets' risk appetite for equities and equity-related investments increased during the six-month period on optimism over the economy. Pioneer Bond Fund | Semiannual Report | 12/31/19 5 Performance of the Fund's allocations to securitized assets was mixed for the six-month period. Selection results were positive for the Fund versus the benchmark among holdings of pass-through MBS, as our focus on owning call-protected, specified pools was rewarded when prepayments on underlying loans accelerated with the decline in interest rates over much of the six-month period. Conversely, the Fund's overweights to ABS, CMBS, and collateralized mortgage obligations (CMOs) modestly constrained benchmark-relative performance. The Fund's approximate 5% allocation to Treasury Inflation-Protected Securities (TIPS) was another positive contributor to benchmark-relative performance for the six-month period as inflation expectations recovered towards the end of 2019. A small portfolio position in floating-rate bank loans slightly aided the Fund's relative returns over the six-month period, as did the portfolio's exposure to insurance-linked securities. The portfolio's short-duration positioning compared with the Bloomberg Barclays Index slightly detracted from the Fund's benchmark-relative performance during the six-month period, as Treasury yields finished the period lower than where they began the period. (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.) Q Did the Fund have any exposure to derivative securities during the six-month period ended December 31, 2019? If so, did the derivatives have any material impact on performance? A Yes, we invested the portfolio in Treasury futures and credit-default swaps during the six-month period. We invest in Treasury futures as part of our duration-management strategy for the Fund. We believe the use of Treasury futures allows us to express our views on duration and yield-curve positioning in the most efficient manner. We invest in credit-default swaps to either gain or reduce portfolio exposure to corporate bonds very quickly, as cash-bond transactions take a little more time to settle. The use of derivatives did not materially impact the Fund's performance, as they were used as hedging instruments. 6 Pioneer Bond Fund | Semiannual Report | 12/31/19 Q What factors affected the Fund's yield, or distributions to shareholders, during the six-month period ended December 31, 2019? A The overall decline in Treasury yields contributed to a lowering of the Fund's distributions* over the six-month period, as did the tightening of credit spreads. (Credit spreads are commonly defined as the differences in yield between Treasuries and other types of fixed-income securities with similar maturities.) Q What is your investment outlook and how is the Fund currently positioned? A We remain comfortable with a more or less neutral portfolio weighting to corporate credit. Based on historical averages, credit valuations are relatively tight. At the same time, the asset class has continued to receive support from the accommodative direction of global central banks, including the Fed, while the risks to economic growth from an uncontrolled trade war seem to have receded. As a result, we do not view current valuations as extreme, given our expectations for a continued low default rate. We see near-term performance of corporate credit as most likely to be driven by the coupon component of return as opposed to further spread-tightening. Under conditions featuring tight spreads, market jitters over any sign of recession, and elevated geopolitical uncertainty, we expect to see performance dispersion among individual issuers within corporate credit. As a result, we view security selection as being of heightened importance in the current environment. In that vein, we have become more cautious on investment-grade corporate credit outside of the banking sector. While not extreme, valuations are not inexpensive following the rally of early 2019, and as the use of leverage to finance share buybacks and mergers and acquisitions has risen, so has the risk of companies in the BBB-quality range being downgraded to high-yield status. One area of focus for us in managing the Fund is the subordinated debt of systemically significant banks in core Europe, as we believe the category presents a favorable risk/return profile. * Distributions are not guaranteed. Pioneer Bond Fund | Semiannual Report | 12/31/19 7 On balance, we are most positive on securitized assets, where valuations are less extended and a healthy consumer has continued to support fundamentals. More broadly, unlike with the corporate sector, the quality of securitized assets typically is not as vulnerable to a cyclical increase in the use of leverage. In particular, we view residential MBS (RMBS) as attractive, due to a number of factors. For example, housing is in historically short supply, which has been helping to drive up valuations for underlying MBS collateral, while unemployment has remained low and consumer balance sheets are sound in aggregate. In broad terms, we have maintained significant Fund exposure overall to assets such as agency MBS, which feature a high degree of liquidity. Our goal is to position the Fund's portfolio in such a way that we are able to take advantage of any opportunities to add credit exposure, especially if those opportunities are created by market volatility that is disconnected from economic fundamentals. Please refer to the Schedule of Investments on pages 19-92 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. 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. Investments in the Fund are subject to possible loss due to the financial failure of the issuers of the underlying securities and their inability to meet their debt obligations. 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. Investments in high-yield or lower-rated securities are subject to greater-than-average price volatility, illiquidity and possibility of default. The securities issued by U.S. Government-sponsored entities (i.e., Fannie Mae, Freddie Mac) are neither guaranteed nor issued by the U.S. Government. 8 Pioneer Bond Fund | Semiannual Report | 12/31/19 The portfolio may invest in mortgage-backed securities, which during times of fluctuating interest rates may increase or decrease more than other fixed-income securities. Mortgage-backed securities are also subject to pre-payments. 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 Amundi Pioneer Asset Management, Inc., 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 Bond Fund | Semiannual Report | 12/31/19 9 Portfolio Summary | 12/31/19 Portfolio Diversification -------------------------------------------------------------------------------- (As a percentage of total investments)* [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] Corporate Bonds 29.2% Collateralized Mortgage Obligations 25.5% U.S. Government and Agency Obligations 25.3% Asset Backed Securities 14.8% Insurance-Linked Securities 3.1% Senior Secured Floating Rate Loan Interests 1.5% Foreign Government Bond 0.2% Municipal Bonds 0.2% Convertible Preferred Stock 0.2% 10 Largest Holdings -------------------------------------------------------------------------------- (As a percentage of total investments)* 1. U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/46 1.38% ---------------------------------------------------------------------------------------------------- 2. U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/48 1.17 ---------------------------------------------------------------------------------------------------- 3. U.S. Treasury Inflation Indexed Bonds, 0.875%, 2/15/47 1.13 ---------------------------------------------------------------------------------------------------- 4. U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/49 0.95 ---------------------------------------------------------------------------------------------------- 5. Government National Mortgage Association II, 4.5%, 8/20/49 0.67 ---------------------------------------------------------------------------------------------------- 6. Mill City Mortgage Loan Trust, Series 2018-4, Class A1B, 3.5%, 4/25/66 (144A) 0.48 ---------------------------------------------------------------------------------------------------- 7. Federal Home Loan Mortgage Corp., 3.0%, 11/1/49 0.48 ---------------------------------------------------------------------------------------------------- 8. Government National Mortgage Association II, 4.5%, 7/20/49 0.44 ---------------------------------------------------------------------------------------------------- 9. Liberty Mutual Insurance Co., 7.697%, 10/15/97 (144A) 0.43 ---------------------------------------------------------------------------------------------------- 10. Federal Home Loan Mortgage Corp., 4.0%, 7/1/49 0.42 ---------------------------------------------------------------------------------------------------- * Excludes temporary cash investments and all derivative contracts except for options purchased. 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. 10 Pioneer Bond Fund | Semiannual Report | 12/31/19 Prices and Distributions | 12/31/19 Net Asset Value per Share -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Class 12/31/19 6/30/19 -------------------------------------------------------------------------------- A $9.88 $9.79 -------------------------------------------------------------------------------- C $9.77 $9.68 -------------------------------------------------------------------------------- K $9.87 $9.78 -------------------------------------------------------------------------------- R $9.97 $9.88 -------------------------------------------------------------------------------- Y $9.79 $9.70 -------------------------------------------------------------------------------- Distributions per Share: 7/1/19-12/31/19 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Net Investment Short-Term Long-Term Class Income Capital Gains Capital Gains -------------------------------------------------------------------------------- A $0.1581 $ -- $ -- -------------------------------------------------------------------------------- C $0.1252 $ -- $ -- -------------------------------------------------------------------------------- K $0.1830 $ -- $ -- -------------------------------------------------------------------------------- R $0.1484 $ -- $ -- -------------------------------------------------------------------------------- Y $0.1764 $ -- $ -- -------------------------------------------------------------------------------- Index Definition -------------------------------------------------------------------------------- The Bloomberg Barclays U.S. Aggregate Bond Index is an unmanaged measure of the U.S. bond market. Index returns are calculated monthly, 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 12-16. Pioneer Bond Fund | Semiannual Report | 12/31/19 11 Performance Update | 12/31/19 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 Bond Fund at public offering price during the periods shown, compared to that of the Bloomberg Barclays U.S. Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2019) --------------------------------------------------- Bloomberg Net Public Barclays U.S. Asset Offering Aggregate Value Price Bond Period (NAV) (POP) Index --------------------------------------------------- 10 years 4.53% 4.05% 3.75% 5 years 3.20 2.26 3.05 1 year 8.94 4.03 8.72 --------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2019) --------------------------------------------------- Gross --------------------------------------------------- 0.84% --------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Bloomberg Barclays U.S. Pioneer Bond Fund Aggregate Bond Index 12/09 $ 9,550 $10,000 12/10 $10,452 $10,654 12/11 $10,982 $11,490 12/12 $11,933 $11,974 12/13 $11,991 $11,732 12/14 $12,701 $12,431 12/15 $12,700 $12,500 12/16 $13,230 $12,831 12/17 $13,772 $13,285 12/18 $13,651 $13,287 12/19 $14,871 $14,445 Call 1-800-225-6292 or visit www.amundipioneer.com/us 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. NAV 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 Bond Fund | Semiannual Report | 12/31/19 Performance Update | 12/31/19 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 Bond Fund during the periods shown, compared to that of the Bloomberg Barclays U.S. Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2019) --------------------------------------------------- Bloomberg Barclays U.S. Aggregate If If Bond Period Held Redeemed Index --------------------------------------------------- 10 years 3.69% 3.69% 3.75% 5 years 2.46 2.46 3.05 1 year 8.18 8.18 8.72 --------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2019) --------------------------------------------------- Gross --------------------------------------------------- 1.49% --------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Bloomberg Barclays U.S. Pioneer Bond Fund Aggregate Bond Index 12/09 $10,000 $10,000 12/10 $10,840 $10,654 12/11 $11,293 $11,490 12/12 $12,295 $11,974 12/13 $12,108 $11,732 12/14 $12,721 $12,431 12/15 $12,619 $12,500 12/16 $13,052 $12,831 12/17 $13,488 $13,285 12/18 $13,278 $13,287 12/19 $14,364 $14,445 Call 1-800-225-6292 or visit www.amundipioneer.com/us 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 you paid a 1% sales charge, your returns would be lower than those shown above. "If Held" results represent the percent change in net asset value per share. NAV 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 Bond Fund | Semiannual Report | 12/31/19 13 Performance Update | 12/31/19 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 Bond Fund during the periods shown, compared to that of the Bloomberg Barclays U.S. Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2019) --------------------------------------------------- Bloomberg Net Barclays U.S. Asset Aggregate Value Bond Period (NAV) Index --------------------------------------------------- 10 years 4.80% 3.75% 5 years 3.63 3.05 1 year 9.35 8.72 --------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2019) --------------------------------------------------- Gross --------------------------------------------------- 0.34% --------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Bloomberg Barclays U.S. Pioneer Bond Fund Aggregate Bond Index 12/09 $5,000,000 $5,000,000 12/10 $5,472,005 $5,327,086 12/11 $5,749,936 $5,744,826 12/12 $6,242,051 $5,986,961 12/13 $6,297,775 $5,865,804 12/14 $6,684,281 $6,215,740 12/15 $6,716,093 $6,249,924 12/16 $7,023,407 $6,415,389 12/17 $7,339,264 $6,642,611 12/18 $7,304,169 $6,643,366 12/19 $7,987,355 $7,222,448 Call 1-800-225-6292 or visit www.amundipioneer.com/us 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. 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. 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 Bond Fund | Semiannual Report | 12/31/19 Performance Update | 12/31/19 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 Bond Fund during the periods shown, compared to that of the Bloomberg Barclays U.S. Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2019) --------------------------------------------------- Bloomberg Net Barclays U.S. Asset Aggregate Value Bond Period (NAV) Index --------------------------------------------------- 10 years 4.20% 3.75% 5 years 2.95 3.05 1 year 8.62 8.72 --------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2019) --------------------------------------------------- Gross --------------------------------------------------- 1.09% --------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Bloomberg Barclays U.S. Pioneer Bond Fund Aggregate Bond Index 12/09 $10,000 $10,000 12/10 $10,908 $10,654 12/11 $11,419 $11,490 12/12 $12,342 $11,974 12/13 $12,355 $11,732 12/14 $13,054 $12,431 12/15 $13,022 $12,500 12/16 $13,531 $12,831 12/17 $14,049 $13,285 12/18 $13,896 $13,287 12/19 $15,094 $14,445 Call 1-800-225-6292 or visit www.amundipioneer.com/us 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 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 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 Bond Fund | Semiannual Report | 12/31/19 15 Performance Update | 12/31/19 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 Bond Fund during the periods shown, compared to that of the Bloomberg Barclays U.S. Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2019) --------------------------------------------------- Bloomberg Net Barclays U.S. Asset Aggregate Value Bond Period (NAV) Index --------------------------------------------------- 10 years 4.80% 3.75% 5 years 3.52 3.05 1 year 9.28 8.72 --------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2019) --------------------------------------------------- Gross --------------------------------------------------- 0.46% --------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Bloomberg Barclays U.S. Pioneer Bond Fund Aggregate Bond Index 12/09 $5,000,000 $5,000,000 12/10 $5,487,667 $5,327,086 12/11 $5,780,714 $5,744,826 12/12 $6,291,035 $5,986,961 12/13 $6,332,402 $5,865,804 12/14 $6,724,638 $6,215,740 12/15 $6,741,087 $6,249,924 12/16 $7,043,060 $6,415,389 12/17 $7,352,473 $6,642,611 12/18 $7,313,752 $6,643,366 12/19 $7,992,598 $7,222,448 Call 1-800-225-6292 or visit www.amundipioneer.com/us 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. 16 Pioneer Bond Fund | Semiannual Report | 12/31/19 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 Bond Fund Based on actual returns from July 1, 2019 through December 31, 2019. ------------------------------------------------------------------------------------------- Share Class A C K R Y ------------------------------------------------------------------------------------------- Beginning $1,000.00 $1,000.00 $1,000.00 $1,000.00 $1,000.00 Account Value on 7/1/19 ------------------------------------------------------------------------------------------- Ending Account $1,025.60 $1,022.40 $1,028.20 $1,024.30 $1,027.80 Value (after expenses) on 12/31/19 ------------------------------------------------------------------------------------------- Expenses Paid $4.23 $7.42 $1.68 $5.44 $2.24 During Period* ------------------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.83%, 1.46%, 0.33%, 1.07%, and 0.44% 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 184/366 (to reflect the one-half year period). Pioneer Bond Fund | Semiannual Report | 12/31/19 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 Bond Fund Based on a hypothetical 5% per year return before expenses, reflecting the period from July 1, 2019 through December 31, 2019. ------------------------------------------------------------------------------------------- Share Class A C K R Y ------------------------------------------------------------------------------------------- Beginning $1,000.00 $1,000.00 $1,000.00 $1,000.00 $1,000.00 Account Value on 7/1/19 ------------------------------------------------------------------------------------------- Ending Account $1,020.96 $1,017.80 $1,023.48 $1,019.76 $1,022.92 Value (after expenses) on 12/31/19 ------------------------------------------------------------------------------------------- Expenses Paid $4.22 $7.41 $1.68 $5.43 $2.24 During Period* ------------------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.83%, 1.46%, 0.33%, 1.07%, and 0.44% 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 184/366 (to reflect the one-half year period). 18 Pioneer Bond Fund | Semiannual Report | 12/31/19 Schedule of Investments | 12/31/19 (unaudited) --------------------------------------------------------------------------------------------------------------------- Shares Value --------------------------------------------------------------------------------------------------------------------- UNAFFILIATED ISSUERS -- 99.4% CONVERTIBLE PREFERRED STOCK -- 0.2% of Net Assets Banks -- 0.2% 9,656(a) Wells Fargo & Co., 7.5% $ 14,001,200 -------------- Total Banks $ 14,001,200 --------------------------------------------------------------------------------------------------------------------- TOTAL CONVERTIBLE PREFERRED STOCK (Cost $10,558,494) $ 14,001,200 --------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- 14.6% of Net Assets 613,758(b) 321 Henderson Receivables I LLC, Series 2005-1A, Class A1, 1.97% (1 Month USD LIBOR + 23 bps), 11/15/40 (144A) $ 597,677 500,000 321 Henderson Receivables III LLC, Series 2008-1A, Class B, 8.37%, 1/15/46 (144A) 614,378 2,000,000(b) 522 Funding Clo I, Ltd., Series 2019-1A, Class D, 0.0% (3 Month USD LIBOR + 420 bps), 1/15/33 (144A) 2,003,742 12,500,000 A10 Bridge Asset Financing LLC, Series 2019-B, Class A1, 3.085%, 8/15/40 (144A) 12,420,552 161,726 ACC Trust, Series 2018-1, Class A, 3.7%, 12/21/20 (144A) 161,832 4,300,000 Access Point Funding I LLC, Series 2017-A, Class B, 3.97%, 4/15/29 (144A) 4,314,162 4,000,000 American Credit Acceptance Receivables Trust, Series 2019-2, Class E, 4.29%, 6/12/25 (144A) 4,049,502 800,000 Amur Equipment Finance Receivables V LLC, Series 2018-1A, Class C, 3.74%, 4/22/24 (144A) 810,409 1,249,999 Amur Equipment Finance Receivables V LLC, Series 2018-1A, Class D, 3.98%, 4/22/24 (144A) 1,267,600 1,675,000 Amur Equipment Finance Receivables VI LLC, Series 2018-2A, Class C, 4.27%, 1/20/23 (144A) 1,729,128 5,784,000 Amur Equipment Finance Receivables VI LLC, Series 2018-2A, Class D, 4.45%, 6/20/23 (144A) 5,961,112 3,833,000 Amur Equipment Finance Receivables VII LLC, Series 2019-1A, Class B, 2.8%, 3/20/25 (144A) 3,845,734 2,676,000 Amur Equipment Finance Receivables VII LLC, Series 2019-1A, Class E, 4.47%, 3/20/25 (144A) 2,684,226 5,900,000 Aqua Finance Trust, Series 2019-A, Class C, 4.01%, 7/16/40 (144A) 5,883,498 7,000,000 Arivo Acceptance Auto Loan Receivables Trust, Series 2019-1, Class B, 3.37%, 6/15/25 (144A) 6,940,472 1,100,000 Ascentium Equipment Receivables Trust, Series 2018-1A, Class D, 3.99%, 12/11/23 (144A) 1,128,911 1,750,000 Avid Automobile Receivables Trust, Series 2018-1, Class B, 3.85%, 7/15/24 (144A) 1,763,994 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 19 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 2,000,000 Avid Automobile Receivables Trust, Series 2019-1, Class C, 3.14%, 7/15/26 (144A) $ 1,992,910 4,434,942(c) Bayview Koitere Fund Trust, Series 2017-RT4, Class A, 3.5%, 7/28/57 (144A) 4,510,937 3,001,551(c) Bayview Opportunity Master Fund IVa Trust, Series 2017-RT1, Class A1, 3.0%, 3/28/57 (144A) 3,023,714 1,416,000 BCC Funding XIV LLC, Series 2018-1A, Class B, 3.39%, 8/21/23 (144A) 1,438,103 2,059(b) Bear Stearns Asset Backed Securities Trust, Series 2006-SD2, Class A3, 2.282% (1 Month USD LIBOR + 49 bps), 6/25/36 2,057 2,000,000(b) Benefit Street Partners CLO XIX, Ltd., Series 2019-19A, Class E, 0.0% (3 Month USD LIBOR + 702 bps), 1/15/33 (144A) 1,970,000 794,182 BXG Receivables Note Trust, Series 2015-A, Class A, 2.88%, 5/2/30 (144A) 791,734 2,500,000(b) Carlyle US CLO, Ltd., Series 2019-4A, Class C, 0.0% (3 Month USD LIBOR + 400 bps), 1/15/33 (144A) 2,500,000 8,723,407(c) Cascade MH Asset Trust, Series 2019-MH1, Class A, 4.0%, 11/25/44 (144A) 8,723,095 3,498,616 Cazenovia Creek Funding II LLC, Series 2018-1A, Class A, 3.561%, 7/15/30 (144A) 3,518,554 8,600,000 CIG Auto Receivables Trust, Series 2019-1A, Class B, 3.59%, 8/15/24 (144A) 8,729,552 1,036,817(b) Commonbond Student Loan Trust, Series 2017-BGS, Class A2, 2.442% (1 Month USD LIBOR + 65 bps), 9/25/42 (144A) 1,024,660 1,463,364 Conn's Receivables Funding LLC, Series 2019-A, Class A, 3.4%, 10/16/23 (144A) 1,473,122 4,790,000 Conn's Receivables Funding LLC, Series 2019-B, Class B, 3.62%, 6/17/24 (144A) 4,790,900 7,600,000 Continental Credit Card ABS LLC, Series 2019-1A, Class A, 3.83%, 8/15/26 (144A) 7,654,686 3,000,000 CoreVest American Finance Trust, Series 2017-1, Class C, 3.756%, 10/15/49 (144A) 3,024,771 1,679,585 Diamond Resorts Owner Trust, Series 2019-1A, Class B, 3.53%, 2/20/32 (144A) 1,678,399 9,300,000 Domino's Pizza Master Issuer LLC, Series 2019-1A, Class A2, 3.668%, 10/25/49 (144A) 9,301,581 237,654(b) DRB Prime Student Loan Trust, Series 2016-B, Class A1, 3.592% (1 Month USD LIBOR + 180 bps), 6/25/40 (144A) 241,231 2,122,357 Drive Auto Receivables Trust, Series 2018-1, Class C, 3.22%, 3/15/23 2,127,107 4,000,000 Drive Auto Receivables Trust, Series 2019-1, Class C, 3.78%, 4/15/25 4,068,948 37,925(b) Drug Royalty II LP 2, Series 2014-1, Class A1, 5.153% (3 Month USD LIBOR + 285 bps), 7/15/23 (144A) 37,944 The accompanying notes are an integral part of these financial statements. 20 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 4,500,000 Elm Trust, Series 2018-2A, Class A2, 4.605%, 10/20/27 (144A) $ 4,521,449 1,300,000 Engs Commercial Finance Trust, Series 2016-1A, Class B, 3.45%, 3/22/22 (144A) 1,305,938 1,900,000 Engs Commercial Finance Trust, Series 2016-1A, Class D, 5.22%, 1/22/24 (144A) 1,908,299 4,000,000 ExteNet LLC, Series 2019-1A, Class C, 5.219%, 7/26/49 (144A) 4,018,357 1,701,335 FCI Funding LLC, Series 2019-1A, Class A, 3.63%, 2/18/31 (144A) 1,708,544 2,093,951 FCI Funding LLC, Series 2019-1A, Class B, 0.0%, 2/18/31 (144A) 2,102,857 10,392,610 Finance of America Structured Securities Trust, Series 2019-A, Class JR2, 0.0%, 3/25/69 10,733,399 3,000,000(c) Finance of America Structured Securities Trust, Series 2019-HB1, Class M2, 3.676%, 4/25/29 (144A) 3,001,500 1,700,000(c) Finance of America Structured Securities Trust, Series 2019-HB1, Class M3, 3.813%, 4/25/29 (144A) 1,722,100 21,836,990 Finance of America Structured Securities Trust, Series 2019-JR3, Class JR2, 2.0%, 9/25/69 21,946,495 4,500,000(b) First Eagle BSL CLO, Ltd., Series 2019-1A, Class C, 0.0% (3 Month USD LIBOR + 435 bps), 1/20/33 (144A) 4,451,841 1,000,000(b) First Eagle BSL CLO, Ltd., Series 2019-1A, Class D, 0.0% (3 Month USD LIBOR + 770 bps), 1/20/33 (144A) 929,409 1,140,000 Ford Credit Auto Owner Trust, Series 2018-2, Class A, 3.47%, 1/15/30 (144A) 1,190,331 3,750,000 Foundation Finance Trust, Series 2019-1A, Class B, 4.22%, 11/15/34 (144A) 3,870,027 4,200,000 Four Seas LP, Series 2017-1A, Class A2, 5.927%, 8/28/27 (144A) 4,184,086 1,750,000 Foursight Capital Automobile Receivables Trust, Series 2019-1, Class D, 3.27%, 6/16/25 (144A) 1,769,767 5,080,000 Genesis Sales Finance Master Trust, Series 2019-AA, Class A, 4.68%, 8/20/23 (144A) 5,171,119 6,000,000 GLS Auto Receivables Issuer Trust, Series 2019-1A, Class C, 3.87%, 12/16/24 (144A) 6,141,678 10,141(d) GMAT Trust, Series 2013-1A, Class A, 6.967%, 11/25/43 (144A) 10,139 4,390,000(b) Goldentree Loan Management US CLO 6, Ltd., Series 2019-6A, Class D, 5.607% (3 Month USD LIBOR + 385 bps), 1/20/33 (144A) 4,389,851 4,833,813 Hardee's Funding LLC, Series 2018-1A, Class A2II, 4.959%, 6/20/48 (144A) 4,947,987 2,250,000(b) Hertz Fleet Lease Funding LP, Series 2016-1, Class E, 5.215% (1 Month USD LIBOR + 350 bps), 4/10/30 (144A) 2,256,385 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 21 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 1,850,000 Hertz Fleet Lease Funding LP, Series 2018-1, Class C, 3.77%, 5/10/32 (144A) $ 1,877,727 2,800,000 Hertz Fleet Lease Funding LP, Series 2018-1, Class D, 4.17%, 5/10/32 (144A) 2,848,113 4,296,000 HOA Funding LLC, Series 2014-1A, Class A2, 4.846%, 8/20/44 (144A) 4,296,730 5,187,862(b) Home Partners of America Trust, Series 2018-1, Class A, 2.637% (1 Month USD LIBOR + 90 bps), 7/17/37 (144A) 5,187,038 3,713,964 Home Partners of America Trust, Series 2019-1, Class D, 3.406%, 9/17/39 (144A) 3,666,924 5,015,826 Home Partners of America Trust, Series 2019-2, Class E, 3.32%, 10/19/39 (144A) 4,916,261 5,250,000 Horizon Funding, Series 2019-1A, Class A1, 4.21%, 9/15/27 (144A) 5,249,562 722,762 Icon Brand Holdings LLC, Series 2012-1A, Class A, 4.229%, 1/25/43 (144A) 510,088 198,017 Icon Brand Holdings LLC, Series 2013-1A, Class A2, 4.352%, 1/25/43 (144A) 139,741 3,650,000(b) Invitation Homes Trust, Series 2018-SFR1, Class C, 2.987% (1 Month USD LIBOR + 125 bps), 3/17/37 (144A) 3,641,084 4,730,000(b) Invitation Homes Trust, Series 2018-SFR2, Class D, 3.19% (1 Month USD LIBOR + 145 bps), 6/17/37 (144A) 4,735,880 6,860,000(b) Invitation Homes Trust, Series 2018-SFR3, Class D, 3.387% (1 Month USD LIBOR + 165 bps), 7/17/37 (144A) 6,883,490 8,960,000(b) Invitation Homes Trust, Series 2018-SFR3, Class E, 3.737% (1 Month USD LIBOR + 200 bps), 7/17/37 (144A) 8,988,056 313,510 JG Wentworth XXII LLC, Series 2010-3A, Class A, 3.82%, 12/15/48 (144A) 323,156 3,842,043 JG Wentworth XLI LLC, Series 2018-1A, Class A, 3.74%, 10/17/72 (144A) 4,001,842 6,411,263 JG Wentworth XLIII LLC, Series 2019-1A, Class A, 3.82%, 8/17/71 (144A) 6,707,606 6,000,000 Kabbage Funding LLC, Series 2019-1, Class A, 3.825%, 3/15/24 (144A) 6,066,224 14,500,000 Kabbage Funding LLC, Series 2019-1, Class B, 4.071%, 3/15/24 (144A) 14,642,722 2,100,000 LL ABS Trust, Series 2019-1A, Class B, 3.52%, 3/15/27 (144A) 2,101,277 6,000,000(b) M360 LLC, Series 2019-CRE2, Class A, 3.14% (1 Month USD LIBOR + 140 bps), 9/15/34 (144A) 5,999,204 3,750,000(b) Madison Park Funding XXXVI, Ltd., Series 2019-36A, Class D, 3.75% (3 Month USD LIBOR + 375 bps), 1/15/33 (144A) 3,749,929 The accompanying notes are an integral part of these financial statements. 22 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 4,400,000(b) Madison Park Funding XXXVI, Ltd., Series 2019-36A, Class E, 7.25% (3 Month USD LIBOR + 725 bps), 1/15/33 (144A) $ 4,399,784 1,710,525 Marlette Funding Trust, Series 2018-3A, Class A, 3.2%, 9/15/28 (144A) 1,713,846 5,950,000 Marlette Funding Trust, Series 2019-2A, Class C, 4.11%, 7/16/29 (144A) 6,029,007 1,750,000 Marlin Receivables LLC, Series 2018-1A, Class C, 3.7%, 6/20/23 (144A) 1,779,161 8,726,000(c) Mill City Mortgage Loan Trust, Series 2016-1, Class B2, 3.971%, 4/25/57 (144A) 8,916,201 11,444,359(c) Mill City Mortgage Loan Trust, Series 2018-2, Class M1, 3.75%, 5/25/58 (144A) 11,851,825 9,467,816(c) Mill City Mortgage Loan Trust, Series 2018-3, Class M3, 3.25%, 8/25/58 (144A) 8,949,447 6,582,000(c) Mill City Mortgage Trust, Series 2015-1, Class B3, 3.812%, 6/25/56 (144A) 6,180,429 5,531,129 Mosaic Solar Loan Trust, Series 2019-2A, Class A, 2.88%, 9/20/40 (144A) 5,526,942 2,540,000 Mosaic Solar Loan Trust, Series 2019-2A, Class C, 4.35%, 9/20/40 (144A) 2,539,514 2,645,000(c) Nationstar HECM Loan Trust, Series 2018-3A, Class M3, 4.353%, 11/25/28 (144A) 2,685,106 2,957,279(b) Newtek Small Business Loan Trust, Series 2017-1, Class A, 3.792% (1 Month USD LIBOR + 200 bps), 2/15/43 (144A) 2,977,600 3,000,000 NFAS LLC, Series 2019-1, Class A, 4.172%, 8/15/24 (144A) 3,019,740 1,500,000 NMEF Funding 2015-A LLC, Series 2019-A, Class B, 3.06%, 8/15/26 (144A) 1,499,820 720,000 NMEF Funding 2015-A LLC, Series 2019-A, Class D, 4.39%, 8/15/26 (144A) 717,302 1,104,171(b) NovaStar Mortgage Funding Trust, Series 2005-3, Class M1, 2.467% (1 Month USD LIBOR + 68 bps), 1/25/36 1,103,198 2,237,366 Orange Lake Timeshare Trust, Series 2019-A, Class A, 3.06%, 4/9/38 (144A) 2,258,008 5,898,556 Orange Lake Timeshare Trust, Series 2019-A, Class D, 4.93%, 4/9/38 (144A) 6,000,758 359,970 Oxford Finance Funding LLC, Series 2016-1A, Class A, 3.968%, 6/17/24 (144A) 361,629 3,000,000 Oxford Finance Funding LLC, Series 2019-1A, Class B, 5.438%, 2/15/27 (144A) 3,054,617 5,500,000 Perimeter Master Note Business Trust, Series 2019-2A, Class B, 5.21%, 5/15/24 (144A) 5,498,900 3,730,000 Progress Residential Trust, Series 2017-SFR1, Class E, 4.261%, 8/17/34 (144A) 3,802,183 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 23 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 6,180,000 Progress Residential Trust, Series 2017-SFR2, Class E, 4.142%, 12/17/34 (144A) $ 6,214,786 3,250,000 Progress Residential Trust, Series 2018-SFR2, Class E, 4.656%, 8/17/35 (144A) 3,321,476 5,810,000 Progress Residential Trust, Series 2018-SFR3, Class E, 4.873%, 10/17/35 (144A) 5,982,897 8,370,000 Progress Residential Trust, Series 2019-SFR2, Class E, 4.142%, 5/17/36 (144A) 8,485,467 2,000,000 Purchasing Power Funding LLC, Series 2018-A, Class A, 3.34%, 8/15/22 (144A) 2,002,937 8,000,000 Republic Finance Issuance Trust, Series 2019-A, Class A, 3.43%, 11/22/27 (144A) 7,986,239 2,000,000(c) RMF Buyout Issuance Trust, Series 2019-1, Class M3, 3.011%, 7/25/29 (144A) 2,001,274 1,324,633 SCF Equipment Leasing LLC, Series 2017-2A, Class A, 3.41%, 12/20/23 (144A) 1,325,472 2,250,000 SCF Equipment Leasing LLC, Series 2018-1A, Class C, 4.21%, 4/20/27 (144A) 2,258,898 7,400,000 SCF Equipment Leasing LLC, Series 2019-1A, Class C, 3.92%, 11/20/26 (144A) 7,446,068 3,000,000 SCF Equipment Leasing LLC, Series 2019-2A, Class A2, 2.47%, 4/20/26 (144A) 2,994,902 7,350,000 SCF Equipment Leasing LLC, Series 2019-2A, Class C, 3.11%, 6/21/27 (144A) 7,340,704 1,162,000 Small Business Lending Trust, Series 2019-A, Class B, 3.42%, 7/15/26 (144A) 1,158,378 4,000,000(b) Sound Point CLO XXV, Ltd., Series 2019-4A, Class D, 0.0% (3 Month USD LIBOR + 411 bps), 1/15/33 (144A) 3,960,000 4,100,000(b) Sound Point CLO XXV, Ltd., Series 2019-4A, Class E, 0.0% (3 Month USD LIBOR + 762 bps), 1/15/33 (144A) 3,977,000 11,831,503 SpringCastle Funding Asset-Backed Notes, Series 2019-AA, Class A, 3.2%, 5/27/36 (144A) 11,875,445 1,465,000 STORE Master Funding I LLC, Series 2015-1A, Class A1, 3.75%, 4/20/45 (144A) 1,467,107 3,200,000 Tidewater Auto Receivables Trust, Series 2018-AA, Class C, 3.84%, 11/15/24 (144A) 3,246,658 1,078,000 Tidewater Auto Receivables Trust, Series 2018-AA, Class D, 4.3%, 11/15/24 (144A) 1,097,928 362,555 TLF National Tax Lien Trust, Series 2017-1A, Class B, 3.84%, 12/15/29 (144A) 363,690 12,500,000(c) Towd Point Mortgage Trust, Series 2015-2, Class 1B3, 3.799%, 11/25/60 (144A) 12,497,699 6,000,000(c) Towd Point Mortgage Trust, Series 2015-6, Class B1, 4.022%, 4/25/55 (144A) 6,387,100 9,700,000(c) Towd Point Mortgage Trust, Series 2016-1, Class B1, 4.286%, 2/25/55 (144A) 10,398,541 The accompanying notes are an integral part of these financial statements. 24 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 9,750,000(c) Towd Point Mortgage Trust, Series 2016-2, Class B2, 3.552%, 8/25/55 (144A) $ 9,744,290 13,750,000(c) Towd Point Mortgage Trust, Series 2016-3, Class B1, 4.143%, 4/25/56 (144A) 14,525,372 9,000,000(c) Towd Point Mortgage Trust, Series 2016-4, Class B1, 4.023%, 7/25/56 (144A) 9,431,048 14,130,000(c) Towd Point Mortgage Trust, Series 2016-4, Class M1, 3.25%, 7/25/56 (144A) 14,254,802 6,000,000(c) Towd Point Mortgage Trust, Series 2016-5, Class M2, 3.375%, 10/25/56 (144A) 6,016,624 18,130,000(c) Towd Point Mortgage Trust, Series 2017-1, Class B2, 3.988%, 10/25/56 (144A) 18,388,405 8,250,000(c) Towd Point Mortgage Trust, Series 2017-2, Class B2, 4.178%, 4/25/57 (144A) 8,592,750 12,600,000(c) Towd Point Mortgage Trust, Series 2017-2, Class M2, 3.75%, 4/25/57 (144A) 13,020,433 13,920,000(c) Towd Point Mortgage Trust, Series 2017-4, Class B1, 3.623%, 6/25/57 (144A) 14,207,635 23,000,000(c) Towd Point Mortgage Trust, Series 2017-4, Class M2, 3.25%, 6/25/57 (144A) 22,980,590 20,071,000(c) Towd Point Mortgage Trust, Series 2017-6, Class A2, 3.0%, 10/25/57 (144A) 20,152,549 7,000,000(c) Towd Point Mortgage Trust, Series 2017-6, Class M1, 3.25%, 10/25/57 (144A) 7,060,176 14,500,000(c) Towd Point Mortgage Trust, Series 2017-6, Class M2, 3.25%, 10/25/57 (144A) 14,389,134 5,161,000(c) Towd Point Mortgage Trust, Series 2018-1, Class B1, 4.026%, 1/25/58 (144A) 5,272,154 19,865,000(c) Towd Point Mortgage Trust, Series 2018-2, Class A2, 3.5%, 3/25/58 (144A) 20,204,948 3,250,000(c) Towd Point Mortgage Trust, Series 2018-3, Class A2, 3.875%, 5/25/58 (144A) 3,394,770 16,185,000(c) Towd Point Mortgage Trust, Series 2018-3, Class M2, 3.875%, 5/25/58 (144A) 16,461,194 9,000,000(c) Towd Point Mortgage Trust, Series 2018-5, Class A1B, 3.25%, 7/25/58 (144A) 9,196,061 6,637,348(c) Towd Point Mortgage Trust, Series 2018-SJ1, Class A1, 4.0%, 10/25/58 (144A) 6,683,729 3,151,569(c) Towd Point Mortgage Trust, Series 2018-SJ1, Class XA, 5.0%, 10/25/58 (144A) 3,137,864 22,685,000(c) Towd Point Mortgage Trust, Series 2019-2, Class A2, 3.75%, 12/25/58 (144A) 23,772,351 10,150,000(c) Towd Point Mortgage Trust, Series 2019-3, Class M1, 4.25%, 2/25/59 (144A) 10,837,199 13,515,000(b) Towd Point Mortgage Trust, Series 2019-HY2, Class A2, 3.192% (1 Month USD LIBOR + 140 bps), 5/25/58 (144A) 13,668,768 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 25 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 10,623,420(c) Towd Point Mortgage Trust, Series 2019-HY2, Class XA, 5.0%, 5/25/58 (144A) $ 10,609,028 5,614,000(b) Towd Point Mortgage Trust, Series 2019-HY3, Class A2, 3.092% (1 Month USD LIBOR + 130 bps), 10/25/59 (144A) 5,654,369 8,337,975(c) Towd Point Mortgage Trust, Series 2019-MH1, Class A1, 3.0%, 11/25/58 (144A) 8,376,830 5,022,154(c) Towd Point Mortgage Trust, Series 2019-SJ1, Class A1, 3.75%, 11/25/58 (144A) 5,052,481 14,550,000(c) Towd Point Mortgage Trust, Series 2019-SJ3, Class A2, 3.0%, 11/25/59 (144A) 14,570,035 3,000,000(b) Trafigura Securitisation Finance Plc, Series 2017-1A, Class A1, 2.59% (1 Month USD LIBOR + 85 bps), 12/15/20 (144A) 3,001,437 8,500,000 Tricon American Homes Trust, Series 2017-SFR2, Class B, 3.275%, 1/17/36 (144A) 8,559,414 9,411,000 Tricon American Homes Trust, Series 2019-SFR1, Class A, 2.75%, 3/17/38 (144A) 9,428,815 1,250,000 United Auto Credit Securitization Trust, Series 2019-1, Class D, 3.47%, 8/12/24 (144A) 1,263,112 2,125,000 United Auto Credit Securitization Trust, Series 2019-1, Class E, 4.29%, 8/12/24 (144A) 2,147,694 26,395 United States Small Business Administration, 6.14%, 1/1/22 26,894 141,986 United States Small Business Administration, Series 2005-20B, Class 1, 4.625%, 2/1/25 147,861 130,206 United States Small Business Administration, Series 2005-20E, Class 1, 4.84%, 5/1/25 136,173 194,740 United States Small Business Administration, Series 2008-20D, Class 1, 5.37%, 4/1/28 208,927 203,178 United States Small Business Administration, Series 2008-20H, Class 1, 6.02%, 8/1/28 219,267 124,768 United States Small Business Administration, Series 2008-20J, Class 1, 5.63%, 10/1/28 134,627 111,906 United States Small Business Administration, Series 2008-20L, Class 1, 6.22%, 12/1/28 122,383 49,720 United States Small Business Administration, Series 2009-20A, Class 1, 5.72%, 1/1/29 53,732 120,029 United States Small Business Administration, Series 2009-20I, Class 1, 4.2%, 9/1/29 126,067 2,450,000 US Auto Funding LLC, Series 2019-1A, Class B, 3.99%, 12/15/22 (144A) 2,480,819 446,835 Welk Resorts LLC, Series 2015-AA, Class A, 2.79%, 6/16/31 (144A) 447,154 1,648,773 Welk Resorts LLC, Series 2017-AA, Class B, 3.41%, 6/15/33 (144A) 1,656,408 2,284,236 Welk Resorts LLC, Series 2019-AA, Class C, 3.34%, 6/15/38 (144A) 2,296,832 The accompanying notes are an integral part of these financial statements. 26 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- (continued) 1,096,421 Welk Resorts LLC, Series 2019-AA, Class D, 4.03%, 6/15/38 (144A) $ 1,102,356 989,869 Westgate Resorts LLC, Series 2016-1A, Class B, 4.5%, 12/20/28 (144A) 990,100 811,116 Westgate Resorts LLC, Series 2017-1A, Class A, 3.05%, 12/20/30 (144A) 814,268 4,786,154 Westgate Resorts LLC, Series 2018-1A, Class C, 4.1%, 12/20/31 (144A) 4,833,578 3,870,000 Westlake Automobile Receivables Trust, Series 2018-3A, Class E, 4.9%, 12/15/23 (144A) 3,992,306 2,900,000 Westlake Automobile Receivables Trust, Series 2019-3A, Class E, 3.59%, 3/17/25 (144A) 2,903,920 2,333,632 WRG Debt Funding II LLC, Series 2017-1, Class A, 4.458%, 3/15/26 (144A) 2,333,632 ---------------------------------------------------------------------------------------------------------------------- TOTAL ASSET BACKED SECURITIES (Cost $892,709,043) $ 901,354,194 ---------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- 25.2% of Net Assets 3,190,000 A10 Term Asset Financing LLC, Series 2017-1A, Class B, 3.15%, 3/15/36 (144A) $ 3,190,347 16,492(b) Alternative Loan Trust, Series 2003-14T1, Class A9, 2.242% (1 Month USD LIBOR + 45 bps), 8/25/18 16,492 2,800,000 American Homes 4 Rent, Series 2014-SFR3, Class C, 4.596%, 12/17/36 (144A) 2,962,814 700,000 American Homes 4 Rent, Series 2014-SFR3, Class D, 5.04%, 12/17/36 (144A) 748,219 1,300,000 American Homes 4 Rent Trust, Series 2015-SFR1, Class C, 4.11%, 4/17/52 (144A) 1,347,455 2,320,000(c) Angel Oak Mortgage Trust I LLC, Series 2019-1, Class M1, 4.5%, 11/25/48 (144A) 2,386,493 6,700,000(c) Angel Oak Mortgage Trust I LLC, Series 2019-2, Class M1, 4.065%, 3/25/49 (144A) 6,820,791 3,500,000(c) BAMLL Commercial Mortgage Securities Trust, Series 2016-FR14, Class A, 2.949%, 2/27/48 (144A) 3,493,929 7,460,000 BANK, Series 2017-BNK5, Class AS, 3.624%, 6/15/60 7,829,907 10,350,000 BANK, Series 2017-BNK7, Class AS, 3.748%, 9/15/60 10,997,588 4,034,403(d)(e) Bayview Commercial Asset Trust, Series 2007-2A, Class IO, 0.0%, 7/25/37 (144A) -- 5,678,056(c) Bayview Opportunity Master Fund IVb Trust, Series 2017-RT2, Class A, 3.5%, 8/28/57 (144A) 5,743,431 2,477,619(c) Bayview Opportunity Master Fund IVb Trust, Series 2017-SPL4, Class A, 3.5%, 1/28/55 (144A) 2,505,357 1,179,385(b) Bellemeade Re, Ltd., Series 2017-1, Class M1, 3.492% (1 Month USD LIBOR + 170 bps), 10/25/27 (144A) 1,181,962 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 27 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 4,948,048(b) Bellemeade Re, Ltd., Series 2018-1A, Class M1B, 3.392% (1 Month USD LIBOR + 160 bps), 4/25/28 (144A) $ 4,954,806 5,430,000(b) Bellemeade Re, Ltd., Series 2018-2A, Class M1B, 3.142% (1 Month USD LIBOR + 135 bps), 8/25/28 (144A) 5,443,680 6,720,000(b) Bellemeade Re, Ltd., Series 2018-3A, Class M1B, 3.642% (1 Month USD LIBOR + 185 bps), 10/25/28 (144A) 6,732,738 5,250,000(b) Bellemeade Re, Ltd., Series 2018-3A, Class M2, 4.542% (1 Month USD LIBOR + 275 bps), 10/25/28 (144A) 5,308,955 4,530,000(b) Bellemeade Re, Ltd., Series 2019-1A, Class M1B, 3.542% (1 Month USD LIBOR + 175 bps), 3/25/29 (144A) 4,519,378 4,060,000(b) Bellemeade Re, Ltd., Series 2019-1A, Class M2, 4.492% (1 Month USD LIBOR + 270 bps), 3/25/29 (144A) 4,075,868 7,000,000 Benchmark Mortgage Trust, Series 2018-B2, Class A4, 3.615%, 2/15/51 7,489,046 4,200,000 Benchmark Mortgage Trust, Series 2018-B5, Class A3, 3.944%, 7/15/51 4,607,891 7,400,000 Benchmark Mortgage Trust, Series 2018-B8, Class A4, 3.963%, 1/15/52 8,147,230 7,725,000 Benchmark Mortgage Trust, Series 2019-B14, Class AS, 3.352%, 12/15/62 7,986,662 4,700,000(b) BTH-13 Mortgage Backed Securities Trust, Series 2018-13, Class A, 4.209% (1 Month USD LIBOR + 250 bps), 8/18/21 (144A) 4,705,204 18,960,000 BX Trust, Series 2019-OC11, Class A, 3.202%, 12/9/41 (144A) 19,500,976 4,326,000 Cantor Commercial Real Estate Lending, Series 2019-CF1, Class D, 3.0%, 5/15/52 (144A) 3,859,810 3,596,884(c) Cascade Funding Mortgage Trust, Series 2018-RM2, Class A, 4.0%, 10/25/68 (144A) 3,690,290 3,138,201(c) Cascade Funding Mortgage Trust, Series 2018-RM2, Class C, 4.0%, 10/25/68 (144A) 3,085,401 3,250,000 CCRESG Commercial Mortgage Trust, Series 2016-HEAT, Class A, 3.357%, 4/10/29 (144A) 3,272,339 3,675,000 CD Mortgage Trust, Series 2018-CD7, Class A3, 4.013%, 8/15/51 4,055,997 4,000,000 CFCRE Commercial Mortgage Trust, Series 2016-C3, Class A2, 3.597%, 1/10/48 4,225,603 18,289,673(c) Chase Home Lending Mortgage Trust, Series 2019-1, Class A3, 3.5%, 3/25/50 (144A) 18,572,596 9,283,429(c) Chase Home Lending Mortgage Trust, Series 2019-ATR2, Class A4, 3.5%, 7/25/49 (144A) 9,373,527 The accompanying notes are an integral part of these financial statements. 28 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 3,668,012(c) Chase Home Lending Mortgage Trust, Series 2019-ATR2, Class A15, 3.5%, 7/25/49 (144A) $ 3,708,705 9,866,872(b) Chase Mortgage Reference Notes, Series 2019-CL1, Class M1, 3.142% (1 Month USD LIBOR + 135 bps), 4/25/47 9,830,308 4,969,120(b) Chase Mortgage Reference Notes, Series 2019-CL1, Class M2, 3.492% (1 Month USD LIBOR + 170 bps), 4/25/47 4,953,319 3,439,940(b) Chase Mortgage Reference Notes, Series 2019-CL1, Class M3, 3.892% (1 Month USD LIBOR + 210 bps), 4/25/47 3,431,104 135,406(c) CHL Mortgage Pass-Through Trust, Series 2003-56, Class 4A2, 4.165%, 12/25/33 135,210 20,984,747(c) CIM Trust, Series 2019-INV1, Class A1, 4.0%, 2/25/49 (144A) 21,297,717 3,400,000(c) Citigroup Commercial Mortgage Trust, Series 2014-GC19, Class B, 4.805%, 3/10/47 3,670,318 6,000,000(c) Citigroup Commercial Mortgage Trust, Series 2014-GC25, Class B, 4.345%, 10/10/47 6,350,413 3,100,000 Citigroup Commercial Mortgage Trust, Series 2015-GC27, Class A5, 3.137%, 2/10/48 3,203,691 6,052,000(c) Citigroup Commercial Mortgage Trust, Series 2015-GC33, Class B, 4.572%, 9/10/58 6,539,072 4,621,000 Citigroup Commercial Mortgage Trust, Series 2016-P5, Class D, 3.0%, 10/10/49 (144A) 4,095,370 7,700,000 Citigroup Commercial Mortgage Trust, Series 2019-SMRT, Class A, 4.149%, 1/10/36 (144A) 8,178,280 8,358,711(c) Citigroup Mortgage Loan Trust, Series 2018-RP1, Class A1, 3.0%, 9/25/64 (144A) 8,408,249 9,566,499(c) Citigroup Mortgage Loan Trust, Series 2018-RP2, Class A1, 3.5%, 2/25/58 (144A) 9,797,579 11,098,635(c) Citigroup Mortgage Loan Trust, Series 2019-RP1, Class A1, 3.5%, 1/25/66 (144A) 11,332,296 CAD 7,492,239 Classic RMBS Trust, Series 2019-1A, Class A, 3.064%, 8/16/49 (144A) 5,773,380 601,076 Colony American Finance, Ltd., Series 2015-1, Class A, 2.896%, 10/15/47 (144A) 600,572 2,400,000(d) Colony American Finance, Ltd., Series 2016-1, Class D, 5.972%, 6/15/48 (144A) 2,457,275 2,400,000(d) Colony American Finance, Ltd., Series 2016-2, Class D, 5.028%, 11/15/48 (144A) 2,448,463 2,090,000 COMM Mortgage Trust, Series 2012-CR2, Class AM, 3.791%, 8/15/45 2,145,192 2,933,640 COMM Mortgage Trust, Series 2012-CR3, Class A3, 2.822%, 10/15/45 2,968,458 5,000,000(c) COMM Mortgage Trust, Series 2013-CR11, Class C, 5.116%, 8/10/50 (144A) 5,276,142 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 29 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 2,500,000(c) COMM Mortgage Trust, Series 2014-CR16, Class C, 4.928%, 4/10/47 $ 2,656,666 7,325,000(c) COMM Mortgage Trust, Series 2014-CR20, Class C, 4.513%, 11/10/47 7,675,505 232,564(b) COMM Mortgage Trust, Series 2014-FL5, Class B, 3.152% (1 Month USD LIBOR + 215 bps), 10/15/31 (144A) 232,586 6,268,659 COMM Mortgage Trust, Series 2014-UBS3, Class A3, 3.546%, 6/10/47 6,567,787 4,500,000(c) COMM Mortgage Trust, Series 2014-UBS3, Class C, 4.739%, 6/10/47 4,651,638 4,100,000 COMM Mortgage Trust, Series 2014-UBS4, Class A4, 3.42%, 8/10/47 4,269,915 5,200,000 COMM Mortgage Trust, Series 2015-3BP, Class A, 3.178%, 2/10/35 (144A) 5,384,085 4,000,000(c) COMM Mortgage Trust, Series 2015-CR23, Class CMD, 3.685%, 5/10/48 (144A) 4,001,764 3,104,000(c) COMM Mortgage Trust, Series 2015-CR25, Class B, 4.54%, 8/10/48 3,309,480 6,300,000 COMM Mortgage Trust, Series 2015-CR26, Class A3, 3.359%, 10/10/48 6,575,506 4,500,000(c) COMM Mortgage Trust, Series 2015-DC1, Class B, 4.035%, 2/10/48 4,639,758 4,100,000(b) Connecticut Avenue Securities Trust, Series 2019-HRP1, Class B1, 10.958% (1 Month USD LIBOR + 925 bps), 11/25/39 (144A) 4,369,334 15,470,000(b) Connecticut Avenue Securities Trust, Series 2019-R01, Class 2M2, 4.242% (1 Month USD LIBOR + 245 bps), 7/25/31 (144A) 15,658,352 1,440,000(b) Connecticut Avenue Securities Trust, Series 2019-R02, Class 1M2, 4.092% (1 Month USD LIBOR + 230 bps), 8/25/31 (144A) 1,453,297 4,480,000(b) Connecticut Avenue Securities Trust, Series 2019-R03, Class 1M2, 3.942% (1 Month USD LIBOR + 215 bps), 9/25/31 (144A) 4,513,722 10,720,000(b) Connecticut Avenue Securities Trust, Series 2019-R06, Class 2M2, 3.892% (1 Month USD LIBOR + 210 bps), 9/25/39 (144A) 10,821,120 12,710,000(b) Connecticut Avenue Securities Trust, Series 2019-R07, Class 1M2, 3.892% (1 Month USD LIBOR + 210 bps), 10/25/39 (144A) 12,829,415 8,375,000(b) Credit Suisse Mortgage Capital Certificates, Series 2019-ICE4, Class E, 3.89% (1 Month USD LIBOR + 215 bps), 5/15/36 (144A) 8,388,117 7,120,000(c) CSAIL Commercial Mortgage Trust, Series 2016-C5, Class C, 4.577%, 11/15/48 7,560,672 7,330,335(c) CSMC Trust, Series 2013-6, Class 2A3, 3.5%, 8/25/43 (144A) 7,405,308 The accompanying notes are an integral part of these financial statements. 30 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 3,525,873(c) CSMC Trust, Series 2013-IVR3, Class A1, 2.5%, 5/25/43 (144A) $ 3,460,741 2,410,036(c) CSMC Trust, Series 2013-IVR3, Class B4, 3.446%, 5/25/43 (144A) 2,349,241 2,649,741(c) CSMC Trust, Series 2013-IVR5, Class B4, 3.646%, 10/25/43 (144A) 2,698,633 19,237,946(c) CSMC Trust, Series 2019-RPL1, Class A1A, 3.65%, 7/25/58 (144A) 19,876,565 942,148(c) Deephaven Residential Mortgage Trust, Series 2017-3A, Class A1, 2.577%, 10/25/47 (144A) 941,570 2,382,086(c) Deephaven Residential Mortgage Trust, Series 2018-1A, Class A1, 2.976%, 12/25/57 (144A) 2,380,571 3,724,437(b) Eagle Re, Ltd., Series 2018-1, Class M1, 3.492% (1 Month USD LIBOR + 170 bps), 11/25/28 (144A) 3,729,612 11,100,000(b) Eagle Re, Ltd., Series 2019-1, Class M1B, 3.592% (1 Month USD LIBOR + 180 bps), 4/25/29 (144A) 11,115,580 5,744,804(c) EverBank Mortgage Loan Trust, Series 2013-2, Class A, 3.0%, 6/25/43 (144A) 5,785,954 8,304,243(b) Fannie Mae Connecticut Avenue Securities, Series 2016-C05, Class 2M2, 6.242% (1 Month USD LIBOR + 445 bps), 1/25/29 8,770,768 13,220,000(b) Fannie Mae Connecticut Avenue Securities, Series 2018-C03, Class 1M2, 3.942% (1 Month USD LIBOR + 215 bps), 10/25/30 13,321,339 2,500,000(b) Fannie Mae Connecticut Avenue Securities, Series 2018-C04, Class 2M2, 4.342% (1 Month USD LIBOR + 255 bps), 12/25/30 2,544,213 3,900,000(b) Fannie Mae Connecticut Avenue Securities, Series 2018-C05, Class 1M2, 4.142% (1 Month USD LIBOR + 235 bps), 1/25/31 3,955,575 3,450,000(b) Fannie Mae Connecticut Avenue Securities, Series 2019-R04, Class 2M2, 3.892% (1 Month USD LIBOR + 210 bps), 6/25/39 (144A) 3,470,534 400,982(c) Fannie Mae Grantor Trust, Series 2004-T2, Class 2A, 4.571%, 7/25/43 421,720 7,365(b) Federal Home Loan Mortgage Corp. REMICS, Series 3780, Class FE, 2.14% (1 Month USD LIBOR + 40 bps), 12/15/20 7,375 11,722,968(b)(e) Federal Home Loan Mortgage Corp. REMICS, Series 4091, Class SH, 4.81% (1 Month USD LIBOR + 655 bps), 8/15/42 2,461,842 4,028,591 Federal Home Loan Mortgage Corp. Whole Loan Securities Trust, Series 2017-SC02, Class 2A1, 3.5%, 5/25/47 4,068,480 204,628 Federal National Mortgage Association REMICS, Series 2009-36, Class HX, 4.5%, 6/25/29 213,567 781,531 Federal National Mortgage Association REMICS, Series 2013-128, Class DV, 3.0%, 6/25/23 790,884 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 31 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 2,852,125 Finance of America Structured Securities Trust, Series 2018-A, Class JR2, 1.646%, 12/26/68 $ 3,113,898 13,222,813(c) Finance of America Structured Securities Trust, Series 2019-JR2, Class JR2, 0.0%, 6/25/69 13,716,774 13,500,000 Finance of America Structured Securities Trust, Series 2019-JR4, Class JR2, 2.0%, 11/25/69 13,555,072 2,197,000(c) FirstKey Mortgage Trust, Series 2015-1, Class B4, 3.918%, 3/25/45 (144A) 2,206,987 11,338,912(c) Flagstar Mortgage Trust, Series 2018-2, Class A6, 3.5%, 4/25/48 (144A) 11,466,583 5,352,865(c) Flagstar Mortgage Trust, Series 2018-2, Class A14, 3.5%, 4/25/48 (144A) 5,479,574 4,604,750(c) Flagstar Mortgage Trust, Series 2018-3INV, Class B1, 4.503%, 5/25/48 (144A) 4,906,180 4,769,240(c) Flagstar Mortgage Trust, Series 2018-3INV, Class B3, 4.503%, 5/25/48 (144A) 4,992,798 4,230,000(b) Freddie Mac Stacr Trust, Series 2018-HQA2, Class B1, 6.042% (1 Month USD LIBOR + 425 bps), 10/25/48 (144A) 4,575,711 9,880,000(b) Freddie Mac Stacr Trust, Series 2018-HQA2, Class M2, 4.092% (1 Month USD LIBOR + 230 bps), 10/25/48 (144A) 10,007,151 8,162,259(b) Freddie Mac Stacr Trust, Series 2019-DNA2, Class M2, 4.242% (1 Month USD LIBOR + 245 bps), 3/25/49 (144A) 8,233,948 6,260,000(b) Freddie Mac Stacr Trust, Series 2019-DNA3, Class M2, 3.842% (1 Month USD LIBOR + 205 bps), 7/25/49 (144A) 6,289,006 4,350,000(b) Freddie Mac Stacr Trust, Series 2019-HQA1, Class B2, 14.042% (1 Month USD LIBOR + 1,225 bps), 2/25/49 (144A) 5,933,932 3,926,000(b) Freddie Mac Stacr Trust, Series 2019-HQA1, Class M2, 4.142% (1 Month USD LIBOR + 235 bps), 2/25/49 (144A) 3,966,248 3,165,000(b) Freddie Mac Stacr Trust, Series 2019-HQA2, Class B2, 13.042% (1 Month USD LIBOR + 1,125 bps), 4/25/49 (144A) 4,099,800 3,530,000(b) Freddie Mac Stacr Trust, Series 2019-HQA2, Class M2, 3.842% (1 Month USD LIBOR + 205 bps), 4/25/49 (144A) 3,546,176 1,151,461(b) Freddie Mac Structured Agency Credit Risk Debt Notes, Series 2016-DNA4, Class M2, 3.092% (1 Month USD LIBOR + 130 bps), 3/25/29 1,153,762 11,465,925(b) Freddie Mac Structured Agency Credit Risk Debt Notes, Series 2017-DNA2, Class M2, 5.242% (1 Month USD LIBOR + 345 bps), 10/25/29 12,212,929 8,940,000(b) Freddie Mac Structured Agency Credit Risk Debt Notes, Series 2017-DNA3, Class M2, 4.292% (1 Month USD LIBOR + 250 bps), 3/25/30 9,149,201 The accompanying notes are an integral part of these financial statements. 32 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 932,848(b) Freddie Mac Structured Agency Credit Risk Debt Notes, Series 2018-HQA1, Class M1, 2.492% (1 Month USD LIBOR + 70 bps), 9/25/30 $ 932,872 1,484,270(c) Freddie Mac Structured Agency Credit Risk Debt Notes, Series 2018-SPI3, Class M1, 4.152%, 8/25/48 (144A) 1,489,113 890,000(c) FREMF Mortgage Trust, Series 2010-K9, Class B, 5.208%, 9/25/45 (144A) 902,966 902,511(b) FREMF Mortgage Trust, Series 2014-KF05, Class B, 5.697% (1 Month USD LIBOR + 400 bps), 9/25/22 (144A) 913,171 2,653,276(b) FREMF Mortgage Trust, Series 2014-KS02, Class B, 6.697% (1 Month USD LIBOR + 500 bps), 8/25/23 (144A) 2,683,809 3,700,000(c) FREMF Mortgage Trust, Series 2015-K51, Class B, 3.954%, 10/25/48 (144A) 3,862,284 2,623,000(c) FREMF Mortgage Trust, Series 2017-K66, Class B, 4.035%, 7/25/27 (144A) 2,759,268 4,783,627(c) FREMF Mortgage Trust, Series 2019-KJ24, Class B, 7.6%, 10/25/27 (144A) 4,536,314 5,000,000(b) FREMF Mortgage Trust, Series 2019-KS12, Class C, 8.705% (1 Month USD LIBOR + 690 bps), 8/25/29 4,740,350 5,384,262(c) FRESB Mortgage Trust, Series 2018-SB52, Class A7F, 3.39%, 6/25/25 5,599,260 6,788,507(c) FWD Securitization Trust, Series 2019-INV1, Class A1, 2.81%, 6/25/49 (144A) 6,779,123 2,150,000(c) FWD Securitization Trust, Series 2019-INV1, Class M1, 3.48%, 6/25/49 (144A) 2,158,777 992,283 Government National Mortgage Association, Series 2005-61, Class UZ, 5.25%, 8/16/35 1,040,168 444,776 Government National Mortgage Association, Series 2012-130, Class PA, 3.0%, 4/20/41 450,055 597,952 Government National Mortgage Association, Series 2013-169, Class TE, 3.25%, 4/16/27 613,603 37,653,828(c)(e) Government National Mortgage Association, Series 2017-21, Class IO, 0.775%, 10/16/58 2,481,323 3,560,770 Government National Mortgage Association, Series 2018-20, Class A, 2.5%, 9/16/49 3,557,647 6,500,000 GS Mortgage Securities Trust, Series 2015-GC28, Class A5, 3.396%, 2/10/48 6,793,922 3,429,940(c) GS Mortgage-Backed Securities Trust, Series 2014-EB1A, Class B3, 3.115%, 7/25/44 (144A) 3,441,212 6,212,065 GS Mortgage-Backed Securities Trust, Series 2018-RPL1, Class A1A, 3.75%, 10/25/57 (144A) 6,418,417 2,836,616(c) GS Mortgage-Backed Securities Trust, Series 2019-PJ1, Class B1, 4.351%, 8/25/49 (144A) 2,958,619 8,691,635(c) GS Mortgage-Backed Securities Trust, Series 2019-PJ2, Class A4, 4.0%, 11/25/49 (144A) 8,794,987 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 33 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 7,880,559(c) GS Mortgage-Backed Securities Trust, Series 2019-PJ3, Class A1, 3.5%, 3/25/50 (144A) $ 7,982,565 16,757,223(c) GS Mortgage-Backed Securities Trust, Series 2019-SL1, Class A1, 2.625%, 1/25/59 (144A) 16,625,521 5,500,000(c) GS Mortgage-Backed Securities Trust, Series 2019-SL1, Class A2, 2.875%, 1/25/59 (144A) 5,443,917 750,000(b) Home Partners of America Trust, Series 2017-1, Class B, 3.087% (1 Month USD LIBOR + 135 bps), 7/17/34 (144A) 750,254 1,486,215(b) Home Re, Ltd., Series 2018-1, Class M1, 3.392% (1 Month USD LIBOR + 160 bps), 10/25/28 (144A) 1,486,665 5,495,885(b) Home Re, Ltd., Series 2019-1, Class M1, 3.442% (1 Month USD LIBOR + 165 bps), 5/25/29 (144A) 5,499,488 8,951,000 ILPT Trust, Series 2019-SURF, Class A, 4.145%, 2/11/41 (144A) 9,992,569 1,900,000(c) JP Morgan Chase Commercial Mortgage Securities Trust, Series 2012-C8, Class B, 3.977%, 10/15/45 (144A) 1,954,703 4,597,183 JP Morgan Chase Commercial Mortgage Securities Trust, Series 2016-JP2, Class A4, 2.822%, 8/15/49 4,681,661 5,925,000(c) JP Morgan Chase Commercial Mortgage Securities Trust, Series 2018-BCON, Class C, 3.756%, 1/5/31 (144A) 6,064,779 6,700,000 JP Morgan Chase Commercial Mortgage Securities Trust, Series 2018-WPT, Class AFX, 4.248%, 7/5/33 (144A) 7,127,025 3,321,264(c) JP Morgan Mortgage Trust, Series 2017-5, Class A1A, 3.0%, 10/26/48 (144A) 3,327,376 1,661,539(c) JP Morgan Mortgage Trust, Series 2017-5, Class A2, 3.155%, 10/26/48 (144A) 1,701,919 2,879,759(c) JP Morgan Mortgage Trust, Series 2018-1, Class B1, 3.744%, 6/25/48 (144A) 2,947,609 3,755,674(c) JP Morgan Mortgage Trust, Series 2018-3, Class B1, 3.762%, 9/25/48 (144A) 3,857,198 4,969,284(c) JP Morgan Mortgage Trust, Series 2019-7, Class B1A, 2.988%, 2/25/50 (144A) 4,575,988 8,348,795(c) JP Morgan Mortgage Trust, Series 2019-7, Class B2A, 3.238%, 2/25/50 (144A) 7,783,288 10,484,054(c) JP Morgan Mortgage Trust, Series 2019-8, Class A4, 3.5%, 3/25/50 (144A) 10,592,989 2,428,209(c) JP Morgan Mortgage Trust, Series 2019-8, Class A15, 3.5%, 3/25/50 (144A) 2,455,755 8,270,974(c) JP Morgan Mortgage Trust, Series 2019-8, Class B1A, 2.997%, 3/25/50 (144A) 8,093,515 4,984,316(c) JP Morgan Mortgage Trust, Series 2019-8, Class B2A, 3.247%, 3/25/50 (144A) 4,898,800 The accompanying notes are an integral part of these financial statements. 34 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 24,649,513(c) JP Morgan Mortgage Trust, Series 2019-9, Class A3, 3.5%, 5/25/50 (144A) $ 25,015,411 6,971,580(c) JP Morgan Mortgage Trust, Series 2019-9, Class A15, 3.5%, 5/25/50 (144A) 7,040,208 6,378,738(c) JP Morgan Mortgage Trust, Series 2019-INV1, Class B3, 5.151%, 10/25/49 (144A) 6,751,365 14,208,217(c) JP Morgan Mortgage Trust, Series 2019-INV2, Class A15, 3.5%, 2/25/50 (144A) 14,285,844 9,867,368(c) JP Morgan Mortgage Trust, Series 2019-INV2, Class B3A, 3.822%, 2/25/50 (144A) 9,850,786 9,500,000(c) JP Morgan Mortgage Trust, Series 2019-INV3, Class A3, 3.5%, 5/25/50 (144A) 9,682,579 12,631,923(c) JP Morgan Mortgage Trust, Series 2019-LTV1, Class A3, 4.0%, 6/25/49 (144A) 12,794,762 7,004,270(c) JP Morgan Mortgage Trust, Series 2019-LTV1, Class A15, 4.0%, 6/25/49 (144A) 7,126,321 5,468,923(c) JP Morgan Mortgage Trust, Series 2019-LTV2, Class A3, 3.5%, 12/25/49 (144A) 5,536,431 4,639,778(c) JP Morgan Mortgage Trust, Series 2019-LTV2, Class A15, 3.5%, 12/25/49 (144A) 4,691,811 9,861,568(c) JP Morgan Mortgage Trust, Series 2019-LTV3, Class A3, 3.5%, 3/25/50 (144A) 9,983,299 12,770,400(c) JP Morgan Mortgage Trust, Series 2019-LTV3, Class A4, 3.5%, 3/25/50 (144A) 12,931,026 5,195,362(c) JP Morgan Mortgage Trust, Series 2019-LTV3, Class A15, 3.5%, 3/25/50 (144A) 5,251,701 4,143,106(c) JP Morgan Trust, Series 2015-3, Class B3, 3.663%, 5/25/45 (144A) 4,187,863 3,450,000(c) JPMDB Commercial Mortgage Securities Trust, Series 2016-C2, Class B, 3.99%, 6/15/49 3,616,782 6,650,000 JPMDB Commercial Mortgage Securities Trust, Series 2016-C4, Class A3, 3.141%, 12/15/49 6,904,783 2,000,000(c) JPMDB Commercial Mortgage Securities Trust, Series 2016-C4, Class D, 3.091%, 12/15/49 (144A) 1,814,827 7,640,000 JPMDB Commercial Mortgage Securities Trust, Series 2018-C8, Class A4, 4.211%, 6/15/51 8,525,208 45,714,000(c)(e) JPMDB Commercial Mortgage Securities Trust, Series 2018-C8, Class XB, 0.113%, 6/15/51 500,783 3,054,000 JPMDB Commercial Mortgage Securities Trust, Series 2019-COR6, Class AS, 3.41%, 11/13/52 3,154,704 1,701,690 La Hipotecaria El Salvadorian Mortgage Trust, Series 2016-1A, Class A, 3.358%, 1/15/46 (144A) 1,774,012 775,140(b) La Hipotecaria Panamanian Mortgage Trust, Series 2010-1GA, Class A, 2.75% (Panamanian Mortgage Reference Rate - 300 bps), 9/8/39 (144A) 780,954 2,549,235(b) La Hipotecaria Panamanian Mortgage Trust, Series 2014-1A, Class A1, 3.508% (Panamanian Mortgage Reference Rate - 224 bps), 11/24/42 (144A) 2,638,458 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 35 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 4,388,544(b) LSTAR Securities Investment, Ltd., Series 2019-4, Class A1, 3.209% (1 Month USD LIBOR + 150 bps), 5/1/24 (144A) $ 4,383,470 5,414,511(c) Metlife Securitization Trust, Series 2019-1A, Class A1A, 3.75%, 4/25/58 (144A) 5,586,296 28,450,000(c) Mill City Mortgage Loan Trust, Series 2018-4, Class A1B, 3.5%, 4/25/66 (144A) 29,072,725 8,992,634(c) Mill City Mortgage Loan Trust, Series 2019-1, Class A1, 3.25%, 10/25/69 (144A) 9,158,715 14,473,342(c) Mill City Mortgage Loan Trust, Series 2019-1, Class M1, 3.5%, 10/25/69 (144A) 14,701,174 21,014,294(c) Mill City Mortgage Loan Trust, Series 2019-1, Class M2, 3.5%, 10/25/69 (144A) 20,979,452 5,126,427(c) Mill City Mortgage Loan Trust, Series 2019-GS1, Class A1, 2.75%, 7/25/59 (144A) 5,152,175 7,500,000(c) Mill City Mortgage Loan Trust, Series 2019-GS1, Class M1, 3.0%, 7/25/59 (144A) 7,374,734 7,800,000(c) Mill City Mortgage Loan Trust, Series 2019-GS1, Class M3, 3.25%, 7/25/59 (144A) 7,473,375 16,961,000 Mill City Mortgage Loan Trust, Series 2019-GS2, Class M1, 3.0%, 8/25/59 (144A) 16,772,839 2,819,053(b) MMFL Re-REMIC Trust, Series 2019-1, Class A, 3.192% (1 Month USD LIBOR + 140 bps), 1/28/24 (144A) 2,804,190 4,804,066 Morgan Stanley Bank of America Merrill Lynch Trust, Series 2012-C6, Class A4, 2.858%, 11/15/45 4,872,935 3,563,500(c) Morgan Stanley Bank of America Merrill Lynch Trust, Series 2015-C21, Class C, 4.153%, 3/15/48 3,660,497 6,900,000 Morgan Stanley Capital I Trust, Series 2018-MP, Class A, 4.418%, 7/11/40 (144A) 7,723,427 4,193,338(b) Multifamily Connecticut Avenue Securities Trust, Series 2019-01, Class M7, 3.492% (1 Month USD LIBOR + 170 bps), 10/15/49 (144A) 4,209,219 10,673,684(b) New Residential Mortgage Loan Trust, Series 2018-4A, Class A1S, 2.542% (1 Month USD LIBOR + 75 bps), 1/25/48 (144A) 10,644,623 3,155,650(c) New Residential Mortgage Loan Trust, Series 2018-5A, Class A1, 4.75%, 12/25/57 (144A) 3,311,488 12,919,951(c) New Residential Mortgage Loan Trust, Series 2018-RPL1, Class A1, 3.5%, 12/25/57 (144A) 13,260,424 12,388,662(c) New Residential Mortgage Loan Trust, Series 2019-NQM4, Class A1, 2.492%, 9/25/59 (144A) 12,333,690 13,261,508(c) New Residential Mortgage Loan Trust, Series 2019-RPL2, Class A1, 3.25%, 2/25/59 (144A) 13,480,995 5,200,241(c) NRP Mortgage Trust, Series 2013-1, Class B1, 3.311%, 7/25/43 (144A) 5,269,015 The accompanying notes are an integral part of these financial statements. 36 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 3,999,822(c) NRP Mortgage Trust, Series 2013-1, Class B2, 3.311%, 7/25/43 (144A) $ 4,046,258 2,457,000(b) Oaktown Re II, Ltd., Series 2018-1A, Class M2, 4.642% (1 Month USD LIBOR + 285 bps), 7/25/28 (144A) 2,487,256 1,801,143(c) OBX Trust, Series 2018-EXP1, Class 1A6, 4.5%, 4/25/48 (144A) 1,817,225 4,166,842(c) OBX Trust, Series 2019-EXP1, Class 1A3, 4.0%, 1/25/59 (144A) 4,241,151 10,200,000(c) OBX Trust, Series 2019-INV1, Class A10, 4.0%, 11/25/48 (144A) 10,518,832 10,740,567(c) OBX Trust, Series 2019-INV2, Class A5, 4.0%, 5/27/49 (144A) 10,977,316 118,725(b) Pepper Residential Securities Trust No. 18, Series 18A, Class A1UA, 2.686% (1 Month USD LIBOR + 95 bps), 3/12/47 (144A) 118,726 7,792,887(c) PMT Loan Trust, Series 2013-J1, Class A11, 3.5%, 9/25/43 (144A) 7,971,882 4,800,000 Progress Residential Trust, Series 2017-SFR1, Class B, 3.017%, 8/17/34 (144A) 4,794,480 700,000 Progress Residential Trust, Series 2017-SFR1, Class D, 3.565%, 8/17/34 (144A) 704,322 5,135,000 Progress Residential Trust, Series 2017-SFR2, Class B, 3.196%, 12/17/34 (144A) 5,129,441 8,725,000(c) Provident Funding Mortgage Trust, Series 2019-1, Class A2, 3.0%, 12/25/49 (144A) 8,776,809 2,433,162(b) Radnor Re, Ltd., Series 2018-1, Class M1, 3.192% (1 Month USD LIBOR + 140 bps), 3/25/28 (144A) 2,433,160 11,160,000(b) Radnor Re, Ltd., Series 2019-1, Class M1B, 3.742% (1 Month USD LIBOR + 195 bps), 2/25/29 (144A) 11,146,394 3,437,000(b) Radnor Re, Ltd., Series 2019-1, Class M2, 4.992% (1 Month USD LIBOR + 320 bps), 2/25/29 (144A) 3,486,901 2,719 RALI Trust, Series 2003-QS14, Class A1, 5.0%, 7/25/18 2,655 698,686 ReadyCap Commercial Mortgage Trust, Series 2019-6, Class A, 2.832%, 10/25/52 (144A) 699,151 227,861(b) RESIMAC Premier, Series 2017-1A, Class A1A, 2.668% (1 Month USD LIBOR + 95 bps), 9/11/48 (144A) 227,691 7,376,004(c) RMF Proprietary Issuance Trust, Series 2019-1, Class A, 2.75%, 10/25/63 (144A) 7,301,990 2,529,079(c) Sequoia Mortgage Trust, Series 2012-6, Class B3, 3.73%, 12/25/42 2,577,721 6,490,033(c) Sequoia Mortgage Trust, Series 2013-4, Class A1, 2.325%, 4/25/43 6,340,365 6,578,594(c) Sequoia Mortgage Trust, Series 2013-5, Class A1, 2.5%, 5/25/43 (144A) 6,474,085 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 37 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 14,180,812(c) Sequoia Mortgage Trust, Series 2013-5, Class A2, 3.0%, 5/25/43 (144A) $ 14,292,316 6,559,708(c) Sequoia Mortgage Trust, Series 2013-6, Class A1, 2.5%, 5/25/43 6,419,758 9,919,109(c) Sequoia Mortgage Trust, Series 2013-6, Class A2, 3.0%, 5/25/43 9,990,408 7,497,960(c) Sequoia Mortgage Trust, Series 2013-7, Class A1, 2.5%, 6/25/43 7,379,355 9,243,819(c) Sequoia Mortgage Trust, Series 2013-7, Class A2, 3.0%, 6/25/43 9,260,988 9,178,507(c) Sequoia Mortgage Trust, Series 2013-8, Class A1, 3.0%, 6/25/43 9,244,253 12,686,599(c) Sequoia Mortgage Trust, Series 2013-10, Class A1, 3.5%, 8/25/43 (144A) 12,894,265 1,756,374(c) Sequoia Mortgage Trust, Series 2017-CH2, Class A1, 4.0%, 12/25/47 (144A) 1,814,806 3,152,970(c) Sequoia Mortgage Trust, Series 2018-CH3, Class A1, 4.5%, 8/25/48 (144A) 3,258,851 18,549,242(c) Sequoia Mortgage Trust, Series 2019-CH3, Class A1, 4.0%, 9/25/49 (144A) 18,908,967 10,870,000(b) STACR Trust, Series 2018-DNA3, Class M2, 3.892% (1 Month USD LIBOR + 210 bps), 9/25/48 (144A) 10,956,752 11,220,000(b) STACR Trust, Series 2018-HRP2, Class B1, 5.992% (1 Month USD LIBOR + 420 bps), 2/25/47 (144A) 12,047,082 6,450,000(b) STACR Trust, Series 2018-HRP2, Class M3, 4.192% (1 Month USD LIBOR + 240 bps), 2/25/47 (144A) 6,603,459 2,950,000(b) Starwood Waypoint Homes Trust, Series 2017-1, Class B, 2.91% (1 Month USD LIBOR + 117 bps), 1/17/35 (144A) 2,946,574 9,375,000(c) Towd Point Mortgage Trust, Series 2015-5, Class M1, 3.5%, 5/25/55 (144A) 9,538,952 7,540,000(c) Towd Point Mortgage Trust, Series 2015-6, Class M1, 3.75%, 4/25/55 (144A) 7,929,341 10,011,000(c) Towd Point Mortgage Trust, Series 2016-3, Class M1, 3.5%, 4/25/56 (144A) 10,245,523 3,524,651(c) Towd Point Mortgage Trust, Series 2017-5, Class XA, 3.5%, 2/25/57 (144A) 3,509,620 335,555(c) Towd Point Mortgage Trust, Series 2019-4, Class A1, 2.9%, 10/25/59 (144A) 337,484 20,000,000(c) Towd Point Mortgage Trust, Series 2019-4, Class A2, 3.25%, 10/25/59 (144A) 20,163,888 8,000,000(c) Towd Point Mortgage Trust, Series 2019-4, Class M1, 3.5%, 10/25/59 (144A) 7,915,918 162,704 Vendee Mortgage Trust, Series 2008-1, Class GD, 5.25%, 1/15/32 168,022 245,222 Vendee Mortgage Trust, Series 2010-1, Class DA, 4.25%, 2/15/35 250,011 The accompanying notes are an integral part of these financial statements. 38 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- (continued) 14,317,425(c) Visio Trust, Series 2019-2, Class A1, 2.722%, 11/25/54 (144A) $ 14,321,425 3,810,000 Wells Fargo Commercial Mortgage Trust, Series 2015-NXS3, Class A4, 3.617%, 9/15/57 4,045,501 8,200,000 Wells Fargo Commercial Mortgage Trust, Series 2016-C32, Class A3, 3.294%, 1/15/59 8,563,782 10,000,000 Wells Fargo Commercial Mortgage Trust, Series 2016-LC24, Class A3, 2.684%, 10/15/49 10,121,444 4,200,000(c) WFRBS Commercial Mortgage Trust, Series 2013-C12, Class D, 4.404%, 3/15/48 (144A) 4,231,566 6,023,446 WFRBS Commercial Mortgage Trust, Series 2013-C16, Class A4, 4.136%, 9/15/46 6,311,483 2,727,759(c) WinWater Mortgage Loan Trust, Series 2014-2, Class B4, 4.094%, 9/20/44 (144A) 2,761,178 --------------------------------------------------------------------------------------------------------------------- TOTAL COLLATERALIZED MORTGAGE OBLIGATIONS (Cost $1,531,096,081) $1,550,891,419 --------------------------------------------------------------------------------------------------------------------- CORPORATE BONDS -- 28.9% of Net Assets Aerospace & Defense -- 0.9% 9,560,000 Boeing Co., 3.75%, 2/1/50 $ 10,167,227 14,425,000 Boeing Co., 3.9%, 5/1/49 15,660,414 13,470,000 Rockwell Collins, Inc., 3.2%, 3/15/24 14,019,725 7,910,000 United Technologies Corp., 4.125%, 11/16/28 8,899,494 -------------- Total Aerospace & Defense $ 48,746,860 --------------------------------------------------------------------------------------------------------------------- Agriculture -- 0.5% 12,540,000 Philip Morris International, Inc., 3.25%, 11/10/24 $ 13,169,667 14,708,000 Reynolds American, Inc., 4.45%, 6/12/25 15,838,828 -------------- Total Agriculture $ 29,008,495 --------------------------------------------------------------------------------------------------------------------- Airlines -- 0.1% 6,566,645 Air Canada 2017-1 Class AA Pass Through Trust, 3.3%, 1/15/30 (144A) $ 6,693,851 -------------- Total Airlines $ 6,693,851 --------------------------------------------------------------------------------------------------------------------- Auto Manufacturers -- 0.8% 6,885,000 Ford Motor Credit Co. LLC, 5.584%, 3/18/24 $ 7,453,286 2,300,000 General Motors Financial Co., Inc., 3.7%, 11/24/20 2,327,255 10,710,000 General Motors Financial Co., Inc., 4.0%, 1/15/25 11,258,634 12,300,000 Hyundai Capital Services, Inc., 3.0%, 8/29/22 (144A) 12,444,726 3,590,000 Nissan Motor Acceptance Corp., 2.15%, 7/13/20 (144A) 3,588,477 7,495,000 Nissan Motor Acceptance Corp., 3.15%, 3/15/21 (144A) 7,568,154 7,040,000 Volkswagen Group of America Finance LLC, 4.0%, 11/12/21 (144A) 7,281,357 -------------- Total Auto Manufacturers $ 51,921,889 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 39 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Banks -- 5.6% 16,040,000(c) AIB Group Plc, 4.263% (3 Month USD LIBOR + 187 bps), 4/10/25 (144A) $ 16,991,114 20,595,000(c) Bank of America Corp., 2.884% (3 Month USD LIBOR + 1 bps), 10/22/30 20,775,933 1,150,000 Bank of America Corp., 4.2%, 8/26/24 1,234,886 10,345,000(b) Bank of New York Mellon Corp., 2.986% (3 Month USD LIBOR + 105 bps), 10/30/23 10,525,417 6,525,000(a)(c) Barclays Plc, 7.75% (5 Year USD Swap Rate + 484 bps) 7,128,562 5,205,000(a)(c) Barclays Plc, 8.0% (5 Year CMT Index + 567 bps) 5,823,094 13,875,000(a)(c) BNP Paribas SA, 6.625% (5 Year USD Swap Rate + 415 bps) (144A) 14,985,000 6,900,000 BPCE SA, 2.25%, 1/27/20 6,899,983 3,860,000 BPCE SA, 4.875%, 4/1/26 (144A) 4,248,349 21,955,000(b) Canadian Imperial Bank of Commerce, 2.217% (3 Month USD LIBOR + 32 bps), 2/2/21 21,989,508 8,475,000 Capital One NA, 2.15%, 9/6/22 8,489,388 3,435,000 Cooperatieve Rabobank UA, 3.875%, 2/8/22 3,577,516 7,175,000 Cooperatieve Rabobank UA, 3.95%, 11/9/22 7,502,225 11,725,000(a)(c) Credit Suisse Group AG, 7.125% (5 Year USD Swap Rate + 511 bps) 12,619,031 7,300,000 Credit Suisse Group Funding Guernsey, Ltd., 3.8%, 9/15/22 7,600,372 5,337,000 Danske Bank AS, 5.375%, 1/12/24 (144A) 5,842,062 4,700,000(a)(c) Danske Bank AS, 6.125% (7 Year USD Swap Rate + 390 bps) 4,830,312 7,891,000(c) Goldman Sachs Group, Inc., 3.272% (3 Month USD LIBOR + 120 bps), 9/29/25 8,169,584 6,335,000(c) Goldman Sachs Group, Inc., 4.223% (3 Month USD LIBOR + 130 bps), 5/1/29 6,984,839 1,305,000 HSBC Bank Plc, 7.65%, 5/1/25 1,579,314 2,400,000(b) HSBC Holdings Plc, 2.904% (3 Month USD LIBOR + 100 bps), 5/18/24 2,419,492 6,937,000 Intesa Sanpaolo S.p.A., 4.7%, 9/23/49 (144A) 7,072,864 5,550,000(a)(c) Intesa Sanpaolo S.p.A., 7.7% (5 Year USD Swap Rate + 546 bps) (144A) 6,014,813 17,815,000(a)(c) JPMorgan Chase & Co., 5.0% (SOFRRATE + 338 bps) 18,527,600 7,378,000 KeyCorp, 5.1%, 3/24/21 7,656,987 8,675,000 Lloyds Banking Group Plc, 4.65%, 3/24/26 9,436,660 5,450,000 Morgan Stanley, 4.1%, 5/22/23 5,754,980 19,200,000 Nordea Bank Abp, 4.25%, 9/21/22 (144A) 20,158,778 8,524,000 Nordea Bank Abp, 4.875%, 5/13/21 (144A) 8,838,441 6,630,000 PNC Bank N.A., 2.7%, 10/22/29 6,621,841 10,505,000(a)(c) Royal Bank of Scotland Group Plc, 8.625% (5 Year USD Swap Rate + 760 bps) 11,266,613 The accompanying notes are an integral part of these financial statements. 40 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Banks -- (continued) 9,051,000(a)(c) Societe Generale SA, 7.375% (5 Year USD Swap Rate + 624 bps) (144A) $ 9,594,060 11,891,000 Sumitomo Mitsui Financial Group, Inc., 3.202%, 9/17/29 12,065,206 12,575,000 SunTrust Bank, 2.45%, 8/1/22 12,711,751 2,250,000(c) Turkiye Garanti Bankasi AS, 6.125% (5 Year USD Swap Rate + 422 bps), 5/24/27 (144A) 2,127,375 10,350,000 UBS AG, 7.625%, 8/17/22 11,667,658 11,650,000(a)(c) UBS Group AG, 7.0% (5 Year USD Swap Rate + 434 bps) (144A) 12,727,625 4,497,000(a)(c) UBS Group AG, 7.125% (5 Year USD Swap Rate + 588 bps) 4,761,199 -------------- Total Banks $ 347,220,432 --------------------------------------------------------------------------------------------------------------------- Beverages -- 0.5% 17,710,000 Anheuser-Busch InBev Worldwide, Inc., 5.55%, 1/23/49 $ 23,010,892 7,630,000 Bacardi, Ltd., 5.3%, 5/15/48 (144A) 8,865,131 -------------- Total Beverages $ 31,876,023 --------------------------------------------------------------------------------------------------------------------- Biotechnology -- 0.2% 3,550,000 Biogen, Inc., 3.625%, 9/15/22 $ 3,694,965 6,835,000 Biogen, Inc., 5.2%, 9/15/45 8,254,972 -------------- Total Biotechnology $ 11,949,937 --------------------------------------------------------------------------------------------------------------------- Building Materials -- 0.4% 11,000,000 CRH America, Inc., 3.875%, 5/18/25 (144A) $ 11,754,222 7,680,000 Fortune Brands Home & Security, Inc., 3.0%, 6/15/20 7,706,294 3,250,000 Fortune Brands Home & Security, Inc., 4.0%, 9/21/23 3,434,622 4,385,000 Standard Industries, Inc., 5.5%, 2/15/23 (144A) 4,456,256 -------------- Total Building Materials $ 27,351,394 --------------------------------------------------------------------------------------------------------------------- Chemicals -- 0.5% 11,835,000 Albemarle Wodgina Pty Ltd., 3.45%, 11/15/29 (144A) $ 11,840,046 1,567,000 CF Industries, Inc., 4.95%, 6/1/43 1,633,597 7,860,000 CF Industries, Inc., 5.375%, 3/15/44 8,567,400 722,000 NOVA Chemicals Corp., 4.875%, 6/1/24 (144A) 745,465 EUR 2,515,000 OCI NV, 3.125%, 11/1/24 (144A) 2,934,059 1,755,000 OCI NV, 5.25%, 11/1/24 (144A) 1,820,813 5,650,000 Olin Corp., 5.625%, 8/1/29 5,967,530 -------------- Total Chemicals $ 33,508,910 --------------------------------------------------------------------------------------------------------------------- Commercial Services -- 0.4% 3,950,000 ERAC USA Finance LLC, 3.3%, 12/1/26 (144A) $ 4,066,970 1,300,000 ERAC USA Finance LLC, 3.8%, 11/1/25 (144A) 1,374,195 2,400,000 Moody's Corp., 3.25%, 6/7/21 2,444,452 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 41 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Commercial Services -- (continued) 2,600,000 President & Fellows of Harvard College, 2.3%, 10/1/23 $ 2,624,650 3,580,000 Sotheby's, 7.375%, 10/15/27 (144A) 3,624,750 3,915,000 United Rentals North America, Inc., 3.875%, 11/15/27 3,997,019 5,942,000 Verisk Analytics, Inc., 5.5%, 6/15/45 7,395,541 -------------- Total Commercial Services $ 25,527,577 --------------------------------------------------------------------------------------------------------------------- Diversified Financial Services -- 1.0% 800,000(b) AIG Global Funding, 2.389% (3 Month USD LIBOR + 48 bps), 7/2/20 (144A) $ 801,475 4,885,000 Capital One Financial Corp., 3.3%, 10/30/24 5,087,700 9,675,000 Capital One Financial Corp., 3.75%, 4/24/24 10,189,889 5,200,000 Capital One Financial Corp., 4.25%, 4/30/25 5,661,862 4,031,000 GE Capital International Funding Co. Unlimited Co., 2.342%, 11/15/20 4,034,254 2,878,000 Nationstar Mortgage Holdings, Inc., 9.125%, 7/15/26 (144A) 3,187,385 6,200,000 TD Ameritrade Holding Corp., 3.3%, 4/1/27 6,494,720 11,625,000 USAA Capital Corp., 2.45%, 8/1/20 (144A) 11,666,571 4,550,000 Visa, Inc., 2.2%, 12/14/20 4,568,121 -------------- Total Diversified Financial Services $ 51,691,977 --------------------------------------------------------------------------------------------------------------------- Electric -- 2.4% 5,483,000 Adani Renewable Energy RJ, Ltd./Kodangal Solar Parks Pvt, Ltd./Wardha Solar Maharash, 4.625%, 10/15/39 (144A) $ 5,554,279 5,920,000 Adani Transmission, Ltd., 4.25%, 5/21/36 (144A) 5,979,952 1,749,000(c) AES Gener SA, 7.125% (5 Year USD Swap Rate + 464 bps), 3/26/79 (144A) 1,836,866 1,880,000 Clearway Energy Operating LLC, 4.75%, 3/15/28 (144A) 1,905,850 8,385,000 Consolidated Edison Co. of New York, Inc., 4.625%, 12/1/54 10,189,784 2,700,000 Dominion Energy, Inc., 2.75%, 1/15/22 2,739,077 4,027,000(d) Dominion Energy, Inc., 3.071%, 8/15/24 4,148,482 12,004,000(a)(c) Dominion Energy, Inc., 4.65% (5 Year CMT Index + 299 bps) 12,246,121 4,170,000(c) Enel S.p.A., 8.75% (5 Year USD Swap Rate + 588 bps), 9/24/73 (144A) 4,894,538 6,365,000 Exelon Corp., 2.85%, 6/15/20 6,379,639 4,655,000 Iberdrola International BV, 6.75%, 7/15/36 6,520,091 2,725,000 Indiana Michigan Power Co., 4.55%, 3/15/46 3,182,685 610,000 Israel Electric Corp., Ltd., 9.375%, 1/28/20 (144A) 613,355 290,482 Kiowa Power Partners LLC, 5.737%, 3/30/21 (144A) 296,035 6,574,000 New York State Electric & Gas Corp., 3.3%, 9/15/49 (144A) 6,298,834 The accompanying notes are an integral part of these financial statements. 42 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Electric -- (continued) 10,270,000 NextEra Energy Capital Holdings, Inc., 3.55%, 5/1/27 $ 10,911,845 2,327,000 NRG Energy, Inc., 5.75%, 1/15/28 2,524,795 11,910,000 PPL Capital Funding, Inc., 3.1%, 5/15/26 12,125,906 1,196,429 San Diego Gas & Electric Co., 1.914%, 2/1/22 1,192,258 9,720,000 Sempra Energy, 3.4%, 2/1/28 10,076,553 2,366,071 Southern California Edison Co., 1.845%, 2/1/22 2,337,320 8,605,000 Southern California Edison Co., 4.875%, 3/1/49 10,208,697 11,475,000 Southwestern Electric Power Co., 3.9%, 4/1/45 12,005,061 19,115,000 Vistra Operations Co. LLC, 3.7%, 1/30/27 (144A) 18,993,952 -------------- Total Electric $ 153,161,975 --------------------------------------------------------------------------------------------------------------------- Electronics -- 0.7% 8,412,000 Amphenol Corp., 3.125%, 9/15/21 $ 8,524,497 3,065,000 Amphenol Corp., 3.2%, 4/1/24 3,180,333 7,391,000 Amphenol Corp., 4.35%, 6/1/29 8,275,945 5,780,000 Flex, Ltd., 4.75%, 6/15/25 6,294,720 18,573,000 Flex, Ltd., 4.875%, 6/15/29 20,177,620 -------------- Total Electronics $ 46,453,115 --------------------------------------------------------------------------------------------------------------------- Energy-Alternate Sources -- 0.1% 372,960 Alta Wind Holdings LLC, 7.0%, 6/30/35 (144A) $ 416,012 6,970,000 TerraForm Power Operating LLC, 4.75%, 1/15/30 (144A) 7,091,975 -------------- Total Energy-Alternate Sources $ 7,507,987 --------------------------------------------------------------------------------------------------------------------- Environmental Control -- 0.1% 2,678,000 Republic Services, Inc., 2.9%, 7/1/26 $ 2,743,763 -------------- Total Environmental Control $ 2,743,763 --------------------------------------------------------------------------------------------------------------------- Food -- 0.3% 6,250,000 JBS USA LUX SA/JBS USA Food Co./JBS USA Finance, Inc., 5.5%, 1/15/30 (144A) $ 6,713,125 4,119,000 Mondelez International Holdings Netherlands BV, 2.0%, 10/28/21 (144A) 4,119,478 2,500,000 Smithfield Foods, Inc., 2.65%, 10/3/21 (144A) 2,485,557 3,430,000(b) Tyson Foods, Inc., 2.345% (3 Month USD LIBOR + 45 bps), 8/21/20 3,433,413 3,075,000(b) Tyson Foods, Inc., 2.457% (3 Month USD LIBOR + 55 bps), 6/2/20 3,079,083 -------------- Total Food $ 19,830,656 --------------------------------------------------------------------------------------------------------------------- Forest Products & Paper -- 0.1% 1,275,000 International Paper Co., 4.8%, 6/15/44 $ 1,401,276 2,575,000 International Paper Co., 6.0%, 11/15/41 3,214,351 -------------- Total Forest Products & Paper $ 4,615,627 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 43 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Gas -- 0.1% 3,060,000 Boston Gas Co., 3.15%, 8/1/27 (144A) $ 3,164,457 1,850,722 Nakilat, Inc., 6.267%, 12/31/33 (144A) 2,207,356 -------------- Total Gas $ 5,371,813 --------------------------------------------------------------------------------------------------------------------- Healthcare-Products -- 0.3% 4,155,000 Abbott Laboratories, 3.75%, 11/30/26 $ 4,539,967 11,200,000 Thermo Fisher Scientific, Inc., 3.0%, 4/15/23 11,516,667 -------------- Total Healthcare-Products $ 16,056,634 --------------------------------------------------------------------------------------------------------------------- Healthcare-Services -- 0.6% 6,585,000 Anthem, Inc., 3.35%, 12/1/24 $ 6,873,641 4,506,000 Anthem, Inc., 3.65%, 12/1/27 4,771,812 1,140,000 Anthem, Inc., 4.101%, 3/1/28 1,238,723 1,940,000 Centene Corp., 4.25%, 12/15/27 (144A) 1,995,775 3,870,000 Centene Corp., 4.625%, 12/15/29 (144A) 4,068,724 3,630,000 Humana, Inc., 3.95%, 3/15/27 3,906,898 2,400,000 NYU Hospitals Center, 4.428%, 7/1/42 2,704,852 4,785,000 Tenet Healthcare Corp., 4.875%, 1/1/26 (144A) 5,011,809 3,990,000 Tenet Healthcare Corp., 5.125%, 11/1/27 (144A) 4,214,438 -------------- Total Healthcare-Services $ 34,786,672 --------------------------------------------------------------------------------------------------------------------- Home Builders -- 0.2% 8,711,000 DR Horton, Inc., 2.5%, 10/15/24 $ 8,721,204 4,320,000 Meritage Homes Corp., 6.0%, 6/1/25 4,827,600 -------------- Total Home Builders $ 13,548,804 --------------------------------------------------------------------------------------------------------------------- Household Products & Wares -- 0.1% 8,203,000 Church & Dwight Co., Inc., 2.45%, 8/1/22 $ 8,273,020 -------------- Total Household Products & Wares $ 8,273,020 --------------------------------------------------------------------------------------------------------------------- Insurance -- 1.6% 2,335,000 AXA SA, 8.6%, 12/15/30 $ 3,392,403 912,000 CNO Financial Group, Inc., 5.25%, 5/30/25 1,010,040 2,862,000 CNO Financial Group, Inc., 5.25%, 5/30/29 3,194,707 1,850,000 Delphi Financial Group, Inc., 7.875%, 1/31/20 1,857,592 2,960,000(c) Farmers Exchange Capital III, 5.454% (3 Month USD LIBOR + 345 bps), 10/15/54 (144A) 3,408,334 9,610,000(c) Farmers Insurance Exchange, 4.747% (3 Month USD LIBOR + 323 bps), 11/1/57 (144A) 10,033,417 5,045,000 Great-West Lifeco Finance 2018 LP, 4.581%, 5/17/48 (144A) 5,834,572 18,482,000 Liberty Mutual Insurance Co., 7.697%, 10/15/97 (144A) 26,323,483 13,250,000 MassMutual Global Funding II, 2.75%, 6/22/24 (144A) 13,594,469 6,200,000 MassMutual Global Funding II, 2.95%, 1/11/25 (144A) 6,368,766 The accompanying notes are an integral part of these financial statements. 44 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Insurance -- (continued) 6,330,000 Nationwide Financial Services, Inc., 3.9%, 11/30/49 (144A) $ 6,597,099 7,265,000 New York Life Global Funding, 2.875%, 4/10/24 (144A) 7,495,734 7,300,000 New York Life Insurance Co., 4.45%, 5/15/69 (144A) 8,368,136 1,090,000 Prudential Financial, Inc., 4.5%, 11/16/21 1,144,270 690,000 Teachers Insurance & Annuity Association of America, 6.85%, 12/16/39 (144A) 1,004,488 2,631,000 Willis North America, Inc., 2.95%, 9/15/29 2,607,740 -------------- Total Insurance $ 102,235,250 --------------------------------------------------------------------------------------------------------------------- Internet -- 0.6% 7,170,000 Booking Holdings, Inc., 3.55%, 3/15/28 $ 7,640,649 1,925,000 Booking Holdings, Inc., 3.6%, 6/1/26 2,055,060 7,875,000 Booking Holdings, Inc., 3.65%, 3/15/25 8,408,569 11,421,000 Expedia Group, Inc., 3.25%, 2/15/30 (144A) 10,992,274 4,125,000 Expedia Group, Inc., 3.8%, 2/15/28 4,219,365 2,985,000 Expedia Group, Inc., 4.5%, 8/15/24 3,186,768 271,000 Expedia Group, Inc., 5.0%, 2/15/26 298,977 -------------- Total Internet $ 36,801,662 --------------------------------------------------------------------------------------------------------------------- Iron & Steel -- 0.1% 3,550,000 Commercial Metals Co., 4.875%, 5/15/23 $ 3,692,000 1,525,000 Commercial Metals Co., 5.75%, 4/15/26 1,593,625 1,828,000 Steel Dynamics, Inc., 3.45%, 4/15/30 1,849,715 -------------- Total Iron & Steel $ 7,135,340 --------------------------------------------------------------------------------------------------------------------- Machinery-Construction & Mining -- 0.2% 9,610,000 Caterpillar Financial Services Corp., 1.9%, 9/6/22 $ 9,629,403 -------------- Total Machinery-Construction & Mining $ 9,629,403 --------------------------------------------------------------------------------------------------------------------- Media -- 0.1% 7,745,000 Comcast Corp., 4.15%, 10/15/28 $ 8,723,534 -------------- Total Media $ 8,723,534 --------------------------------------------------------------------------------------------------------------------- Mining -- 0.4% 1,325,000 Anglo American Capital Plc, 4.0%, 9/11/27 (144A) $ 1,388,530 3,193,000 Anglo American Capital Plc, 4.5%, 3/15/28 (144A) 3,422,155 2,750,000 Anglo American Capital Plc, 4.75%, 4/10/27 (144A) 3,008,171 6,600,000 Anglo American Capital Plc, 4.875%, 5/14/25 (144A) 7,252,573 6,453,000 Freeport-McMoRan, Inc., 5.45%, 3/15/43 6,678,855 -------------- Total Mining $ 21,750,284 --------------------------------------------------------------------------------------------------------------------- Miscellaneous Manufacturers -- 0.0%+ 1,392,000 General Electric Co., 5.3%, 2/11/21 $ 1,436,167 -------------- Total Miscellaneous Manufacturers $ 1,436,167 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 45 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Multi-National -- 0.5% 11,165,000 Africa Finance Corp., 4.375%, 4/17/26 (144A) $ 11,832,109 6,065,000 African Export-Import Bank, 3.994%, 9/21/29 (144A) 6,150,395 7,150,000 Banque Ouest Africaine de Developpement, 4.7%, 10/22/31 (144A) 7,258,966 2,230,000 Banque Ouest Africaine de Developpement, 5.0%, 7/27/27 (144A) 2,363,577 4,450,000 Banque Ouest Africaine de Developpement, 5.5%, 5/6/21 (144A) 4,609,399 -------------- Total Multi-National $ 32,214,446 --------------------------------------------------------------------------------------------------------------------- Oil & Gas -- 1.5% 1,480,000 Apache Corp., 4.25%, 1/15/30 $ 1,535,084 13,130,000 Apache Corp., 4.375%, 10/15/28 13,733,827 6,360,000 BP Capital Markets Plc, 3.062%, 3/17/22 6,522,147 7,213,000 Cenovus Energy, Inc., 6.75%, 11/15/39 9,189,855 5,275,000 CNOOC Nexen Finance 2014 ULC, 4.25%, 4/30/24 5,636,091 14,000,000 EQT Corp., 3.9%, 10/1/27 13,025,629 215,000 Motiva Enterprises LLC, 5.75%, 1/15/20 (144A) 215,218 1,770,000 Newfield Exploration Co., 5.375%, 1/1/26 1,919,766 1,400,000 Newfield Exploration Co., 5.625%, 7/1/24 1,538,439 12,720,000 Noble Energy, Inc., 5.25%, 11/15/43 14,332,566 4,750,000 Sinopec Group Overseas Development 2014, Ltd., 4.375%, 4/10/24 (144A) 5,124,467 10,050,000 Sinopec Group Overseas Development 2015, Ltd., 2.5%, 4/28/20 (144A) 10,057,437 8,468,000 Valero Energy Corp., 6.625%, 6/15/37 11,204,629 -------------- Total Oil & Gas $ 94,035,155 --------------------------------------------------------------------------------------------------------------------- Oil & Gas Services -- 0.0%+ 2,250,000 Halliburton Co., 7.6%, 8/15/96 (144A) $ 3,119,460 -------------- Total Oil & Gas Services $ 3,119,460 --------------------------------------------------------------------------------------------------------------------- Pharmaceuticals -- 1.1% 7,003,000 AbbVie, Inc., 4.05%, 11/21/39 (144A) $ 7,360,553 5,758,000 AbbVie, Inc., 4.25%, 11/21/49 (144A) 6,113,951 12,975,000 AbbVie, Inc., 4.875%, 11/14/48 14,990,484 4,900,000 Bayer US Finance II LLC, 4.25%, 12/15/25 (144A) 5,288,325 3,522,000(b) Becton Dickinson & Co., 2.836% (3 Month USD LIBOR + 88 bps), 12/29/20 3,523,730 6,225,000 Cigna Corp., 4.375%, 10/15/28 6,896,603 435,443 CVS Pass-Through Trust, 5.298%, 1/11/27 (144A) 465,217 2,449,777 CVS Pass-Through Trust, 5.773%, 1/10/33 (144A) 2,762,996 1,700,277 CVS Pass-Through Trust, 5.926%, 1/10/34 (144A) 1,982,216 3,029,303 CVS Pass-Through Trust, 6.036%, 12/10/28 3,384,337 4,508,328 CVS Pass-Through Trust, 8.353%, 7/10/31 (144A) 5,750,354 1,391,000 Perrigo Finance Unlimited Co., 3.5%, 3/15/21 1,404,126 The accompanying notes are an integral part of these financial statements. 46 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Pharmaceuticals -- (continued) 4,570,000 Perrigo Finance Unlimited Co., 3.9%, 12/15/24 $ 4,697,345 6,382,000 Teva Pharmaceutical Finance Netherlands III BV, 3.15%, 10/1/26 5,313,015 5,175,000 Teva Pharmaceutical Finance Netherlands III BV, 7.125%, 1/31/25 (144A) 5,315,760 -------------- Total Pharmaceuticals $ 75,249,012 --------------------------------------------------------------------------------------------------------------------- Pipelines -- 3.5% 3,025,000 Cameron LNG LLC, 3.302%, 1/15/35 (144A) $ 3,055,218 8,064,000 Cameron LNG LLC, 3.402%, 1/15/38 (144A) 8,093,401 2,265,000 Cheniere Energy Partners LP, 4.5%, 10/1/29 (144A) 2,327,514 5,595,000 Cheniere Energy Partners LP, 5.25%, 10/1/25 5,830,494 750,000 DCP Midstream Operating LP, 5.35%, 3/15/20 (144A) 753,750 3,450,000 DCP Midstream Operating LP, 5.375%, 7/15/25 3,751,875 4,025,000 DCP Midstream Operating LP, 5.6%, 4/1/44 3,894,187 3,629,000 Enable Midstream Partners LP, 4.4%, 3/15/27 3,624,560 14,441,000 Enable Midstream Partners LP, 4.95%, 5/15/28 14,628,229 10,550,000 Enbridge, Inc., 3.7%, 7/15/27 11,175,031 1,149,000 Energy Transfer Operating LP, 5.5%, 6/1/27 1,291,769 4,085,000 Energy Transfer Operating LP, 6.0%, 6/15/48 4,766,528 1,125,000 Energy Transfer Operating LP, 6.125%, 12/15/45 1,304,692 4,207,000 Energy Transfer Operating LP, 6.5%, 2/1/42 5,004,243 510,000 EnLink Midstream LLC, 5.375%, 6/1/29 479,400 8,316,000 EnLink Midstream Partners LP, 5.45%, 6/1/47 6,715,170 4,299,000 EnLink Midstream Partners LP, 5.6%, 4/1/44 3,482,190 3,573,000 Enterprise Products Operating LLC, 2.8%, 2/15/21 3,607,098 4,680,000 Hess Midstream Operations LP, 5.125%, 6/15/28 (144A) 4,738,500 10,830,000 Kinder Morgan, Inc., 5.05%, 2/15/46 12,153,345 4,724,000 Midwest Connector Capital Co. LLC, 4.625%, 4/1/29 (144A) 5,160,695 5,914,000(b) MPLX LP, 2.785% (3 Month USD LIBOR + 90 bps), 9/9/21 5,932,102 9,940,000 MPLX LP, 4.25%, 12/1/27 (144A) 10,465,958 3,875,000 MPLX LP, 4.875%, 12/1/24 4,212,874 3,045,000 MPLX LP, 4.875%, 6/1/25 3,326,483 6,920,000 MPLX LP, 5.5%, 2/15/49 7,861,708 12,125,000 Phillips 66 Partners LP, 3.75%, 3/1/28 12,630,023 10,675,000 Sabine Pass Liquefaction LLC, 5.0%, 3/15/27 11,750,923 6,730,000 Sunoco Logistics Partners Operations LP, 5.35%, 5/15/45 7,237,743 10,876,000 Sunoco Logistics Partners Operations LP, 5.4%, 10/1/47 11,825,242 786,000 Sunoco Logistics Partners Operations LP, 6.1%, 2/15/42 881,279 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 47 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Pipelines -- (continued) 2,713,000 Targa Resources Partners LP/Targa Resources Partners Finance Corp., 5.0%, 1/15/28 $ 2,767,260 8,870,000 Texas Eastern Transmission LP, 3.5%, 1/15/28 (144A) 9,112,889 17,007,000 Williams Cos., Inc., 5.75%, 6/24/44 20,155,756 2,475,000 Williams Cos., Inc., 7.75%, 6/15/31 3,300,993 -------------- Total Pipelines $ 217,299,122 --------------------------------------------------------------------------------------------------------------------- Real Estate -- 0.2% 10,250,000(a)(c) AT Securities BV, 5.25% (5 Year USD Swap Rate + 355 bps) $ 10,665,125 -------------- Total Real Estate $ 10,665,125 --------------------------------------------------------------------------------------------------------------------- REITs -- 1.7% 1,350,000 Alexandria Real Estate Equities, Inc., 3.95%, 1/15/27 $ 1,453,936 2,555,000 Alexandria Real Estate Equities, Inc., 4.3%, 1/15/26 2,805,025 5,957,000 Boston Properties LP, 3.4%, 6/21/29 6,224,698 3,450,000 Duke Realty LP, 3.625%, 4/15/23 3,586,401 8,560,000 Duke Realty LP, 3.75%, 12/1/24 9,099,792 9,500,000 Essex Portfolio LP, 3.5%, 4/1/25 9,974,435 1,480,000 Essex Portfolio LP, 3.625%, 5/1/27 1,561,649 6,805,000 Healthcare Trust of America Holdings LP, 3.5%, 8/1/26 7,103,834 4,675,000 Healthcare Trust of America Holdings LP, 3.75%, 7/1/27 4,937,856 2,032,000 Highwoods Realty LP, 3.2%, 6/15/21 2,058,084 3,390,000 Highwoods Realty LP, 3.625%, 1/15/23 3,501,813 7,105,000 Highwoods Realty LP, 4.125%, 3/15/28 7,609,286 6,765,000 iStar, Inc., 4.25%, 8/1/25 6,839,144 5,410,000 iStar, Inc., 4.75%, 10/1/24 5,606,112 8,596,000 MPT Operating Partnership LP/MPT Finance Corp., 4.625%, 8/1/29 8,853,880 1,800,000 SBA Tower Trust, 2.877%, 7/9/21 (144A) 1,806,001 6,975,000 SBA Tower Trust, 3.869%, 10/8/24 (144A) 7,261,517 1,520,000 UDR, Inc., 2.95%, 9/1/26 1,547,663 6,077,000 UDR, Inc., 4.0%, 10/1/25 6,563,748 5,300,000 UDR, Inc., 4.4%, 1/26/29 5,919,768 -------------- Total REITs $ 104,314,642 --------------------------------------------------------------------------------------------------------------------- Retail -- 0.1% 3,994,000 AutoZone, Inc., 2.5%, 4/15/21 $ 4,015,881 -------------- Total Retail $ 4,015,881 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 48 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Semiconductors -- 0.2% 4,470,000 Broadcom, Inc., 3.625%, 10/15/24 (144A) $ 4,648,304 3,485,000 Broadcom, Inc., 4.25%, 4/15/26 (144A) 3,701,668 -------------- Total Semiconductors $ 8,349,972 --------------------------------------------------------------------------------------------------------------------- Software -- 0.2% 5,501,000 Fiserv, Inc., 3.8%, 10/1/23 $ 5,810,965 5,650,000 salesforce.com, Inc., 3.7%, 4/11/28 6,198,508 -------------- Total Software $ 12,009,473 --------------------------------------------------------------------------------------------------------------------- Telecommunications -- 0.3% 5,227,000 CommScope Technologies LLC, 5.0%, 3/15/27 (144A) $ 4,913,380 3,950,000 Level 3 Financing, Inc., 4.625%, 9/15/27 (144A) 4,044,010 3,989,000 Level 3 Financing, Inc., 5.375%, 1/15/24 4,053,821 -------------- Total Telecommunications $ 13,011,211 --------------------------------------------------------------------------------------------------------------------- Transportation -- 0.2% 13,715,000 Union Pacific Corp., 3.375%, 2/1/35 $ 14,214,599 -------------- Total Transportation $ 14,214,599 --------------------------------------------------------------------------------------------------------------------- Trucking & Leasing -- 0.4% 6,623,000 Penske Truck Leasing Co. LP/PTL Finance Corp., 2.7%, 3/14/23 (144A) $ 6,694,104 4,183,000 Penske Truck Leasing Co. LP/PTL Finance Corp., 3.35%, 11/1/29 (144A) 4,180,083 4,825,000 Penske Truck Leasing Co. LP/PTL Finance Corp., 3.375%, 2/1/22 (144A) 4,927,705 4,615,000 Penske Truck Leasing Co. LP/PTL Finance Corp., 4.2%, 4/1/27 (144A) 4,949,167 -------------- Total Trucking & Leasing $ 20,751,059 --------------------------------------------------------------------------------------------------------------------- Water -- 0.1% 3,340,000 Aqua America, Inc., 3.566%, 5/1/29 $ 3,513,791 -------------- Total Water $ 3,513,791 --------------------------------------------------------------------------------------------------------------------- TOTAL CORPORATE BONDS (Cost $1,687,444,651) $1,778,321,999 --------------------------------------------------------------------------------------------------------------------- FOREIGN GOVERNMENT BOND -- 0.2% of Net Assets Mexico -- 0.2% 13,425,000 Mexico Government International Bond, 4.6%, 2/10/48 $ 14,700,509 -------------- Total Mexico $ 14,700,509 --------------------------------------------------------------------------------------------------------------------- TOTAL FOREIGN GOVERNMENT BOND (Cost $12,369,708) $ 14,700,509 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 49 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- INSURANCE-LINKED SECURITIES -- 3.0% of Net Assets(f) Event Linked Bonds -- 1.0% Earthquakes -- California -- 0.2% 2,700,000(b) Ursa Re, 5.046% (3 Month U.S. Treasury Bill + 350 bps), 5/27/20 (144A) $ 2,670,030 2,000,000(b) Ursa Re, 7.296% (3 Month U.S. Treasury Bill + 575 bps), 12/10/22 (144A) 2,002,000 800,000(b) Ursa Re, 7.546% (3 Month U.S. Treasury Bill + 600 bps), 5/27/20 (144A) 791,120 -------------- $ 5,463,150 --------------------------------------------------------------------------------------------------------------------- Earthquakes -- Chile -- 0.0%+ 1,500,000(b) International Bank for Reconstruction & Development, 4.21% (3 Month USD LIBOR + 250 bps), 2/15/21 (144A) $ 1,476,600 --------------------------------------------------------------------------------------------------------------------- Earthquakes -- Colombia -- 0.0%+ 1,250,000(b) International Bank for Reconstruction & Development, 4.71% (3 Month USD LIBOR + 300 bps), 2/15/21 (144A) $ 1,240,375 --------------------------------------------------------------------------------------------------------------------- Earthquakes -- Mexico -- 0.0%+ 1,050,000(b) International Bank for Reconstruction & Development, 4.21% (3 Month USD LIBOR + 250 bps), 2/14/20 (144A) $ 1,045,170 --------------------------------------------------------------------------------------------------------------------- Earthquakes -- U.S. -- 0.0%+ 1,150,000(b) Acorn Re, 4.551% (3 Month USD LIBOR + 275 bps), 11/10/21 (144A) $ 1,134,705 --------------------------------------------------------------------------------------------------------------------- Health -- U.S. -- 0.1% 2,900,000(b) Vitality Re VII, 3.696% (3 Month U.S. Treasury Bill + 215 bps), 1/7/20 (144A) $ 2,899,420 1,000,000(b) Vitality Re VII, 4.196% (3 Month U.S. Treasury Bill + 265 bps), 1/7/20 (144A) 999,800 -------------- $ 3,899,220 --------------------------------------------------------------------------------------------------------------------- Inland Flood -- U.S. -- 0.0%+ 250,000(b) FloodSmart Re, 12.794% (3 Month U.S. Treasury Bill + 1,125 bps), 3/7/22 (144A) $ 249,875 --------------------------------------------------------------------------------------------------------------------- Multiperil -- U.S. -- 0.3% 2,000,000(b) Bowline Re, 6.046% (3 Month U.S. Treasury Bill + 450 bps), 5/23/22 (144A) $ 1,974,600 1,350,000(b) Caelus Re IV, 6.794% (3 Month U.S. Treasury Bill + 525 bps), 3/6/20 (144A) 1,354,860 1,000,000(b) Caelus Re V, 2.044% (1 Month U.S. Treasury Bill + 50 bps), 6/5/20 (144A) 410,000 750,000(b) Caelus Re V, 4.674% (3 Month U.S. Treasury Bill + 313 bps), 6/5/20 (144A) 734,475 2,000,000(b) Kilimanjaro Re, 6.783% (3 Month USD LIBOR + 494 bps), 5/6/22 (144A) 1,968,000 The accompanying notes are an integral part of these financial statements. 50 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Multiperil -- U.S. -- (continued) 2,600,000(b) Kilimanjaro II Re, 7.909% (6 Month USD LIBOR + 630 bps), 4/20/21 (144A) $ 2,574,000 500,000(b) Kilimanjaro II Re, 7.929% (6 Month USD LIBOR + 630 bps), 4/21/22 (144A) 495,000 3,500,000(b) Kilimanjaro II Re, 9.519% (6 Month USD LIBOR + 791 bps), 4/20/21 (144A) 3,450,650 1,250,000+(b) Panthera Re, 5.044% (3 Month U.S. Treasury Bill + 350 bps), 3/9/20 (144A) 1,267,875 2,500,000(b) Residential Reinsurance 2016, 5.514% (3 Month U.S. Treasury Bill + 397 bps), 12/6/20 (144A) 2,476,000 1,600,000(b) Sanders Re, 4.591% (6 Month USD LIBOR + 299 bps), 12/6/21 (144A) 1,562,240 1,000,000(b) Skyline Re, 4.044% (3 Month U.S. Treasury Bill + 250 bps), 1/6/20 (144A) 995,000 -------------- $ 19,262,700 --------------------------------------------------------------------------------------------------------------------- Multiperil -- U.S. Regional -- 0.1% 2,500,000(b) Long Point Re III, 4.294% (3 Month U.S. Treasury Bill + 275 bps), 6/1/22 (144A) $ 2,475,750 --------------------------------------------------------------------------------------------------------------------- Multiperil -- U.S. & Canada -- 0.1% 4,000,000(b) Kilimanjaro III Re, 11.044% (3 Month U.S. Treasury Bill + 950 bps), 12/19/23 (144A) $ 3,994,000 500,000(b) Mona Lisa Re, Series B, 9.546% (3 Month U.S. Treasury Bill + 800 bps), 1/9/23 500,000 -------------- $ 4,494,000 --------------------------------------------------------------------------------------------------------------------- Multiperil -- Worldwide -- 0.1% 1,500,000(b) Galilei Re, 6.421% (6 Month USD LIBOR + 479 bps), 1/8/21 (144A) $ 1,494,600 1,300,000(b) Galilei Re, 6.651% (6 Month USD LIBOR + 479 bps), 1/8/20 (144A) 1,299,870 1,200,000(b) Galilei Re, 7.231% (6 Month USD LIBOR + 560 bps), 1/8/21 (144A) 1,195,200 1,300,000(b) Galilei Re, 7.461% (6 Month USD LIBOR + 560 bps), 1/8/20 (144A) 1,299,870 1,400,000(b) Galilei Re, 8.641% (6 Month USD LIBOR + 678 bps), 1/8/20 (144A) 1,399,720 1,500,000(b) Galilei Re, 8.661% (6 Month USD LIBOR + 678 bps), 1/8/21 (144A) 1,492,200 -------------- $ 8,181,460 --------------------------------------------------------------------------------------------------------------------- Pandemic -- Worldwide -- 0.0%+ 1,700,000(b) International Bank for Reconstruction & Development, 8.713% (6 Month USD LIBOR + 690 bps), 7/15/20 (144A) $ 1,703,910 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 51 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Windstorm -- Florida -- 0.1% 1,400,000(b) Casablanca Re, 5.516% (6 Month USD LIBOR + 402 bps), 6/4/20 (144A) $ 1,414,000 3,250,000(b) Everglades Re II, 6.774% (3 Month U.S. Treasury Bill + 523 bps), 5/8/20 (144A) 3,272,750 -------------- $ 4,686,750 --------------------------------------------------------------------------------------------------------------------- Windstorm -- Japan -- 0.0%+ 500,000(b) Aozora Re, 4.193% (6 Month USD LIBOR + 229 bps), 4/7/20 (144A) $ 465,000 --------------------------------------------------------------------------------------------------------------------- Windstorm -- Louisiana -- 0.0%+ 250,000(b) Pelican IV Re, 3.545% (6 Month USD LIBOR + 204 bps), 5/5/20 (144A) $ 249,125 --------------------------------------------------------------------------------------------------------------------- Windstorm -- Texas -- 0.0%+ 1,700,000(b) Alamo Re, 5.356% (3 Month U.S. Treasury Bill + 381 bps), 6/8/20 (144A) $ 1,708,330 --------------------------------------------------------------------------------------------------------------------- Windstorm -- U.S. Multistate -- 0.0%+ 1,000,000(b) Citrus Re, 2.044% (1 Month U.S. Treasury Bill + 50 bps), 4/9/20 (144A) $ 250,000 -------------- Total Event Linked Bonds $ 57,986,120 --------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------------- Face Amount USD ($) --------------------------------------------------------------------------------------------------------------------- Collateralized Reinsurance -- 0.3% Earthquakes -- California -- 0.0%+ 2,500,000+(g) Adare Re, 1/31/21 $ 2,406,675 --------------------------------------------------------------------------------------------------------------------- Multiperil -- Massachusetts -- 0.0%+ 3,000,000+(g)(h) Denning Re 2019, 7/31/20 $ 3,012,910 --------------------------------------------------------------------------------------------------------------------- Multiperil -- U.S. -- 0.0%+ 600,000+(g)(h) Dingle Re 2019, 2/1/20 $ 612,315 2,800,000+(g)(h) Kingsbarns Re 2017, 5/19/20 2,800 2,000,000+(g)(h) Port Royal Re 2019, 5/31/20 2,020,060 1,600,000+(g)(h) Riviera Re 2019, 5/31/20 1,611,731 -------------- $ 4,246,906 --------------------------------------------------------------------------------------------------------------------- Multiperil -- U.S. Regional -- 0.1% 2,500,000+(g)(h) Ailsa Re 2019, 6/30/20 $ 2,598,291 2,500,000+(g)(h) Ocean View Re 2019, 6/30/20 2,503,259 -------------- $ 5,101,550 --------------------------------------------------------------------------------------------------------------------- Multiperil -- Worldwide -- 0.1% 4,918,415+(g)(h) Kilarney Re 2018, 4/15/20 $ 2,482,816 28,000+(h) Limestone Re 2016-1, 8/31/21 33,928 82,000+(h) Limestone Re 2016-1, 8/31/21 99,359 1,500,000+(g)(h) Limestone Re 2019-2, 3/1/23 (144A) 1,500,150 The accompanying notes are an integral part of these financial statements. 52 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Face Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Multiperil -- Worldwide -- (continued) 1,420,000+(g) Limestone Re, 2020-1, 3/1/24 $ 1,420,000 1,500,000+(g)(h) Mid Ocean Re 2019, 7/31/20 1,468,043 3,600,000+(g)(h) Resilience Re, 4/6/20 360 567,400+(g)(h) Seminole Re 2018, 1/15/20 110,359 142,857+(g)(h) Seminole Re 2019, 1/31/20 145,785 553,333+(g)(h) Walton Health Re 2018, 6/15/20 276,667 350,000+(g)(h) Walton Health Re 2019, 6/30/20 320,475 -------------- $ 7,857,942 --------------------------------------------------------------------------------------------------------------------- Windstorm -- Florida -- 0.0%+ 1,500,000+(g)(h) Formby Re 2018, 2/28/20 $ 475,296 511,212+(g)(h) Formby Re 2018-2, 3/31/20 4,192 -------------- $ 479,488 --------------------------------------------------------------------------------------------------------------------- Windstorm -- North Carolina -- 0.0%+ 1,500,000+(g)(h) Lahinch Re 2019, 5/31/20 $ 1,522,205 --------------------------------------------------------------------------------------------------------------------- Windstorm -- U.S. Regional -- 0.1% 1,000,000+(g)(h) Oakmont Re 2017, 4/15/20 $ 29,400 2,500,000+(g)(h) Oakmont Re 2019, 4/30/20 1,730,750 250,000+(h) Resilience Re, 6/15/20 121,250 -------------- $ 1,881,400 -------------- Total Collateralized Reinsurance $ 26,509,076 --------------------------------------------------------------------------------------------------------------------- Industry Loss Warranties -- 0.1% Multiperil -- U.S. -- 0.1% 2,300,000+(g)(h) Cypress Re 2019, 1/31/20 $ 2,345,722 -------------- Total Industry Loss Warranties $ 2,345,722 --------------------------------------------------------------------------------------------------------------------- Reinsurance Sidecars -- 1.6% Multiperil -- U.S. -- 0.1% 3,000,000+(g)(h) Carnoustie Re 2015, 7/31/20 $ 9,600 3,600,000+(g)(h) Carnoustie Re 2016, 11/30/20 97,200 4,500,000+(g)(h) Carnoustie Re 2017, 11/30/21 611,325 2,000,000+(h) Carnoustie Re 2018, 12/31/21 22,400 1,139,928+(g)(h) Carnoustie Re 2019, 12/31/22 1,260,646 1,300,000+(g)(h) Castle Stuart Re 2018, 12/1/21 1,096,420 2,000,000+(g)(i) Harambee Re 2018, 12/31/21 310,200 5,000,000+(g)(i) Harambee Re 2019, 12/31/22 5,552,500 1,000,000+(g)(h) Prestwick Re 2015-1, 7/31/20 17,000 1,200,007+(g)(h) Sector Re V, Series 7, Class G, 3/1/22 (144A) 191,073 -------------- $ 9,168,364 --------------------------------------------------------------------------------------------------------------------- Multiperil -- Worldwide -- 1.5% 440,000+(g) Alturas Re, 12/9/23 $ 440,000 2,800,000+(g)(h) Alturas Re 2019-1, 3/10/22 3,062,360 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 53 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Face Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Multiperil -- Worldwide -- (continued) 550,000+(g)(h) Alturas Re 2019-2, 3/10/23 $ 625,790 250,000+(g)(h) Alturas Re 2019-3, 9/12/23 272,275 1,735,000+(g) Alturas Re, 2020-2R, 3/10/23 1,735,000 900,000+(g)(h) Arlington Re 2015, 2/1/20 43,740 2,000,000+(g)(h) Bantry Re 2016, 3/30/20 161,200 1,500,000+(g)(h) Bantry Re 2017, 3/31/20 354,150 2,000,000+(g)(h) Bantry Re 2018, 12/31/21 22,800 5,000,000+(g)(h) Bantry Re 2019, 12/31/22 5,292,849 2,000,000+(g)(h) Berwick Re 2017-1, 2/1/20 66,200 10,192,268+(g)(h) Berwick Re 2018-1, 12/31/21 1,627,705 7,281,734+(g)(h) Berwick Re 2019-1, 12/31/22 7,537,323 1,250,000+(g)(i) Blue Lotus Re 2018, 12/31/21 1,372,125 125,000+(h) Eden Re II, 3/22/22 (144A) 163,300 185,850+(h) Eden Re II, 3/22/22 (144A) 208,264 600,000+(g)(h) Eden Re II, 3/22/23 (144A) 624,240 5,906,150+(g)(h) Eden Re II, 3/22/23 (144A) 6,140,624 2,600,000+(g) Eden Re II, 3/22/24 (144A) 2,600,000 6,400,000+(g) Eden Re II, 3/22/24 (144A) 6,400,000 3,500,000+(h) Gleneagles Re 2016, 11/30/20 109,200 1,000,000+(g)(h) Gleneagles Re 2018, 12/31/21 118,300 886,832+(g)(h) Gleneagles Re 2019, 12/31/22 965,316 2,118,314+(g)(h) Gullane Re 2018, 12/31/21 1,988,043 72,000+(h) Limestone Re 2018, 3/1/22 246,650 500,000+(g)(h) Limestone Re 2019, 9/9/22 552,500 500,000+(g)(i) Lion Rock Re 2019, 1/31/20 550,800 5,000,000+(g)(i) Lorenz Re 2018, 7/1/21 507,500 2,993,180+(g)(i) Lorenz Re 2019, 6/30/22 2,609,754 7,000,000+(g)(h) Merion Re 2018-2, 12/31/21 7,126,000 1,000,000+(g)(i) NCM Re 2019, 12/31/22 1,072,600 3,600,000+(h) Pangaea Re 2015-1, 2/1/20 4,709 4,000,000+(h) Pangaea Re 2015-2, 5/29/20 5,964 4,500,000+(h) Pangaea Re 2016-1, 11/30/20 9,989 3,000,000+(h) Pangaea Re 2016-2, 11/30/20 8,928 3,000,000+(g)(h) Pangaea Re 2017-1, 11/30/21 48,300 3,800,000+(g)(h) Pangaea Re 2018-1, 12/31/21 223,440 6,500,000+(g)(h) Pangaea Re 2018-3, 7/1/22 134,832 4,017,011+(g)(h) Pangaea Re 2019-1, 2/1/23 3,996,123 4,779,537+(g)(h) Pangaea Re 2019-3, 7/1/23 4,649,056 2,100,000+(g)(h) Sector Re V, 12/1/23 (144A) 1,702,178 2,000,000+(g) Sector Re V, 12/1/24 (144A) 2,010,373 400,000+(g)(h) Sector Re V, Series 8, Class D, 12/1/23 (144A) 324,224 758+(h) Sector Re V, Series 8, Class F, 3/1/23 (144A) 46,358 2,557+(h) Sector Re V, Series 8, Class G, 3/1/23 (144A) 112,616 1,500,000+(g)(h) Sector Re V, Series 9, Class A, 3/1/24 (144A) 1,189,246 The accompanying notes are an integral part of these financial statements. 54 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Face Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Multiperil -- Worldwide -- (continued) 900,000+(g)(h) Sector Re V, Series 9, Class G, 3/1/24 (144A) $ 1,034,732 3,000,000+(g)(h) St. Andrews Re 2017-1, 2/1/20 203,400 1,737,984+(g)(h) St. Andrews Re 2017-4, 6/1/20 171,018 3,599,594+(g) Thopas Re, 12/31/23 3,599,594 500,000+(g)(i) Thopas Re 2018, 12/31/21 37,050 3,000,000+(g)(i) Thopas Re 2019, 12/31/22 2,961,600 4,000,000+(g)(h) Versutus Re 2017, 11/30/21 52,800 2,000,000+(g)(h) Versutus Re 2018, 12/31/21 -- 1,765,095+(g)(h) Versutus Re 2019-A, 12/31/21 1,964,551 1,734,905+(g)(h) Versutus Re 2019-B, 12/31/21 1,930,949 1,000,000+(g)(i) Viribus Re 2018, 12/31/21 55,300 3,650,000+(g)(i) Viribus Re 2019, 12/31/22 4,499,355 1,623,326+(g)(h) Woburn Re 2018, 12/31/21 324,990 4,979,452+(g)(h) Woburn Re 2019, 12/31/22 5,151,243 -------------- $ 91,049,526 -------------- Total Reinsurance Sidecars $ 100,217,890 --------------------------------------------------------------------------------------------------------------------- TOTAL INSURANCE-LINKED SECURITIES (Cost $191,517,122) $ 187,058,808 --------------------------------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) --------------------------------------------------------------------------------------------------------------------- MUNICIPAL BONDS -- 0.2% of Net Assets(j) Municipal General -- 0.0%+ 2,335,000 Virginia Commonwealth Transportation Board, Transportation Capital Projects, 4.0%, 5/15/32 $ 2,547,602 -------------- Total Municipal General $ 2,547,602 --------------------------------------------------------------------------------------------------------------------- Municipal Higher Education -- 0.2% 525,000 Amherst College, 3.794%, 11/1/42 $ 559,964 7,425,000 Massachusetts Development Finance Agency, Harvard University, Series A, 5.0%, 7/15/40 10,633,491 -------------- Total Municipal Higher Education $ 11,193,455 --------------------------------------------------------------------------------------------------------------------- Municipal Transportation -- 0.0%+ 600,000 Port Authority of New York & New Jersey, Consolidated-174TH, 4.458%, 10/1/62 $ 733,920 -------------- Total Municipal Transportation $ 733,920 --------------------------------------------------------------------------------------------------------------------- TOTAL MUNICIPAL BONDS (Cost $13,892,320) $ 14,474,977 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 55 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- SENIOR SECURED FLOATING RATE LOAN INTERESTS -- 1.5% of Net Assets*(b) Automobile -- 0.2% 3,115,354 American Axle & Manufacturing, Inc., Tranche B Term Loan, 4.068% (LIBOR + 225 bps), 4/6/24 $ 3,112,432 1,340,216 Cooper-Standard Automotive, Inc., Additional Term B-1 Loan, 3.799% (LIBOR + 200 bps), 11/2/23 1,265,834 1,153,630 CWGS Group LLC (aka Camping World, Inc.), Term Loan, 4.444% (LIBOR + 275 bps), 11/8/23 1,092,343 1,396,667 Goodyear Tire & Rubber Co., Second Lien Term Loan, 3.97% (LIBOR + 200 bps), 3/3/25 1,400,158 725,794 Navistar, Inc., Tranche B Term Loan, 5.24% (LIBOR + 350 bps), 11/6/24 724,887 1,334,117 TI Group Automotive Systems LLC, Initial US Term Loan, 4.299% (LIBOR + 250 bps), 6/30/22 1,341,065 -------------- Total Automobile $ 8,936,719 --------------------------------------------------------------------------------------------------------------------- Beverage, Food & Tobacco -- 0.1% 1,673,075 Darling Ingredients, Inc. (fka Darling International, Inc.), Term B Loan, 3.8% (LIBOR + 200 bps), 12/18/24 $ 1,678,931 3,710,755 JBS USA Lux SA (fka JBS USA LLC), New Term Loan, 3.799% (LIBOR + 200 bps), 5/1/26 3,741,569 -------------- Total Beverage, Food & Tobacco $ 5,420,500 --------------------------------------------------------------------------------------------------------------------- Broadcasting & Entertainment -- 0.0%+ 1,820,438 Sinclair Television Group, Inc., Tranche B-2b Term Loan, 4.24% (LIBOR + 250 bps), 9/30/26 $ 1,829,256 -------------- Total Broadcasting & Entertainment $ 1,829,256 --------------------------------------------------------------------------------------------------------------------- Buildings & Real Estate -- 0.0%+ 47,419 Builders FirstSource, Inc., Refinancing Term Loan, 4.799% (LIBOR + 300 bps), 2/29/24 $ 47,644 1,584,465 Uniti Group, Inc., Shortfall Term Loan, 6.799% (LIBOR + 500 bps), 10/24/22 1,559,510 -------------- Total Buildings & Real Estate $ 1,607,154 --------------------------------------------------------------------------------------------------------------------- Chemicals, Plastics & Rubber -- 0.0%+ 989,924 Axalta Coating Systems Dutch Holding B BV (Axalta Coating Systems U.S. Holdings, Inc.), Term B-3 Dollar Loan, 3.695% (LIBOR + 175 bps), 6/1/24 $ 993,513 486,153 Berry Global, Inc. (fka Berry Plastics Corp.), Term X Loan, 3.715% (LIBOR + 200 bps), 1/19/24 488,735 234,038 Element Solutions, Inc. (Macdermid, Inc.), Tranche B-1 Term Loan, 3.799% (LIBOR + 200 bps), 1/31/26 235,611 511,929 Omnova Solutions, Inc., Term B-2 Loan, 5.049% (LIBOR + 325 bps), 8/25/23 512,251 1,349,145 Tronox Finance LLC, First Lien Initial Dollar Term Loan, 4.609% (LIBOR + 275 bps), 9/23/24 1,353,151 -------------- Total Chemicals, Plastics & Rubber $ 3,583,261 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 56 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Computers & Electronics -- 0.1% 1,055,011 Energy Acquisition LP (aka Electrical Components International), First Lien Initial Term Loan, 6.195% (LIBOR + 425 bps), 6/26/25 $ 981,160 2,135,722 Microchip Technology, Inc., Initial Term Loan, 3.8% (LIBOR + 200 bps), 5/29/25 2,157,080 796,045 ON Semiconductor Corp., 2019 New Replacement Term B-4 Loan, 3.799% (LIBOR + 200 bps), 9/19/26 802,786 -------------- Total Computers & Electronics $ 3,941,026 --------------------------------------------------------------------------------------------------------------------- Diversified & Conglomerate Service -- 0.2% 560,830 Bright Horizons Family Solutions LLC (fka Bright Horizons Family Solutions, Inc.), Term B Loan, 3.549% (LIBOR + 175 bps), 11/7/23 $ 566,088 979,652 Change Healthcare Holdings, Inc. (fka Emdeon, Inc.), Closing Date Term Loan, 4.299% (LIBOR + 250 bps), 3/1/24 984,448 477,736 Filtration Group Corp., Initial Dollar Term Loan, 4.799% (LIBOR + 300 bps), 3/29/25 480,304 2,316,391 NVA Holdings, Inc., First Lien Term B-3 Loan, 6.5% (PRIME + 175 bps), 2/2/25 2,317,297 1,069,750 Team Health Holdings, Inc., Initial Term Loan, 4.549% (LIBOR + 275 bps), 2/6/24 870,317 -------------- Total Diversified & Conglomerate Service $ 5,218,454 --------------------------------------------------------------------------------------------------------------------- Electric & Electrical -- 0.0%+ 1,199,495 Dell International LLC (EMC Corp.), Refinancing Term B-1 Loan, 3.8% (LIBOR + 200 bps), 9/19/25 $ 1,208,969 458,254 Rackspace Hosting, Inc., First Lien Term B Loan, 4.902% (LIBOR + 300 bps), 11/3/23 449,089 -------------- Total Electric & Electrical $ 1,658,058 --------------------------------------------------------------------------------------------------------------------- Electronics -- 0.2% 125,865 Avast Software BV, 2018 Refinancing Dollar Term Loan, 4.195% (LIBOR + 225 bps), 9/29/23 $ 127,025 4,923,132 Scientific Games International, Inc., Initial Term B-5 Loan, 4.549% (LIBOR + 275 bps), 8/14/24 4,943,351 4,151,148 Western Digital Corp., US Term B-4 Loan, 3.452% (LIBOR + 175 bps), 4/29/23 4,177,939 -------------- Total Electronics $ 9,248,315 --------------------------------------------------------------------------------------------------------------------- Environmental Services -- 0.0%+ 950,788 GFL Environmental, Inc., Effective Date Incremental Term Loan, 4.799% (LIBOR + 300 bps), 5/30/25 $ 953,420 -------------- Total Environmental Services $ 953,420 --------------------------------------------------------------------------------------------------------------------- Financial Services -- 0.1% 2,370,007 RPI Finance Trust, Initial Term B-6 Loan, 3.799% (LIBOR + 200 bps), 3/27/23 $ 2,392,062 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 57 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Financial Services -- (continued) 1,159,320 Trans Union LLC 2019 Replacement Term B-5 Loan, 3.549% (LIBOR + 175 bps), 11/16/26 $ 1,165,751 -------------- Total Financial Services $ 3,557,813 --------------------------------------------------------------------------------------------------------------------- Healthcare -- 0.0%+ 727,215 Grifols Worldwide Operations Ltd. Dollar Tranche B Term Loan, 3.74% (LIBOR + 200 bps), 11/15/27 $ 734,078 -------------- Total Healthcare $ 734,078 --------------------------------------------------------------------------------------------------------------------- Healthcare & Pharmaceuticals -- 0.1% 714,260 Alkermes, Inc., 2023 Term Loan, 3.99% (LIBOR + 225 bps), 3/27/23 $ 712,028 488,750 Alphabet Holding Co., Inc. (aka Nature's Bounty), First Lien Initial Term Loan, 5.299% (LIBOR + 350 bps), 9/26/24 472,458 4,970,781 Endo Luxembourg Finance Co. I S.a r.l., Initial Term Loan, 6.063% (LIBOR + 425 bps), 4/29/24 4,735,559 396,931 Gentiva Health Services, Inc., First Lien Closing Date Initial Term Loan, 5.563% (LIBOR + 375 bps), 7/2/25 399,536 1,401,943 HCA, Inc. Tranche B-13 Term Loan, 3.549% (LIBOR + 175 bps), 3/18/26 1,411,581 700,000 Sotera Health Holdings LLC, First Lien Initial Term Loan, 6.289% (LIBOR + 450 bps), 12/11/26 703,208 -------------- Total Healthcare & Pharmaceuticals $ 8,434,370 --------------------------------------------------------------------------------------------------------------------- Healthcare, Education & Childcare -- 0.0%+ 760,000 Alliance HealthCare Services, Inc., First Lien Initial Term Loan, 6.299% (LIBOR + 450 bps), 10/24/23 $ 695,400 528,978 Bausch Health Cos., Inc. (fka Valeant Pharmaceuticals International, Inc.), Initial Term Loan, 4.74% (LIBOR + 300 bps), 6/2/25 532,862 2,182,923 KUEHG Corp. (fka KC MergerSub, Inc.) (aka KinderCare), Term B-3 Loan, 5.695% (LIBOR + 375 bps), 2/21/25 2,191,109 1,043,506 Select Medical Corp., Tranche B Term Loan, 4.58% (LIBOR + 250 bps), 3/6/25 1,047,080 -------------- Total Healthcare, Education & Childcare $ 4,466,451 --------------------------------------------------------------------------------------------------------------------- Hotel, Gaming & Leisure -- 0.0%+ 1,415,451 1011778 BC Unlimited Liability Co. (New Red Finance, Inc.) (aka Burger King/Tim Hortons), Term B-4 Loan, 3.549% (LIBOR + 175 bps), 11/19/26 $ 1,418,981 -------------- Total Hotel, Gaming & Leisure $ 1,418,981 --------------------------------------------------------------------------------------------------------------------- Insurance -- 0.1% 3,810,097 Asurion LLC (fka Asurion Corp.), New Term B-7 Loan, 4.799% (LIBOR + 300 bps), 11/3/24 $ 3,835,499 420,807 MPH Acquisition Holdings LLC, Initial Term Loan, 4.695% (LIBOR + 275 bps), 6/7/23 416,249 The accompanying notes are an integral part of these financial statements. 58 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Insurance -- (continued) 830,875 USI, Inc. (fka Compass Investors, Inc.), 2017 New Term Loan, 4.945% (LIBOR + 300 bps), 5/16/24 $ 831,810 -------------- Total Insurance $ 5,083,558 --------------------------------------------------------------------------------------------------------------------- Leasing -- 0.1% 941,582 Avolon TLB Borrower 1 (US) LLC, Term B-3 Loan, 3.515% (LIBOR + 175 bps), 1/15/25 $ 948,644 2,701,875 IBC Capital I, Ltd. (aka Goodpack, Ltd.), First Lien Tranche B-1 Term Loan, 5.649% (LIBOR + 375 bps), 9/11/23 2,708,630 -------------- Total Leasing $ 3,657,274 --------------------------------------------------------------------------------------------------------------------- Leisure & Entertainment -- 0.0%+ 547,520 AMC Entertainment Holdings, Inc. (fka AMC Entertainment, Inc.), Term B-1 Loan, 4.8% (LIBOR + 300 bps), 4/22/26 $ 552,174 316,384 Fitness International LLC, Term B Loan, 5.049% (LIBOR + 325 bps), 4/18/25 316,681 1,250,953 Six Flags Theme Parks, Inc., Tranche B Term Loan, 3.55% (LIBOR + 175 bps), 4/17/26 1,258,459 -------------- Total Leisure & Entertainment $ 2,127,314 --------------------------------------------------------------------------------------------------------------------- Machinery -- 0.1% 1,153,342 NN, Inc., Tranche B Term Loan, 7.049% (LIBOR + 525 bps), 10/19/22 $ 1,127,392 -------------- Total Machinery $ 1,127,392 --------------------------------------------------------------------------------------------------------------------- Metals & Mining -- 0.0%+ 498,223 BWay Holding Co., Initial Term Loan, 5.234% (LIBOR + 325 bps), 4/3/24 $ 497,366 -------------- Total Metals & Mining $ 497,366 --------------------------------------------------------------------------------------------------------------------- Professional & Business Services -- 0.0%+ 982,500 Lamar Media Corp., Term B Loan, 3.563% (LIBOR + 175 bps), 3/14/25 $ 991,097 -------------- Total Professional & Business Services $ 991,097 --------------------------------------------------------------------------------------------------------------------- Retail -- 0.0%+ 532,325 Staples, Inc., 2019 Refinancing New Term B-2 Loan, 6.191% (LIBOR + 450 bps), 9/12/24 $ 525,338 -------------- Total Retail $ 525,338 --------------------------------------------------------------------------------------------------------------------- Securities & Trusts -- 0.1% 4,780,000 Stonepeak Lonestar Holdings LLC, Initial Term Loan, 6.299% (LIBOR + 450 bps), 10/19/26 $ 4,726,225 -------------- Total Securities & Trusts $ 4,726,225 --------------------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 59 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- Telecommunications -- 0.1% 4,095,056 CenturyLink, Inc., Initial Term B Loan, 4.549% (LIBOR + 275 bps), 1/31/25 $ 4,116,670 891,000 Ciena Corp., Refinancing Term Loan, 3.765% (LIBOR + 200 bps), 9/26/25 896,383 898,766 Go Daddy Operating Co. LLC (GD Finance Co., Inc.), Tranche B-1 Term Loan, 3.549% (LIBOR + 175 bps), 2/15/24 904,783 809,587 Level 3 Financing, Inc., Tranche B 2027 Term Loan, 3.549% (LIBOR + 175 bps), 3/1/27 814,478 1,264,250 Sprint Communications, Inc., Initial Term Loan, 4.313% (LIBOR + 250 bps), 2/2/24 1,255,945 -------------- Total Telecommunications $ 7,988,259 --------------------------------------------------------------------------------------------------------------------- Utilities -- 0.0%+ 919,812 Eastern Power LLC (Eastern Covert Midco LLC) (aka TPF II LC LLC), Term Loan, 5.549% (LIBOR + 375 bps), 10/2/23 $ 923,620 623,924 Vistra Operations Co. LLC (fka Tex Operations Co. LLC) 2018 Incremental Term Loan, 3.537% (LIBOR + 175 bps), 12/31/25 628,331 -------------- Total Utilities $ 1,551,951 --------------------------------------------------------------------------------------------------------------------- TOTAL SENIOR SECURED FLOATING RATE LOAN INTERESTS (Cost $89,326,871) $ 89,283,630 --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- 25.0% of Net Assets 954,986 Fannie Mae, 2.5%, 7/1/30 $ 968,484 981,553 Fannie Mae, 2.5%, 7/1/30 995,612 1,655,218 Fannie Mae, 2.5%, 7/1/30 1,680,617 213,798 Fannie Mae, 2.5%, 12/1/42 212,106 216,313 Fannie Mae, 2.5%, 12/1/42 215,270 198,439 Fannie Mae, 2.5%, 1/1/43 197,487 80,761 Fannie Mae, 2.5%, 2/1/43 80,372 109,679 Fannie Mae, 2.5%, 2/1/43 108,472 2,201,898 Fannie Mae, 2.5%, 2/1/43 2,191,281 310,349 Fannie Mae, 2.5%, 3/1/43 308,853 115,827 Fannie Mae, 2.5%, 4/1/43 115,268 243,528 Fannie Mae, 2.5%, 8/1/43 242,354 203,527 Fannie Mae, 2.5%, 12/1/43 202,546 159,655 Fannie Mae, 2.5%, 3/1/44 158,885 195,635 Fannie Mae, 2.5%, 4/1/45 194,691 300,941 Fannie Mae, 2.5%, 4/1/45 299,490 394,061 Fannie Mae, 2.5%, 4/1/45 392,162 405,617 Fannie Mae, 2.5%, 4/1/45 403,660 416,978 Fannie Mae, 2.5%, 4/1/45 414,970 517,456 Fannie Mae, 2.5%, 4/1/45 514,960 The accompanying notes are an integral part of these financial statements. 60 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,109,196 Fannie Mae, 2.5%, 4/1/45 $ 1,103,846 1,250,274 Fannie Mae, 2.5%, 4/1/45 1,244,244 68,662 Fannie Mae, 2.5%, 5/1/45 68,331 74,230 Fannie Mae, 2.5%, 7/1/45 73,872 246,557 Fannie Mae, 2.5%, 8/1/45 245,368 85,646 Fannie Mae, 2.5%, 1/1/46 85,202 2,544,636 Fannie Mae, 3.0%, 9/1/28 2,635,395 2,461,656 Fannie Mae, 3.0%, 10/1/30 2,539,193 950,113 Fannie Mae, 3.0%, 4/1/31 978,210 14,341,178 Fannie Mae, 3.0%, 8/1/42 14,776,424 3,537,110 Fannie Mae, 3.0%, 9/1/42 3,643,892 1,061,233 Fannie Mae, 3.0%, 12/1/42 1,093,820 2,033,809 Fannie Mae, 3.0%, 2/1/43 2,096,267 552,399 Fannie Mae, 3.0%, 5/1/43 569,363 7,392,380 Fannie Mae, 3.0%, 5/1/43 7,612,892 516,796 Fannie Mae, 3.0%, 7/1/43 532,187 1,289,246 Fannie Mae, 3.0%, 8/1/43 1,327,313 3,633,187 Fannie Mae, 3.0%, 9/1/43 3,740,465 672,151 Fannie Mae, 3.0%, 3/1/45 691,934 5,646,694 Fannie Mae, 3.0%, 6/1/45 5,826,832 590,620 Fannie Mae, 3.0%, 5/1/46 611,120 743,379 Fannie Mae, 3.0%, 5/1/46 766,195 4,166,918 Fannie Mae, 3.0%, 9/1/46 4,267,788 7,673,608 Fannie Mae, 3.0%, 10/1/46 7,859,365 7,820,348 Fannie Mae, 3.0%, 11/1/46 8,009,662 6,479,265 Fannie Mae, 3.0%, 1/1/47 6,704,161 2,491,061 Fannie Mae, 3.0%, 3/1/47 2,551,332 3,889,299 Fannie Mae, 3.0%, 9/1/49 4,024,236 2,118,393 Fannie Mae, 3.5%, 6/1/28 2,203,022 879,899 Fannie Mae, 3.5%, 11/1/40 927,323 451,988 Fannie Mae, 3.5%, 10/1/41 482,000 3,382,061 Fannie Mae, 3.5%, 11/1/41 3,536,512 385,534 Fannie Mae, 3.5%, 6/1/42 407,918 2,249,253 Fannie Mae, 3.5%, 7/1/42 2,370,532 2,413,020 Fannie Mae, 3.5%, 8/1/42 2,543,605 328,631 Fannie Mae, 3.5%, 10/1/42 346,036 197,897 Fannie Mae, 3.5%, 11/1/42 210,710 425,312 Fannie Mae, 3.5%, 12/1/42 452,841 437,345 Fannie Mae, 3.5%, 12/1/42 465,643 4,087,144 Fannie Mae, 3.5%, 2/1/44 4,290,616 2,059,882 Fannie Mae, 3.5%, 9/1/44 2,155,479 4,599,812 Fannie Mae, 3.5%, 2/1/45 4,897,358 1,357,011 Fannie Mae, 3.5%, 4/1/45 1,429,725 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 61 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 5,167,382 Fannie Mae, 3.5%, 6/1/45 $ 5,409,508 1,915,357 Fannie Mae, 3.5%, 8/1/45 1,999,585 6,437,232 Fannie Mae, 3.5%, 8/1/45 6,900,134 5,056,220 Fannie Mae, 3.5%, 9/1/45 5,270,436 5,943,624 Fannie Mae, 3.5%, 9/1/45 6,206,386 1,228,363 Fannie Mae, 3.5%, 10/1/45 1,288,056 9,948,979 Fannie Mae, 3.5%, 11/1/45 10,664,426 1,992,008 Fannie Mae, 3.5%, 12/1/45 2,077,826 2,099,852 Fannie Mae, 3.5%, 12/1/45 2,190,254 3,788,040 Fannie Mae, 3.5%, 12/1/45 3,955,179 4,239,435 Fannie Mae, 3.5%, 1/1/46 4,425,554 5,700,578 Fannie Mae, 3.5%, 1/1/46 5,951,550 2,352,163 Fannie Mae, 3.5%, 2/1/46 2,460,069 3,920,662 Fannie Mae, 3.5%, 2/1/46 4,093,007 1,492,439 Fannie Mae, 3.5%, 3/1/46 1,558,268 3,261,825 Fannie Mae, 3.5%, 4/1/46 3,402,118 2,240,061 Fannie Mae, 3.5%, 5/1/46 2,369,987 4,739,063 Fannie Mae, 3.5%, 7/1/46 4,929,711 7,288,008 Fannie Mae, 3.5%, 9/1/46 7,585,240 422,220 Fannie Mae, 3.5%, 10/1/46 442,804 972,729 Fannie Mae, 3.5%, 10/1/46 1,010,268 1,007,879 Fannie Mae, 3.5%, 11/1/46 1,046,809 3,824,967 Fannie Mae, 3.5%, 12/1/46 3,972,760 1,778,321 Fannie Mae, 3.5%, 1/1/47 1,846,973 3,990,466 Fannie Mae, 3.5%, 1/1/47 4,144,402 5,539,569 Fannie Mae, 3.5%, 1/1/47 5,860,678 9,018,295 Fannie Mae, 3.5%, 1/1/47 9,457,695 72,266 Fannie Mae, 3.5%, 2/1/47 75,611 5,081,343 Fannie Mae, 3.5%, 2/1/47 5,277,068 6,074,707 Fannie Mae, 3.5%, 5/1/47 6,306,219 6,772,503 Fannie Mae, 3.5%, 5/1/47 7,029,602 267,375 Fannie Mae, 3.5%, 7/1/47 278,802 2,218,525 Fannie Mae, 3.5%, 7/1/47 2,303,445 6,574,620 Fannie Mae, 3.5%, 7/1/47 6,807,599 10,063,947 Fannie Mae, 3.5%, 7/1/47 10,448,507 1,140,245 Fannie Mae, 3.5%, 8/1/47 1,183,877 15,738,794 Fannie Mae, 3.5%, 8/1/47 16,340,095 152,344 Fannie Mae, 3.5%, 10/1/47 159,403 2,602,582 Fannie Mae, 3.5%, 11/1/47 2,702,826 479,176 Fannie Mae, 3.5%, 12/1/47 513,600 6,709,677 Fannie Mae, 3.5%, 12/1/47 6,968,382 11,028,240 Fannie Mae, 3.5%, 12/1/47 11,453,090 13,141,339 Fannie Mae, 3.5%, 12/1/47 13,644,546 The accompanying notes are an integral part of these financial statements. 62 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 3,522,435 Fannie Mae, 3.5%, 1/1/48 $ 3,655,849 2,744,602 Fannie Mae, 3.5%, 2/1/48 2,851,497 467,452 Fannie Mae, 3.5%, 2/1/49 480,166 479,690 Fannie Mae, 3.5%, 4/1/49 490,370 1,570,714 Fannie Mae, 3.5%, 5/1/49 1,668,507 2,213,556 Fannie Mae, 3.5%, 5/1/49 2,371,662 49,632 Fannie Mae, 3.5%, 7/1/49 52,253 2,823,206 Fannie Mae, 3.5%, 9/1/49 3,004,764 728,536 Fannie Mae, 3.771%, 12/1/20 737,969 5,066 Fannie Mae, 4.0%, 9/1/20 5,280 157,003 Fannie Mae, 4.0%, 4/1/25 163,772 191,578 Fannie Mae, 4.0%, 11/1/34 204,039 1,910,148 Fannie Mae, 4.0%, 4/1/39 2,047,175 5,179,715 Fannie Mae, 4.0%, 10/1/40 5,618,842 955,325 Fannie Mae, 4.0%, 12/1/40 1,036,493 1,010,267 Fannie Mae, 4.0%, 4/1/41 1,083,580 620,174 Fannie Mae, 4.0%, 5/1/41 665,188 1,184,888 Fannie Mae, 4.0%, 10/1/41 1,270,801 689,896 Fannie Mae, 4.0%, 12/1/41 725,148 288,672 Fannie Mae, 4.0%, 1/1/42 309,087 1,878,467 Fannie Mae, 4.0%, 1/1/42 2,010,839 1,781,167 Fannie Mae, 4.0%, 2/1/42 1,907,266 4,894,823 Fannie Mae, 4.0%, 2/1/42 5,240,479 82,880 Fannie Mae, 4.0%, 4/1/42 86,210 447,284 Fannie Mae, 4.0%, 4/1/42 478,441 1,880,784 Fannie Mae, 4.0%, 4/1/42 2,012,789 3,630,480 Fannie Mae, 4.0%, 5/1/42 3,882,166 79,492 Fannie Mae, 4.0%, 6/1/42 85,072 206,764 Fannie Mae, 4.0%, 6/1/42 216,343 123,364 Fannie Mae, 4.0%, 7/1/42 131,976 5,674,445 Fannie Mae, 4.0%, 8/1/42 6,077,964 315,570 Fannie Mae, 4.0%, 10/1/42 339,789 1,057,877 Fannie Mae, 4.0%, 10/1/42 1,134,430 3,225,255 Fannie Mae, 4.0%, 8/1/43 3,438,029 4,170,454 Fannie Mae, 4.0%, 9/1/43 4,449,338 2,698,811 Fannie Mae, 4.0%, 11/1/43 2,905,528 94,607 Fannie Mae, 4.0%, 1/1/44 100,567 3,980,485 Fannie Mae, 4.0%, 2/1/44 4,231,100 57,830 Fannie Mae, 4.0%, 6/1/44 61,272 65,046 Fannie Mae, 4.0%, 6/1/44 68,125 214,310 Fannie Mae, 4.0%, 7/1/44 227,093 3,796,848 Fannie Mae, 4.0%, 7/1/44 4,022,719 146,884 Fannie Mae, 4.0%, 8/1/44 155,637 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 63 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 175,674 Fannie Mae, 4.0%, 8/1/44 $ 186,133 894,101 Fannie Mae, 4.0%, 8/1/44 947,296 2,582,189 Fannie Mae, 4.0%, 8/1/44 2,727,810 30,424 Fannie Mae, 4.0%, 9/1/44 32,236 245,223 Fannie Mae, 4.0%, 9/1/44 259,827 312,819 Fannie Mae, 4.0%, 9/1/44 331,459 1,048,453 Fannie Mae, 4.0%, 10/1/44 1,098,171 77,459 Fannie Mae, 4.0%, 11/1/44 82,089 88,328 Fannie Mae, 4.0%, 11/1/44 93,586 138,182 Fannie Mae, 4.0%, 11/1/44 144,671 3,749,106 Fannie Mae, 4.0%, 11/1/44 3,972,297 29,884 Fannie Mae, 4.0%, 12/1/44 31,666 383,970 Fannie Mae, 4.0%, 12/1/44 406,839 53,111 Fannie Mae, 4.0%, 1/1/45 56,285 170,229 Fannie Mae, 4.0%, 1/1/45 180,390 244,657 Fannie Mae, 4.0%, 1/1/45 259,222 40,256 Fannie Mae, 4.0%, 2/1/45 42,655 129,229 Fannie Mae, 4.0%, 2/1/45 137,007 286,245 Fannie Mae, 4.0%, 2/1/45 303,310 3,085,632 Fannie Mae, 4.0%, 3/1/45 3,269,354 141,580 Fannie Mae, 4.0%, 6/1/45 150,130 305,733 Fannie Mae, 4.0%, 7/1/45 327,401 1,950,933 Fannie Mae, 4.0%, 10/1/45 2,056,977 3,028,696 Fannie Mae, 4.0%, 10/1/45 3,208,773 3,559,673 Fannie Mae, 4.0%, 10/1/45 3,771,936 45,725 Fannie Mae, 4.0%, 11/1/45 47,872 2,433,851 Fannie Mae, 4.0%, 11/1/45 2,578,691 4,292,754 Fannie Mae, 4.0%, 12/1/45 4,548,604 1,780,879 Fannie Mae, 4.0%, 1/1/46 1,885,938 4,585,584 Fannie Mae, 4.0%, 2/1/46 4,863,903 1,151,798 Fannie Mae, 4.0%, 4/1/46 1,218,120 3,979,585 Fannie Mae, 4.0%, 6/1/46 4,206,362 4,057,344 Fannie Mae, 4.0%, 7/1/46 4,276,251 5,675,813 Fannie Mae, 4.0%, 7/1/46 5,993,283 3,247,813 Fannie Mae, 4.0%, 8/1/46 3,426,350 3,898,551 Fannie Mae, 4.0%, 8/1/46 4,106,915 1,327,744 Fannie Mae, 4.0%, 11/1/46 1,396,215 10,008,584 Fannie Mae, 4.0%, 1/1/47 10,518,207 2,566,965 Fannie Mae, 4.0%, 4/1/47 2,700,316 2,760,725 Fannie Mae, 4.0%, 4/1/47 2,938,402 3,956,547 Fannie Mae, 4.0%, 4/1/47 4,210,722 511,774 Fannie Mae, 4.0%, 6/1/47 543,863 1,493,442 Fannie Mae, 4.0%, 6/1/47 1,584,784 The accompanying notes are an integral part of these financial statements. 64 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 2,543,452 Fannie Mae, 4.0%, 6/1/47 $ 2,676,084 4,161,190 Fannie Mae, 4.0%, 6/1/47 4,377,969 7,122,772 Fannie Mae, 4.0%, 6/1/47 7,489,027 2,343,679 Fannie Mae, 4.0%, 7/1/47 2,463,572 2,379,437 Fannie Mae, 4.0%, 7/1/47 2,531,298 1,957,636 Fannie Mae, 4.0%, 8/1/47 2,043,329 3,721,063 Fannie Mae, 4.0%, 8/1/47 3,884,218 5,449,687 Fannie Mae, 4.0%, 12/1/47 5,718,300 6,814,436 Fannie Mae, 4.0%, 4/1/48 7,105,577 485,344 Fannie Mae, 4.0%, 11/1/48 509,586 253,541 Fannie Mae, 4.0%, 6/1/49 272,824 1,821,379 Fannie Mae, 4.0%, 9/1/49 1,900,592 20,852,668 Fannie Mae, 4.0%, 10/1/49 21,772,011 1,200 Fannie Mae, 4.5%, 11/1/20 1,239 28,951 Fannie Mae, 4.5%, 11/1/20 29,888 146,051 Fannie Mae, 4.5%, 10/1/35 158,278 339,741 Fannie Mae, 4.5%, 8/1/40 368,367 761,410 Fannie Mae, 4.5%, 8/1/40 826,870 1,260,386 Fannie Mae, 4.5%, 11/1/40 1,368,894 425,390 Fannie Mae, 4.5%, 2/1/41 456,238 1,111,126 Fannie Mae, 4.5%, 4/1/41 1,206,586 58,270 Fannie Mae, 4.5%, 5/1/41 63,270 1,587,048 Fannie Mae, 4.5%, 5/1/41 1,723,353 2,070,797 Fannie Mae, 4.5%, 5/1/41 2,248,253 2,669,160 Fannie Mae, 4.5%, 5/1/41 2,931,506 804,724 Fannie Mae, 4.5%, 7/1/41 874,026 1,140,870 Fannie Mae, 4.5%, 7/1/41 1,239,136 2,962,518 Fannie Mae, 4.5%, 1/1/42 3,216,949 3,766,960 Fannie Mae, 4.5%, 1/1/42 4,090,634 377,531 Fannie Mae, 4.5%, 11/1/43 406,272 3,113,841 Fannie Mae, 4.5%, 12/1/43 3,356,869 4,921,166 Fannie Mae, 4.5%, 12/1/43 5,294,963 3,761,480 Fannie Mae, 4.5%, 1/1/44 4,049,102 2,025,441 Fannie Mae, 4.5%, 2/1/44 2,178,320 2,361,783 Fannie Mae, 4.5%, 2/1/44 2,535,179 3,772,820 Fannie Mae, 4.5%, 5/1/46 4,023,927 499,020 Fannie Mae, 4.5%, 1/1/47 533,069 421,446 Fannie Mae, 4.5%, 2/1/47 450,408 2,220,434 Fannie Mae, 4.5%, 2/1/47 2,347,888 430,464 Fannie Mae, 4.5%, 6/1/49 455,573 15,999,095 Fannie Mae, 4.5%, 10/1/49 16,883,328 1,210,807 Fannie Mae, 4.5%, 12/1/49 1,278,838 496 Fannie Mae, 5.0%, 1/1/20 512 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 65 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 74 Fannie Mae, 5.0%, 2/1/20 $ 77 14,643 Fannie Mae, 5.0%, 10/1/20 15,128 2,667 Fannie Mae, 5.0%, 2/1/22 2,759 25,281 Fannie Mae, 5.0%, 2/1/22 26,117 31,486 Fannie Mae, 5.0%, 3/1/23 32,536 117,726 Fannie Mae, 5.0%, 5/1/23 123,668 33,841 Fannie Mae, 5.0%, 7/1/34 35,457 142,091 Fannie Mae, 5.0%, 10/1/34 154,940 512,229 Fannie Mae, 5.0%, 2/1/39 564,395 381,767 Fannie Mae, 5.0%, 6/1/40 417,838 425,388 Fannie Mae, 5.0%, 6/1/40 469,075 305,022 Fannie Mae, 5.0%, 7/1/40 336,412 466,199 Fannie Mae, 5.0%, 7/1/40 514,330 634,363 Fannie Mae, 5.0%, 7/1/40 690,328 537,734 Fannie Mae, 5.0%, 8/1/40 592,832 2,191,056 Fannie Mae, 5.0%, 2/1/41 2,414,616 7,017,543 Fannie Mae, 5.0%, 12/1/44 7,736,055 1,012,821 Fannie Mae, 5.0%, 6/1/49 1,084,407 1,680,972 Fannie Mae, 5.0%, 9/1/49 1,860,502 5,768,642 Fannie Mae, 5.0%, 9/1/49 6,504,379 1,032,412 Fannie Mae, 5.0%, 10/1/49 1,104,750 13,364 Fannie Mae, 5.5%, 6/1/33 15,026 61,620 Fannie Mae, 5.5%, 7/1/33 68,851 363,847 Fannie Mae, 5.5%, 7/1/34 409,536 192,194 Fannie Mae, 5.5%, 3/1/36 215,986 80,467 Fannie Mae, 5.5%, 5/1/36 88,901 108,952 Fannie Mae, 5.5%, 6/1/36 122,559 40,504 Fannie Mae, 5.72%, 11/1/28 41,153 22,365 Fannie Mae, 5.72%, 6/1/29 22,428 17,822 Fannie Mae, 5.9%, 11/1/27 17,850 64,556 Fannie Mae, 5.9%, 4/1/28 66,227 552 Fannie Mae, 6.0%, 9/1/29 618 2,656 Fannie Mae, 6.0%, 1/1/32 3,029 8,258 Fannie Mae, 6.0%, 2/1/32 9,347 3,566 Fannie Mae, 6.0%, 3/1/32 4,089 2,364 Fannie Mae, 6.0%, 8/1/32 2,710 257 Fannie Mae, 6.0%, 9/1/32 295 29,967 Fannie Mae, 6.0%, 10/1/32 34,340 5,492 Fannie Mae, 6.0%, 2/1/33 6,045 44,843 Fannie Mae, 6.0%, 3/1/33 51,376 49,166 Fannie Mae, 6.0%, 4/1/33 54,329 31,736 Fannie Mae, 6.0%, 7/1/33 34,925 99,149 Fannie Mae, 6.0%, 7/1/33 110,432 The accompanying notes are an integral part of these financial statements. 66 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 23,072 Fannie Mae, 6.0%, 11/1/33 $ 26,423 78,328 Fannie Mae, 6.0%, 8/1/34 89,773 3,535 Fannie Mae, 6.0%, 9/1/34 3,972 16,683 Fannie Mae, 6.0%, 9/1/34 19,136 17,195 Fannie Mae, 6.0%, 9/1/34 19,046 62,442 Fannie Mae, 6.0%, 9/1/34 68,813 7,478 Fannie Mae, 6.0%, 10/1/34 8,568 6,893 Fannie Mae, 6.0%, 11/1/34 7,902 112,295 Fannie Mae, 6.0%, 11/1/34 125,119 2,486 Fannie Mae, 6.0%, 2/1/35 2,847 5,196 Fannie Mae, 6.0%, 2/1/35 5,871 108,740 Fannie Mae, 6.0%, 4/1/35 124,608 17,993 Fannie Mae, 6.0%, 5/1/35 19,835 79,386 Fannie Mae, 6.0%, 10/1/35 87,448 146,440 Fannie Mae, 6.0%, 12/1/35 166,867 13,291 Fannie Mae, 6.0%, 12/1/37 15,196 126,440 Fannie Mae, 6.0%, 6/1/38 140,987 28,392 Fannie Mae, 6.0%, 7/1/38 31,512 5,742 Fannie Mae, 6.5%, 7/1/29 6,373 941 Fannie Mae, 6.5%, 1/1/31 1,045 1,610 Fannie Mae, 6.5%, 4/1/31 1,787 3,254 Fannie Mae, 6.5%, 5/1/31 3,612 7,633 Fannie Mae, 6.5%, 8/1/31 8,472 2,648 Fannie Mae, 6.5%, 9/1/31 2,939 2,939 Fannie Mae, 6.5%, 9/1/31 3,262 1,680 Fannie Mae, 6.5%, 10/1/31 1,865 109,435 Fannie Mae, 6.5%, 12/1/31 121,466 4,118 Fannie Mae, 6.5%, 2/1/32 4,571 33,392 Fannie Mae, 6.5%, 3/1/32 37,063 67,016 Fannie Mae, 6.5%, 7/1/32 75,069 62,486 Fannie Mae, 6.5%, 10/1/32 69,356 12,588 Fannie Mae, 6.5%, 7/1/34 13,972 71,124 Fannie Mae, 6.5%, 11/1/37 81,522 14,239 Fannie Mae, 6.5%, 11/1/47 15,236 536 Fannie Mae, 7.0%, 12/1/30 554 5,707 Fannie Mae, 7.0%, 12/1/30 6,361 4,397 Fannie Mae, 7.0%, 4/1/31 5,055 5,591 Fannie Mae, 7.0%, 9/1/31 6,399 13,855 Fannie Mae, 7.0%, 12/1/31 14,168 11,819 Fannie Mae, 7.0%, 1/1/32 13,814 2,080,822 Federal Home Loan Mortgage Corp., 3.0%, 8/1/29 2,154,502 1,860,249 Federal Home Loan Mortgage Corp., 3.0%, 10/1/29 1,916,410 814,614 Federal Home Loan Mortgage Corp., 3.0%, 9/1/42 839,871 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 67 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 5,215,161 Federal Home Loan Mortgage Corp., 3.0%, 11/1/42 $ 5,376,818 628,370 Federal Home Loan Mortgage Corp., 3.0%, 2/1/43 648,832 1,565,404 Federal Home Loan Mortgage Corp., 3.0%, 2/1/43 1,616,376 1,803,925 Federal Home Loan Mortgage Corp., 3.0%, 5/1/43 1,858,768 1,202,932 Federal Home Loan Mortgage Corp., 3.0%, 5/1/45 1,235,362 1,037,287 Federal Home Loan Mortgage Corp., 3.0%, 8/1/45 1,062,989 4,181,791 Federal Home Loan Mortgage Corp., 3.0%, 6/1/46 4,307,553 3,396,628 Federal Home Loan Mortgage Corp., 3.0%, 9/1/46 3,480,925 1,095,138 Federal Home Loan Mortgage Corp., 3.0%, 12/1/46 1,128,073 1,781,951 Federal Home Loan Mortgage Corp., 3.0%, 12/1/46 1,826,163 5,064,704 Federal Home Loan Mortgage Corp., 3.0%, 2/1/47 5,190,367 748,120 Federal Home Loan Mortgage Corp., 3.0%, 3/1/47 764,369 249,615 Federal Home Loan Mortgage Corp., 3.0%, 7/1/47 253,336 28,556,671 Federal Home Loan Mortgage Corp., 3.0%, 11/1/49 28,974,572 157,957 Federal Home Loan Mortgage Corp., 3.5%, 3/1/26 163,735 1,209,233 Federal Home Loan Mortgage Corp., 3.5%, 4/1/42 1,279,037 469,000 Federal Home Loan Mortgage Corp., 3.5%, 5/1/43 491,024 2,208,220 Federal Home Loan Mortgage Corp., 3.5%, 8/1/43 2,328,901 5,150,561 Federal Home Loan Mortgage Corp., 3.5%, 7/1/44 5,402,597 598,104 Federal Home Loan Mortgage Corp., 3.5%, 8/1/44 626,662 446,758 Federal Home Loan Mortgage Corp., 3.5%, 9/1/44 472,915 1,813,138 Federal Home Loan Mortgage Corp., 3.5%, 10/1/44 1,898,609 94,838 Federal Home Loan Mortgage Corp., 3.5%, 11/1/44 99,154 4,774,678 Federal Home Loan Mortgage Corp., 3.5%, 12/1/44 4,995,504 2,330,315 Federal Home Loan Mortgage Corp., 3.5%, 3/1/45 2,434,615 569,045 Federal Home Loan Mortgage Corp., 3.5%, 4/1/45 594,504 5,857,420 Federal Home Loan Mortgage Corp., 3.5%, 6/1/45 6,201,014 150,101 Federal Home Loan Mortgage Corp., 3.5%, 7/1/45 159,745 5,096,971 Federal Home Loan Mortgage Corp., 3.5%, 10/1/45 5,376,346 5,617,345 Federal Home Loan Mortgage Corp., 3.5%, 10/1/45 5,868,337 6,055,977 Federal Home Loan Mortgage Corp., 3.5%, 11/1/45 6,353,914 2,929,574 Federal Home Loan Mortgage Corp., 3.5%, 3/1/46 3,055,271 5,003,517 Federal Home Loan Mortgage Corp., 3.5%, 5/1/46 5,211,357 5,252,818 Federal Home Loan Mortgage Corp., 3.5%, 7/1/46 5,595,617 7,389,836 Federal Home Loan Mortgage Corp., 3.5%, 8/1/46 7,823,132 7,660,064 Federal Home Loan Mortgage Corp., 3.5%, 8/1/46 8,075,206 9,184,070 Federal Home Loan Mortgage Corp., 3.5%, 8/1/46 9,682,033 3,117,363 Federal Home Loan Mortgage Corp., 3.5%, 12/1/46 3,241,229 9,070,735 Federal Home Loan Mortgage Corp., 3.5%, 12/1/46 9,602,624 1,202,493 Federal Home Loan Mortgage Corp., 3.5%, 1/1/47 1,267,625 1,806,974 Federal Home Loan Mortgage Corp., 3.5%, 1/1/47 1,877,899 534,523 Federal Home Loan Mortgage Corp., 3.5%, 6/1/47 563,315 1,671,310 Federal Home Loan Mortgage Corp., 3.5%, 6/1/47 1,736,059 The accompanying notes are an integral part of these financial statements. 68 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 3,510,774 Federal Home Loan Mortgage Corp., 3.5%, 6/1/47 $ 3,647,053 7,858,629 Federal Home Loan Mortgage Corp., 3.5%, 7/1/47 8,163,686 7,661,182 Federal Home Loan Mortgage Corp., 3.5%, 8/1/47 7,959,310 8,888,979 Federal Home Loan Mortgage Corp., 3.5%, 10/1/47 9,240,936 3,049,734 Federal Home Loan Mortgage Corp., 3.5%, 11/1/47 3,171,300 4,254,622 Federal Home Loan Mortgage Corp., 3.5%, 11/1/47 4,421,543 3,029,673 Federal Home Loan Mortgage Corp., 3.5%, 1/1/48 3,150,983 6,137,014 Federal Home Loan Mortgage Corp., 3.5%, 1/1/48 6,376,321 5,049,145 Federal Home Loan Mortgage Corp., 3.5%, 8/1/49 5,189,146 7,096,307 Federal Home Loan Mortgage Corp., 4.0%, 11/1/41 7,716,918 244,814 Federal Home Loan Mortgage Corp., 4.0%, 6/1/42 262,064 82,442 Federal Home Loan Mortgage Corp., 4.0%, 7/1/42 88,294 3,137,512 Federal Home Loan Mortgage Corp., 4.0%, 10/1/42 3,358,118 53,950 Federal Home Loan Mortgage Corp., 4.0%, 11/1/42 57,848 1,225,906 Federal Home Loan Mortgage Corp., 4.0%, 1/1/44 1,304,577 3,422,214 Federal Home Loan Mortgage Corp., 4.0%, 5/1/44 3,628,375 3,197,981 Federal Home Loan Mortgage Corp., 4.0%, 6/1/44 3,390,705 4,605,546 Federal Home Loan Mortgage Corp., 4.0%, 7/1/44 4,883,224 1,830,473 Federal Home Loan Mortgage Corp., 4.0%, 9/1/44 1,947,747 1,228,979 Federal Home Loan Mortgage Corp., 4.0%, 12/1/44 1,303,043 872,848 Federal Home Loan Mortgage Corp., 4.0%, 4/1/45 925,516 3,463,652 Federal Home Loan Mortgage Corp., 4.0%, 12/1/45 3,672,378 1,363,493 Federal Home Loan Mortgage Corp., 4.0%, 1/1/46 1,444,912 221,387 Federal Home Loan Mortgage Corp., 4.0%, 5/1/46 230,385 447,097 Federal Home Loan Mortgage Corp., 4.0%, 5/1/46 472,897 3,121,772 Federal Home Loan Mortgage Corp., 4.0%, 6/1/46 3,295,528 3,739,636 Federal Home Loan Mortgage Corp., 4.0%, 7/1/46 3,951,498 3,186,600 Federal Home Loan Mortgage Corp., 4.0%, 8/1/46 3,362,117 54,889 Federal Home Loan Mortgage Corp., 4.0%, 10/1/46 57,124 1,140,851 Federal Home Loan Mortgage Corp., 4.0%, 3/1/47 1,202,136 1,737,833 Federal Home Loan Mortgage Corp., 4.0%, 4/1/47 1,850,853 2,651,291 Federal Home Loan Mortgage Corp., 4.0%, 4/1/47 2,816,875 5,120,382 Federal Home Loan Mortgage Corp., 4.0%, 4/1/47 5,394,387 5,909,466 Federal Home Loan Mortgage Corp., 4.0%, 4/1/47 6,293,008 7,722,521 Federal Home Loan Mortgage Corp., 4.0%, 4/1/47 8,121,985 8,915,282 Federal Home Loan Mortgage Corp., 4.0%, 5/1/47 9,321,699 1,110,784 Federal Home Loan Mortgage Corp., 4.0%, 6/1/47 1,170,143 2,627,822 Federal Home Loan Mortgage Corp., 4.0%, 7/1/47 2,765,252 5,450,017 Federal Home Loan Mortgage Corp., 4.0%, 10/1/47 5,716,653 1,090,925 Federal Home Loan Mortgage Corp., 4.0%, 5/1/49 1,139,303 24,851,747 Federal Home Loan Mortgage Corp., 4.0%, 7/1/49 25,835,558 8,604,792 Federal Home Loan Mortgage Corp., 4.0%, 9/1/49 8,957,064 1,289 Federal Home Loan Mortgage Corp., 4.5%, 3/1/20 1,332 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 69 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 18,254 Federal Home Loan Mortgage Corp., 4.5%, 10/1/20 $ 18,852 1,952,966 Federal Home Loan Mortgage Corp., 4.5%, 11/1/40 2,122,183 1,223,612 Federal Home Loan Mortgage Corp., 4.5%, 3/1/42 1,329,441 2,642,098 Federal Home Loan Mortgage Corp., 4.5%, 3/1/42 2,871,149 108,579 Federal Home Loan Mortgage Corp., 4.5%, 11/1/43 116,956 4,844,999 Federal Home Loan Mortgage Corp., 4.5%, 5/1/47 5,139,560 1,389,626 Federal Home Loan Mortgage Corp., 4.5%, 11/1/48 1,465,030 1,424,737 Federal Home Loan Mortgage Corp., 4.5%, 6/1/49 1,507,470 14,642,912 Federal Home Loan Mortgage Corp., 4.5%, 6/1/49 15,453,444 1,220,817 Federal Home Loan Mortgage Corp., 4.5%, 7/1/49 1,288,719 2,178,065 Federal Home Loan Mortgage Corp., 4.5%, 7/1/49 2,298,609 7,606,189 Federal Home Loan Mortgage Corp., 4.5%, 7/1/49 8,056,806 4,089,978 Federal Home Loan Mortgage Corp., 4.5%, 8/1/49 4,332,282 28,479 Federal Home Loan Mortgage Corp., 5.0%, 10/1/20 29,432 2,670 Federal Home Loan Mortgage Corp., 5.0%, 12/1/21 2,760 7,477 Federal Home Loan Mortgage Corp., 5.0%, 11/1/34 8,252 53,355 Federal Home Loan Mortgage Corp., 5.0%, 6/1/35 57,009 205,751 Federal Home Loan Mortgage Corp., 5.0%, 9/1/38 226,832 200,073 Federal Home Loan Mortgage Corp., 5.0%, 10/1/38 220,579 5,522,484 Federal Home Loan Mortgage Corp., 5.0%, 9/1/49 5,911,203 1,196,248 Federal Home Loan Mortgage Corp., 5.0%, 10/1/49 1,280,911 10,761,296 Federal Home Loan Mortgage Corp., 5.0%, 10/1/49 11,527,028 20,204,278 Federal Home Loan Mortgage Corp., 5.0%, 12/1/49 21,640,922 126,850 Federal Home Loan Mortgage Corp., 5.5%, 9/1/33 142,533 6,455 Federal Home Loan Mortgage Corp., 5.5%, 1/1/34 7,103 5,236 Federal Home Loan Mortgage Corp., 5.5%, 11/1/34 5,636 64,818 Federal Home Loan Mortgage Corp., 5.5%, 11/1/34 72,967 70,679 Federal Home Loan Mortgage Corp., 5.5%, 8/1/35 77,085 17,711 Federal Home Loan Mortgage Corp., 5.5%, 11/1/35 19,909 699,481 Federal Home Loan Mortgage Corp., 5.5%, 6/1/41 786,677 40,573 Federal Home Loan Mortgage Corp., 6.0%, 1/1/33 44,769 51,539 Federal Home Loan Mortgage Corp., 6.0%, 1/1/33 57,469 2,066 Federal Home Loan Mortgage Corp., 6.0%, 2/1/33 2,282 28,689 Federal Home Loan Mortgage Corp., 6.0%, 2/1/33 32,898 10,333 Federal Home Loan Mortgage Corp., 6.0%, 3/1/33 11,375 91,357 Federal Home Loan Mortgage Corp., 6.0%, 3/1/33 104,803 61,768 Federal Home Loan Mortgage Corp., 6.0%, 9/1/33 70,827 10,240 Federal Home Loan Mortgage Corp., 6.0%, 11/1/33 11,740 22,945 Federal Home Loan Mortgage Corp., 6.0%, 11/1/33 25,429 8,064 Federal Home Loan Mortgage Corp., 6.0%, 12/1/33 8,886 108,254 Federal Home Loan Mortgage Corp., 6.0%, 12/1/33 119,592 17,732 Federal Home Loan Mortgage Corp., 6.0%, 1/1/34 20,343 32,232 Federal Home Loan Mortgage Corp., 6.0%, 1/1/34 35,766 The accompanying notes are an integral part of these financial statements. 70 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 88,368 Federal Home Loan Mortgage Corp., 6.0%, 5/1/34 $ 97,548 275,306 Federal Home Loan Mortgage Corp., 6.0%, 5/1/34 315,688 58,362 Federal Home Loan Mortgage Corp., 6.0%, 8/1/34 64,667 14,409 Federal Home Loan Mortgage Corp., 6.0%, 4/1/35 15,866 43,447 Federal Home Loan Mortgage Corp., 6.0%, 6/1/35 47,844 47,191 Federal Home Loan Mortgage Corp., 6.0%, 4/1/36 52,173 6,748 Federal Home Loan Mortgage Corp., 6.0%, 7/1/36 7,731 30,815 Federal Home Loan Mortgage Corp., 6.0%, 7/1/36 33,959 19,819 Federal Home Loan Mortgage Corp., 6.0%, 12/1/36 22,590 43,592 Federal Home Loan Mortgage Corp., 6.0%, 1/1/38 49,981 52,787 Federal Home Loan Mortgage Corp., 6.0%, 7/1/38 59,307 219 Federal Home Loan Mortgage Corp., 6.5%, 11/1/30 243 137 Federal Home Loan Mortgage Corp., 6.5%, 1/1/31 152 307 Federal Home Loan Mortgage Corp., 6.5%, 3/1/31 341 1,128 Federal Home Loan Mortgage Corp., 6.5%, 3/1/31 1,253 4,551 Federal Home Loan Mortgage Corp., 6.5%, 5/1/31 5,054 4,574 Federal Home Loan Mortgage Corp., 6.5%, 5/1/31 5,080 439 Federal Home Loan Mortgage Corp., 6.5%, 8/1/31 488 3,483 Federal Home Loan Mortgage Corp., 6.5%, 8/1/31 3,868 93 Federal Home Loan Mortgage Corp., 6.5%, 6/1/32 103 7,276 Federal Home Loan Mortgage Corp., 6.5%, 7/1/32 8,200 82 Federal Home Loan Mortgage Corp., 6.5%, 1/1/33 91 23,031 Federal Home Loan Mortgage Corp., 6.5%, 10/1/33 26,689 6,329 Federal Home Loan Mortgage Corp., 7.0%, 8/1/22 6,367 31,862 Federal Home Loan Mortgage Corp., 7.0%, 9/1/22 32,762 1,849 Federal Home Loan Mortgage Corp., 7.0%, 11/1/30 2,100 994 Federal Home Loan Mortgage Corp., 7.0%, 6/1/31 995 72,230 Federal Home Loan Mortgage Corp., 7.0%, 10/1/46 74,452 6,113,027 Government National Mortgage Association I, 3.5%, 11/15/41 6,431,680 4,736,101 Government National Mortgage Association I, 3.5%, 7/15/42 4,999,547 1,195,523 Government National Mortgage Association I, 3.5%, 10/15/42 1,257,709 710,699 Government National Mortgage Association I, 3.5%, 1/15/44 748,825 7,409,169 Government National Mortgage Association I, 3.5%, 1/15/45 7,793,025 2,079,816 Government National Mortgage Association I, 3.5%, 8/15/46 2,170,068 7,179 Government National Mortgage Association I, 4.0%, 5/15/39 7,509 2,691 Government National Mortgage Association I, 4.0%, 6/15/39 2,864 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 71 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 4,779 Government National Mortgage Association I, 4.0%, 8/15/40 $ 5,088 213,815 Government National Mortgage Association I, 4.0%, 8/15/40 223,635 4,435 Government National Mortgage Association I, 4.0%, 9/15/40 4,678 91,506 Government National Mortgage Association I, 4.0%, 9/15/40 95,709 4,471 Government National Mortgage Association I, 4.0%, 10/15/40 4,760 5,784 Government National Mortgage Association I, 4.0%, 11/15/40 6,050 23,480 Government National Mortgage Association I, 4.0%, 11/15/40 24,582 14,045 Government National Mortgage Association I, 4.0%, 1/15/41 14,955 48,995 Government National Mortgage Association I, 4.0%, 1/15/41 52,167 7,074 Government National Mortgage Association I, 4.0%, 2/15/41 7,531 46,294 Government National Mortgage Association I, 4.0%, 6/15/41 49,199 100,167 Government National Mortgage Association I, 4.0%, 7/15/41 106,653 2,080 Government National Mortgage Association I, 4.0%, 9/15/41 2,176 268,302 Government National Mortgage Association I, 4.0%, 9/15/41 285,662 5,230 Government National Mortgage Association I, 4.0%, 10/15/41 5,471 5,484 Government National Mortgage Association I, 4.0%, 10/15/41 5,783 3,018 Government National Mortgage Association I, 4.0%, 11/15/41 3,157 3,022 Government National Mortgage Association I, 4.0%, 11/15/41 3,200 4,590 Government National Mortgage Association I, 4.0%, 12/15/41 4,889 17,758 Government National Mortgage Association I, 4.0%, 2/15/42 19,043 202,063 Government National Mortgage Association I, 4.0%, 2/15/42 211,343 800,306 Government National Mortgage Association I, 4.0%, 8/15/43 847,832 18,356 Government National Mortgage Association I, 4.0%, 11/15/43 19,424 7,567 Government National Mortgage Association I, 4.0%, 3/15/44 8,124 The accompanying notes are an integral part of these financial statements. 72 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 77,233 Government National Mortgage Association I, 4.0%, 3/15/44 $ 81,054 444,377 Government National Mortgage Association I, 4.0%, 3/15/44 470,779 2,628,725 Government National Mortgage Association I, 4.0%, 3/15/44 2,784,593 3,246 Government National Mortgage Association I, 4.0%, 4/15/44 3,395 20,022 Government National Mortgage Association I, 4.0%, 4/15/44 21,504 1,938,043 Government National Mortgage Association I, 4.0%, 4/15/44 2,080,645 270,431 Government National Mortgage Association I, 4.0%, 8/15/44 290,399 48,009 Government National Mortgage Association I, 4.0%, 9/15/44 50,856 163,012 Government National Mortgage Association I, 4.0%, 9/15/44 171,516 207,378 Government National Mortgage Association I, 4.0%, 9/15/44 219,653 294,472 Government National Mortgage Association I, 4.0%, 9/15/44 308,537 1,633,850 Government National Mortgage Association I, 4.0%, 9/15/44 1,730,903 74,529 Government National Mortgage Association I, 4.0%, 10/15/44 79,638 201,489 Government National Mortgage Association I, 4.0%, 11/15/44 211,446 1,567,327 Government National Mortgage Association I, 4.0%, 12/15/44 1,660,487 333,166 Government National Mortgage Association I, 4.0%, 1/15/45 357,639 884,787 Government National Mortgage Association I, 4.0%, 1/15/45 929,917 1,113,184 Government National Mortgage Association I, 4.0%, 1/15/45 1,179,236 1,458,311 Government National Mortgage Association I, 4.0%, 1/15/45 1,528,948 757,786 Government National Mortgage Association I, 4.0%, 2/15/45 802,177 1,123,603 Government National Mortgage Association I, 4.0%, 2/15/45 1,190,044 65,591 Government National Mortgage Association I, 4.0%, 3/15/45 68,604 1,470,637 Government National Mortgage Association I, 4.0%, 3/15/45 1,557,924 2,448,961 Government National Mortgage Association I, 4.0%, 4/15/45 2,629,115 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 73 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,357,565 Government National Mortgage Association I, 4.0%, 5/15/45 $ 1,457,573 3,374,979 Government National Mortgage Association I, 4.0%, 6/15/45 3,623,839 530,147 Government National Mortgage Association I, 4.0%, 7/15/45 569,261 461,612 Government National Mortgage Association I, 4.0%, 8/15/45 489,032 134,372 Government National Mortgage Association I, 4.5%, 6/15/25 138,555 36,621 Government National Mortgage Association I, 4.5%, 7/15/33 39,367 121,134 Government National Mortgage Association I, 4.5%, 9/15/33 131,356 128,663 Government National Mortgage Association I, 4.5%, 10/15/33 136,999 131,271 Government National Mortgage Association I, 4.5%, 10/15/33 142,204 20,751 Government National Mortgage Association I, 4.5%, 2/15/34 22,209 14,552 Government National Mortgage Association I, 4.5%, 3/15/35 15,494 48,983 Government National Mortgage Association I, 4.5%, 3/15/35 52,161 18,906 Government National Mortgage Association I, 4.5%, 4/15/35 20,127 129,029 Government National Mortgage Association I, 4.5%, 4/15/35 139,498 5,182 Government National Mortgage Association I, 4.5%, 9/15/35 5,520 56,232 Government National Mortgage Association I, 4.5%, 10/15/35 60,242 45,080 Government National Mortgage Association I, 4.5%, 4/15/38 47,953 715,134 Government National Mortgage Association I, 4.5%, 12/15/39 776,962 273,093 Government National Mortgage Association I, 4.5%, 1/15/40 298,807 159,102 Government National Mortgage Association I, 4.5%, 9/15/40 173,057 594,434 Government National Mortgage Association I, 4.5%, 10/15/40 646,369 286,842 Government National Mortgage Association I, 4.5%, 4/15/41 307,903 631,208 Government National Mortgage Association I, 4.5%, 5/15/41 686,369 665,221 Government National Mortgage Association I, 4.5%, 6/15/41 723,283 The accompanying notes are an integral part of these financial statements. 74 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 227,681 Government National Mortgage Association I, 4.5%, 7/15/41 $ 247,604 561,053 Government National Mortgage Association I, 4.5%, 8/15/41 603,156 44,383 Government National Mortgage Association I, 5.0%, 7/15/33 48,892 47,199 Government National Mortgage Association I, 5.0%, 9/15/33 52,256 52,069 Government National Mortgage Association I, 5.0%, 4/15/34 57,646 295,945 Government National Mortgage Association I, 5.0%, 4/15/35 327,720 121,022 Government National Mortgage Association I, 5.0%, 7/15/40 134,053 41,332 Government National Mortgage Association I, 5.5%, 1/15/29 44,316 8,805 Government National Mortgage Association I, 5.5%, 6/15/33 9,700 42,918 Government National Mortgage Association I, 5.5%, 7/15/33 48,112 45,611 Government National Mortgage Association I, 5.5%, 7/15/33 51,146 13,176 Government National Mortgage Association I, 5.5%, 8/15/33 14,775 21,341 Government National Mortgage Association I, 5.5%, 8/15/33 23,933 92,565 Government National Mortgage Association I, 5.5%, 8/15/33 100,991 30,971 Government National Mortgage Association I, 5.5%, 9/15/33 33,227 39,238 Government National Mortgage Association I, 5.5%, 9/15/33 42,078 30,555 Government National Mortgage Association I, 5.5%, 10/15/33 33,068 37,939 Government National Mortgage Association I, 5.5%, 10/15/33 42,511 213,141 Government National Mortgage Association I, 5.5%, 7/15/34 239,015 21,280 Government National Mortgage Association I, 5.5%, 10/15/34 23,292 271,438 Government National Mortgage Association I, 5.5%, 11/15/34 304,427 83,302 Government National Mortgage Association I, 5.5%, 1/15/35 92,531 16,001 Government National Mortgage Association I, 5.5%, 2/15/35 17,385 35,009 Government National Mortgage Association I, 5.5%, 2/15/35 37,550 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 75 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 28,436 Government National Mortgage Association I, 5.5%, 6/15/35 $ 30,506 263,259 Government National Mortgage Association I, 5.5%, 7/15/35 289,246 30,564 Government National Mortgage Association I, 5.5%, 10/15/35 34,249 98,385 Government National Mortgage Association I, 5.5%, 10/15/35 110,392 24,808 Government National Mortgage Association I, 5.5%, 2/15/37 27,816 3,383 Government National Mortgage Association I, 5.72%, 4/15/29 3,647 70,769 Government National Mortgage Association I, 6.0%, 12/15/23 75,039 5,895 Government National Mortgage Association I, 6.0%, 1/15/24 6,491 24,161 Government National Mortgage Association I, 6.0%, 4/15/28 27,192 94,926 Government National Mortgage Association I, 6.0%, 9/15/28 105,283 5,301 Government National Mortgage Association I, 6.0%, 10/15/28 5,856 43,258 Government National Mortgage Association I, 6.0%, 2/15/29 48,760 44,800 Government National Mortgage Association I, 6.0%, 2/15/29 49,690 23,823 Government National Mortgage Association I, 6.0%, 6/15/31 26,229 12,429 Government National Mortgage Association I, 6.0%, 11/15/31 14,089 906 Government National Mortgage Association I, 6.0%, 3/15/32 1,032 3,994 Government National Mortgage Association I, 6.0%, 8/15/32 4,556 48,992 Government National Mortgage Association I, 6.0%, 9/15/32 54,333 77,801 Government National Mortgage Association I, 6.0%, 9/15/32 85,657 80,778 Government National Mortgage Association I, 6.0%, 9/15/32 88,935 5,740 Government National Mortgage Association I, 6.0%, 10/15/32 6,320 21,914 Government National Mortgage Association I, 6.0%, 10/15/32 24,381 5,535 Government National Mortgage Association I, 6.0%, 11/15/32 6,094 5,932 Government National Mortgage Association I, 6.0%, 11/15/32 6,530 The accompanying notes are an integral part of these financial statements. 76 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 7,280 Government National Mortgage Association I, 6.0%, 12/15/32 $ 8,070 7,854 Government National Mortgage Association I, 6.0%, 12/15/32 8,737 47,207 Government National Mortgage Association I, 6.0%, 12/15/32 52,125 102,746 Government National Mortgage Association I, 6.0%, 12/15/32 113,121 130,289 Government National Mortgage Association I, 6.0%, 12/15/32 143,445 154,219 Government National Mortgage Association I, 6.0%, 12/15/32 169,960 249,365 Government National Mortgage Association I, 6.0%, 12/15/32 275,932 17,754 Government National Mortgage Association I, 6.0%, 1/15/33 19,547 30,183 Government National Mortgage Association I, 6.0%, 1/15/33 33,920 97,510 Government National Mortgage Association I, 6.0%, 1/15/33 111,367 16,298 Government National Mortgage Association I, 6.0%, 2/15/33 18,355 48,926 Government National Mortgage Association I, 6.0%, 2/15/33 53,867 56,487 Government National Mortgage Association I, 6.0%, 2/15/33 63,393 82,325 Government National Mortgage Association I, 6.0%, 2/15/33 92,124 26,894 Government National Mortgage Association I, 6.0%, 3/15/33 29,641 37,945 Government National Mortgage Association I, 6.0%, 3/15/33 43,119 48,837 Government National Mortgage Association I, 6.0%, 3/15/33 53,768 66,160 Government National Mortgage Association I, 6.0%, 3/15/33 75,570 70,391 Government National Mortgage Association I, 6.0%, 3/15/33 80,387 89,078 Government National Mortgage Association I, 6.0%, 3/15/33 100,805 144,339 Government National Mortgage Association I, 6.0%, 3/15/33 164,840 252,171 Government National Mortgage Association I, 6.0%, 3/15/33 287,264 9,664 Government National Mortgage Association I, 6.0%, 4/15/33 10,640 12,463 Government National Mortgage Association I, 6.0%, 4/15/33 13,721 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 77 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 29,833 Government National Mortgage Association I, 6.0%, 4/15/33 $ 32,939 16,545 Government National Mortgage Association I, 6.0%, 5/15/33 18,216 97,456 Government National Mortgage Association I, 6.0%, 5/15/33 109,051 6,697 Government National Mortgage Association I, 6.0%, 6/15/33 7,641 7,711 Government National Mortgage Association I, 6.0%, 9/15/33 8,490 11,854 Government National Mortgage Association I, 6.0%, 9/15/33 13,180 38,694 Government National Mortgage Association I, 6.0%, 9/15/33 44,181 34,378 Government National Mortgage Association I, 6.0%, 10/15/33 39,039 86,940 Government National Mortgage Association I, 6.0%, 11/15/33 95,730 148,153 Government National Mortgage Association I, 6.0%, 3/15/34 168,723 36,546 Government National Mortgage Association I, 6.0%, 6/15/34 41,738 24,252 Government National Mortgage Association I, 6.0%, 8/15/34 27,690 41,560 Government National Mortgage Association I, 6.0%, 8/15/34 45,757 20,268 Government National Mortgage Association I, 6.0%, 9/15/34 23,084 34,753 Government National Mortgage Association I, 6.0%, 9/15/34 38,269 92,960 Government National Mortgage Association I, 6.0%, 9/15/34 106,219 42,016 Government National Mortgage Association I, 6.0%, 10/15/34 46,405 44,363 Government National Mortgage Association I, 6.0%, 10/15/34 48,843 92,720 Government National Mortgage Association I, 6.0%, 10/15/34 102,082 85,461 Government National Mortgage Association I, 6.0%, 11/15/34 95,802 500,723 Government National Mortgage Association I, 6.0%, 9/15/35 571,302 136,120 Government National Mortgage Association I, 6.0%, 8/15/36 155,667 77,352 Government National Mortgage Association I, 6.0%, 10/15/36 85,647 28,861 Government National Mortgage Association I, 6.0%, 11/15/37 32,997 The accompanying notes are an integral part of these financial statements. 78 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 26,200 Government National Mortgage Association I, 6.0%, 8/15/38 $ 29,483 10,195 Government National Mortgage Association I, 6.5%, 10/15/24 10,911 1,406 Government National Mortgage Association I, 6.5%, 2/15/28 1,551 5,591 Government National Mortgage Association I, 6.5%, 4/15/28 6,167 29,859 Government National Mortgage Association I, 6.5%, 4/15/28 32,938 5,627 Government National Mortgage Association I, 6.5%, 6/15/28 6,328 4,606 Government National Mortgage Association I, 6.5%, 8/15/28 5,081 2,117 Government National Mortgage Association I, 6.5%, 10/15/28 2,335 9,217 Government National Mortgage Association I, 6.5%, 10/15/28 10,167 18,694 Government National Mortgage Association I, 6.5%, 1/15/29 20,622 852 Government National Mortgage Association I, 6.5%, 2/15/29 940 3,991 Government National Mortgage Association I, 6.5%, 2/15/29 4,403 9,624 Government National Mortgage Association I, 6.5%, 2/15/29 10,616 3,385 Government National Mortgage Association I, 6.5%, 3/15/29 3,734 4,287 Government National Mortgage Association I, 6.5%, 3/15/29 4,729 5,804 Government National Mortgage Association I, 6.5%, 3/15/29 6,402 14,636 Government National Mortgage Association I, 6.5%, 3/15/29 16,145 62,622 Government National Mortgage Association I, 6.5%, 3/15/29 69,080 1,508 Government National Mortgage Association I, 6.5%, 5/15/29 1,664 2,408 Government National Mortgage Association I, 6.5%, 5/15/29 2,657 36,641 Government National Mortgage Association I, 6.5%, 5/15/29 41,363 20,836 Government National Mortgage Association I, 6.5%, 6/15/29 22,985 37,376 Government National Mortgage Association I, 6.5%, 4/15/31 42,839 9,664 Government National Mortgage Association I, 6.5%, 5/15/31 11,073 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 79 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 10,018 Government National Mortgage Association I, 6.5%, 5/15/31 $ 11,556 33,813 Government National Mortgage Association I, 6.5%, 5/15/31 37,299 4,483 Government National Mortgage Association I, 6.5%, 6/15/31 4,946 11,468 Government National Mortgage Association I, 6.5%, 7/15/31 12,651 25,276 Government National Mortgage Association I, 6.5%, 8/15/31 27,883 15,595 Government National Mortgage Association I, 6.5%, 9/15/31 17,203 4,146 Government National Mortgage Association I, 6.5%, 10/15/31 4,574 11,815 Government National Mortgage Association I, 6.5%, 10/15/31 13,034 41,470 Government National Mortgage Association I, 6.5%, 10/15/31 45,747 2,600 Government National Mortgage Association I, 6.5%, 11/15/31 2,868 38,609 Government National Mortgage Association I, 6.5%, 11/15/31 42,590 15,567 Government National Mortgage Association I, 6.5%, 1/15/32 17,173 64,496 Government National Mortgage Association I, 6.5%, 1/15/32 73,025 4,423 Government National Mortgage Association I, 6.5%, 2/15/32 4,879 11,142 Government National Mortgage Association I, 6.5%, 2/15/32 12,630 13,256 Government National Mortgage Association I, 6.5%, 2/15/32 15,194 18,019 Government National Mortgage Association I, 6.5%, 2/15/32 19,877 22,840 Government National Mortgage Association I, 6.5%, 2/15/32 26,002 9,100 Government National Mortgage Association I, 6.5%, 3/15/32 10,038 68,256 Government National Mortgage Association I, 6.5%, 3/15/32 76,001 3,987 Government National Mortgage Association I, 6.5%, 4/15/32 4,399 6,776 Government National Mortgage Association I, 6.5%, 4/15/32 7,475 8,175 Government National Mortgage Association I, 6.5%, 4/15/32 9,018 46,739 Government National Mortgage Association I, 6.5%, 4/15/32 53,856 The accompanying notes are an integral part of these financial statements. 80 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 3,082 Government National Mortgage Association I, 6.5%, 5/15/32 $ 3,400 4,705 Government National Mortgage Association I, 6.5%, 5/15/32 5,190 6,982 Government National Mortgage Association I, 6.5%, 5/15/32 7,702 7,579 Government National Mortgage Association I, 6.5%, 5/15/32 8,749 8,114 Government National Mortgage Association I, 6.5%, 6/15/32 8,951 8,829 Government National Mortgage Association I, 6.5%, 6/15/32 9,808 9,078 Government National Mortgage Association I, 6.5%, 6/15/32 10,014 7,847 Government National Mortgage Association I, 6.5%, 7/15/32 8,656 8,879 Government National Mortgage Association I, 6.5%, 7/15/32 9,795 89,518 Government National Mortgage Association I, 6.5%, 7/15/32 102,690 3,383 Government National Mortgage Association I, 6.5%, 8/15/32 3,738 26,746 Government National Mortgage Association I, 6.5%, 8/15/32 30,973 29,864 Government National Mortgage Association I, 6.5%, 8/15/32 32,943 14,013 Government National Mortgage Association I, 6.5%, 9/15/32 16,040 32,676 Government National Mortgage Association I, 6.5%, 9/15/32 36,045 34,523 Government National Mortgage Association I, 6.5%, 9/15/32 38,465 37,161 Government National Mortgage Association I, 6.5%, 10/15/32 40,994 33,037 Government National Mortgage Association I, 6.5%, 11/15/32 38,210 202,260 Government National Mortgage Association I, 6.5%, 12/15/32 234,862 2,239 Government National Mortgage Association I, 6.5%, 1/15/33 2,571 223,629 Government National Mortgage Association I, 6.5%, 1/15/33 259,927 27,335 Government National Mortgage Association I, 6.5%, 5/15/33 30,154 1,450 Government National Mortgage Association I, 6.5%, 10/15/33 1,606 100,672 Government National Mortgage Association I, 6.5%, 6/15/34 111,542 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 81 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 3,651 Government National Mortgage Association I, 6.5%, 9/15/34 $ 4,027 36,516 Government National Mortgage Association I, 6.5%, 4/15/35 40,282 5,875 Government National Mortgage Association I, 6.5%, 6/15/35 6,480 16,519 Government National Mortgage Association I, 6.5%, 7/15/35 18,222 59,002 Government National Mortgage Association I, 6.5%, 7/15/35 65,086 9,621 Government National Mortgage Association I, 7.0%, 8/15/23 10,050 30,244 Government National Mortgage Association I, 7.0%, 9/15/24 32,462 10,805 Government National Mortgage Association I, 7.0%, 7/15/25 11,515 4,626 Government National Mortgage Association I, 7.0%, 11/15/26 5,096 11,062 Government National Mortgage Association I, 7.0%, 6/15/27 12,252 10,418 Government National Mortgage Association I, 7.0%, 1/15/28 11,244 8,613 Government National Mortgage Association I, 7.0%, 2/15/28 8,965 10,589 Government National Mortgage Association I, 7.0%, 3/15/28 10,768 4,313 Government National Mortgage Association I, 7.0%, 4/15/28 4,321 10,156 Government National Mortgage Association I, 7.0%, 7/15/28 11,164 783 Government National Mortgage Association I, 7.0%, 8/15/28 870 10,025 Government National Mortgage Association I, 7.0%, 11/15/28 11,446 27,650 Government National Mortgage Association I, 7.0%, 11/15/28 31,403 19,040 Government National Mortgage Association I, 7.0%, 4/15/29 19,546 19,832 Government National Mortgage Association I, 7.0%, 4/15/29 21,287 19,627 Government National Mortgage Association I, 7.0%, 5/15/29 19,953 2,585 Government National Mortgage Association I, 7.0%, 6/15/29 2,589 6,628 Government National Mortgage Association I, 7.0%, 7/15/29 7,332 37,565 Government National Mortgage Association I, 7.0%, 11/15/29 41,148 The accompanying notes are an integral part of these financial statements. 82 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,407 Government National Mortgage Association I, 7.0%, 12/15/30 $ 1,407 1,704 Government National Mortgage Association I, 7.0%, 12/15/30 1,730 22,831 Government National Mortgage Association I, 7.0%, 12/15/30 26,296 33,638 Government National Mortgage Association I, 7.0%, 12/15/30 34,039 37,780 Government National Mortgage Association I, 7.0%, 1/15/31 38,150 4,676 Government National Mortgage Association I, 7.0%, 3/15/31 4,764 17,184 Government National Mortgage Association I, 7.0%, 6/15/31 20,060 2,057 Government National Mortgage Association I, 7.0%, 7/15/31 2,397 93,054 Government National Mortgage Association I, 7.0%, 8/15/31 108,974 10,050 Government National Mortgage Association I, 7.0%, 9/15/31 10,449 26,479 Government National Mortgage Association I, 7.0%, 9/15/31 29,428 7,223 Government National Mortgage Association I, 7.0%, 11/15/31 7,509 43,081 Government National Mortgage Association I, 7.0%, 3/15/32 47,826 32,611 Government National Mortgage Association I, 7.0%, 4/15/32 36,218 60,015 Government National Mortgage Association I, 7.0%, 5/15/32 71,396 2,566 Government National Mortgage Association I, 7.5%, 3/15/23 2,597 17,257 Government National Mortgage Association I, 7.5%, 10/15/23 18,202 1,002 Government National Mortgage Association I, 7.5%, 6/15/24 1,014 7,108 Government National Mortgage Association I, 7.5%, 8/15/25 7,172 3,132 Government National Mortgage Association I, 7.5%, 9/15/25 3,359 1,860 Government National Mortgage Association I, 7.5%, 12/15/25 1,860 8,304 Government National Mortgage Association I, 7.5%, 2/15/27 8,998 19,500 Government National Mortgage Association I, 7.5%, 3/15/27 22,215 28,429 Government National Mortgage Association I, 7.5%, 10/15/27 31,269 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 83 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 12,954 Government National Mortgage Association I, 7.5%, 6/15/29 $ 14,291 2,354 Government National Mortgage Association I, 7.5%, 8/15/29 2,382 7,076 Government National Mortgage Association I, 7.5%, 8/15/29 7,142 13,590 Government National Mortgage Association I, 7.5%, 9/15/29 13,621 5,037 Government National Mortgage Association I, 7.5%, 10/15/29 5,185 12,681 Government National Mortgage Association I, 7.5%, 2/15/31 12,800 14,026 Government National Mortgage Association I, 7.5%, 2/15/31 14,410 6,251 Government National Mortgage Association I, 7.5%, 3/15/31 6,411 38,860 Government National Mortgage Association I, 7.5%, 12/15/31 40,384 1,930 Government National Mortgage Association I, 7.75%, 2/15/30 1,952 639 Government National Mortgage Association I, 8.5%, 8/15/21 640 42 Government National Mortgage Association I, 9.0%, 9/15/21 42 966 Government National Mortgage Association I, 9.0%, 6/15/22 978 471,706 Government National Mortgage Association II, 3.5%, 3/20/45 492,928 486,963 Government National Mortgage Association II, 3.5%, 4/20/45 508,923 698,679 Government National Mortgage Association II, 3.5%, 4/20/45 730,362 965,677 Government National Mortgage Association II, 3.5%, 4/20/45 1,010,967 1,319,640 Government National Mortgage Association II, 3.5%, 3/20/46 1,397,824 5,277,169 Government National Mortgage Association II, 4.0%, 7/20/44 5,595,952 144,306 Government National Mortgage Association II, 4.0%, 9/20/44 152,997 1,243,973 Government National Mortgage Association II, 4.0%, 10/20/44 1,318,171 4,611,855 Government National Mortgage Association II, 4.0%, 10/20/46 4,815,787 1,733,744 Government National Mortgage Association II, 4.0%, 2/20/48 1,829,844 1,867,684 Government National Mortgage Association II, 4.0%, 4/20/48 1,971,910 The accompanying notes are an integral part of these financial statements. 84 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 12,385,000 Government National Mortgage Association II, 4.0%, 1/1/49 (TBA) $ 12,818,475 46,187 Government National Mortgage Association II, 4.5%, 12/20/34 48,715 164,342 Government National Mortgage Association II, 4.5%, 1/20/35 173,012 30,699 Government National Mortgage Association II, 4.5%, 3/20/35 32,357 849,180 Government National Mortgage Association II, 4.5%, 9/20/41 917,381 4,213,740 Government National Mortgage Association II, 4.5%, 9/20/44 4,418,559 1,223,447 Government National Mortgage Association II, 4.5%, 10/20/44 1,310,280 2,530,807 Government National Mortgage Association II, 4.5%, 11/20/44 2,710,140 5,303,626 Government National Mortgage Association II, 4.5%, 2/20/48 5,598,770 25,388,627 Government National Mortgage Association II, 4.5%, 7/20/49 26,668,105 38,992,904 Government National Mortgage Association II, 4.5%, 8/20/49 41,002,200 31 Government National Mortgage Association II, 5.0%, 1/20/20 31 125,858 Government National Mortgage Association II, 5.5%, 3/20/34 141,600 106,503 Government National Mortgage Association II, 5.5%, 4/20/34 119,812 53,357 Government National Mortgage Association II, 5.5%, 10/20/37 56,859 63,460 Government National Mortgage Association II, 5.75%, 6/20/33 68,258 21,202 Government National Mortgage Association II, 5.9%, 1/20/28 22,958 47,415 Government National Mortgage Association II, 5.9%, 7/20/28 50,960 11,714 Government National Mortgage Association II, 6.0%, 10/20/31 13,037 59,956 Government National Mortgage Association II, 6.0%, 1/20/33 68,525 63,824 Government National Mortgage Association II, 6.0%, 10/20/33 72,902 36,754 Government National Mortgage Association II, 6.0%, 6/20/34 42,318 42,952 Government National Mortgage Association II, 6.45%, 7/20/32 46,426 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 85 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 74,924 Government National Mortgage Association II, 6.45%, 1/20/33 $ 80,983 9,865 Government National Mortgage Association II, 6.5%, 1/20/24 10,258 26,015 Government National Mortgage Association II, 6.5%, 8/20/28 29,311 1,246 Government National Mortgage Association II, 6.5%, 2/20/29 1,420 501 Government National Mortgage Association II, 6.5%, 3/20/29 568 14,983 Government National Mortgage Association II, 6.5%, 4/20/29 16,988 8,413 Government National Mortgage Association II, 6.5%, 4/20/31 9,621 5,767 Government National Mortgage Association II, 6.5%, 6/20/31 6,622 27,353 Government National Mortgage Association II, 6.5%, 10/20/32 31,507 38,288 Government National Mortgage Association II, 6.5%, 3/20/34 44,522 4,020 Government National Mortgage Association II, 7.0%, 5/20/26 4,375 11,595 Government National Mortgage Association II, 7.0%, 8/20/27 13,041 12,371 Government National Mortgage Association II, 7.0%, 6/20/28 14,096 41,623 Government National Mortgage Association II, 7.0%, 11/20/28 47,528 45,237 Government National Mortgage Association II, 7.0%, 1/20/29 51,685 4,334 Government National Mortgage Association II, 7.0%, 2/20/29 4,936 1,249 Government National Mortgage Association II, 7.0%, 12/20/30 1,435 6,588 Government National Mortgage Association II, 7.0%, 1/20/31 7,670 3,263 Government National Mortgage Association II, 7.0%, 3/20/31 3,810 18,758 Government National Mortgage Association II, 7.0%, 7/20/31 21,935 6,713 Government National Mortgage Association II, 7.0%, 11/20/31 7,820 7,762 Government National Mortgage Association II, 7.5%, 5/20/30 9,128 2,313 Government National Mortgage Association II, 7.5%, 6/20/30 2,663 The accompanying notes are an integral part of these financial statements. 86 Pioneer Bond Fund | Semiannual Report | 12/31/19 --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 4,863 Government National Mortgage Association II, 7.5%, 7/20/30 $ 5,540 7,286 Government National Mortgage Association II, 7.5%, 8/20/30 8,535 3,772 Government National Mortgage Association II, 7.5%, 12/20/30 4,440 8 Government National Mortgage Association II, 8.0%, 5/20/25 8 1,136 Government National Mortgage Association II, 9.0%, 3/20/22 1,140 152 Government National Mortgage Association II, 9.0%, 4/20/22 152 1,658 Government National Mortgage Association II, 9.0%, 11/20/24 1,663 480,857 New Valley Generation V, 4.929%, 1/15/21 491,008 8,573,736 U.S. Treasury Inflation Indexed Bonds, 0.75%, 2/15/45 8,891,060 64,354,523 U.S. Treasury Inflation Indexed Bonds, 0.875%, 2/15/47 68,958,440 76,271,373 U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/46 83,873,041 64,572,131 U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/48 71,447,171 52,315,707 U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/49 58,130,434 --------------------------------------------------------------------------------------------------------------------- TOTAL U.S. GOVERNMENT AND AGENCY OBLIGATIONS (Cost $1,507,415,352) $1,543,642,619 --------------------------------------------------------------------------------------------------------------------- TEMPORARY CASH INVESTMENTS -- 0.6% of Net Assets REPURCHASE AGREEMENTS -- 0.6% 10,000,000 $10,000,000 ScotiaBank, 1.56%, dated 12/31/19 plus accrued interest on 1/2/20 collateralized by $10,200,884 Federal National Mortgage Association, 4.0%, 10/1/47 $ 10,000,000 22,000,000 $22,000,000 RBC Capital Market LLC 1.56%, dated 12/31/19 plus accrued interest on 1/2/20 collateralized by the following : $12,353,249 Freddie Mac Giant, 2.5% - 5.5%, 8/1/23 - 8/1/49 $10,088,696 Federal National Mortgage Association, 2.4% - 4.5%, 6/1/29 - 6/1/51 22,000,000 4,025,000 $4,025,000 TD Securities USA LLC, 1.57%, dated 12/31/19 plus accrued interest on 1/2/20 collateralized by $4,105,501 Federal National Mortgage Association, 3.0%, 11/1/49 4,025,000 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 87 Schedule of Investments | 12/31/19 (unaudited) (continued) --------------------------------------------------------------------------------------------------------------------- Principal Amount USD ($) Value --------------------------------------------------------------------------------------------------------------------- REPURCHASE AGREEMENTS -- (continued) 4,025,000 $4,025,000 TD Securities USA LLC, 1.55%, dated 12/31/19 plus accrued interest on 1/2/20 collateralized by $4,105,525 U.S. Treasury Notes, 2.9% - 7.9%, 1/16/20 - 11/15/46 $ 4,025,000 -------------- $ 40,050,000 --------------------------------------------------------------------------------------------------------------------- TOTAL TEMPORARY CASH INVESTMENTS (Cost $40,050,000) $ 40,050,000 --------------------------------------------------------------------------------------------------------------------- TOTAL INVESTMENTS IN UNAFFILIATED ISSUERS -- 99.4% (Cost $5,976,379,642) $6,133,779,355 --------------------------------------------------------------------------------------------------------------------- OTHER ASSETS AND LIABILITIES -- 0.6% $ 32,017,682 --------------------------------------------------------------------------------------------------------------------- NET ASSETS -- 100.0% $6,165,797,037 ===================================================================================================================== bps Basis Points. CMT Constant Maturity Treasury Index. FREMF Freddie Mac Multifamily Fixed-Rate Mortgage Loans. FRESB Freddie Mac Multifamily Small Balance Certificates. ICE Intercontinental Exchange. LIBOR London Interbank Offered Rate. PRIME U.S. Federal Funds Rate. REIT Real Estate Investment Trust. REMICS Real Estate Mortgage Investment Conduits. SOFRRATE Secured Overnight Financing Rate. (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 December 31, 2019, the value of these securities amounted to $2,706,945,066, or 43.9% of net assets. (TBA) "To Be Announced" Securities. + Amount rounds to less than 0.1%. * Senior secured 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, (ii) the prime rate offered by one or more major United States banks, (iii) the rate of a certificate of deposit or (iv) other base lending rates used by commercial lenders. The interest rate shown is the rate accruing at December 31, 2019. + Security that used significant unobservable inputs to determine its value. (a) Security is perpetual in nature and has no stated maturity date. (b) Floating rate note. Coupon rate, reference index and spread shown at December 31, 2019. The accompanying notes are an integral part of these financial statements. 88 Pioneer Bond Fund | Semiannual Report | 12/31/19 (c) The interest rate is subject to change periodically. The interest rate and/or reference index and spread shown at December 31, 2019. (d) Debt obligation initially issued at one coupon which converts to a higher coupon at a specific date. The rate shown is the rate at December 31, 2019. (e) Security represents the interest-only portion payments on a pool of underlying mortgages or mortgage-backed securities. (f) Securities are restricted as to resale. (g) Non-income producing security. (h) Issued as participation notes. (i) Issued as preference shares. (j) Consists of Revenue Bonds unless otherwise indicated. FUTURES CONTRACTS FIXED INCOME INDEX FUTURES CONTRACTS --------------------------------------------------------------------------------------------- Number of Contracts Expiration Notional Unrealized Long Description Date Amount Market Value (Depreciation) --------------------------------------------------------------------------------------------- 1,062 U.S. 2 Year 3/31/20 $ 228,984,797 $ 228,861,000 $ (123,797) Note (CBT) 7,034 U.S. 5 Year 3/31/20 837,273,438 834,298,344 (2,975,094) Note (CBT) 877 U.S. Ultra 3/20/20 164,658,437 159,312,531 (5,345,906) Bond (CBT) --------------------------------------------------------------------------------------------- $1,230,916,672 $1,222,471,875 $(8,444,797) ============================================================================================= ------------------------------------------------------------------------------------------- Number of Contracts Expiration Notional Unrealized Short Description Date Amount Market Value Appreciation ------------------------------------------------------------------------------------------- 1,951 U.S. 10 Year 3/20/20 $252,775,328 $250,551,078 $2,224,250 Note (CBT) 3,334 U.S. 10 Year 3/20/20 475,225,180 469,104,219 6,120,961 Ultra 342 U.S. Long 3/20/20 54,477,454 53,319,938 1,157,516 Bond (CBT) ------------------------------------------------------------------------------------------- $782,477,962 $772,975,235 $9,502,727 ------------------------------------------------------------------------------------------- TOTAL FUTURES CONTRACTS $448,438,710 $449,496,640 $1,057,930 =========================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 89 Schedule of Investments | 12/31/19 (unaudited) (continued) SWAP CONTRACT CENTRALLY CLEARED CREDIT DEFAULT SWAP CONTRACT -- BUY PROTECTION ------------------------------------------------------------------------------------------------------------------------------- Annual Notional Reference Pay/ Fixed Expiration Premiums Unrealized Market Amount ($)(1) Obligation/Index Receive(2) Rate Date (Received) (Depreciation) Value ------------------------------------------------------------------------------------------------------------------------------- 176,210,000 Markit CDX North America High Receive 1.00% 12/20/24 $(3,357,094) $(1,271,508) $(4,628,602) Yield Index Series 31 ------------------------------------------------------------------------------------------------------------------------------- CENTRALLY CLEARED CREDIT DEFAULT SWAP CONTRACT -- BUY PROTECTION $(3,357,094) $(1,271,508) $(4,628,602) =============================================================================================================================== (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) Receives quarterly. Principal amounts are denominated in U.S. dollars ("USD") unless otherwise noted. CAD -- Canadian Dollar EUR -- Euro Purchases and sales of securities (excluding temporary cash investments) for the six months ended December 31, 2019 were as follows: ----------------------------------------------------------------------------------- Purchases Sales ----------------------------------------------------------------------------------- Long-Term U.S. Government Securities $ 372,114,836 $347,986,305 Other Long-Term Securities $1,679,497,063 $938,133,247 The Fund is permitted to engage in purchase and sale transactions ("cross trades") with certain funds and accounts for which Amundi Pioneer Asset Management, Inc. (the "Adviser") 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 six months ended December 31, 2019, the Fund engaged in purchases of $20,976,361 which resulted in a net realized gain/(loss) of $0. During the six months ended December 31, 2019, the Fund did not engage in sales pursuant to these procedures. At December 31, 2019, the net unrealized appreciation on investments based on cost for federal tax purposes of $5,982,840,770 was as follows: Aggregate gross unrealized appreciation for all investments in which there is an excess of value over tax cost $194,720,143 Aggregate gross unrealized depreciation for all investments in which there is an excess of tax cost over value (47,352,230) ------------ Net unrealized appreciation $147,367,913 ============ Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels 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 risks, 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. 90 Pioneer Bond Fund | Semiannual Report | 12/31/19 The following is a summary of the inputs used as of December 31, 2019, in valuing the Fund's investments: ----------------------------------------------------------------------------------------------------------- Level 1 Level 2 Level 3 Total ----------------------------------------------------------------------------------------------------------- Convertible Preferred Stock $14,001,200 $ -- $ -- $ 14,001,200 Asset Backed Securities -- 901,354,194 -- 901,354,194 Collateralized Mortgage Obligations -- 1,550,891,419 -- 1,550,891,419 Corporate Bonds -- 1,778,321,999 -- 1,778,321,999 Foreign Government Bond -- 14,700,509 -- 14,700,509 Insurance-Linked Securities Event Linked Bonds Multiperil - U.S. -- 17,994,825 1,267,875 19,262,700 Collateralized Reinsurance Earthquakes - California -- -- 2,406,675 2,406,675 Multiperil - Massachusetts -- -- 3,012,910 3,012,910 Multiperil - U.S. -- -- 4,246,906 4,246,906 Multiperil - U.S. Regional -- -- 5,101,550 5,101,550 Multiperil - Worldwide -- -- 7,857,942 7,857,942 Windstorm - Florida -- -- 479,488 479,488 Windstorm - North Carolina -- -- 1,522,205 1,522,205 Windstorm - U.S. Regional -- -- 1,881,400 1,881,400 Industry Loss Warranties Multiperil - U.S. -- -- 2,345,722 2,345,722 Reinsurance Sidecars Multiperil - U.S. -- -- 9,168,364 9,168,364 Multiperil - Worldwide -- -- 91,049,526 91,049,526 All Other Insurance-Linked Securities -- 38,723,420 -- 38,723,420 Municipal Bonds -- 14,474,977 -- 14,474,977 Senior Secured Floating Rate Loan Interests -- 89,283,630 -- 89,283,630 U.S. Government and Agency Obligations -- 1,543,642,619 -- 1,543,642,619 Repurchase Agreements -- 40,050,000 -- 40,050,000 ----------------------------------------------------------------------------------------------------------- Total Investments in Securities $14,001,200 $5,989,437,592 $130,340,563 $6,133,779,355 ----------------------------------------------------------------------------------------------------------- Other Financial Instruments Net unrealized appreciation on futures contracts $ 1,057,930 $ -- $ -- $ 1,057,930 Swap contracts, at value -- (4,628,602) -- (4,628,602) ----------------------------------------------------------------------------------------------------------- Total Other Financial Instruments $ 1,057,930 $ (4,628,602) $ -- $ (3,570,672) =========================================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 91 Schedule of Investments | 12/31/19 (unaudited) (continued) The following is a reconciliation of assets valued using significant unobservable inputs (Level 3): ---------------------------------------------------------------------------------------- Insurance- Linked Securities ---------------------------------------------------------------------------------------- Balance as of 6/30/19 $119,118,336 Realized gain (loss)(1) (518,457) Changed in unrealized appreciation (depreciation)(2) 954,571 Accrued discounts/premiums (6,828) Purchases 34,508,534 Sales (23,715,593) Transfers in to Level 3* -- Transfers out of Level 3* -- ---------------------------------------------------------------------------------------- Balance as of 12/31/19 $130,340,563 ======================================================================================== (1) Realized gain (loss) on these securities is included in the realized gain (loss) from investments on the Statement of Operations. (2) Unrealized appreciation (depreciation) on these securities is included in the change in unrealized appreciation (depreciation) from investments on the Statement of Operations. * Transfers are calculated on the beginning of period values. For the six months ended December 31, 2019, there were no transfers between Levels 1, 2 and 3. Net change in unrealized appreciation (depreciation) of Level 3 investments still held and considered Level 3 at December 31, 2019: $677,901 -------- The accompanying notes are an integral part of these financial statements. 92 Pioneer Bond Fund | Semiannual Report | 12/31/19 Statement of Assets and Liabilities | 12/31/19 (unaudited) ASSETS: Investments in unaffiliated issuers, at value (cost $5,976,379,642) $6,133,779,355 Cash 42,829,541 Futures collateral 1,741,389 Swaps collateral 1,542,693 Due from broker for futures 3,749,942 Due from broker for swaps 4,627,157 Variation margin for centrally cleared swap contracts 22,994 Net unrealized appreciation on futures contracts 1,057,930 Receivables -- Investment securities sold 13,819,427 Fund shares sold 25,445,990 Interest 28,368,866 Other assets 147,753 ------------------------------------------------------------------------------------------- Total assets $6,257,133,037 =========================================================================================== LIABILITIES: Payables -- Investment securities purchased $ 51,061,228 Fund shares repurchased 30,551,131 Distributions 1,855,431 Variation margin for futures contracts 605,474 Swap contracts, at value (net premiums received $(3,357,094)) 4,628,602 Due to affiliates 380,143 Accrued expenses 2,253,991 ------------------------------------------------------------------------------------------- Total liabilities $ 91,336,000 =========================================================================================== NET ASSETS: Paid-in capital $6,038,603,748 Distributable earnings 127,193,289 ------------------------------------------------------------------------------------------- Net assets $6,165,797,037 =========================================================================================== NET ASSET VALUE PER SHARE: No par value (unlimited number of shares authorized) Class A (based on $996,894,184/100,917,352 shares) $ 9.88 Class C (based on $62,667,701/6,412,219 shares) $ 9.77 Class K (based on $1,455,028,685/147,374,556 shares) $ 9.87 Class R (based on $195,294,168/19,591,117 shares) $ 9.97 Class Y (based on $3,455,912,299/353,075,372 shares) $ 9.79 MAXIMUM OFFERING PRICE PER SHARE: Class A (based on $9.88 net asset value per share/100%-4.50% maximum sales charge) $ 10.35 =========================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 93 Statement of Operations (unaudited) FOR THE SIX MONTHS ENDED 12/31/19 INVESTMENT INCOME: Interest from unaffiliated issuers $98,760,121 Dividends from unaffiliated issuers (net of foreign taxes withheld $817) 1,356,547 ----------------------------------------------------------------------------------------------------- Total investment income $100,116,668 ===================================================================================================== EXPENSES: Management fees $ 8,283,706 Administrative expense 722,797 Transfer agent fees Class A 1,224,041 Class C 36,406 Class K 2,429 Class R 232,543 Class Y 1,809,975 Distribution fees Class A 1,250,649 Class C 312,974 Class R 495,000 Shareowner communications expense 121,043 Custodian fees 126,259 Registration fees 107,942 Professional fees 150,183 Printing expense 9,950 Pricing fees 126,814 Trustees' fees 142,473 Insurance expense 34,200 Miscellaneous 78,850 ----------------------------------------------------------------------------------------------------- Total expenses $ 15,268,234 ----------------------------------------------------------------------------------------------------- Net investment income $ 84,848,434 ----------------------------------------------------------------------------------------------------- REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS: Net realized gain (loss) on: Investments in unaffiliated issuers $33,479,759 Forward foreign currency exchange contracts 41,468 Futures contracts (6,008,460) Swap contracts (194,627) Other assets and liabilities denominated in foreign currencies (40,153) $ 27,277,987 ----------------------------------------------------------------------------------------------------- Change in net unrealized appreciation (depreciation) on: Investments in unaffiliated issuers $42,216,329 Futures contracts 1,254,109 Swap contracts (1,445,851) Other assets and liabilities denominated in foreign currencies 8,249 $ 42,032,836 ----------------------------------------------------------------------------------------------------- Net realized and unrealized gain (loss) on investments $ 69,310,823 ----------------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $154,159,257 ===================================================================================================== The accompanying notes are an integral part of these financial statements. 94 Pioneer Bond Fund | Semiannual Report | 12/31/19 Statements of Changes in Net Assets ----------------------------------------------------------------------------------------------------------- Six Months Ended 12/31/19 Year Ended (unaudited) 6/30/19 ----------------------------------------------------------------------------------------------------------- FROM OPERATIONS: Net investment income (loss) $ 84,848,434 $ 162,175,422 Net realized gain (loss) on investments 27,277,987 (13,746,777) Change in net unrealized appreciation (depreciation) on investments 42,032,836 212,991,665 ----------------------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 154,159,257 $ 361,420,310 ----------------------------------------------------------------------------------------------------------- DISTRIBUTIONS TO SHAREOWNERS: Class A ($0.16 and $0.30 per share, respectively) $ (15,909,794) $ (31,768,715) Class C ($0.13 and $0.23 per share, respectively) (797,135) (1,624,633) Class K ($0.18 and $0.34 per share, respectively) (25,401,208) (38,746,201) Class R ($0.15 and $0.28 per share, respectively) (2,926,070) (5,436,508) Class Y ($0.18 and $0.33 per share, respectively) (59,226,564) (96,979,642) ----------------------------------------------------------------------------------------------------------- Total distributions to shareowners $ (104,260,771) $ (174,555,699) ----------------------------------------------------------------------------------------------------------- FROM FUND SHARE TRANSACTIONS: Net proceeds from sales of shares $1,158,435,574 $ 2,280,096,185 Reinvestment of distributions 87,311,835 140,968,997 Cost of shares repurchased (698,211,127) (2,027,763,106) ----------------------------------------------------------------------------------------------------------- Net increase in net assets resulting from Fund share transactions $ 547,536,282 $ 393,302,076 ----------------------------------------------------------------------------------------------------------- Net increase in net assets $ 597,434,768 $ 580,166,687 NET ASSETS: Beginning of period $5,568,362,269 $ 4,988,195,582 ----------------------------------------------------------------------------------------------------------- End of period $6,165,797,037 $ 5,568,362,269 =========================================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 95 Statement of Changes in Net Assets (continued) ------------------------------------------------------------------------------------------------------------------ Six Months Six Months Ended Ended 12/31/19 12/31/19 Year Ended Year Ended Shares Amount 6/30/19 6/30/19 (unaudited) (unaudited) Shares Amount ------------------------------------------------------------------------------------------------------------------ Class A Shares sold 15,872,315 $ 156,934,405 26,995,582 $ 255,919,620 Reinvestment of distributions 1,157,933 11,458,107 2,394,810 22,690,254 Less shares repurchased (16,209,737) (160,224,089) (43,647,656) (412,375,791) ------------------------------------------------------------------------------------------------------------------ Net increase (decrease) 820,511 $ 8,168,423 (14,257,264) $ (133,765,917) ================================================================================================================== Class C Shares sold 1,061,014 $ 10,380,126 1,620,055 $ 15,140,871 Reinvestment of distributions 62,465 611,362 129,683 1,215,362 Less shares repurchased (1,159,157) (11,342,098) (3,785,268) (35,370,201) ------------------------------------------------------------------------------------------------------------------ Net decrease (35,678) $ (350,610) (2,035,530) $ (19,013,968) ================================================================================================================== Class K Shares sold 28,444,989 $ 280,976,462 80,341,266 $ 760,556,110 Reinvestment of distributions 2,026,822 20,042,886 3,212,139 30,464,825 Less shares repurchased (13,282,733) (131,208,586) (52,786,664) (497,673,237) ------------------------------------------------------------------------------------------------------------------ Net increase 17,189,078 $ 169,810,762 30,766,741 $ 293,347,698 ================================================================================================================== Class R Shares sold 2,077,505 $ 20,720,079 4,802,537 $ 45,936,991 Reinvestment of distributions 287,400 2,869,743 525,321 5,026,777 Less shares repurchased (2,862,191) (28,551,932) (4,077,850) (38,900,021) ------------------------------------------------------------------------------------------------------------------ Net increase (decrease) (497,286) $ (4,962,110) 1,250,008 $ 12,063,747 ================================================================================================================== Class Y Shares sold 70,377,483 $ 689,424,502 128,196,595 $ 1,202,542,593 Reinvestment of distributions 5,336,516 52,329,737 8,677,520 81,571,779 Less shares repurchased (37,460,407) (366,884,422) (111,303,616) (1,043,443,856) ------------------------------------------------------------------------------------------------------------------ Net increase 38,253,592 $ 374,869,817 25,570,499 $ 240,670,516 ================================================================================================================== The accompanying notes are an integral part of these financial statements. 96 Pioneer Bond Fund | Semiannual Report | 12/31/19 Financial Highlights ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/19 Ended Ended Ended Ended Ended (unaudited) 6/30/19 6/30/18 6/30/17 6/30/16* 6/30/15* ------------------------------------------------------------------------------------------------------------------------------------ Class A Net asset value, beginning of period $ 9.79 $ 9.45 $ 9.71 $ 9.76 $ 9.68 $ 9.88 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.13(a) $ 0.27(a) $ 0.26(a) $ 0.25(a) $ 0.25(a) $ 0.27 Net realized and unrealized gain (loss) on investments 0.12 0.37 (0.24) (0.01) 0.12 (0.14) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 0.25 $ 0.64 $ 0.02 $ 0.24 $ 0.37 $ 0.13 ------------------------------------------------------------------------------------------------------------------------------------ Distributions to shareowners: Net investment income $ (0.16) $ (0.30) $ (0.28) $ (0.29) $ (0.27) $ (0.29) Net realized gain -- -- -- -- (0.02) (0.04) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.16) $ (0.30) $ (0.28) $ (0.29) $ (0.29) $ (0.33) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ 0.09 $ 0.34 $ (0.26) $ (0.05) $ 0.08 $ (0.20) ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.88 $ 9.79 $ 9.45 $ 9.71 $ 9.76 $ 9.68 ==================================================================================================================================== Total return (b) 2.56%(c) 6.93% 0.14% 2.48% 3.93% 1.32% Ratio of net expenses to average net assets 0.83%(d) 0.85% 0.85% 0.85% 0.85% 0.85% Ratio of net investment income (loss) to average net assets 2.55%(d) 2.88% 2.71% 2.60% 2.58% 2.68% Portfolio turnover rate 23%(c) 52% 45% 44% 43% 81% Net assets, end of period (in thousands) $996,894 $ 979,874 $1,081,121 $1,156,940 $1,177,941 $1,044,659 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Total expenses to average net assets 0.83%(d) 0.87% 0.96% 0.99% 0.98% 0.93% Net investment income (loss) to average net assets 2.55%(d) 2.86% 2.60% 2.46% 2.45% 2.60% ==================================================================================================================================== * The Fund was audited by an independent registered public accounting firm other than Ernst & Young LLP. (a) The per-share data presented above is based on the average shares outstanding for the period presented. (b) 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. (c) Not annualized. (d) Annualized. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 97 Financial Highlights (continued) ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/19 Ended Ended Ended Ended Ended (unaudited) 6/30/19 6/30/18 6/30/17 6/30/16* 6/30/15* ------------------------------------------------------------------------------------------------------------------------------------ Class C Net asset value, beginning of period $ 9.68 $ 9.35 $ 9.60 $ 9.66 $ 9.57 $ 9.77 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.09(a) $ 0.21(a) $ 0.19(a) $ 0.18(a) $ 0.17(a) $ 0.19 Net realized and unrealized gain (loss) on investments 0.13 0.35 (0.24) (0.03) 0.14 (0.14) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 0.22 $ 0.56 $ (0.05) $ 0.15 $ 0.31 $ 0.05 ------------------------------------------------------------------------------------------------------------------------------------ Distributions to shareowners: Net investment income $ (0.13) $ (0.23) $ (0.20) $ (0.21) $ (0.20) $ (0.21) Net realized gain -- -- -- -- (0.02) (0.04) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.13) $ (0.23) $ (0.20) $ (0.21) $ (0.22) $ (0.25) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ 0.09 $ 0.33 $ (0.25) $ (0.06) $ 0.09 $ (0.20) ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.77 $ 9.68 $ 9.35 $ 9.60 $ 9.66 $ 9.57 ==================================================================================================================================== Total return (b) 2.24%(c) 6.10% (0.52)% 1.62% 3.28% 0.49% Ratio of net expenses to average net assets 1.46%(d) 1.52% 1.60% 1.59% 1.60% 1.63% Ratio of net investment income (loss) to average net assets 1.92%(d) 2.21% 1.96% 1.84% 1.84% 1.89% Portfolio turnover rate 23%(c) 52% 45% 44% 43% 81% Net assets, end of period (in thousands) $62,668 $62,447 $79,308 $96,547 $134,299 $114,222 ==================================================================================================================================== * The Fund was audited by an independent registered public accounting firm other than Ernst & Young LLP. (a) The per-share data presented above is based on the average shares outstanding for the period presented. (b) 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. (c) Not annualized. (d) Annualized. The accompanying notes are an integral part of these financial statements. 98 Pioneer Bond Fund | Semiannual Report | 12/31/19 ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/19 Ended Ended Ended Ended Ended (unaudited) 6/30/19 6/30/18 6/30/17 6/30/16* 6/30/15* ------------------------------------------------------------------------------------------------------------------------------------ Class K Net asset value, beginning of period $ 9.78 $ 9.45 $ 9.71 $ 9.76 $ 9.68 $ 9.87 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.15(a) $ 0.32(a) $ 0.30(a) $ 0.29(a) $ 0.29(a) $ 0.30 Net realized and unrealized gain (loss) on investments 0.12 0.35 (0.25) (0.01) 0.12 (0.13) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 0.27 $ 0.67 $ 0.05 $ 0.28 $ 0.41 $ 0.17 ------------------------------------------------------------------------------------------------------------------------------------ Distributions to shareowners: Net investment income $ (0.18) $ (0.34) $ (0.31) $ (0.33) $ (0.31) $ (0.32) Net realized gain -- -- -- -- (0.02) (0.04) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.18) $ (0.34) $ (0.31) $ (0.33) $ (0.33) $ (0.36) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ 0.09 $ 0.33 $ (0.26) $ (0.05) $ 0.08 $ (0.19) ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.87 $ 9.78 $ 9.45 $ 9.71 $ 9.76 $ 9.68 ==================================================================================================================================== Total return (b) 2.82%(c) 7.28% 0.54% 2.87% 4.32% 1.80% Ratio of net expenses to average net assets 0.33%(d) 0.37% 0.46% 0.47% 0.47% 0.47% Ratio of net investment income (loss) to average net assets 3.05%(d) 3.37% 3.11% 3.01% 2.98% 3.03% Portfolio turnover rate 23%(c) 52% 45% 44% 43% 81% Net assets, end of period (in thousands) $1,455,029 $1,273,821 $939,272 $726,063 $340,096 $179,135 ==================================================================================================================================== * The Fund was audited by an independent registered public accounting firm other than Ernst & Young LLP. (a) The per-share data presented above is based on the average shares outstanding for the period presented. (b) 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. (c) Not annualized. (d) Annualized. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 99 Financial Highlights (continued) ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/19 Ended Ended Ended Ended Ended (unaudited) 6/30/19 6/30/18 6/30/17 6/30/16* 6/30/15* ------------------------------------------------------------------------------------------------------------------------------------ Class R Net asset value, beginning of period $ 9.88 $ 9.54 $ 9.80 $ 9.85 $ 9.77 $ 9.97 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.12(a) $ 0.25(a) $ 0.24(a) $ 0.23(a) $ 0.23(a) $ 0.25 Net realized and unrealized gain (loss) on investments 0.12 0.37 (0.25) (0.01) 0.12 (0.15) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 0.24 $ 0.62 $ (0.01) $ 0.22 $ 0.35 $ 0.10 ------------------------------------------------------------------------------------------------------------------------------------ Distributions to shareowners: Net investment income $ (0.15) $ (0.28) $ (0.25) $ (0.27) $ (0.25) $ (0.26) Net realized gain -- -- -- -- (0.02) (0.04) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.15) $ (0.28) $ (0.25) $ (0.27) $ (0.27) $ (0.30) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ 0.09 $ 0.34 $ (0.26) $ (0.05) $ 0.08 $ (0.20) ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.97 $ 9.88 $ 9.54 $ 9.80 $ 9.85 $ 9.77 ==================================================================================================================================== Total return (b) 2.43%(c) 6.62% (0.08)% 2.23% 3.66% 1.06% Ratio of net expenses to average net assets 1.07%(d) 1.10% 1.10% 1.10% 1.10% 1.10% Ratio of net investment income (loss) to average net assets 2.31%(d) 2.64% 2.64% 2.35% 2.33% 2.43% Portfolio turnover rate 23%(c) 52% 45% 44% 43% 81% Net assets, end of period (in thousands) $195,294 $198,457 $179,729 $178,770 $156,110 $116,815 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Total expenses to average net assets 1.07%(d) 1.12% 1.21% 1.24% 1.21% 1.21% Net investment income (loss) to average net assets 2.31%(d) 2.62% 2.35% 2.21% 2.22% 2.32% ==================================================================================================================================== * The Fund was audited by an independent registered public accounting firm other than Ernst & Young LLP. (a) The per-share data presented above is based on the average shares outstanding for the period presented. (b) 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. (c) Not annualized. (d) Annualized. The accompanying notes are an integral part of these financial statements. 100 Pioneer Bond Fund | Semiannual Report | 12/31/19 ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/19 Ended Ended Ended Ended Ended (unaudited) 6/30/19 6/30/18 6/30/17 6/30/16* 6/30/15* ------------------------------------------------------------------------------------------------------------------------------------ Class Y Net asset value, beginning of period $ 9.70 $ 9.36 $ 9.62 $ 9.67 $ 9.59 $ 9.79 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.14(a) $ 0.31(a) $ 0.28(a) $ 0.28(a) $ 0.27(a) $ 0.30 Net realized and unrealized gain (loss) on investments 0.13 0.36 (0.24) (0.02) 0.12 (0.15) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 0.27 $ 0.67 $ 0.04 $ 0.26 $ 0.39 $ 0.15 ------------------------------------------------------------------------------------------------------------------------------------ Distributions to shareowners: Net investment income $ (0.18) $ (0.33) $ (0.30) $ (0.31) $ (0.29) $ (0.31) Net realized gain -- -- -- -- (0.02) (0.04) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.18) $ (0.33) $ (0.30) $ (0.31) $ (0.31) $ (0.35) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ 0.09 $ 0.34 $ (0.26) $ (0.05) $ 0.08 $ (0.20) ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.79 $ 9.70 $ 9.36 $ 9.62 $ 9.67 $ 9.59 ==================================================================================================================================== Total return (b) 2.78%(c) 7.30% 0.40% 2.76% 4.22% 1.59% Ratio of net expenses to average net assets 0.44%(d) 0.49% 0.58% 0.58% 0.58% 0.58% Ratio of net investment income (loss) to average net assets 2.94%(d) 3.26% 2.98% 2.87% 2.85% 2.95% Portfolio turnover rate 23%(c) 52% 45% 44% 43% 81% Net assets, end of period (in thousands) $3,455,912 $3,053,763 $2,708,766 $2,558,262 $2,136,681 $1,644,161 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Total expenses to average net assets 0.44%(d) 0.49% 0.58% 0.59% 0.59% 0.58% Net investment income (loss) to average net assets 2.94%(d) 3.26% 2.98% 2.86% 2.84% 2.95% ==================================================================================================================================== * The Fund was audited by an independent registered public accounting firm other than Ernst & Young LLP. (a) The per-share data presented above is based on the average shares outstanding for the period presented. (b) 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. (c) Not annualized. (d) Annualized. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/19 101 Notes to Financial Statements | 12/31/19 (unaudited) 1. Organization and Significant Accounting Policies Pioneer Bond Fund (the "Fund") is 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 current income consistent with preservation of capital. The Fund offers five classes of shares designated as Class A, Class C, Class K, Class R and Class Y shares. 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 shareowner approval. Under per-share voting, each share of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a shareowner'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. Amundi Pioneer Asset Management, Inc., an indirect, wholly owned subsidiary of Amundi and Amundi's wholly owned subsidiary, Amundi USA, Inc., serves as the Fund's investment adviser (the "Adviser"). Amundi Pioneer Distributor, Inc., an affiliate of Amundi Pioneer Asset Management, Inc., serves as the Fund's distributor (the "Distributor"). In August 2018, the Securities and Exchange Commission ("SEC") released a Disclosure Update and Simplification Final Rule. The Final Rule amends Regulation S-X disclosures requirements to conform them to U.S. Generally Accepted Accounting Principles ("U.S. GAAP") for investment companies. The Fund's financial statements were prepared in compliance with the new amendments to Regulation S-X. During March 2017, the Financial Accounting Standards Board (FASB) issued an Accounting Standard Update, ASU 2017-08, Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20), Premium Amortization on Purchased Callable Debt Securities ("ASU 2017-08"), which shortens the amortization period for purchased non-contingently callable debt securities held at a premium. ASU 2017-08 specifies that the premium amortization period ends 102 Pioneer Bond Fund | Semiannual Report | 12/31/19 at the earliest call date, for certain purchased non-contingently callable debt securities. ASU 2017-08 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018. The Portfolio has adopted ASU 2017-08 as of December 31, 2019. The implementation of ASU 2017-08 did not have a material impact on the Portfolio's Financial Statements. The Fund is an investment company and follows investment company accounting and reporting guidance under U.S. GAAP. U.S. GAAP requires 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 gain or loss on investments during the reporting period. Actual results could differ from those estimates. The following is a summary of significant accounting policies followed by the Fund in the preparation of its financial statements: 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. Pioneer Bond Fund | Semiannual Report | 12/31/19 103 Event-linked bonds are valued at the bid price obtained from an independent third party pricing service. Other insurance-linked securities (including reinsurance 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. 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. 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. Futures contracts are generally valued at the closing settlement price established by the exchange on which they are traded. 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 Dealers Association members. Centrally cleared swaps are valued at the daily settlement price provided by the central clearing counterparty. 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 104 Pioneer Bond Fund | Semiannual Report | 12/31/19 valued by a fair valuation team comprised of certain personnel of the Adviser pursuant to procedures adopted by the Fund's Board of Trustees. The Adviser's fair valuation team uses fair value methods approved by the Valuation Committee of the Board of Trustees. The Adviser'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 December 31, 2019, 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 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 and net of income accrued on defaulted securities. Interest and dividend income payable by delivery of additional shares is reclassified as PIK (payment-in-kind) income upon receipt and is included in interest and dividend income, respectively. 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. Pioneer Bond Fund | Semiannual Report | 12/31/19 105 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 exchange 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 on 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 gain or loss 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 June 30, 2019, 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 on the Statement of Operations. Tax returns filed within the prior three years remain 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 over distributions 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. 106 Pioneer Bond Fund | Semiannual Report | 12/31/19 The tax character of current year distributions payable will be determined at the end of the current taxable year. The tax character of distributions paid during the year ended June 30, 2019 was as follows: -------------------------------------------------------------------------- 2019 -------------------------------------------------------------------------- Distributions paid from: Ordinary income $174,555,699 -------------------------------------------------------------------------- Total $174,555,699 ========================================================================== The following shows the components of distributable earnings (losses) on a federal income tax basis at June 30, 2019: -------------------------------------------------------------------------- 2019 -------------------------------------------------------------------------- Distributable earnings: Undistributed ordinary income $ 11,461,661 Capital Loss Carryforward (36,502,414) Current year dividends payable (2,986,562) Net unrealized appreciation 105,322,118 -------------------------------------------------------------------------- Total $ 77,294,803 ========================================================================== The difference between book basis and tax basis net unrealized appreciation is attributable to the tax deferral of losses on wash sales, adjustments relating to catastrophe bonds, swaps, the tax treatment of premium and amortization and the mark to market of futures contracts. E. Fund Shares The Fund records sales and repurchases of its shares as of trade date. The Distributor earned $23,226 in underwriting commissions on the sale of Class A shares during the six months ended December 31, 2019. F. 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). Pioneer Bond Fund | Semiannual Report | 12/31/19 107 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 K, Class R 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. A general rise in interest rates could adversely affect the price and liquidity of fixed-income securities and could also result in increased redemptions from the Fund. 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 investments in foreign markets and countries with limited developing markets may subject the Fund to a greater degree of risk than investments in a developed market. These risks include disruptive political or economic conditions and the imposition of adverse governmental laws or currency exchange restrictions. The Fund invests in below-investment-grade (high-yield) debt securities and preferred stocks. Some of these high-yield securities may be convertible into equity securities of the issuer. Debt securities rated below-investment-grade are commonly referred to as "junk bonds" and are considered speculative. These securities involve greater risk of loss, are subject to greater price volatility, and are less liquid, especially during periods of economic uncertainty or change, than higher rated debt securities. With the increased use of technologies such as the Internet to conduct business, the Fund is susceptible to operational, information security and related risks. While the Fund's Adviser has established business continuity plans in the event of, and risk management systems to prevent, limit or mitigate, such cyber-attacks, there are inherent limitations in such plans and systems, including the possibility that certain risks have not been identified. Furthermore, the Fund cannot control the cybersecurity plans and systems 108 Pioneer Bond Fund | Semiannual Report | 12/31/19 put in place by service providers to the Fund such as Brown Brothers Harriman & Co., the Fund's custodian and accounting agent, and DST Asset Manager Solutions, Inc., the Fund's transfer agent. In addition, many beneficial owners of Fund shares hold them through accounts at broker-dealers, retirement platforms and other financial market participants over which neither the Fund nor Amundi Pioneer exercises control. Each of these may in turn rely on service providers to them, which are also subject to the risk of cyber-attacks. Cybersecurity failures or breaches at Amundi Pioneer or the Fund's service providers or intermediaries have the ability to cause disruptions and impact business operations, potentially resulting in financial losses, interference with the Fund's ability to calculate its net asset value, impediments to trading, the inability of Fund shareowners to effect share purchases, redemptions or exchanges or receive distributions, loss of or unauthorized access to private shareowner information and violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, or additional compliance costs. Such costs and losses may not be covered under any insurance. In addition, maintaining vigilance against cyber-attacks may involve substantial costs over time, and system enhancements may themselves be subject to cyber-attacks. 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 ILS. The Fund could lose a portion or all of the principal it has invested in an ILS, and the right to additional interest or dividend payments with respect to the security, upon the occurrence of one or more trigger events, as defined within the terms of an insurance-linked security. Trigger events, generally, are hurricanes, earthquakes, or other natural events of a specific size or magnitude that occur in a designated geographic region during a specified time period, and/or that involve losses or other metrics that exceed a specific amount. There is no way to accurately predict whether a trigger event will occur, and accordingly, ILS carry significant risk. The Fund is entitled to receive principal, and interest and/or dividend payments so long as no trigger event occurs of the description and magnitude specified by the instrument. In addition to the specified trigger events, ILS 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 event-linked bonds. ILS also may include special purpose vehicles ("SPVs") or similar instruments structured to comprise a portion of a reinsurer's catastrophe-oriented business, known Pioneer Bond Fund | Semiannual Report | 12/31/19 109 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. Where the ILS 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 the Adviser 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 the Adviser 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 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 sub-custodian of the Fund. The Adviser 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 at December 31, 2019, are disclosed in the Schedule of Investments. J. Forward Foreign Currency Exchange Contracts The Fund may enter into forward foreign currency exchange 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 110 Pioneer Bond Fund | Semiannual Report | 12/31/19 applicable exchange rates, and any resulting unrealized appreciation or depreciation is 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 6). During the six months ended December 31, 2019, the Fund had entered into various forward foreign currency exchange contracts that obligated 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 exchange contract, the Fund may close out such contract by entering into an offsetting contract. The average market value of forward foreign currency exchange contracts open during the six months ended December 31, 2019, was $(401,008). There were no open forward foreign currency exchange contracts at December 31, 2019. K. 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 December 31, 2019, is recorded as "Futures collateral" 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. Cash received from or paid to the broker related to previous margin movement is held in a segregated account at the broker and is recorded as either "Due from broker for futures" or "Due to broker for futures" on the Statement of Assets and Liabilities. When the contract is closed, the Fund realizes a 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. With futures, there is reduced counterparty credit risk Pioneer Bond Fund | Semiannual Report | 12/31/19 111 to the Fund since futures are exchange-traded and the exchange's clearinghouse, as counterparty to all exchange-traded futures, guarantees the futures against default. The average market value of futures contracts open during the six months ended December 31, 2019, was $388,511,733. Open futures contracts outstanding at December 31, 2019, are listed in the Schedule of Investments. L. Credit Default Swap Contracts A credit default swap is a contract between a buyer of protection and a seller of protection against a pre-defined credit event or an underlying reference obligation, which may be a single security or a basket or index of securities. The Fund may buy or sell credit default swap contracts to seek to increase the 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. As a buyer of protection, the Fund 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 within the "Swap contracts, at value" line item on the Statement of Assets and Liabilities. Periodic payments received or paid by the Fund are recorded as realized gains or losses on 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 within the "Swap contracts, at value" line item on 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 on the Statement of Operations. 112 Pioneer Bond Fund | Semiannual Report | 12/31/19 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. In addition, obligations under sell protection credit default swaps may be partially offset by net amounts received from settlement of buy protection credit default swaps entered into by the Fund for the same reference obligation with the same counterparty. 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 margin deposit, either in cash or in securities. The daily change in value on open centrally cleared contracts is recorded as "Variation margin for centrally cleared swap contracts" on the Statement of Assets and Liabilities. Cash received from or paid to the broker related to previous margin movement is held in a segregated account at the broker and is recorded as either "Due from broker for swaps" or "Due to broker for swaps" on the Statement of Assets and Liabilities. The amount of cash deposited with a broker as collateral at December 31, 2019, is recorded as "Swaps collateral" on the Statement of Assets and Liabilities. The average market value of credit default swap contracts open during the six months ended December 31, 2019, was $(1,784,396). Open credit default swap contracts at December 31, 2019, are listed in the Schedule of Investments. 2. Management Agreement The Adviser manages the Fund's portfolio. Effective October 1, 2018, management fees are calculated daily at the annual rate of 0.40% of the Fund's average daily net assets up to $500 million, 0.35% of the next $500 million of the Fund's average daily net assets, 0.30% of the next $1 billion of the Fund's average daily net assets, 0.25% of the next $8 billion of the Fund's average daily net assets, and 0.225% of the Fund's average daily net assets over $10 billion. The fee is accrued daily and paid monthly. Prior to October 1, 2018, the management fee was calculated daily at the annual rate of 0.40% of the Fund's average daily net assets. For the six months ended December 31, 2019, the effective management fee was equivalent to 0.28% (annualized) of the Fund's average daily net assets. Pioneer Bond Fund | Semiannual Report | 12/31/19 113 The Adviser 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) to the extent required to reduce Fund expenses to 0.85%, 1.10% and 0.50% of the average daily net assets attributable to Class A, Class R and Class Y shares, respectively. Fees waived and expenses reimbursed during the six months ended December 31, 2019 are reflected on the Statement of Operations. These expense limitations are in effect through November 1, 2020. 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 $324,043 in management fees, administrative costs and certain other reimbursements payable to the Adviser at December 31, 2019. 3. Transfer Agent DST Asset Manager Solutions, 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 shareowner communications activities such as proxy and statement mailings, and outgoing phone calls. For the six months ended December 31, 2019, such out-of-pocket expenses by class of shares were as follows: -------------------------------------------------------------------------------- Shareowner Communications: -------------------------------------------------------------------------------- Class A $ 38,075 Class C 3,549 Class K 6,183 Class R 466 Class Y 72,770 -------------------------------------------------------------------------------- Total $121,043 ================================================================================ 4. Distribution and Service Plans 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 R shares. Pursuant to the Plan, the Fund pays the Distributor 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 114 Pioneer Bond Fund | Semiannual Report | 12/31/19 services with regard to Class A shares. Pursuant to the Plan, the Fund also pays the Distributor 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 also pays the Distributor 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 $56,100 in distribution fees payable to the Distributor at December 31, 2019. The Fund also has adopted a separate service plan for Class R shares (the "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 Class A and Class C 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 the Distributor. For the six months ended December 31, 2019, CDSCs in the amount of $4,522 were paid to the Distributor. 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 credit facility or the limits set for borrowing by the Fund's prospectus and the 1940 Act. The Fund participates in a credit facility in the amount of $250 million. Under such facility, depending on the type of loan, interest on borrowings is payable at the London Interbank Offered Rate ("LIBOR") plus a credit spread. The Fund also pays 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 six months ended December 31, 2019, the Fund had no borrowings under the credit facility. Pioneer Bond Fund | Semiannual Report | 12/31/19 115 6. Additional Disclosures about Derivative Instruments and Hedging Activities The Fund's use of derivatives may enhance or mitigate the Fund's exposure 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 rate 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. The fair value of open derivative instruments (not considered to be hedging instruments for accounting disclosure purposes) by risk exposure at December 31, 2019, was as follows: ---------------------------------------------------------------------------------------------- Foreign Statement of Assets Interest Credit Exchange Equity Commodity and Liabilities Rate Risk Risk Rate Risk Risk Risk ---------------------------------------------------------------------------------------------- Assets: Net unrealized appreciation on futures contracts $1,057,930 $ -- $ -- $ -- $ -- ---------------------------------------------------------------------------------------------- Total Value $1,057,930 $ -- $ -- $ -- $ -- ============================================================================================== Liabilities: Swap contracts, at value $ -- $4,628,602 $ -- $ -- $ -- ---------------------------------------------------------------------------------------------- Total Value $ -- $4,628,602 $ -- $ -- $ -- ============================================================================================== 116 Pioneer Bond Fund | Semiannual Report | 12/31/19 The effect of derivative instruments (not considered to be hedging instruments for accounting disclosure purposes) on the Statement of Operations by risk exposure at December 31, 2019, was as follows: ---------------------------------------------------------------------------------------------------- Foreign Statement of Interest Credit Exchange Equity Commodity Operations Rate Risk Risk Rate Risk Risk Risk ---------------------------------------------------------------------------------------------------- Net realized gain (loss) on: Forward foreign currency exchange contracts $ -- $ -- $41,468 $ -- $ -- Futures contracts (6,008,460) -- -- -- -- Swap contracts -- (194,627) -- -- -- ---------------------------------------------------------------------------------------------------- Total Value $(6,008,460) $ (194,627) $41,468 $ -- $ -- ==================================================================================================== Change in net unrealized appreciation (depreciation) on: Futures contracts $ 1,254,109 $ -- $ -- $ -- $ -- Swap contracts -- (1,445,851) -- -- -- ---------------------------------------------------------------------------------------------------- Total Value $ 1,254,109 $(1,445,851) $ -- $ -- $ -- ==================================================================================================== Pioneer Bond Fund | Semiannual Report | 12/31/19 117 Approval of Investment Management Agreement Amundi Pioneer Asset Management, Inc. ("APAM") serves as the investment adviser to Pioneer Bond Fund (the "Fund") pursuant to an investment management agreement between APAM and the Fund. In order for APAM to remain the investment adviser of the Fund, the Trustees of the Fund must determine annually whether to renew the investment management agreement for the Fund. The contract review process began in January 2019 as the Trustees of the Fund agreed on, among other things, an overall approach and timeline for the process. Contract review materials were provided to the Trustees in March 2019, July 2019 and September 2019. In addition, the Trustees reviewed and discussed the Fund's performance at regularly scheduled meetings throughout the year, and took into account other information related to the Fund provided to the Trustees at regularly scheduled meetings, in connection with the review of the Fund's investment management agreement. In March 2019, the Trustees, among other things, discussed the memorandum provided by Fund counsel that summarized the legal standards and other considerations that are relevant to the Trustees in their deliberations regarding the renewal of the investment management agreement, and reviewed and discussed 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. In July 2019, the Trustees, among other things, reviewed the Fund's management fees and total expense ratios, the financial statements of APAM and its parent companies, profitability analyses provided by APAM, and analyses from APAM as to possible economies of scale. The Trustees also reviewed the profitability of the institutional business of APAM and APAM's affiliate, Amundi Pioneer Institutional Asset Management, Inc. ("APIAM" and, together with APAM, "Amundi Pioneer"), as compared to that of APAM's fund management business, and considered the differences between the fees and expenses of the Fund and the fees and expenses of APAM's and APIAM's institutional accounts, as well as the different services provided by APAM to the Fund and by APAM and APIAM to the institutional accounts. The Trustees further considered contract review materials, including additional materials received in response to the Trustees' request, in September 2019. At a meeting held on September 17, 2019, based on their evaluation of the information provided by APAM and third parties, the Trustees of the Fund, including the Independent Trustees voting separately, unanimously approved the renewal of the investment management agreement for another year. In approving the renewal of the investment management agreement, the Trustees 118 Pioneer Bond Fund | Semiannual Report | 12/31/19 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 determining to approve the renewal of the agreement. Nature, Extent and Quality of Services The Trustees considered the nature, extent and quality of the services that had been provided by APAM to the Fund, taking into account the investment objective and strategy of the Fund. The Trustees also reviewed APAM's investment approach for the Fund and its research process. The Trustees considered the resources of APAM and the personnel of APAM who provide investment management services to the Fund. They also reviewed the amount of non-Fund assets managed by the portfolio managers of the Fund. They considered the non-investment resources and personnel of APAM that are involved in APAM's services to the Fund, including APAM's compliance, risk management, and legal resources and personnel. The Trustees noted the substantial attention and high priority given by APAM's senior management to the Pioneer Fund complex. The Trustees considered that APAM 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. The Trustees also considered that, as administrator, APAM is responsible for the administration of the Fund's business and other affairs. The Trustees considered the fees paid to APAM for the provision of administration services. Based on these considerations, the Trustees concluded that the nature, extent and quality of services that had been provided by APAM to the Fund were satisfactory and consistent with the terms of the investment management agreement. Performance of the Fund In considering the Fund's performance, the Trustees regularly review and discuss throughout the year data prepared by APAM and information comparing the Fund's performance with the performance of its peer group of funds, as classified by Morningstar, Inc. (Morningstar), and the performance of the Fund's benchmark index. They also discuss the Fund's performance with APAM on a regular basis. The Trustees' regular reviews and discussions were factored into the Trustees' deliberations concerning the renewal of the investment management agreement. Pioneer Bond Fund | Semiannual Report | 12/31/19 119 Management Fee and Expenses The Trustees considered information showing the fees and expenses of the Fund in comparison to the management fees 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. The peer group comparisons referred to below are organized in quintiles. Each quintile represents one-fifth of the peer group. In all peer group comparisons referred to below, first quintile is most favorable to the Fund's shareowners. The Trustees noted that they separately review and consider the impact of the Fund's transfer agency and Fund- and APAM-paid expenses for 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 for the most recent fiscal year was in the second quintile relative to the management fees paid by other funds in its Morningstar category for the comparable period. The Trustees considered breakpoints that were added to the Fund's management fee schedule, effective October 1, 2018, and the reduced fee rates above certain asset levels. The Trustees considered that the expense ratio of the Fund's Class A shares for the most recent fiscal year was in the fourth quintile relative to its Strategic Insight peer group for the comparable period. The Trustees considered that the expense ratio of the Fund's Class Y shares for the most recent fiscal year was in the fourth quintile relative to its Strategic Insight peer group for the comparable period. The Trustees noted that APAM 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 APAM and APIAM to institutional and other clients, including publicly offered European funds sponsored by APAM's affiliates, unaffiliated U.S. registered investment companies (in a sub-advisory capacity), and unaffiliated foreign and domestic separate accounts. The Trustees also considered APAM's costs in providing services to the Fund and APAM's and APIAM'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 APAM's and APIAM'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 the investment management agreement with the Fund, 120 Pioneer Bond Fund | Semiannual Report | 12/31/19 APAM performs 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 entrepreneurial risks associated with APAM's management of the Fund. The Trustees concluded that the management fee payable by the Fund to APAM was reasonable in relation to the nature and quality of the services provided by APAM. Profitability The Trustees considered information provided by APAM regarding the profitability of APAM with respect to the advisory services provided by APAM to the Fund, including the methodology used by APAM in allocating certain of its costs to the management of the Fund. The Trustees also considered APAM's profit margin in connection with the overall operation of the Fund. They further reviewed the financial results, including the profit margins, realized by APAM and APIAM from non-fund businesses. The Trustees considered APAM's profit margins 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 APAM's profitability with respect to the management of the Fund was not unreasonable. Economies of Scale The Trustees considered APAM'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 noted the breakpoints in the management fee schedule. 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 APAM in research and analytical capabilities and APAM'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. Pioneer Bond Fund | Semiannual Report | 12/31/19 121 Other Benefits The Trustees considered the other benefits that APAM 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 investment management agreement, for services provided by APAM and its affiliates. The Trustees further considered the revenues and profitability of APAM's businesses other than the Fund business. To the extent applicable, the Trustees also considered the benefits to the Fund and to APAM 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 Amundi Pioneer is the principal U.S. asset management business of Amundi, which is one of the largest asset managers globally. Amundi's worldwide asset management business manages over $1.6 trillion in assets (including the Pioneer Funds). The Trustees considered that APAM's relationship with Amundi creates potential opportunities for APAM, APIAM and Amundi that derive from APAM's relationships with the Fund, including Amundi's ability to market the services of APAM globally. The Trustees noted that APAM has access to additional research and portfolio management capabilities as a result of its relationship with Amundi and Amundi's enhanced global presence that may contribute to an increase in the resources available to APAM. The Trustees considered that APAM and the Fund 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 APAM 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 investment management agreement for the Fund, including the fees payable thereunder, was fair and reasonable and voted to approve the proposed renewal of the investment management agreement. 122 Pioneer Bond Fund | Semiannual Report | 12/31/19 Trustees, Officers and Service Providers Trustees Officers Thomas J. Perna, Chairman Lisa M. Jones, President and John E. Baumgardner, Jr. Chief Executive Officer Diane Durnin Mark E. Bradley, Treasurer and Benjamin M. Friedman Chief Financial and Lisa M. Jones Accounting Officer Lorraine H. Monchak Christopher J. Kelley, Secretary and Marguerite A. Piret Chief Legal Officer Fred J. Ricciardi Kenneth J. Taubes Investment Adviser and Administrator Amundi Pioneer Asset Management, Inc. Custodian and Sub-Administrator Brown Brothers Harriman & Co. Principal Underwriter Amundi Pioneer Distributor, Inc. Legal Counsel Morgan, Lewis & Bockius LLP Transfer Agent DST Asset Manager Solutions, 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 www.amundipioneer.com/us. This information is also available on the Securities and Exchange Commission's web site at www.sec.gov. Pioneer Bond Fund | Semiannual Report | 12/31/19 123 This page was intentionally left blank. 124 Pioneer Bond Fund | Semiannual Report | 12/31/19 How to Contact Amundi 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 FactFoneSM for automated fund yields, prices, account information and transactions 1-800-225-4321 Retirement plans information 1-800-622-0176 Write to us: -------------------------------------------------------------------------------- Amundi Pioneer P.O. Box 219427 Kansas City, MO 64121-9427 Our toll-free fax 1-800-225-4240 Our internet e-mail address us.askamundipioneer@amundipioneer.com (for general questions about Amundi Pioneer only) Visit our web site: www.amundipioneer.com/us This report must be preceded or accompanied by a prospectus. The Fund files a complete schedule of portfolio holdings with the Securities and Exchange Commission for the first and third quarters of each fiscal year as an exhibit to its reports on Form N-PORT. Shareholders may view the filed Form N-PORT by visiting the Commission's web site at https://www.sec.gov. [LOGO] Amundi Pioneer ============== ASSET MANAGEMENT Amundi Pioneer Asset Management, Inc. 60 State Street Boston, MA 02109 www.amundipioneer.com/us Securities offered through Amundi Pioneer Distributor, Inc. 60 State Street, Boston, MA 02109 Underwriter of Pioneer Mutual Funds, Member SIPC [C] 2020 Amundi Pioneer Asset Management 18633-14-0220 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)). Mr. David R. Bock, 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. N/A (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. N/A (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. N/A (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. N/A (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 Amudi Pioneer Asset Management, Inc, 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. N/A (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. N/A (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. Item 12. Disclosure of Securities Lending Activities for Closed-End Management Investment Companies. (a) If the registrant is a closed-end management investment company, provide the following dollar amounts of income and compensation related to the securities lending activities of the registrant during its most recent fiscal year: N/A (1) Gross income from securities lending activities; N/A (2) All fees and/or compensation for each of the following securities lending activities and related services: any share of revenue generated by the securities lending program paid to the securities lending agent(s) (revenue split); fees paid for cash collateral management services (including fees deducted from a pooled cash collateral reinvestment vehicle) that are not included in the revenue split; administrative fees that are not included in the revenue split; fees for indemnification that are not included in the revenue split; rebates paid to borrowers; and any other fees relating to the securities lending program that are not included in the revenue split, including a description of those other fees; N/A (3) The aggregate fees/compensation disclosed pursuant to paragraph (2); and N/A (4) Net income from securities lending activities (i.e., the dollar amount in paragraph (1) minus the dollar amount in paragraph (3)). If a fee for a service is included in the revenue split, state that the fee is included in the revenue split. N/A (b) If the registrant is a closed-end management investment company, describe the services provided to the registrant by the securities lending agent in the registrants most recent fiscal year. N/A ITEM 13. 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 Bond Fund By (Signature and Title)* /s/ Lisa M. Jones Lisa M. Jones, President & Chief Executive Officer Date March 3, 2020 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 March 3, 2020 By (Signature and Title)* /s/ Mark E. Bradley Mark E. Bradley, Treasurer & Chief Accounting & Financial Officer Date March 3, 2020 * Print the name and title of each signing officer under his or her signature.