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, Pioneer Investment Management, Inc., 60 State Street, Boston, MA 02109 (Name and address of agent for service) Registrant's telephone number, including area code: (617) 742-7825 Date of fiscal year end: June 30 Date of reporting period: July 1, 2016 through December 31, 2016 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, 2016 -------------------------------------------------------------------------------- Ticker Symbols: Class A PIOBX Class C PCYBX Class K PBFKX Class R PBFRX Class Y PICYX [LOGO] PIONEER Investments(R) visit us: us.pioneerinvestments.com Table of Contents President's Letter 2 Portfolio Management Discussion 4 Portfolio Summary 9 Prices and Distributions 10 Performance Update 11 Comparing Ongoing Fund Expenses 16 Schedule of Investments 18 Financial Statements 91 Notes to Financial Statements 100 Approval of Investment Advisory Agreement 115 Trustees, Officers and Service Providers 120 Pioneer Bond Fund | Semiannual Report | 12/31/16 1 President's Letter Dear Shareowner, The 2016 calendar year featured many swings in market sentiment, both in the equity and fixed-income markets. After a slow start to the year, the markets began to rally in mid-February 2016 with a recovery in the prices of oil and other commodities, as well as slow, positive progress in US employment figures. The rally persisted throughout much of the remaining 10 months of 2016, gaining further momentum in the second half of the year when US gross domestic product (GDP) growth showed solid improvement during the third quarter and unemployment continued to decline. Finally, in November, the election of Donald Trump as the 45th President of the United States sparked a dramatic late-year market upturn that saw US equities briefly climb to all-time highs. Speculation that the new Trump administration's policies would stimulate the US economy through reduced taxes, less regulation, and increased government spending on infrastructure, fueled the year-end rally. For the full 12 months ended December 31, 2016, the Standard & Poor's 500 Index, a broad measure of US stock market performance, returned a strong 11.9%. In bond markets, the Federal Reserve Board's (the Fed's) 0.25% hike in the Federal funds rate in December 2016, its first rate increase in a year, contributed to a sell-off in US Treasuries. The pullback from Treasuries also derived from the market's increased inflation and growth expectations under the incoming Trump administration. Elsewhere within fixed income, corporate credit, particularly in the high-yield segment of the market, performed well over the fourth quarter and the full calendar year. US high-yield securities, as measured by the Bank of America Merrill Lynch US High Yield Index, returned a robust 17.5% for the 12 months ended December 31, 2016, with a rally in the energy sector following the recovery in oil and other commodity prices last February bolstering the high-yield market's performance. Meanwhile, the Bloomberg Barclays US Aggregate Bond Index, which tracks the performance of Treasury and agency issues, corporate bond issues, and mortgage-backed securities, returned 2.7% for the same 12-month period, reflecting the relative weakness in government bonds. The US economy's underlying fundamentals seem solid, and growth prospects for 2017 appear healthy. However, we remain concerned about risks to the economy of potentially disruptive trade policies pursued by the Trump administration. Barring a damaging trade war, though, we anticipate the Fed will continue to hike short-term interest rates gradually during 2017. In addition, we expect the Fed to consider carefully the potential economic effects of any fiscal policies enacted by the new Trump administration and the Republican-controlled Congress. In that regard, we believe President Trump's economic policies, if they come to fruition, could help boost real GDP growth. However, the impact of Trump's policies on US GDP may be greater in 2018 rather than in 2017. Still, even prior to the late-year "Trump rally," US GDP growth appeared to settling in at a sustainable annual pace of more than 2% as 2016 drew to a close, following some weaker performance in the first half of the year. Continued improvement in the employment market driven in part by gains in manufacturing output were among the factors behind the bounce-back in GDP. 2 Pioneer Bond Fund | Semiannual Report | 12/31/16 While economic conditions inside the US appear solid, many economies around the world continue to experience slow growth rates. Moreover, several countries in various regions face a number of challenges in 2017 and beyond, including the shifting geopolitics driving "Brexit" - the United Kingdom's pending exit from the European Union - as well as related populist movements in Europe, limited productivity gains, aging populations, and transitioning economic models in China and other emerging markets. In recent years, global central banks have kept interest rates at close to zero in an effort to stimulate economic growth. While financial markets often benefited from the low rates, it now appears that those policies may be losing their effectiveness, leaving central banks little room to maneuver going forward. Moreover, the low interest rates have caused government bond yields to plummet, presenting a dilemma for the income-oriented investor. Against this backdrop of still-low global interest rates, shifting priorities of central banks, evolving demographics, and numerous geopolitical concerns, we believe investors are likely to face ongoing challenges and much uncertainty when it comes to finding opportunities for both income and capital appreciation. While much has been made of passive investing as a possible source of stability in this uncertain environment, it is our view that all investment decisions are active choices. Throughout Pioneer's history, we have believed in the importance of active management. During challenging market conditions, we view the value of active management as even more compelling. Our experienced and tenured investment teams focus on identifying value across global markets using proprietary research, careful risk management, and a long-term perspective. We believe our shareowners can benefit from the experience and tenure of our investment teams as well as the insights generated from our extensive research process. As always, and particularly during times of market uncertainty, we encourage you to work with your financial advisor to develop an overall investment plan that addresses both your short- and long-term goals, and to implement such a plan in a disciplined manner. We greatly appreciate the trust you have placed in us and look forward to continuing to serve you in the future. Sincerely, /s/ Lisa M. Jones Lisa M. Jones President and CEO Pioneer Investment Management USA Inc. December 31, 2016 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 | 12/31/16 3 Portfolio Management Discussion | 12/31/16 Market interest rates spiked following the U.S. election in November, undermining the valuations of intermediate- and longer-maturity debt, especially Treasuries and other higher-quality securities, and reducing the gains realized earlier in the six-month period ended December 31, 2016. In the following interview, Kenneth J. Taubes and Charles Melchreit review the factors that affected the performance of Pioneer Bond Fund during the six-month period ended December 31, 2016. Mr. Taubes, Executive Vice President, Chief Investment Officer, U.S., and a portfolio manager at Pioneer Investments, is responsible for the daily management of the Fund, along with Mr. Melchreit, Director of Investment-Grade Management, a senior vice president, and a portfolio manager at Pioneer. Q How did the Fund perform during the six-month period ended December 31, 2016? A Pioneer Bond Fund's Class A shares returned 0.13% at net asset value during the six-month period ended December 31, 2016, while the Fund's benchmark, the Bloomberg Barclays Aggregate Bond Index (the Bloomberg Barclays Index), returned -2.53%. During the same period, the average return of the 46 mutual funds in Lipper's Corporate Debt, A-rated Underlying Funds Category was -2.11%, and the average return of the 1,009 mutual funds in Morningstar's Intermediate-Term Bond Funds Category was -1.60%. Q How would you describe the investment environment during the six-month period ended December 31, 2016? A Over the first four months of the period, the bond market produced generally modest, positive results, with longer-maturity, higher-quality securities performing well against a backdrop of declining market interest rates and relatively modest inflation expectations. At the same time, lower-quality debt benefited as sustainable economic growth trends appeared to take hold. Investors remained cautiously optimistic for the most part, while keeping an eye on the volatile political campaign season in the U.S. leading up to the November elections. When the election resulted in the victory of Donald Trump in the presidential contest, however, the market reacted. Interest rates spiked quickly in the bond market, resulting in 4 Pioneer Bond Fund | Semiannual Report | 12/31/16 declines in the values of intermediate- and longer-term bonds, and especially of higher-quality bonds such as Treasuries and investment-grade corporates. In contrast, more credit-sensitive debt, including high-yield securities, tended to rise in price in a "risk-on" rally that also pulled stock market averages higher. Powering the rally was the expectation that Mr. Trump's election would usher in a period of greater fiscal stimulus for the economy, characterized by potentially lower corporate and individual tax rates and the likely easing of some regulatory controls over the business community. At the same time, signals came from the nation's central bank, the U.S. Federal Reserve (the Fed), that a nearly decade-long period of monetary easing, mostly via very low interest rates, was coming to an end, and that further stimulus would have to come from fiscal policies set by the new president and the Congress. The Fed's newer position came in light of stronger economic data, including reports that gross domestic product (GDP) growth in the third calendar quarter of 2016 had increased to a 3.5% annual rate, that manufacturing activity was increasing, and that employment was continuing to grow at a healthy clip. The Fed members also indicated that the possibility of increasing inflationary pressures would become more of a focus for them. Near the end of December 2016, at its final meeting of the year, the Fed followed through on its earlier indications by raising the influential Federal funds rate by one-quarter of one percent (0.25%), matching the increase of one year earlier. Q What were the principal factors that affected the Fund's performance relative to the benchmark Bloomberg Barclays Index during the six-month period ended December 31, 2016? A The Fund generated a modest, positive return during the period, and outperformed the Bloomberg Barclays Index, which finished the period in negative territory. The primary factor in the Fund's benchmark-relative outperformance during the period was sector allocation, specifically, the substantial portfolio underweight to highly interest-rate-sensitive Treasuries. In addition, most of the Fund's exposure to Treasuries was in Treasury Inflation Protected Securities (TIPS), which are not a benchmark component. In fact, the Fund's allocation to TIPS, which outperformed nominal Treasuries over the six-month period, was the second-biggest contributor to benchmark-relative outperformance. Pioneer Bond Fund | Semiannual Report | 12/31/16 5 The Fund's overweight position in corporate bonds also made a positive contribution to benchmark-relative returns, as the down-in-credit bias in the portfolio's corporate bond exposure benefited returns. The Fund's short-duration position relative to the Bloomberg Barclays Index also aided benchmark-relative results, most notably over the final two months of the period. The portfolio's average duration was 1.1 years shorter than that of the benchmark over the six-month 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.) Neither the Fund's barbelled yield-curve positioning (greater allocations to short- and longer-term securities than to intermediates) nor its slight overweight in government-agency mortgages had noteworthy effects on benchmark-relative performance during the period. As of December 31, 2016, the average effective duration of the Fund's portfolio was 5.25 years. On the negative side, the Fund's allocation to collateralized mortgage obligations (CMOs) detracted from benchmark-relative performance in the fourth quarter of 2016, the final three months of the period, as the high- quality non-agency residential mortgage-backed securities held in the portfolio were hurt by extending durations caused by rising interest rates. In December, the final month of the period, the TIPS allocation also detracted from benchmark-relative returns as break-evens fell back from the 2016 highs achieved at the beginning of the month. Overall, however, the Fund's allocation to TIPS was a positive contributor to relative results over the full six-month period. Q Did the Fund have any investments in derivative securities during the six- month period ended December 31, 2016? A Yes, the Fund had a position in Treasury futures during the period, as part of our strategy to keep the portfolio's duration shorter than that of the Bloomberg Barclays Index. The use of the Treasury futures in that way contributed positively to the Fund's performance. 6 Pioneer Bond Fund | Semiannual Report | 12/31/16 Q What factors affected the Fund's yield during the six-month period ended December 31, 2016? A The Fund's yield, or distributions to shareholders, increased over the six months, as the interest rates of Treasuries and other high-grade debt securities moved higher. Q What is your investment outlook? A We believe the underlying fundamentals of credit-sensitive securities, including high-yield bonds, remain firm, but their valuations are less compelling than they were a year ago prior to the rally in high-yield debt. Because of the U.S. economy's underlying strength, however, we have retained a modest overweight in investment-grade corporate bonds, even after upgrading the portfolio's overall credit quality. We expect to look for opportunities to reduce credit risk in the portfolio even further, without giving up too much yield. Growth in U.S. GDP appears to be settling in at a sustainable annual pace of more than 2% per year, with continued improvement in the employment market fueled in part by gains in manufacturing output. The economy's underlying fundamentals appear solid, and the growth prospects for 2017 appear healthy. We anticipate that the Fed will continue to hike short-term interest rates gradually during 2017, while carefully evaluating the effects of fiscal policies enacted by the new Trump administration and the Congress. Given our view, we expect to keep the Fund's overall duration shorter than the Bloomberg Barclays Index's. Pioneer Bond Fund | Semiannual Report | 12/31/16 7 Please refer to the Schedule of Investments on pages 18-90 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 fail- ure 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. 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 Pioneer Investments for a prospectus or summary prospectus containing this information. Read it carefully. Any information in this shareholder report regarding market or economic trends or the factors influencing the Fund's historical or future performance are statements of opinion as of the date of this report. Past performance is no guarantee of future results. 8 Pioneer Bond Fund | Semiannual Report | 12/31/16 Portfolio Summary | 12/31/16 Portfolio Diversification* -------------------------------------------------------------------------------- (As a percentage of total investment portfolio) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] U.S. Government Securities 35.6% U.S. Corporate Bonds 24.6% Collateralized Mortgage Obligations 19.2% International Corporate Bonds 10.0% Asset Backed Securities 4.0% Senior Secured Loans 3.0% Temporary Cash Investment 1.5% Municipal Bonds 1.1% Convertible Preferred Stocks 0.5% Foreign Government Bonds 0.5% * Includes investments in insurance linked securities totaling 3.9% of total investment portfolio. 10 Largest Holdings -------------------------------------------------------------------------------- (As a percentage of total long-term holdings)** 1. U.S. Treasury Bills, 1/12/17 3.42% -------------------------------------------------------------------------------- 2. Fannie Mae, 3.5%, 1/18/17 3.25 -------------------------------------------------------------------------------- 3. U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/46 1.68 -------------------------------------------------------------------------------- 4. U.S. Treasury Inflation Indexed Bonds, 0.75%, 2/15/45 1.38 -------------------------------------------------------------------------------- 5. Fannie Mae, 4.0%, 1/18/17 1.02 -------------------------------------------------------------------------------- 6. Government National Mortgage Association I, 3.5%, 1/24/17 0.74 -------------------------------------------------------------------------------- 7. U.S. Treasury Bills, 1/5/17 0.72 -------------------------------------------------------------------------------- 8. Everglades Re, Ltd., Floating Rate Note, 4/28/17 (Cat Bond) (144A) 0.49 -------------------------------------------------------------------------------- 9. Federal Home Loan Mortgage Corp., 3.0%, 1/18/17 0.46 -------------------------------------------------------------------------------- 10. Fannie Mae, 3.0%, 8/1/42 0.44 -------------------------------------------------------------------------------- ** This list excludes temporary cash investments and derivative instruments. The portfolio is actively managed, and current holdings may be different. The holdings listed should not be considered recommendations to buy or sell any securities listed. Pioneer Bond Fund | Semiannual Report | 12/31/16 9 Prices and Distributions | 12/31/16 Net Asset Value per Share -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Class 12/31/16 6/30/16 -------------------------------------------------------------------------------- A $9.62 $9.76 -------------------------------------------------------------------------------- C $9.51 $9.66 -------------------------------------------------------------------------------- K $9.62 $9.76 -------------------------------------------------------------------------------- R $9.71 $9.85 -------------------------------------------------------------------------------- Y $9.53 $9.67 -------------------------------------------------------------------------------- Distributions per Share: 7/1/16-12/31/16 -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Net Investment Short-Term Long-Term Class Income Capital Gains Capital Gains -------------------------------------------------------------------------------- A $0.1536 $ -- $ -- -------------------------------------------------------------------------------- C $0.1169 $ -- $ -- -------------------------------------------------------------------------------- K $0.1723 $ -- $ -- -------------------------------------------------------------------------------- R $0.1425 $ -- $ -- -------------------------------------------------------------------------------- Y $0.1662 $ -- $ -- -------------------------------------------------------------------------------- Index Definition -------------------------------------------------------------------------------- The Bloomberg Barclays 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 11-15. 10 Pioneer Bond Fund | Semiannual Report | 12/31/16 Performance Update | 12/31/16 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 Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2016) -------------------------------------------------------------------------------- Bloomberg Net Public Barclays Asset Offering Aggregate Value Price Bond Period (NAV) (POP) Index -------------------------------------------------------------------------------- 10 years 5.16% 4.68% 4.34% 5 years 3.79 2.84 2.23 1 year 4.18 -0.53 2.65 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2016) -------------------------------------------------------------------------------- Gross Net -------------------------------------------------------------------------------- 0.98% 0.85% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Bloomberg Barclays Pioneer Bond Fund Aggregate Bond Index 12/06 $ 9,550 $10,000 12/07 $10,130 $10,697 12/08 $ 9,689 $11,257 12/09 $11,404 $11,925 12/10 $12,480 $12,705 12/11 $13,114 $13,701 12/12 $14,249 $14,279 12/13 $14,318 $13,990 12/14 $15,166 $14,824 12/15 $15,164 $14,906 12/16 $15,798 $15,300 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. NAV results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. POP returns reflect deduction of maximum 4.50% sales charge. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The net expense ratio reflects the contractual expense limitation currently in effect through November 1, 2018, for Class A shares. There can be no assurance that Pioneer will extend the expense limitation beyond such time. Please see the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Bond Fund | Semiannual Report | 12/31/16 11 Performance Update | 12/31/16 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 Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2016) -------------------------------------------------------------------------------- Bloomberg Barclays Aggregate If If Bond Period Held Redeemed Index -------------------------------------------------------------------------------- 10 years 4.27% 4.27% 4.34% 5 years 2.94 2.94 2.23 1 year 3.43 3.43 2.65 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 1.60% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Bloomberg Barclays Pioneer Bond Fund Aggregate Bond Index 12/06 $10,000 $10,000 12/07 $10,532 $10,697 12/08 $ 9,980 $11,257 12/09 $11,640 $11,925 12/10 $12,618 $12,705 12/11 $13,145 $13,701 12/12 $14,153 $14,279 12/13 $14,095 $13,990 12/14 $14,808 $14,824 12/15 $14,690 $14,906 12/16 $15,194 $15,300 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class C shares held for less than one year are also subject to a 1% contingent deferred sales charge (CDSC). If 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. Returns would have been lower had sales charges been reflected. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 12 Pioneer Bond Fund | Semiannual Report | 12/31/16 Performance Update | 12/31/16 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 Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2016) -------------------------------------------------------------------------------- Bloomberg Net Barclays Asset Aggregate Value Bond Period (NAV) Index -------------------------------------------------------------------------------- 10 years 5.31% 4.34% 5 years 4.08 2.23 1 year 4.57 2.65 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2016) -------------------------------------------------------------------------------- Gross -------------------------------------------------------------------------------- 0.47% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Bloomberg Barclays Pioneer Bond Fund Aggregate Bond Index 12/06 $5,000,000 $5,000,000 12/07 $5,304,522 $5,348,337 12/08 $5,073,258 $5,628,585 12/09 $5,971,194 $5,962,406 12/10 $6,534,881 $6,352,431 12/11 $6,866,797 $6,850,570 12/12 $7,454,472 $7,139,334 12/13 $7,521,019 $6,994,836 12/14 $7,982,493 $7,412,151 12/15 $8,020,456 $7,452,911 12/16 $8,387,390 $7,650,208 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. The performance shown for Class K shares for the period prior to the commencement of operations of Class K shares on December 20, 2012, is the net asset value performance of the Fund's Class A shares, which has not been restated to reflect any differences in expenses, including Rule 12b-1 fees applicable to Class A shares. Since fees for Class A shares generally are higher than those of Class K shares, the performance of Class K shares prior to their inception would have been higher than the performance shown. 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. Pioneer Bond Fund | Semiannual Report | 12/31/16 13 Performance Update | 12/31/16 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 Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2016) -------------------------------------------------------------------------------- Bloomberg Net Barclays Asset Aggregate Value Bond Period (NAV) Index -------------------------------------------------------------------------------- 10 years 4.81% 4.34% 5 years 3.45 2.23 1 year 3.91 2.65 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2016) -------------------------------------------------------------------------------- Gross Net -------------------------------------------------------------------------------- 1.21% 1.10% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Bloomberg Barclays Pioneer Bond Fund Aggregate Bond Index 12/06 $10,000 $10,000 12/07 $10,597 $10,697 12/08 $10,080 $11,257 12/09 $11,826 $11,925 12/10 $12,899 $12,705 12/11 $13,504 $13,701 12/12 $14,595 $14,279 12/13 $14,611 $13,990 12/14 $15,437 $14,824 12/15 $15,400 $14,906 12/16 $16,001 $15,300 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class R shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The net expense ratio reflects the contractual expense limitation currently in effect through November 1, 2018, for Class R shares. There can be no assurance that Pioneer will extend the expense limitation beyond such time. Please see the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. 14 Pioneer Bond Fund | Semiannual Report | 12/31/16 Performance Update | 12/31/16 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 Aggregate Bond Index. Average Annual Total Returns (As of December 31, 2016) -------------------------------------------------------------------------------- Bloomberg Net Barclays Asset Aggregate Value Bond Period (NAV) Index -------------------------------------------------------------------------------- 10 years 5.43% 4.34% 5 years 4.03 2.23 1 year 4.48 2.65 -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated November 1, 2016) -------------------------------------------------------------------------------- Gross Net -------------------------------------------------------------------------------- 0.59% 0.58% -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5 Million Investment Bloomberg Barclays Pioneer Bond Fund Aggregate Bond Index 12/06 $5,000,000 $5,000,000 12/07 $5,324,500 $5,348,337 12/08 $5,108,545 $5,628,585 12/09 $6,025,642 $5,962,406 12/10 $6,613,343 $6,352,431 12/11 $6,966,502 $6,850,570 12/12 $7,581,459 $7,139,334 12/13 $7,631,311 $6,994,836 12/14 $8,103,974 $7,412,151 12/15 $8,123,771 $7,452,911 12/16 $8,487,617 $7,650,208 Call 1-800-225-6292 or visit us.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class Y shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The net expense ratio reflects the contractual expense limitation currently in effect through November 1, 2018, for Class Y shares. There can be no assurance that Pioneer will extend the expense limitation beyond such time. Please see the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. Please refer to the financial highlights for a more current expense ratio. Pioneer Bond Fund | Semiannual Report | 12/31/16 15 Comparing Ongoing Fund Expenses As a shareowner in the Fund, you incur two types of costs: (1) ongoing costs, including management fees, distribution and/or service (12b-1) fees, and other Fund expenses; and (2) transaction costs, including sales charges (loads) on purchase payments. This example is intended to help you understand your ongoing expenses (in dollars) of investing in the Fund and to compare these costs with the ongoing costs of investing in other mutual funds. The example is based on an investment of $1,000 at the beginning of the Fund's latest six-month period and held throughout the six months. Using the Tables -------------------------------------------------------------------------------- Actual Expenses The first table below provides information about actual account values and actual expenses. You may use the information in this table, together with the amount you invested, to estimate the expenses that you paid over the period as follows: (1) Divide your account value by $1,000 Example: an $8,600 account value (divided by) $1,000 = 8.6 (2) Multiply the result in (1) above by the corresponding share class's number in the third row under the heading entitled "Expenses Paid During Period" to estimate the expenses you paid on your account during this period. Expenses Paid on a $1,000 Investment in Pioneer Bond Fund Based on actual returns from July 1, 2016 through December 31, 2016. -------------------------------------------------------------------------------- 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 7/1/16 -------------------------------------------------------------------------------- Ending Account $1,001.30 $ 996.50 $1,003.20 $1,000.20 $1,002.60 Value (after expenses) on 12/31/16 -------------------------------------------------------------------------------- Expenses Paid $ 4.29 $ 8.00 $ 2.37 $ 5.55 $ 2.93 During Period* -------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.85%, 1.59%, 0.47%, 1.10%, and 0.58% 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 184/365 (to reflect the one-half year period). 16 Pioneer Bond Fund | Semiannual Report | 12/31/16 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, 2016 through December 31, 2016. -------------------------------------------------------------------------------- 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 7/1/16 -------------------------------------------------------------------------------- Ending Account $1,020.92 $1,017.19 $1,022.84 $1,019.66 $1,022.28 Value (after expenses) on 12/31/16 -------------------------------------------------------------------------------- Expenses Paid $ 4.33 $ 8.08 $ 2.40 $ 5.60 $ 2.96 During Period* -------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.85%, 1.59%, 0.47%, 1.10%, and 0.58% 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 184/365 (to reflect the one-half year period). Pioneer Bond Fund | Semiannual Report | 12/31/16 17 Schedule of Investments | 12/31/16 (unaudited) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- CONVERTIBLE PREFERRED STOCKS -- 0.6% BANKS -- 0.6% Diversified Banks -- 0.6% 6,255 Bank of America Corp., 7.25% (Perpetual) $ 7,298,334 14,261 Wells Fargo & Co. (Perpetual) 16,970,590 --------------- $ 24,268,924 --------------- Total Banks $ 24,268,924 --------------------------------------------------------------------------------------------------- TOTAL CONVERTIBLE PREFERRED STOCKS (Cost $23,351,289) $ 24,268,924 --------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- 4.2% ENERGY -- 0.1% Oil & Gas Exploration & Production -- 0.1% 2,400,000 Colony American Finance 2016-2, Ltd., 5.028%, 11/15/48 (Step) (144A) $ 2,263,455 --------------- Total Energy $ 2,263,455 --------------------------------------------------------------------------------------------------- MATERIALS -- 0.0%+ Steel -- 0.0%+ 500,000 1.07 Home Equity Asset Trust 2005-6, Floating Rate Note, 12/25/35 $ 491,374 --------------- Total Materials $ 491,374 --------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.0%+ Hotels, Resorts & Cruise Lines -- 0.0%+ 366,519 Westgate Resorts 2012-A LLC, 3.75%, 8/20/25 (144A) $ 365,876 1,471,492 Westgate Resorts 2015-1 LLC, 2.75%, 5/20/27 (144A) 1,458,773 --------------- $ 1,824,649 --------------- Total Consumer Services $ 1,824,649 --------------------------------------------------------------------------------------------------- FOOD & STAPLES RETAILING -- 0.0%+ Food Retail -- 0.0%+ 1,155,150 CKE Restaurant Holdings, Inc., 4.474%, 3/20/43 (144A) $ 1,140,784 --------------- Total Food & Staples Retailing $ 1,140,784 --------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.0%+ Health Care Distributors -- 0.0%+ 1,500,000 OneMain Financial Issuance Trust 2015-1, 3.19%, 3/18/26 (144A) $ 1,510,646 --------------- Total Health Care Equipment & Services $ 1,510,646 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 18 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- BANKS -- 3.4% Thrifts & Mortgage Finance -- 3.4% 1,293,975 0.93 321 Henderson Receivables I LLC, Floating Rate Note, 11/15/40 (144A) $ 1,228,245 499,053 Access Point Funding I 2015-A LLC, 2.61%, 4/15/20 (144A) 499,053 2,200,000 2.05 American Homes 4 Rent 2014-SFR1, Floating Rate Note, 6/17/31 2,188,327 2,800,000 American Homes 4 Rent 2014-SFR3 Trust, 4.596%, 12/18/36 (144A) 2,877,823 700,000 American Homes 4 Rent 2014-SFR3 Trust, 5.04%, 12/18/36 (144A) 728,440 1,300,000 American Homes 4 Rent 2015-SFR1, 4.11%, 4/18/52 (144A) 1,289,935 2,600,000 Applebee's Funding LLC/ IHOP Funding LLC, 4.277%, 9/5/44 (144A) 2,572,283 2,200,000 Ascentium Equipment Receivables 2015-1 LLC, 3.24%, 1/10/22 (144A) 2,220,986 1,300,000 Ascentium Equipment Receivables 2016-2 Trust, 4.2%, 9/10/22 (144A) 1,277,782 699,990 Axis Equipment Finance Receivables III LLC, 3.41%, 4/20/20 (144A) 668,609 3,571,822 B2R Mortgage Trust 2015-1, 2.524%, 5/15/48 (144A) 3,537,933 138,721 1.34 Bayview Financial Mortgage Pass-Through Trust 2005-C, Floating Rate Note, 6/28/44 138,306 4,890,000 Bayview Opportunity Master Fund IVa Trust 2016-SPL1, 4.0%, 4/28/55 (144A) 5,036,273 7,400,000 4.00 Bayview Opportunity Master Fund IVb Trust 2016-SPL2, Floating Rate Note, 6/28/53 (144A) 7,615,346 1,650,000 BCC Funding Corp., X, 3.622%, 11/20/20 (144A) 1,655,594 769,517 1.51 Bear Stearns Asset Backed Securities I Trust 2005-FR1, Floating Rate Note, 6/25/35 764,859 521,822 1.25 Bear Stearns Asset Backed Securities Trust 2006-SD2, Floating Rate Note, 6/25/36 512,589 1,910,088 BXG Receivables Note Trust 2015-A, 2.88%, 5/2/30 (144A) 1,911,826 1,800,000 Capital Automotive Real Estate Investment Trust, 3.66%, 10/17/44 (144A) 1,748,925 400,000 1.85 Chesapeake Funding LLC, Floating Rate Note, 3/9/26 (144A) 391,960 1,400,000 CIT Equipment Collateral 2014-VT1, 2.65%, 10/20/22 (144A) 1,403,999 358,323 1.51 Citigroup Mortgage Loan Trust, Inc., Floating Rate Note, 5/25/35 (144A) 357,006 5,312,116 Colony American Finance 2015-1, Ltd., 2.896%, 10/18/47 (144A) 5,295,570 3,200,000 2.55 Colony American Homes 2014-1, Floating Rate Note, 5/19/31 (144A) 3,196,348 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 19 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,554,040 Conn's Receivables Funding 2016-B LLC, 3.73%, 10/15/18 (144A) $ 1,557,877 199,894 Consumer Credit Origination Loan Trust 2015-1, 2.82%, 3/15/21 (144A) 200,019 1,500,000 Credit Acceptance Auto Loan Trust 2016-2, 4.29%, 11/15/24 (144A) 1,494,224 356,103 0.88 Credit-Based Asset Servicing & Securitization LLC, Floating Rate Note, 7/25/36 355,428 1,248,776 CRG Issuer 2015-1, 4.07%, 7/11/22 (144A) 1,239,410 430,786 1.81 CWABS Asset-Backed Certificates Trust 2004-7, Floating Rate Note, 12/25/34 429,703 491,250 DB Master Finance LLC 2015-1, 3.98%, 2/20/45 (144A) 491,941 1,897,648 2.56 DRB Prime Student Loan Trust 2016-B, Floating Rate Note, 6/25/40 (144A) 1,922,731 742,629 3.73 Drug Royalty II LP 2, Floating Rate Note, 7/15/23 (144A) 747,761 2,000,000 DT Auto Owner Trust 2015-1, 4.26%, 2/15/22 (144A) 2,028,107 1,300,000 Engs Commercial Finance Trust 2016-1, 3.45%, 3/22/22 (144A) 1,299,852 1,900,000 Engs Commercial Finance Trust 2016-1, 5.22%, 1/22/24 (144A) 1,899,321 6,513,814 1.00 Fieldstone Mortgage Investment Trust Series 2005-3, Floating Rate Note, 2/25/36 6,397,648 452,414 GMAT 2013-1 Trust, 6.9669%, 8/25/53 (Step) 453,283 1,900,000 Green Tree Agency Advance Funding Trust I, 4.0575%, 10/15/48 (144A) 1,884,971 5,301,000 1.24 GSAA Trust, Floating Rate Note, 6/25/35 4,394,450 384,238 1.51 GSAMP Trust 2005-HE1, Floating Rate Note, 12/25/34 381,805 1,092,599 2.11 GSRPM Mortgage Loan Trust 2003-2, Floating Rate Note, 6/25/33 1,057,625 414,536 1.06 GSRPM Mortgage Loan Trust 2006-2, Floating Rate Note, 9/25/36 (144A) 409,998 2,912,750 HOA Funding LLC, 4.846%, 8/22/44 (144A) 2,578,561 102,883 1.14 Home Equity Asset Trust 2005-7, Floating Rate Note, 1/25/36 102,790 861,945 1.13 Home Equity Mortgage Loan Asset-Backed Trust Series INABS 2005-C, Floating Rate Note, 10/25/35 850,390 1,399,082 Icon Brand Holdings LLC, 4.229%, 1/26/43 (144A) 1,273,113 301,925 Icon Brand Holdings LLC, 4.352%, 1/25/43 (144A) 272,768 1,690,949 1.74 Invitation Homes 2014-SFR3 Trust, Floating Rate Note, 12/17/31 (144A) 1,690,947 258,448 2.26 Irwin Whole Loan Home Equity Trust 2003-C, Floating Rate Note, 6/25/28 255,836 2,000,000 3.41 Kabbage Funding 2014-1 Resecuritization Trust, Floating Rate Note, 3/8/18 (144A) 1,994,844 The accompanying notes are an integral part of these financial statements. 20 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 850,000 LEAF Receivables Funding 10 LLC, 2.74%, 3/15/21 (144A) $ 849,284 1,200,000 Leaf Receivables Funding 11 LLC, 4.89%, 1/15/23 (144A) 1,189,992 148,387 Lehman ABS Manufactured Housing Contract Trust 2001-B, 3.01%, 5/15/41 149,195 949,015 Nations Equipment Finance Funding II LLC, 3.276%, 1/22/19 (144A) 950,638 470,620 0.91 Nationstar Home Equity Loan Trust 2007-A, Floating Rate Note, 3/25/37 469,745 1,000,000 6.24 NCF Dealer Floorplan Master Trust, Floating Rate Note, 3/21/22 (144A) 978,885 908,073 1.28 New Century Home Equity Loan Trust 2005-1, Floating Rate Note, 3/25/35 903,496 1,050,000 NextGear Floorplan Master Owner Trust, 1.92%, 10/15/19 (144A) 1,049,999 1,000,000 NextGear Floorplan Master Owner Trust, 2.61%, 10/15/19 (144A) 998,889 1,200,000 1.80 NextGear Floorplan Master Owner Trust, Floating Rate Note, 9/15/21 (144A) 1,200,610 222,717 2.41 NovaStar Mortgage Funding Trust Series 2004-4, Floating Rate Note, 3/25/35 221,447 1,000,000 Ocwen Master Advance Receivables Trust, 2.5207%, 8/17/48 (144A) 996,060 1,600,000 Oportun Funding III LLC, 3.69%, 7/8/21 (144A) 1,598,872 2,100,000 Oxford Finance Funding 2016-1 LLC, 3.968%, 6/17/24 (144A) 2,091,326 1,000,000 1.55 PFS Financing Corp., Floating Rate Note, 10/15/19 (144A) 998,566 775,000 Prestige Auto Receivables Trust 2013-1, 3.04%, 7/15/20 (144A) 779,357 3,200,000 Progreso Receivables Funding III LLC, 3.625%, 1/30/25 (144A) 3,185,002 2,000,000 Progreso Receivables Funding IV LLC, 3.0%, 7/8/20 (144A) 1,998,828 434,585 1.01 RAAC Series 2006-RP2 Trust, Floating Rate Note, 2/25/37 (144A) 431,027 1,700,220 SCF Equipment Trust 2016-1 LLC, 3.62%, 11/20/21 (144A) 1,695,259 3,360,000 2.59 Silver Bay Realty 2014-1 Trust, Floating Rate Note, 9/18/31 (144A) 3,355,613 277,138 Skopos Auto Receivables Trust 2015-1, 3.1%, 12/15/23 (144A) 276,128 600,000 Skopos Auto Receivables Trust 2015-1, 5.43%, 12/15/23 (144A) 602,102 378,986 Springleaf Funding Trust 2014-A, 2.41%, 12/15/22 (144A) 379,126 1,388,333 Store Master Funding I LLC, 3.75%, 4/20/45 (144A) 1,354,530 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 21 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,960,695 STORE Master Funding LLC, 5.77%, 8/20/42 (144A) $ 2,031,124 344,187 0.96 Structured Asset Investment Loan Trust 2006-1, Floating Rate Note, 1/25/36 341,117 185,282 0.98 Structured Asset Securities Corp., Mortgage Loan Trust 2006-GEL4, Floating Rate Note, 10/25/36 (144A) 185,054 25,279 Structured Asset Securities Corp., 5.27%, 10/25/34 (Step) 25,986 541,394 Sunset Mortgage Loan Co., 2014-NPL2 LLC, 3.721%, 11/16/44 (Step) (144A) 540,718 333,062 SVO 2012-A VOI Mortgage LLC, 2.0%, 9/20/29 (144A) 327,130 37,793 Terwin Mortgage Trust Series TMTS 2005-12ALT, 4.79595%, 7/25/36 (Step) 37,724 1,566,385 Terwin Mortgage Trust Series TMTS 2005-16HE, 4.2899%, 9/25/36 (Step) 1,590,654 800,000 2.79 Trafigura Securitisation Finance Plc 2014-1, Floating Rate Note, 4/16/18 (144A) 795,487 2,140,000 United Auto Credit Securitization Trust 2015-1, 2.92%, 6/17/19 (144A) 2,146,108 855,857 VOLT XXXI LLC, 3.375%, 2/25/55 (Step) (144A) 857,921 2,168,918 VOLT XXXIII LLC, 3.5%, 3/25/55 (Step) (144A) 2,175,155 1,522,844 VOLT XXXVI LLC, 3.625%, 7/25/45 (Step) (144A) 1,524,698 2,020,372 VOLT XXXVII LLC, 3.625%, 7/25/45 (Step) (144A) 2,018,424 1,312,492 Welk Resorts 2015-A LLC, 2.79%, 6/16/31 (144A) 1,295,357 3,327,090 Westgate Resorts 2016-1 LLC, 4.5%, 12/20/28 (144A) 3,332,025 1,000,000 Westlake Automobile Receivables Trust 2015-3, 3.05%, 5/17/21 (144A) 1,007,437 1,000,000 Westlake Automobile Receivables Trust 2016-1, 3.29%, 9/15/21 (144A) 1,010,162 3,194,039 3.50 WinWater Mortgage Loan Trust 2015-5, Floating Rate Note, 8/20/45 (144A) 3,217,745 --------------- $ 139,947,422 --------------- Total Banks $ 139,947,422 --------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 0.5% Other Diversified Financial Services -- 0.2% 500,000 American Credit Acceptance Receivables Trust 2014-1, 5.2%, 4/12/21 (144A) $ 506,114 411,424 Diamond Resorts Owner Trust 2015-1, 3.17%, 7/20/27 (144A) 410,141 749,242 PFS Tax Lien Trust 2014-1, 1.44%, 5/15/29 (144A) 744,217 105,549 Sierra Timeshare 2012-3 Receivables Funding LLC, 1.87%, 8/20/29 (144A) 104,882 244,136 Small Business Administration Participation Certificates, 4.2%, 9/1/29 258,171 The accompanying notes are an integral part of these financial statements. 22 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Other Diversified Financial Services -- (continued) 340,911 Small Business Administration Participation Certificates, 4.625%, 2/1/25 $ 359,406 336,819 Small Business Administration Participation Certificates, 4.84%, 5/1/25 356,621 430,942 Small Business Administration Participation Certificates, 5.37%, 4/1/28 468,603 326,458 Small Business Administration Participation Certificates, 5.63%, 10/1/28 358,037 108,582 Small Business Administration Participation Certificates, 5.72%, 1/1/29 119,255 499,712 Small Business Administration Participation Certificates, 6.02%, 8/1/28 556,445 103,966 Small Business Administration Participation Certificates, 6.14%, 1/1/22 110,538 264,731 Small Business Administration Participation Certificates, 6.22%, 12/1/28 294,272 3,300,000 Spirit Master Funding LLC, 4.6291%, 1/20/45 (144A) 3,101,212 --------------- $ 7,747,914 --------------------------------------------------------------------------------------------------- Specialized Finance -- 0.2% 3,539,250 Domino's Pizza Master Issuer LLC, 3.484%, 10/25/45 (144A) $ 3,502,442 1,804,782 Domino's Pizza Master Issuer LLC, 5.216%, 1/27/42 (144A) 1,840,811 2,466,198 Hercules Capital Funding Trust 2014-1, 3.524%, 4/16/21 (144A) 2,470,051 530,393 JG Wentworth XXII LLC, 3.82%, 12/15/48 (144A) 535,739 --------------- $ 8,349,043 --------------------------------------------------------------------------------------------------- Consumer Finance -- 0.1% 2,100,000 First Investors Auto Owner Trust 2014-3, 2.97%, 11/16/20 (144A) $ 2,111,668 510,000 First Investors Auto Owner Trust 2015-1, 3.59%, 1/18/22 (144A) 510,733 --------------- $ 2,622,401 --------------------------------------------------------------------------------------------------- Investment Banking & Brokerage -- 0.0%+ 1,600,000 2.40 Chesapeake Funding LLC, Floating Rate Note, 2/8/27 (144A) $ 1,564,650 --------------- Total Diversified Financials $ 20,284,008 --------------------------------------------------------------------------------------------------- REAL ESTATE -- 0.0%+ Residential REIT -- 0.0%+ 1,250,000 2.45 American Homes 4 Rent 2014-SFR1 REMICS, Floating Rate Note, 6/17/31 (144A) $ 1,247,145 --------------- Total Real Estate $ 1,247,145 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 23 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 0.2% Wireless Telecommunication Services -- 0.2% 6,975,000 3.87 Small Business Administration Participation Certificates, Floating Rate Note, 10/15/49 (144A) $ 7,026,261 --------------- Total Telecommunication Services $ 7,026,261 --------------------------------------------------------------------------------------------------- TOTAL ASSET BACKED SECURITIES (Cost $176,456,479) $ 175,735,744 --------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- 20.1% ENERGY -- 0.2% Oil & Gas Exploration & Production -- 0.2% 7,428,167 N/A Shellpoint Co-Originator Trust 2016-1, Floating Rate Note, 10/25/31 (144A) $ 7,471,693 --------------- Total Energy $ 7,471,693 --------------------------------------------------------------------------------------------------- BANKS -- 19.1% Thrifts & Mortgage Finance -- 19.1% 19,562 A10 Securitization 2013-1 LLC, 2.4%, 11/17/25 (144A) $ 19,560 534,988 A10 Term Asset Financing 2013-2 LLC, 2.62%, 11/15/27 (144A) 532,785 7,151,705 3.61 Agate Bay Mortgage Trust 2013-1, Floating Rate Note, 7/25/43 (144A) 6,996,092 1,788,326 3.90 Agate Bay Mortgage Trust 2014-1 REMICS, Floating Rate Note, 7/25/44 (144A) 1,753,480 5,226,311 3.50 Agate Bay Mortgage Trust 2015-1, Floating Rate Note, 1/25/45 (144A) 5,268,367 3,269,573 3.50 Agate Bay Mortgage Trust 2015-2, Floating Rate Note, 3/27/45 (144A) 3,308,144 3,935,055 3.50 Agate Bay Mortgage Trust 2015-5, Floating Rate Note, 7/25/45 (144A) 3,966,720 6,860,824 3.50 Agate Bay Mortgage Trust 2015-7, Floating Rate Note, 10/25/45 (144A) 7,000,078 3,990,461 3.50 Agate Bay Mortgage Trust 2016-1, Floating Rate Note, 12/25/45 (144A) 4,005,114 185,171 1.21 Alternative Loan Trust 2003-14T1, Floating Rate Note, 8/25/18 166,928 5,000,000 2.29 Arbor Realty Collateralized Loan Obligation 2015-FL1, Ltd., Floating Rate Note, 3/17/25 (144A) 4,935,741 2,580,000 2.90 BAMLL Commercial Mortgage Securities Trust 2014-FL1, Floating Rate Note, 12/17/31 (144A) 2,588,323 1,600,000 2.49 BAMLL Commercial Mortgage Securities Trust 2014-INLD, Floating Rate Note, 12/17/29 (144A) 1,585,130 4,200,000 2.25 BAMLL Commercial Mortgage Securities Trust 2015-ASHF, Floating Rate Note, 1/18/28 (144A) 4,199,874 2,701,202 2.87 BAMLL Re-REMIC Trust 2014-FRR7, Floating Rate Note, 10/26/44 (144A) 2,698,820 606,322 Banc of America Alternative Loan Trust 2004-6, 5.0%, 7/25/19 611,068 The accompanying notes are an integral part of these financial statements. 24 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,900,000 5.81 Banc of America Commercial Mortgage Trust 2007-4, Floating Rate Note, 2/10/51 (144A) $ 1,886,075 503,739 Banc of America Mortgage Trust 2004-11, 5.75%, 1/25/35 510,925 594,454 Banc of America Mortgage Trust 2004-9, 5.5%, 11/25/34 608,680 6,995,240 Bayview Commercial Asset Trust 2007-2, 7/27/37 (Step) (144A) (c) 7 785,471 2.51 Bayview Opportunity Master Fund IVb Trust 2016-CRT1, Floating Rate Note, 10/27/27 (144A) 784,098 887,993 5.21 Bear Stearns Commercial Mortgage Securities Trust 2005-PWR7, Floating Rate Note, 2/11/41 886,750 2,500,000 5.09 Bellemeade Re II, Ltd., Floating Rate Note, 4/25/26 (144A) 2,512,714 2,210,000 2.65 BLCP Hotel Trust, Floating Rate Note, 8/15/29 (144A) 2,186,477 3,250,000 CCRESG Commercial Mortgage Trust 2016-HEAT, 3.357%, 4/10/29 (144A) 3,270,973 4,000,000 3.20 CDGJ Commercial Mortgage Trust 2014-BXCH, Floating Rate Note, 12/15/27 (144A) 3,984,942 13,451,514 3.75 Chase Mortgage Trust 2016-2, Floating Rate Note, 2/25/44 (144A) 13,336,843 341,002 3.41 CHL Mortgage Pass-Through Trust 2003-56, Floating Rate Note, 12/25/33 343,693 5,000,000 Citigroup Commercial Mortgage Trust 2014-GC25 REMICS, 3.371%, 10/11/47 5,118,323 1,149,159 3.50 Citigroup Mortgage Loan Trust 2013-J1, Floating Rate Note, 10/25/43 (144A) 1,146,122 6,853,806 3.75 Citigroup Mortgage Loan Trust 2015-PS1, Floating Rate Note, 9/25/42 (144A) 7,047,993 2,400,000 Colony American Finance 2016-1, Ltd., 5.972%, 6/15/48 (Step) (144A) 2,416,355 2,100,000 2.49 Colony Starwood Homes 2016-2 Trust, Floating Rate Note, 12/19/33 (144A) 2,103,418 450,000 COMM 2012-CCRE2 Mortgage Trust REMICS, 3.791%, 8/17/45 469,883 915,000 COMM 2012-CCRE4 Mortgage Trust, 2.436%, 10/17/45 921,150 4,000,000 COMM 2012-LC4 Mortgage Trust, 4.063%, 12/12/44 4,223,548 5,000,000 5.17 COMM 2013-CCRE11 Mortgage Trust, Floating Rate Note, 8/12/50 (144A) 5,272,286 1,900,000 COMM 2013-LC6 Mortgage Trust, 2.941%, 1/10/46 1,922,588 7,325,000 4.51 COMM 2014-CCRE20 Mortgage Trust, Floating Rate Note, 11/10/47 7,204,448 3,800,000 2.85 COMM 2014-FL5 Mortgage Trust, Floating Rate Note, 10/15/31 (144A) 3,771,745 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 25 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 4,500,000 4.78 COMM 2014-UBS3 Mortgage Trust, Floating Rate Note, 6/12/47 $ 4,331,385 4,100,000 COMM 2014-UBS4 Mortgage Trust, 3.42%, 8/10/47 4,174,357 1,750,000 3.68 COMM 2015-CCRE23 Mortgage Trust, Floating Rate Note, 5/12/48 (144A) 1,737,938 3,104,000 4.55 COMM 2015-CCRE25 Mortgage Trust, Floating Rate Note, 8/12/48 3,242,213 3,375,000 COMM 2015-CCRE26 Mortgage Trust REMICS, 3.63%, 10/13/48 3,473,844 4,225,000 COMM 2015-LC23 Mortgage Trust REMICS, 3.774%, 10/10/53 4,403,773 3,850,000 Commercial Mortgage Pass Through Certificates, 2.822%, 10/17/45 3,897,502 4,699,547 5.54 Credit Suisse Commercial Mortgage Trust Series 2006-C4, Floating Rate Note, 9/15/39 4,705,422 401,979 Credit Suisse Commercial Mortgage Trust Series 2007-C1, 5.361%, 2/15/40 401,490 119,206 Credit Suisse First Boston Mortgage Securities Corp., 5.5%, 6/25/33 120,514 5,700,000 4.54 CSAIL 2016-C5 Commercial Mortgage Trust REMICS, Floating Rate Note, 11/15/48 5,734,581 1,890,000 CSAIL 2016-C6 Commercial Mortgage Trust, 3.0898%, 1/15/49 1,867,490 2,700,000 2.95 CSMC 2015-TWNI Trust, Floating Rate Note, 3/15/28 (144A) 2,647,775 6,413,738 3.00 CSMC Trust 2012-CIM2, Floating Rate Note, 6/25/42 (144A) 6,245,626 5,296,105 3.58 CSMC Trust 2013-7, Floating Rate Note, 8/25/43 (144A) 5,135,022 6,072,918 1.55 CSMC Trust 2013-IVR2, Floating Rate Note, 4/27/43 (144A) 5,723,740 2,803,303 1.55 CSMC Trust 2013-IVR3, Floating Rate Note, 5/25/43 (144A) 2,692,243 3,299,469 3.46 CSMC Trust 2013-IVR3, Floating Rate Note, 5/25/43 (144A) 3,243,930 3,845,715 3.46 CSMC Trust 2013-IVR3, Floating Rate Note, 5/25/43 (144A) 3,646,596 2,331,379 3.00 CSMC Trust 2013-IVR4, Floating Rate Note, 7/27/43 (144A) 2,331,312 1,603,760 3.00 CSMC Trust 2013-IVR4, Floating Rate Note, 7/27/43 (144A) 1,587,795 3,669,971 3.50 CSMC Trust 2014-IVR3 REMICS, Floating Rate Note, 7/25/44 (144A) 3,692,622 1,979,009 3.00 CSMC Trust 2014-OAK1, Floating Rate Note, 11/25/44 (144A) 1,976,179 2,062,304 3.00 CSMC Trust 2014-WIN1, Floating Rate Note, 9/25/44 (144A) 2,059,566 The accompanying notes are an integral part of these financial statements. 26 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 5,402,997 3.94 CSMC Trust 2014-WIN1, Floating Rate Note, 9/25/44 (144A) $ 5,333,089 5,936,765 3.50 CSMC Trust 2014-WIN2, Floating Rate Note, 10/25/44 (144A) 5,911,142 2,888,778 4.01 CSMC Trust 2014-WIN2, Floating Rate Note, 10/25/44 (144A) 2,857,788 11,791,489 CSMC Trust 2015-2, 3.0%, 2/25/45 (144A) 11,671,459 5,017,934 CSMC Trust 2015-2, 3.0%, 2/25/45 (144A) 5,009,288 3,388,370 CSMC Trust 2015-2, 3.5%, 2/25/45 (144A) 3,391,814 2,805,975 3.88 CSMC Trust 2015-WIN1, Floating Rate Note, 12/25/44 (144A) 2,688,941 9,396,555 3.50 CSMLT 2015-1 Trust, Floating Rate Note, 5/25/45 (144A) 9,478,042 3,907,909 3.92 CSMLT 2015-2 Trust, Floating Rate Note, 8/25/45 (144A) 3,713,568 4,584,732 3.50 CSMLT 2015-2 Trust, Floating Rate Note, 8/28/45 (144A) 4,624,491 3,100,000 DBJPM 16-C3 Mortgage Trust, 2.89%, 9/10/49 3,022,173 3,859,960 3.49 EverBank Mortgage Loan Trust REMICS, Floating Rate Note, 4/25/43 (144A) 3,846,865 4,630,000 3.38 GAHR Commercial Mortgage Trust 2015-NRF, Floating Rate Note, 12/15/34 (144A) 4,653,259 897,315 Global Mortgage Securitization, Ltd., 5.25%, 4/25/32 (144A) 878,140 1,216,974 1.03 Global Mortgage Securitization, Ltd., Floating Rate Note, 4/25/32 (144A) 1,146,086 2,000,000 4.63 Government National Mortgage Association, Floating Rate Note, 1/16/50 2,126,743 2,800,000 GS Mortgage Securities Corp., Trust 2012-SHOP, 2.933%, 6/5/31 (144A) 2,839,286 1,250,000 GS Mortgage Securities Corp. II, 3.377%, 5/10/45 1,301,901 1,000,000 GS Mortgage Securities Corp. II, 3.682%, 2/10/46 (144A) 1,019,274 3,500,000 GS Mortgage Securities Trust 2013-GCJ14 REMICS, 4.507%, 8/10/46 (144A) 3,767,946 3,821,536 1.00 HomeBanc Mortgage Trust 2005-3, Floating Rate Note, 7/25/35 3,733,191 2,100,000 2.40 Hyatt Hotel Portfolio Trust 2015-HYT, Floating Rate Note, 11/15/29 (144A) 2,103,536 344,537 0.86 JP Morgan Chase Commercial Mortgage Securities Trust 2006-LDP9, Floating Rate Note, 5/15/47 342,342 1,150,172 JP Morgan Chase Commercial Mortgage Securities Trust 2010-C2, 3.6159%, 11/15/43 (144A) 1,167,380 1,142,174 JP Morgan Chase Commercial Mortgage Securities Trust 2011-C5, 4.1712%, 8/15/46 1,225,014 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 27 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 1,200,000 3.98 JP Morgan Chase Commercial Mortgage Securities Trust 2012-C8, Floating Rate Note, 10/17/45 (144A) $ 1,236,547 4,260,234 JP Morgan Chase Commercial Mortgage Securities Trust 2012-LC9, 2.84%, 12/15/47 4,312,593 4,600,000 2.65 JP Morgan Chase Commercial Mortgage Securities Trust 2014-CBM, Floating Rate Note, 10/15/29 (144A) 4,562,182 2,200,000 2.90 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL4 REMICS, Floating Rate Note, 12/16/30 (144A) 2,177,359 900,000 2.80 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL5 REMICS, Floating Rate Note, 7/15/31 (144A) 887,869 1,260,000 2.05 JP Morgan Chase Commercial Mortgage Securities Trust 2014-FL5, Floating Rate Note, 7/15/31 (144A) 1,264,823 4,000,000 3.45 JP Morgan Chase Commercial Mortgage Securities Trust 2015-SGP, Floating Rate Note, 7/15/36 (144A) 4,024,914 178,131 2.99 JP Morgan Mortgage Trust 2003-A1, Floating Rate Note, 10/25/33 176,657 386,040 JP Morgan Mortgage Trust 2004-S1, 5.0%, 9/25/34 395,523 5,227,176 3.00 JP Morgan Mortgage Trust 2013-1, Floating Rate Note, 3/25/43 (144A) 5,062,498 13,127,693 2.50 JP Morgan Mortgage Trust 2013-1, Floating Rate Note, 3/25/43 (144A) 12,951,296 1,797,074 3.00 JP Morgan Mortgage Trust 2013-1, Floating Rate Note, 3/25/43 (144A) 1,825,598 3,597,591 3.52 JP Morgan Mortgage Trust 2013-1, Floating Rate Note, 3/25/43 (144A) 3,523,951 995,465 3.50 JP Morgan Mortgage Trust 2013-2, Floating Rate Note, 5/25/43 (144A) 1,003,475 5,121,404 3.50 JP Morgan Mortgage Trust 2014-1 REMICS, Floating Rate Note, 1/25/44 (144A) 5,162,616 1,079,530 3.50 JP Morgan Mortgage Trust 2014-1 REMICS, Floating Rate Note, 1/25/44 (144A) 1,086,193 3,183,423 3.76 JP Morgan Mortgage Trust 2014-1 REMICS, Floating Rate Note, 1/25/44 (144A) 3,069,982 6,380,442 3.00 JP Morgan Mortgage Trust 2014-2, Floating Rate Note, 6/25/29 (144A) 6,419,822 5,537,894 3.42 JP Morgan Mortgage Trust 2014-2, Floating Rate Note, 6/25/29 (144A) 5,589,703 1,286,038 3.43 JP Morgan Mortgage Trust 2014-2, Floating Rate Note, 6/25/29 (144A) 1,218,711 3,987,520 3.00 JP Morgan Mortgage Trust 2014-5, Floating Rate Note, 10/25/29 (144A) 4,024,592 The accompanying notes are an integral part of these financial statements. 28 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 2,172,108 3.02 JP Morgan Mortgage Trust 2014-5, Floating Rate Note, 10/25/29 (144A) $ 2,075,672 5,692,164 4.06 JP Morgan Mortgage Trust 2014-OAK4, Floating Rate Note, 9/25/44 (144A) 5,859,725 7,178,910 3.50 JP Morgan Mortgage Trust 2015-4, Floating Rate Note, 6/26/45 (144A) 7,236,678 11,527,553 JP Morgan Mortgage Trust 2016-1, 3.5%, 5/25/46 (144A) 11,627,520 4,253,720 3.90 JP Morgan Mortgage Trust 2016-1, Floating Rate Note, 5/25/46 (144A) 4,222,919 11,652,977 2.69 JP Morgan Mortgage Trust 2016-2, Floating Rate Note, 6/25/46 (144A) 11,527,094 13,315,508 3.00 JP Morgan Mortgage Trust 2016-3, Floating Rate Note, 10/25/46 (144A) 13,430,980 10,561,294 3.50 JP Morgan Mortgage Trust 2016-4, Floating Rate Note, 10/25/46 (144A) 10,732,091 12,400,000 2.60 JP Morgan Mortgage Trust, Floating Rate Note, 12/25/46 (144A) 12,343,812 5,833,983 1.26 JP Morgan Seasoned Mortgage Trust 2014-1, Floating Rate Note, 5/25/33 (144A) 5,539,822 7,455,424 2.64 JP Morgan Trust 2015-1 REMICS, Floating Rate Note, 12/25/44 (144A) 7,382,125 4,076,080 3.00 JP Morgan Trust 2015-3 REMICS, Floating Rate Note, 5/25/45 (144A) 4,056,882 3,235,502 3.70 JP Morgan Trust 2015-3 REMICS, Floating Rate Note, 5/25/45 (144A) 3,265,847 4,422,014 3.70 JP Morgan Trust 2015-3 REMICS, Floating Rate Note, 5/25/45 (144A) 4,197,978 3,906,399 3.50 JP Morgan Trust 2015-6, Floating Rate Note, 10/25/45 (144A) 3,937,834 4,021,774 5.05 JPMBB Commercial Mortgage Securities Trust 2013-C15, Floating Rate Note, 11/15/45 (144A) 3,829,485 3,500,000 JPMBB Commercial Mortgage Securities Trust 2014-C22 REMICS, 3.8012%, 9/15/47 3,651,992 2,000,000 3.10 JPMDB Commercial Mortgage Securities Trust 2016-C4, Floating Rate Note, 12/15/49 (144A) 1,447,265 2,211,288 La Hipotecaria El Salvadorian Mortgage Trust 2016-1, 3.3575%, 1/15/46 (144A) 2,227,528 1,377,298 2.25 La Hipotecaria Panamanian Mortgage Trust 2010-1, Floating Rate Note, 9/8/39 (144A) 1,423,781 3,664,191 3.01 La Hipotecaria Panamanian Mortgage Trust 2014-1, Floating Rate Note, 11/24/42 (144A) 3,703,123 84,217 LB-UBS Commercial Mortgage Trust 2004-C1, 4.568%, 1/15/31 84,195 3,690,000 3.24 LSTAR Commercial Mortgage Trust 2015-3, Floating Rate Note, 4/20/48 (144A) 3,601,582 7,800,000 2.61 LSTAR Commercial Mortgage Trust 2016-7, Floating Rate Note, 12/1/21 (144A) 7,702,500 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 29 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 875,182 2.62 LSTAR Securities Investment, Ltd. 2016-1, Floating Rate Note, 1/1/21 (144A) $ 859,955 3,538,942 2.53 LSTAR Securities Investment, Ltd. 2016-3, Floating Rate Note, 9/1/21 (144A) 3,495,811 8,080,670 2.62 LSTAR Securities Investment, Ltd. 2016-4, Floating Rate Note, 10/1/21 (144A) 7,982,768 596,128 1.14 Mellon Residential Funding Corp., Mortgage Pass-Through Trust Series 2000-TBC3, Floating Rate Note, 12/15/30 567,090 1,225,350 1.32 Merrill Lynch Mortgage Investors Trust Series MLCC 2004-G, Floating Rate Note, 1/25/30 1,152,597 6,881,000 Morgan Stanley Bank of America Merrill Lynch Trust 2016-C31, 3.527%, 10/15/26 6,695,847 4,061,212 Morgan Stanley Capital I Trust 2007-HQ13, 5.569%, 12/15/44 4,140,086 5,309,000 Morgan Stanley Capital I Trust 2016-UBS12, 3.596%, 12/15/49 5,419,376 7,156,654 3.75 New Residential Mortgage Loan Trust 2015-1, Floating Rate Note, 5/28/52 (144A) 7,289,193 4,622,601 3.32 NRP Mortgage Trust 2013-1, Floating Rate Note, 7/25/43 (144A) 4,387,445 6,786,087 3.25 NRP Mortgage Trust 2013-1, Floating Rate Note, 7/25/43 (144A) 6,610,986 4,114,180 3.25 NRP Mortgage Trust 2013-1, Floating Rate Note, 7/25/43 (144A) 4,130,645 6,102,462 3.32 NRP Mortgage Trust 2013-1, Floating Rate Note, 7/25/43 (144A) 5,836,152 5,079,404 3.57 PMT Loan Trust 2013-J1, Floating Rate Note, 9/25/43 (144A) 4,812,361 278,809 RAAC Series 2004-SP2 Trust, 6.0%, 1/25/32 280,043 135,808 RALI Series 2003-QS14 Trust, 5.0%, 7/25/18 136,161 390,734 RALI Series 2004-QS3 Trust, 5.0%, 3/25/19 389,435 2,338,787 2.31 RESI Finance LP 2003-CB1, Floating Rate Note, 7/9/35 2,087,601 324,459 RREF 2015-LT7 LLC, 3.0%, 12/27/32 (144A) 324,459 12,500,000 Seasoned Credit Risk Transfer Trust Series 2016-1, 3.0%, 9/25/55 12,068,362 6,108,178 3.50 Sequoia Mortgage Trust 2012-2, Floating Rate Note, 4/25/42 6,111,177 3,889,220 1.81 Sequoia Mortgage Trust 2012-6, Floating Rate Note, 12/26/42 3,585,538 4,191,620 3.65 Sequoia Mortgage Trust 2013-1, Floating Rate Note, 2/25/43 4,081,343 6,796,966 3.57 Sequoia Mortgage Trust 2013-10, Floating Rate Note, 8/25/43 (144A) 6,748,439 2,138,261 1.87 Sequoia Mortgage Trust 2013-2, Floating Rate Note, 2/25/43 2,042,875 The accompanying notes are an integral part of these financial statements. 30 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 7,314,673 3.53 Sequoia Mortgage Trust 2013-3, Floating Rate Note, 3/25/43 $ 7,319,024 6,802,352 2.33 Sequoia Mortgage Trust 2013-4 REMICS, Floating Rate Note, 4/27/43 6,515,960 1,384,216 1.55 Sequoia Mortgage Trust 2013-4, Floating Rate Note, 4/27/43 1,353,569 6,066,188 3.49 Sequoia Mortgage Trust 2013-4, Floating Rate Note, 4/27/43 6,019,326 2,476,050 2.50 Sequoia Mortgage Trust 2013-5 REMICS, Floating Rate Note, 5/25/43 (144A) 2,441,132 2,211,955 3.00 Sequoia Mortgage Trust 2013-5 REMICS, Floating Rate Note, 5/25/43 (144A) 2,180,762 7,276,366 2.50 Sequoia Mortgage Trust 2013-6, Floating Rate Note, 5/26/43 6,969,834 10,348,880 2.50 Sequoia Mortgage Trust 2013-7, Floating Rate Note, 6/25/43 9,697,904 3,295,618 3.00 Sequoia Mortgage Trust 2013-7, Floating Rate Note, 6/25/43 3,240,904 464,804 2.25 Sequoia Mortgage Trust 2013-8, Floating Rate Note, 6/25/43 445,595 10,211,273 3.00 Sequoia Mortgage Trust 2013-8, Floating Rate Note, 6/25/43 10,054,244 6,148,618 3.54 Sequoia Mortgage Trust 2013-8, Floating Rate Note, 6/25/43 6,083,284 1,395,836 Sequoia Mortgage Trust 2013-9, 3.5%, 7/27/43 (144A) 1,390,493 675,917 Sequoia Mortgage Trust 2013-9, 3.5%, 7/27/43 (144A) 668,676 7,640,007 4.00 Sequoia Mortgage Trust 2014-2, Floating Rate Note, 7/25/44 (144A) 7,773,157 4,894,962 3.00 Sequoia Mortgage Trust 2015-1, Floating Rate Note, 1/25/45 (144A) 4,770,742 8,920,635 3.50 Sequoia Mortgage Trust 2015-2, Floating Rate Note, 5/25/45 (144A) 8,997,995 3,824,275 3.73 Sequoia Mortgage Trust 2015-3, Floating Rate Note, 7/25/45 (144A) 3,776,452 8,809,871 3.00 Sequoia Mortgage Trust 2015-4, Floating Rate Note, 11/25/30 (144A) 8,886,270 5,050,648 3.50 Sequoia Mortgage Trust 2016-2, Floating Rate Note, 8/25/46 (144A) 5,035,395 3,953,899 3.77 Sequoia Mortgage Trust 2016-2, Floating Rate Note, 8/25/46 (144A) 3,812,870 10,072,029 Sequoia Mortgage Trust, 3.5%, 11/25/46 10,134,193 33,117 3.00 Sequoia Mortgage Trust, Floating Rate Note, 9/25/42 32,650 3,642,873 3.50 Sequoia Mortgage Trust, Floating Rate Note, 9/25/42 3,680,839 3,250,000 3.00 Sofi Mortgage Trust 2016-1, Floating Rate Note, 11/25/46 (144A) 3,100,195 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 31 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- (continued) 463,660 0.88 Structured Asset Securities Corp. Trust 2005-14, Floating Rate Note, 7/25/35 $ 373,089 2,120,419 3.02 Velocity Commercial Capital Loan Trust 2015-1, Floating Rate Note, 6/25/45 (144A) 2,129,930 1,013,870 VOLT XXX LLC, 3.625%, 10/25/57 (Step) (144A) 1,013,962 1,179,220 Wells Fargo Commercial Mortgage Trust 2010-C1, 3.349%, 11/18/43 (144A) 1,208,198 1,927,000 Wells Fargo Commercial Mortgage Trust 2012-LC5 REMICS, 3.539%, 10/15/45 1,981,248 4,500,000 Wells Fargo Commercial Mortgage Trust 2014-LC16 REMICS, 3.477%, 8/15/50 4,668,923 5,300,000 2.55 Wells Fargo Commercial Mortgage Trust 2014-TISH REMICS, Floating Rate Note, 2/15/27 (144A) 5,302,158 3,810,000 Wells Fargo Commercial Mortgage Trust 2015-NXS3, 3.617%, 9/17/57 3,924,283 1,493,521 3.51 Wells Fargo Credit Risk Transfer Securities Trust 2015, Floating Rate Note, 11/25/25 (144A) 1,500,023 2,267,050 3.61 Wells Fargo Credit Risk Transfer Securities Trust 2015, Floating Rate Note, 11/25/25 (144A) 2,273,898 1,435,000 5.60 WF-RBS Commercial Mortgage Trust 2011-C2, Floating Rate Note, 2/15/44 (144A) 1,469,019 3,900,000 4.35 WFRBS Commercial Mortgage Trust 2013-C12, Floating Rate Note, 3/15/48 (144A) 3,589,794 6,200,000 WFRBS Commercial Mortgage Trust 2013-C16, 4.136%, 9/17/46 6,644,269 459,362 3.50 WinWater Mortgage Loan Trust 2014-1, Floating Rate Note, 6/20/44 (144A) 462,771 8,434,416 3.91 WinWater Mortgage Loan Trust 2015-2, Floating Rate Note, 2/20/45 (144A) 8,161,127 5,008,412 3.50 WinWater Mortgage Loan Trust 2015-3 REMICS, Floating Rate Note, 3/20/45 (144A) 4,992,996 9,301,502 3.50 WinWater Mortgage Loan Trust 2015-4, Floating Rate Note, 6/20/45 (144A) 9,389,140 6,805,372 3.50 WinWater Mortgage Loan Trust 2015-5, Floating Rate Note, 8/20/45 (144A) 6,798,461 4,790,991 3.80 WinWater Mortgage Loan Trust 2015-5, Floating Rate Note, 8/20/45 (144A) 4,851,793 4,552,061 3.80 WinWater Mortgage Loan Trust 2015-5, Floating Rate Note, 8/20/45 (144A) 4,354,125 3,884,784 3.50 WinWater Mortgage Loan Trust 2016-1, Floating Rate Note, 1/22/46 (144A) 3,850,070 --------------- $ 798,133,754 --------------- Total Banks $ 798,133,754 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 32 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 0.2% Other Diversified Financial Services -- 0.0%+ 1,102,352 3.52 JP Morgan Mortgage Trust 2013-1, Floating Rate Note, 3/25/43 (144A) $ 1,033,568 --------------------------------------------------------------------------------------------------- Specialized Finance -- 0.1% 1,980,000 2.54 BAMLL Commercial Mortgage Securities Trust 2015-ASHF REMICS, Floating Rate Note, 1/15/28 (144A) $ 1,975,604 --------------------------------------------------------------------------------------------------- Asset Management & Custody Banks -- 0.1% 5,062,189 3.62 Agate Bay Mortgage Trust 2015-5, Floating Rate Note, 7/25/45 (144A) $ 4,771,739 --------------- Total Diversified Financials $ 7,780,911 --------------------------------------------------------------------------------------------------- GOVERNMENT -- 0.6% 77,174 0.94 Federal Home Loan Mortgage Corp. REMICS, Floating Rate Note, 12/15/20 $ 77,561 802,223 3.73 Federal National Mortgage Association 2004-T2, Floating Rate Note, 7/25/43 851,887 1,141 Federal National Mortgage Association REMICS, 10.3%, 4/25/19 1,206 1,410,169 Federal National Mortgage Association REMICS, 3.0%, 6/25/23 1,447,985 465,024 Federal National Mortgage Association REMICS, 4.5%, 6/25/29 494,320 3,482,251 Freddie Mac Whole Loan Securities Trust 2015-SC01, 3.5%, 5/25/45 3,492,507 600,000 5.25 FREMF Mortgage Trust 2010-K8, Floating Rate Note, 9/25/43 (144A) 644,775 890,000 5.20 FREMF Mortgage Trust 2010-K9 REMICS, Floating Rate Note, 9/25/45 (144A) 959,722 5,380,000 4.77 FREMF Mortgage Trust 2011-K702, Floating Rate Note, 4/25/44 (144A) 5,538,891 1,250,000 4.88 FREMF Mortgage Trust 2011-K703, Floating Rate Note, 7/25/44 (144A) 1,293,692 3,004,204 4.62 FREMF Mortgage Trust 2014-KF05 REMICS, Floating Rate Note, 9/25/21 (144A) 3,006,066 3,808,130 5.59 FREMF Mortgage Trust 2014-KS02 REMICS, Floating Rate Note, 8/25/23 (144A) 3,795,334 2,010,000 3.82 FREMF Mortgage Trust Class B, Floating Rate Note, 6/25/47 (144A) 2,061,731 806,139 Government National Mortgage Association REMICS, 3.25%, 4/16/27 827,696 1,065,300 Government National Mortgage Association, 3.0%, 4/20/41 1,090,709 950,607 Government National Mortgage Association, 5.25%, 8/16/35 1,034,605 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 33 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Government -- (continued) 416,122 Vendee Mortgage Trust 2008-1, 5.25%, 1/15/32 $ 443,308 783,067 Vendee Mortgage Trust 2010-1, 4.25%, 2/15/35 805,998 --------------- $ 27,867,993 --------------- Total Government $ 27,867,993 --------------------------------------------------------------------------------------------------- TOTAL COLLATERALIZED MORTGAGE OBLIGATIONS (Cost $853,447,893) $ 841,254,351 --------------------------------------------------------------------------------------------------- CORPORATE BONDS -- 36.1% ENERGY -- 4.7% Oil & Gas Drilling -- 0.4% 7,241,000 Ensco Plc, 4.5%, 10/1/24 $ 6,209,158 6,185,000 Rowan Companies, Inc., 4.75%, 1/15/24 5,581,962 5,505,000 Rowan Companies, Inc., 5.85%, 1/15/44 4,266,375 --------------- $ 16,057,495 --------------------------------------------------------------------------------------------------- Oil & Gas Equipment & Services -- 0.1% 2,250,000 Halliburton Co., 7.6%, 8/15/96 (144A) $ 2,804,366 --------------------------------------------------------------------------------------------------- Integrated Oil & Gas -- 0.7% 4,175,000 BP Capital Markets Plc, 3.062%, 3/17/22 $ 4,223,021 5,965,000 Petroleos Mexicanos, 3.5%, 1/30/23 5,475,870 3,525,000 Petroleos Mexicanos, 6.5%, 3/13/27 (144A) 3,636,038 4,750,000 Sinopec Group Overseas Development 2014, Ltd., 4.375%, 4/10/24 (144A) 4,936,000 10,050,000 Sinopec Group Overseas Development 2015, Ltd., 2.5%, 4/28/20 (144A) 9,983,379 --------------- $ 28,254,308 --------------------------------------------------------------------------------------------------- Oil & Gas Exploration & Production -- 0.6% 6,585,000 Canadian Natural Resources, Ltd., 6.25%, 3/15/38 $ 7,491,517 2,830,000 Canadian Natural Resources, Ltd., 6.75%, 2/1/39 3,302,262 5,275,000 CNOOC Nexen Finance 2014 ULC, 4.25%, 4/30/24 5,396,837 2,360,000 Newfield Exploration Co., 5.375%, 1/1/26 2,406,256 1,400,000 Newfield Exploration Co., 5.625%, 7/1/24 1,459,500 4,150,000 WPX Energy, Inc., 7.5%, 8/1/20 4,461,250 --------------- $ 24,517,622 --------------------------------------------------------------------------------------------------- Oil & Gas Refining & Marketing -- 0.4% 5,827,000 EnLink Midstream Partners LP, 4.4%, 4/1/24 $ 5,789,631 1,800,000 EnLink Midstream Partners LP, 4.85%, 7/15/26 1,815,719 3,800,000 Motiva Enterprises LLC, 6.85%, 1/15/40 (144A) 4,593,957 3,180,000 Valero Energy Corp., 6.625%, 6/15/37 3,721,758 2,890,000 Valero Energy Corp., 9.375%, 3/15/19 3,328,124 --------------- $ 19,249,189 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 34 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Oil & Gas Storage & Transportation -- 2.5% 10,945,000 Boardwalk Pipelines LP, 4.95%, 12/15/24 $ 11,237,987 2,575,000 Boardwalk Pipelines LP, 5.95%, 6/1/26 2,797,058 2,900,000 DCP Midstream LLC, 9.75%, 3/15/19 (144A) 3,248,000 4,095,000 5.85 DCP Midstream LLC, Floating Rate Note, 5/21/43 (144A) 3,480,750 8,585,000 Enbridge Energy Partners LP, 7.375%, 10/15/45 10,648,370 3,275,000 Energy Transfer Equity LP, 5.875%, 1/15/24 3,381,438 4,675,000 Kinder Morgan Energy Partners LP, 4.25%, 9/1/24 4,774,316 8,235,000 Kinder Morgan, Inc. Delaware, 5.05%, 2/15/46 8,151,868 7,335,000 Kinder Morgan, Inc. Delaware, 5.55%, 6/1/45 7,714,755 3,875,000 MPLX LP, 4.875%, 12/1/24 3,990,064 1,720,000 MPLX LP, 4.875%, 6/1/25 1,768,413 3,875,000 MPLX LP, 5.5%, 2/15/23 4,031,387 9,165,000 Plains All American Pipeline LP, 4.65%, 10/15/25 9,468,664 5,300,000 Plains All American Pipeline LP, 4.7%, 6/15/44 4,722,470 6,180,000 Sabine Pass Liquefaction LLC, 5.0%, 3/15/27 (144A) 6,234,075 2,475,000 Spectra Energy Capital LLC, 6.2%, 4/15/18 2,587,417 1,500,000 Spectra Energy Capital LLC, 6.75%, 7/15/18 1,582,626 786,000 Sunoco Logistics Partners Operations LP, 6.1%, 2/15/42 812,441 2,475,000 The Williams Companies, Inc., 7.75%, 6/15/31 2,821,500 5,115,000 TransCanada PipeLines, Ltd., 1.875%, 1/12/18 5,123,031 8,230,000 Williams Partners LP, 5.1%, 9/15/45 7,822,195 --------------- $ 106,398,825 --------------- Total Energy $ 197,281,805 --------------------------------------------------------------------------------------------------- MATERIALS -- 1.0% Fertilizers & Agricultural Chemicals -- 0.3% 2,800,000 Agrium, Inc., 4.125%, 3/15/35 $ 2,567,300 10,800,000 Agrium, Inc., 5.25%, 1/15/45 11,246,872 --------------- $ 13,814,172 --------------------------------------------------------------------------------------------------- Construction Materials -- 0.3% 10,600,000 CRH America, Inc., 3.875%, 5/18/25 (144A) $ 10,793,323 --------------------------------------------------------------------------------------------------- Metal & Glass Containers -- 0.1% 2,275,000 Ball Corp., 4.0%, 11/15/23 $ 2,229,500 4,000,000 Ball Corp., 5.25%, 7/1/25 4,180,000 --------------- $ 6,409,500 --------------------------------------------------------------------------------------------------- Paper Packaging -- 0.1% 2,575,000 International Paper Co., 6.0%, 11/15/41 $ 2,891,756 --------------------------------------------------------------------------------------------------- Diversified Metals & Mining -- 0.1% 1,375,000 Amsted Industries, Inc., 5.375%, 9/15/24 (144A) $ 1,350,938 1,850,000 Freeport-McMoRan, Inc., 3.875%, 3/15/23 1,697,375 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 35 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Diversified Metals & Mining -- (continued) 1,650,000 Freeport-McMoRan, Inc., 4.55%, 11/14/24 $ 1,546,875 --------------- $ 4,595,188 --------------------------------------------------------------------------------------------------- Steel -- 0.1% 3,550,000 Commercial Metals Co., 4.875%, 5/15/23 $ 3,567,750 --------------- Total Materials $ 42,071,689 --------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 1.8% Aerospace & Defense -- 0.8% 7,472,000 L3 Technologies, Inc., 3.95%, 5/28/24 $ 7,599,442 7,680,000 Lockheed Martin Corp., 3.1%, 1/15/23 7,763,965 7,855,000 Spirit AeroSystems, Inc., 3.85%, 6/15/26 7,749,429 10,344,000 United Technologies Corp., 1.778%, 5/4/18 (Step) 10,346,255 --------------- $ 33,459,091 --------------------------------------------------------------------------------------------------- Building Products -- 0.7% 7,680,000 Fortune Brands Home & Security, Inc., 3.0%, 6/15/20 $ 7,729,359 8,595,000 Masco Corp., 4.375%, 4/1/26 8,680,950 1,050,000 Masco Corp., 4.45%, 4/1/25 1,065,750 825,000 Masco Corp., 5.95%, 3/15/22 911,625 5,675,000 Owens Corning, 3.4%, 8/15/26 5,390,870 5,150,000 Owens Corning, 4.2%, 12/1/24 5,275,557 --------------- $ 29,054,111 --------------------------------------------------------------------------------------------------- Construction & Engineering -- 0.0%+ 1,368,000 Amsted Industries, Inc., 5.0%, 3/15/22 (144A) $ 1,368,000 --------------------------------------------------------------------------------------------------- Industrial Conglomerates -- 0.1% 1,392,000 General Electric Co., 5.3%, 2/11/21 $ 1,543,809 2,950,000 Tyco Electronics Group SA, 6.55%, 10/1/17 3,059,888 --------------- $ 4,603,697 --------------------------------------------------------------------------------------------------- Trading Companies & Distributors -- 0.2% 5,660,000 GATX Corp., 6.0%, 2/15/18 $ 5,889,536 --------------- Total Capital Goods $ 74,374,435 --------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.2% Environmental & Facilities Services -- 0.1% 2,678,000 Republic Services, Inc., 2.9%, 7/1/26 $ 2,567,265 --------------------------------------------------------------------------------------------------- Research & Consulting Services -- 0.1% 5,942,000 Verisk Analytics, Inc., 5.5%, 6/15/45 $ 6,318,972 --------------- Total Commercial Services & Supplies $ 8,886,237 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 36 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- TRANSPORTATION -- 1.1% Railroads -- 0.9% 14,485,000 Burlington Northern Santa Fe LLC, 4.15%, 4/1/45 $ 14,689,325 6,650,000 TTX Co., 3.6%, 1/15/25 (144A) 6,638,269 3,250,000 TTX Co., 4.2%, 7/1/46 (144A) 3,080,292 13,215,000 Union Pacific Corp., 3.375%, 2/1/35 12,497,994 --------------- $ 36,905,880 --------------------------------------------------------------------------------------------------- Highways & Railtracks -- 0.2% 3,950,000 ERAC USA Finance LLC, 3.3%, 12/1/26 (144A) $ 3,790,096 1,300,000 ERAC USA Finance LLC, 3.8%, 11/1/25 (144A) 1,309,104 4,600,000 ERAC USA Finance LLC, 4.5%, 2/15/45 (144A) 4,386,473 --------------- $ 9,485,673 --------------- Total Transportation $ 46,391,553 --------------------------------------------------------------------------------------------------- AUTOMOBILES & COMPONENTS -- 0.5% Automobile Manufacturers -- 0.5% 4,975,000 Ford Motor Credit Co., LLC, 2.24%, 6/15/18 $ 4,981,741 6,425,000 Ford Motor Credit Co., LLC, 3.219%, 1/9/22 6,353,021 10,045,000 Toyota Motor Credit Corp., 2.125%, 7/18/19 10,088,585 --------------- $ 21,423,347 --------------- Total Automobiles & Components $ 21,423,347 --------------------------------------------------------------------------------------------------- CONSUMER DURABLES & APPAREL -- 0.1% Homebuilding -- 0.1% 5,120,000 Lennar Corp., 4.75%, 4/1/21 $ 5,286,400 --------------- Total Consumer Durables & Apparel $ 5,286,400 --------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.2% Education Services -- 0.2% 2,600,000 President & Fellows of Harvard College, 2.3%, 10/1/23 $ 2,530,172 3,550,000 Tufts University, 5.017%, 4/15/12 3,705,703 --------------- $ 6,235,875 --------------- Total Consumer Services $ 6,235,875 --------------------------------------------------------------------------------------------------- MEDIA -- 0.8% Cable & Satellite -- 0.6% 6,995,000 Charter Communications Operating LLC, 6.384%, 10/23/35 $ 7,987,115 10,310,000 Comcast Corp., 5.65%, 6/15/35 12,321,966 2,440,000 Sirius XM Radio, Inc., 5.375%, 7/15/26 (144A) 2,385,100 650,000 Time Warner Cable LLC, 6.55%, 5/1/37 735,834 675,000 Videotron, Ltd., 5.375%, 6/15/24 (144A) 692,719 --------------- $ 24,122,734 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 37 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Movies & Entertainment -- 0.2% 8,300,000 Time Warner, Inc., 4.7%, 1/15/21 $ 8,871,679 --------------- Total Media $ 32,994,413 --------------------------------------------------------------------------------------------------- RETAILING -- 0.7% Internet Retail -- 0.5% 5,900,000 Expedia, Inc., 4.5%, 8/15/24 $ 5,995,739 950,000 Expedia, Inc., 5.0%, 2/15/26 979,361 3,800,000 Expedia, Inc., 5.95%, 8/15/20 4,153,670 1,925,000 The Priceline Group, Inc., 3.6%, 6/1/26 1,903,833 7,375,000 The Priceline Group, Inc., 3.65%, 3/15/25 7,354,505 --------------- $ 20,387,108 --------------------------------------------------------------------------------------------------- Home Improvement Retail -- 0.1% 4,520,000 The Home Depot, Inc., 2.625%, 6/1/22 $ 4,541,782 --------------------------------------------------------------------------------------------------- Automotive Retail -- 0.1% 3,994,000 AutoZone, Inc., 2.5%, 4/15/21 $ 3,949,123 --------------- Total Retailing $ 28,878,013 --------------------------------------------------------------------------------------------------- FOOD & STAPLES RETAILING -- 0.5% Drug Retail -- 0.3% 650,000 CVS Health Corp., 2.25%, 8/12/19 $ 653,568 582,839 CVS Pass-Through Trust, 5.298%, 1/11/27 (144A) 625,270 2,795,422 CVS Pass-Through Trust, 5.773%, 1/10/33 (144A) 3,129,956 1,913,216 CVS Pass-Through Trust, 5.926%, 1/10/34 (144A) 2,185,513 3,737,896 CVS Pass-Through Trust, 6.036%, 12/10/28 4,190,544 --------------- $ 10,784,851 --------------------------------------------------------------------------------------------------- Food Retail -- 0.2% 1,635,000 The Kroger Co., 1.5%, 9/30/19 $ 1,610,155 6,172,000 The Kroger Co., 2.95%, 11/1/21 6,210,322 1,300,000 The Kroger Co., 3.4%, 4/15/22 1,325,169 --------------- $ 9,145,646 --------------- Total Food & Staples Retailing $ 19,930,497 --------------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 1.0% Brewers -- 0.1% 4,350,000 2.14 Anheuser-Busch InBev Finance, Inc., Floating Rate Note, 2/1/21 $ 4,426,508 --------------------------------------------------------------------------------------------------- Distillers & Vintners -- 0.2% 2,180,000 Constellation Brands, Inc., 3.7%, 12/6/26 $ 2,129,947 9,100,000 Pernod Ricard SA, 3.25%, 6/8/26 (144A) 8,731,714 --------------- $ 10,861,661 --------------------------------------------------------------------------------------------------- Packaged Foods & Meats -- 0.5% 9,100,000 Grupo Bimbo SAB de CV, 3.875%, 6/27/24 (144A) $ 9,053,199 10,040,000 Kraft Heinz Foods Co., 3.5%, 6/6/22 10,210,389 --------------- $ 19,263,588 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 38 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Tobacco -- 0.2% 7,275,000 Reynolds American, Inc., 4.45%, 6/12/25 $ 7,681,025 --------------- Total Food, Beverage & Tobacco $ 42,232,782 --------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.2% Health Care Equipment -- 0.1% 5,219,000 Becton Dickinson and Co., 3.734%, 12/15/24 $ 5,337,064 --------------------------------------------------------------------------------------------------- Health Care Facilities -- 0.1% 1,150,000 HCA, Inc., 5.25%, 6/15/26 $ 1,188,812 2,400,000 NYU Hospitals Center, 4.428%, 7/1/42 2,294,102 --------------- $ 3,482,914 --------------- Total Health Care Equipment & Services $ 8,819,978 --------------------------------------------------------------------------------------------------- PHARMACEUTICALS, BIOTECHNOLOGY & LIFE SCIENCES -- 2.0% Biotechnology -- 1.0% 925,000 AbbVie, Inc., 2.85%, 5/14/23 $ 897,321 1,370,000 AbbVie, Inc., 3.2%, 5/14/26 1,303,455 8,430,000 AbbVie, Inc., 3.6%, 5/14/25 8,349,814 8,035,000 Amgen, Inc., 4.4%, 5/1/45 7,701,917 2,350,000 Amgen, Inc., 5.375%, 5/15/43 2,567,147 12,900,000 Baxalta, Inc., 3.6%, 6/23/22 12,998,724 3,550,000 Biogen, Inc., 3.625%, 9/15/22 3,643,954 4,275,000 Biogen, Inc., 4.05%, 9/15/25 4,401,386 --------------- $ 41,863,718 --------------------------------------------------------------------------------------------------- Pharmaceuticals -- 0.7% 3,150,000 Johnson & Johnson, 4.375%, 12/5/33 $ 3,463,308 11,155,000 Mylan NV, 3.95%, 6/15/26 (144A) 10,439,384 3,300,000 Perrigo Finance Unlimited Co., 3.5%, 3/15/21 3,334,416 1,755,000 Perrigo Finance Unlimited Co., 3.9%, 12/15/24 1,718,006 2,481,000 Perrigo Finance Unlimited Co., 4.375%, 3/15/26 2,483,533 10,140,000 Teva Pharmaceutical Finance Netherlands III BV, 2.8%, 7/21/23 9,598,433 --------------- $ 31,037,080 --------------------------------------------------------------------------------------------------- Life Sciences Tools & Services -- 0.3% 894,000 Agilent Technologies, Inc., 6.5%, 11/1/17 $ 927,474 11,200,000 Thermo Fisher Scientific, Inc., 3.0%, 4/15/23 11,008,110 --------------- $ 11,935,584 --------------- Total Pharmaceuticals, Biotechnology & Life Sciences $ 84,836,382 --------------------------------------------------------------------------------------------------- BANKS -- 4.8% Diversified Banks -- 4.3% 6,485,000 Australia & New Zealand Banking Group, Ltd., 4.5%, 3/19/24 (144A) $ 6,640,361 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 39 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Diversified Banks -- (continued) 4,600,000 9.00 Banco Bilbao Vizcaya Argentaria SA, Floating Rate Note, 12/31/49 (Perpetual) $ 4,788,582 1,150,000 Bank of America Corp., 4.2%, 8/26/24 1,171,510 3,950,000 6.10 Bank of America Corp., Floating Rate Note, 12/31/49 (Perpetual) 3,971,725 2,375,000 1.73 Banque Federative du Credit Mutuel SA, Floating Rate Note, 1/20/17 (144A) 2,375,826 4,450,000 Banque Ouest Africaine de Developpement, 5.5%, 5/6/21 (144A) 4,572,375 2,565,000 Barclays Bank Plc, 6.05%, 12/4/17 (144A) 2,649,868 5,250,000 Barclays Plc, 3.65%, 3/16/25 5,075,816 3,000,000 Barclays Plc, 4.375%, 1/12/26 3,038,466 2,400,000 BBVA Bancomer SA Texas, 4.375%, 4/10/24 (144A) 2,418,000 3,815,000 BBVA Bancomer SA Texas, 6.5%, 3/10/21 (144A) 4,108,755 9,775,000 7.62 BNP Paribas SA, Floating Rate Note, 12/31/49 (Perpetual) (144A) 10,313,602 3,860,000 BPCE SA, 4.875%, 4/1/26 (144A) 3,857,217 3,650,000 1.73 BPCE SA, Floating Rate Note, 2/10/17 3,653,062 3,044,000 5.95 Citigroup, Inc., Floating Rate Note (Perpetual) 3,085,855 8,176,000 6.25 Citigroup, Inc., Floating Rate Note, 12/31/49 (Perpetual) 8,413,104 4,485,000 5.90 Citigroup, Inc., Floating Rate Note, 12/31/49 (Perpetual) 4,535,456 3,435,000 Cooperatieve Rabobank UA, 3.875%, 2/8/22 3,626,721 6,425,000 Cooperatieve Rabobank UA, 3.95%, 11/9/22 6,609,520 7,300,000 7.88 Credit Agricole SA, Floating Rate Note, 12/31/49 (Perpetual) (144A) 7,373,657 9,525,000 8.12 Credit Agricole SA, Floating Rate Note, 12/31/49 (Perpetual) (144A) 10,024,682 11,200,000 Credit Suisse Group Funding Guernsey, Ltd., 3.8%, 9/15/22 11,299,322 1,305,000 HSBC Bank Plc, 7.65%, 5/1/25 1,593,468 4,525,000 6.88 HSBC Holdings Plc, Floating Rate Note, 12/31/49 (Perpetual) 4,773,875 8,166,000 6.50 ING Groep NV, Floating Rate Note, 12/29/49 7,875,086 10,434,000 7.70 Intesa Sanpaolo S.p.A., Floating Rate Note, 12/29/49 (Perpetual) (144A) 9,794,918 5,125,000 Macquarie Bank, Ltd., 4.875%, 6/10/25 (144A) 5,186,454 840,000 Macquarie Bank, Ltd., 6.625%, 4/7/21 (144A) 944,307 4,500,000 Nordea Bank AB, 4.25%, 9/21/22 (144A) 4,687,618 5,600,000 6.12 Nordea Bank AB, Floating Rate Note, 12/31/49 (Perpetual) (144A) 5,419,120 7,005,000 8.62 Royal Bank of Scotland Group Plc, Floating Rate Note, 12/31/49 (Perpetual) 7,145,100 The accompanying notes are an integral part of these financial statements. 40 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Diversified Banks -- (continued) 8,075,000 7.50 Royal Bank of Scotland Group Plc, Floating Rate Note, 12/31/49 (Perpetual) $ 7,651,062 105,263 3.71 SBP DPR Finance Co., Floating Rate Note, 3/15/17 (144A) 105,229 2,600,000 4.50 Scotiabank Peru SAA, Floating Rate Note, 12/13/27 (144A) 2,593,760 4,800,000 Standard Chartered Plc, 3.95%, 1/11/23 (144A) 4,690,699 3,540,000 Wells Fargo Bank NA, 6.0%, 11/15/17 3,673,784 --------------- $ 179,737,962 --------------------------------------------------------------------------------------------------- Regional Banks -- 0.4% 7,000,000 Credit Suisse AG New York NY, 1.75%, 1/29/18 $ 6,986,105 7,378,000 KeyCorp, 5.1%, 3/24/21 8,068,094 1,435,000 PNC Bank NA, 6.0%, 12/7/17 1,490,801 --------------- $ 16,545,000 --------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- 0.1% 2,300,000 Astoria Financial Corp., 5.0%, 6/19/17 $ 2,328,589 --------------- Total Banks $ 198,611,551 --------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 3.4% Other Diversified Financial Services -- 0.4% 5,930,000 Carlyle Holdings II Finance LLC, 5.625%, 3/30/43 (144A) $ 5,867,385 7,189,000 6.75 JPMorgan Chase & Co., Floating Rate Note, 8/29/49 (Perpetual) 7,746,148 1,250,000 0.00 Tiers Trust, Floating Rate Note, 10/15/97 (144A) (d) 1,246,369 --------------- $ 14,859,902 --------------------------------------------------------------------------------------------------- Specialized Finance -- 0.5% 3,200,000 BM&FBovespa SA -- Bolsa de Valores Mercadorias e Futuros, 5.5%, 7/16/20 (144A) $ 3,305,600 2,980,000 Cantor Fitzgerald LP, 7.875%, 10/15/19 (144A) 3,299,924 2,000,000 National Rural Utilities Cooperative Finance Corp., 5.45%, 2/1/18 2,085,858 11,625,000 USAA Capital Corp., 2.45%, 8/1/20 (144A) 11,660,584 --------------- $ 20,351,966 --------------------------------------------------------------------------------------------------- Consumer Finance -- 1.0% 2,250,000 Ally Financial, Inc., 4.625%, 3/30/25 $ 2,216,250 5,050,000 Ally Financial, Inc., 5.125%, 9/30/24 5,138,375 1,125,000 Ally Financial, Inc., 5.75%, 11/20/25 1,122,188 7,695,000 American Honda Finance Corp., 1.2%, 7/14/17 7,701,895 1,465,000 Capital One Bank USA NA, 8.8%, 7/15/19 1,677,769 7,275,000 Capital One Financial Corp., 3.75%, 4/24/24 7,369,720 2,300,000 General Motors Financial Co., Inc., 3.7%, 11/24/20 2,339,675 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 41 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Consumer Finance -- (continued) 7,785,000 General Motors Financial Co., Inc., 4.0%, 1/15/25 $ 7,595,365 2,245,000 Hyundai Capital America, 1.45%, 2/6/17 (144A) 2,245,382 6,200,000 Hyundai Capital America, 2.0%, 3/19/18 (144A) 6,198,872 --------------- $ 43,605,491 --------------------------------------------------------------------------------------------------- Asset Management & Custody Banks -- 0.8% 1,725,000 Blackstone Holdings Finance Co., LLC, 5.0%, 6/15/44 (144A) $ 1,701,533 6,445,000 Blackstone Holdings Finance Co., LLC, 6.25%, 8/15/42 (144A) 7,374,124 733,000 Eaton Vance Corp., 6.5%, 10/2/17 760,584 7,475,000 KKR Group Finance Co. II LLC, 5.5%, 2/1/43 (144A) 7,502,942 2,400,000 Legg Mason, Inc., 3.95%, 7/15/24 2,408,626 2,175,000 Legg Mason, Inc., 4.75%, 3/15/26 2,251,264 10,345,000 1.94 The Bank of New York Mellon Corp., Floating Rate Note, 10/30/23 10,505,120 --------------- $ 32,504,193 --------------------------------------------------------------------------------------------------- Investment Banking & Brokerage -- 0.4% 1,650,000 KKR Group Finance Co., III LLC, 5.125%, 6/1/44 (144A) $ 1,557,869 5,450,000 Morgan Stanley, 4.1%, 5/22/23 5,594,545 300,000 Morgan Stanley, 4.875%, 11/1/22 321,522 4,020,000 5.55 Morgan Stanley, Floating Rate Note, 12/31/49 (Perpetual) 4,065,225 643,000 North American Development Bank, 2.3%, 10/10/18 650,547 4,400,000 UBS AG, 7.625%, 8/17/22 4,988,500 --------------- $ 17,178,208 --------------------------------------------------------------------------------------------------- Diversified Capital Markets -- 0.3% 4,031,000 GE Capital International Funding Co., Unlimited Co., 2.342%, 11/15/20 $ 4,029,077 6,900,000 2.49 ICBCIL Finance Co., Ltd., Floating Rate Note, 11/13/18 (144A) 6,915,049 2,730,000 Macquarie Group, Ltd., 6.0%, 1/14/20 (144A) 2,957,723 --------------- $ 13,901,849 --------------- Total Diversified Financials $ 142,401,609 --------------------------------------------------------------------------------------------------- INSURANCE -- 6.0% Insurance Brokers -- 0.1% 5,400,000 Brown & Brown, Inc., 4.2%, 9/15/24 $ 5,439,874 --------------------------------------------------------------------------------------------------- Life & Health Insurance -- 0.9% 7,000,000 Aflac, Inc., 3.625%, 11/15/24 $ 7,204,393 2,425,000 Principal Life Global Funding II, 1.5%, 4/18/19 (144A) 2,394,523 4,250,000 Protective Life Corp., 7.375%, 10/15/19 4,813,660 The accompanying notes are an integral part of these financial statements. 42 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Life & Health Insurance -- (continued) 1,090,000 Prudential Financial, Inc., 4.5%, 11/16/21 $ 1,178,713 1,500,000 5.62 Prudential Financial, Inc., Floating Rate Note, 6/15/43 1,558,125 8,043,000 5.88 Prudential Financial, Inc., Floating Rate Note, 9/15/42 8,435,096 8,186,000 Teachers Insurance & Annuity Association of America, 6.85%, 12/16/39 (144A) 10,623,169 --------------- $ 36,207,679 --------------------------------------------------------------------------------------------------- Multi-line Insurance -- 0.4% 5,985,000 AIG, 3.875%, 1/15/35 $ 5,621,914 2,335,000 AXA SA, 8.6%, 12/15/30 3,210,625 5,325,000 Liberty Mutual Insurance Co., 7.697%, 10/15/97 (Perpetual) (144A) 6,536,091 --------------- $ 15,368,630 --------------------------------------------------------------------------------------------------- Property & Casualty Insurance -- 0.6% 9,000,000 CNA Financial Corp., 4.5%, 3/1/26 $ 9,411,660 1,850,000 Delphi Financial Group, Inc., 7.875%, 1/31/20 2,078,390 5,573,000 6.50 The Allstate Corp., Floating Rate Note, 5/15/57 6,325,355 7,990,000 The Hanover Insurance Group, Inc., 4.5%, 4/15/26 8,028,847 --------------- $ 25,844,252 --------------------------------------------------------------------------------------------------- Reinsurance -- 4.0% 450,000 4.18 Acorn Re, Ltd., Floating Rate Note, 7/17/18 (Cat Bond) (144A) $ 460,305 1,450,000 6.88 Alamo Re, Ltd., Floating Rate Note, 6/7/17 (Cat Bond) (144A) 1,467,110 2,750,000 6.11 Alamo Re, Ltd., Floating Rate Note, 6/7/18 (Cat Bond) (144A) 2,833,325 500,000 3.11 Aozora Re, Ltd., Floating Rate Note, 4/7/23 (Cat Bond) (144A) 504,150 900,000 Arlington Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 8/31/16 (e)(f) 43,740 750,000 Arlington Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 8/31/17 (e)(f) 785,550 500,000 4.04 Atlas IX Capital DAC, Floating Rate Note, 1/17/19 (Cat Bond) (144A) 507,200 2,000,000 Berwick 2016-1 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 2/1/18 (e)(f) 2,262,600 800,000 Berwick Segregated Account (Artex SAC Ltd.), Variable Rate Note, 1/22/16 (e)(f) 24,000 1,200,000 14.11 Blue Halo Re, Ltd., Floating Rate Note, 6/21/19 (Cat Bond) (144A) 1,243,560 1,350,000 5.50 Caelus Re IV, Ltd., Floating Rate Note, 3/6/20 (Cat Bond) (144A) 1,408,320 2,350,000 7.06 Caelus Re, Ltd., Floating Rate Note, 4/7/17 (Cat Bond) (144A) 2,377,260 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 43 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 3,600,000 Carnosutie 2016-N, Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 11/30/20 (e)(f) $ 4,030,920 3,000,000 Carnoustie Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 2/19/16 (e)(f) 61,200 3,750,000 5.01 Citrus Re, Ltd., Floating Rate Note, 4/18/17 (Cat Bond) (144A) 3,778,125 2,650,000 4.48 Citrus Re, Ltd., Floating Rate Note, 4/24/17 (Cat Bond) (144A) 2,665,370 1,900,000 Denning 2016 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/7/17 (e)(f) 1,879,670 840,000 Eden Re II, Ltd., Variable Rate Notes, 3/22/21 (144A) (e)(f) 840,000 925,000 Eden Re II, Ltd., Variable Rate Notes, 4/23/19 (144A) (e)(f) 1,046,360 2,475,000 Eden Re II, Variable Rate Notes, 4/23/19 (e)(f) 2,798,730 20,650,000 7.30 Everglades Re, Ltd., Floating Rate Note, 4/28/17 (Cat Bond) (144A) 20,959,750 1,400,000 N/A Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) 1,400,000 1,300,000 N/A Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) 1,300,000 1,300,000 N/A Galilei Re, Ltd., Floating Rate Note, 1/8/20 (Cat Bond) (144A) 1,300,000 1,200,000 7.74 Galileo Re, Ltd., Floating Rate Note, 1/9/17 (Cat Bond) (144A) 1,199,760 3,500,000 Gleneagles Segregated Account (Artex SAC Ltd), Variable Rate Notes, 11/30/20 (e)(f) 4,088,700 2,800,000 2.42 Golden State Re II, Ltd., Floating Rate Note, 1/8/19 (Cat Bond) (144A) 2,791,040 5,100,000 Gullane Segregated Account (Artex SAC Ltd.), Variable Rate Note 11/30/20 (e)(f) 5,580,930 700,000 4.06 Kilimanjaro Re, Ltd., Floating Rate Note, 11/25/19 (144A) (e)(f) 708,330 3,000,000 6.75 Kilimanjaro Re, Ltd., Floating Rate Note, 12/6/19 (144A) (e)(f) 3,098,700 1,500,000 9.25 Kilimanjaro Re, Ltd., Floating Rate Note, 12/6/19 (144A) (e)(f) 1,560,900 3,700,000 5.06 Kilimanjaro Re, Ltd., Floating Rate Note, 4/30/18 (Cat Bond) (144A) 3,780,660 350,000 4.81 Kilimanjaro Re, Ltd., Floating Rate Note, 4/30/18 (Cat Bond) (144A) 356,335 3,600,000 Kingsbarns Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 5/15/17 (e)(f) 3,504,600 1,000,000 Lahinch Re, Variable Rate Notes, 5/10/21 (e)(f) 17,800 600,000 Limestone Re, Ltd., 8/31/21 (Cat Bond) (c) 600,000 1,750,000 Limestone Re, Ltd., 8/31/21 (Cat Bond) (c) 1,750,000 250,000 10.09 Loma Reinsurance Bermuda, Ltd., Floating Rate Note, 1/8/18 (Cat Bond) (144A) 256,700 The accompanying notes are an integral part of these financial statements. 44 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 4,000,000 3.75 Long Point Re III, Ltd., Floating Rate Note, 5/23/18 (Cat Bond) (144A) $ 4,069,200 1,300,000 Lorenz Re, Ltd., Variable Rate Notes, 3/31/18 (e)(f) 7,540 4,050,000 Lorenz Re, Ltd., Variable Rate Notes, 3/31/19 (e)(f) 4,258,980 2,000,000 Madison Re, Variable Rate Notes, 3/31/19 (e)(f) 2,097,600 1,000,000 2.25 Merna Re V, Ltd., Floating Rate Note, 4/7/17 (Cat Bond) (144A) 998,000 6,350,000 9.10 Mythen Re, Ltd., Series 2012-2 Class A, Floating Rate Note, 1/5/17 (Cat Bond) (144A) 6,350,000 3,600,000 Pangaea Re, Series 2015-1, Principal at Risk Notes, 2/1/19 (e)(f) 141,120 4,000,000 Pangaea Re, Series 2015-2, Principal at Risk Notes, 11/30/19 (e)(f) 368,000 3,000,000 Pangaea Re, Series 2016-2, Principal at Risk Notes, 11/30/20 (e)(f) 3,323,100 4,500,000 Pangaea Re., Variable Rate Notes, 2/1/20 (e)(f) 5,080,950 2,500,000 6.50 Pelican Re, Ltd., Floating Rate Note, 5/15/17 (Cat Bond) (144A) 2,532,500 3,200,000 4.81 PennUnion Re, Ltd., Floating Rate Note, 12/7/18 (Cat Bond) (144A) 3,245,760 2,000,000 Port Rush Re, Variable Rate Notes, 6/15/17 (e)(f) 1,988,400 1,000,000 Prestwick Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/1/16 (e)(f) 74,900 1,900,000 3.67 Queen City Re, Ltd., Floating Rate Note, 1/6/17 (Cat Bond) (144A) 1,898,290 2,000,000 6.15 Queen Street XI Re Dac, Floating Rate Note, 6/7/19 (Cat Bond) (144A) 2,044,400 600,000 9.75 Residential Reinsurance 2013, Ltd., Floating Rate Note, 6/6/17 (Cat Bond) (144A) 612,660 2,500,000 0.00 Residential Reinsurance 2016, Ltd., Floating Rate Note, 12/6/23 (Cat Bond) (144A) 2,472,000 3,600,000 Resilience Re, Ltd., Variable Rate Notes, 4/7/17 (Cat Bond) 3,588,120 1,800,000 Resilience Re, Ltd., Variable Rate Notes, 6/12/17 (Cat Bond) 1,791,000 1,799,960 4.50 Resilience Re, Ltd., Variable Rate Note, 1/9/17 (Cat Bond) 1,799,960 2,550,000 3.31 Sanders Re, Ltd., Floating Rate Note, 5/25/18 (Cat Bond) (144A) 2,567,340 1,250,000 4.21 Sanders Re, Ltd., Floating Rate Note, 5/5/17 (Cat Bond) (144A) 1,249,625 1,200,000 3.81 Sanders Re, Ltd., Floating Rate Note, 5/5/17 (Cat Bond) (144A) 1,198,320 2,000,000 3.97 Sanders Re, Ltd., Floating Rate Note, 6/7/17 (Cat Bond) (144A) 2,011,200 1,100,000 Sector Re V, Ltd., Variable Rate Notes, 12/1/21 (144A) (e)(f) 1,102,860 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 45 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Reinsurance -- (continued) 2,400,000 Sector Re V, Ltd., Variable Rate Notes, 3/1/21 (e)(f) $ 2,594,880 400,000 Sector Re V, Ltd., Variable Rate Notes, 3/1/21 (144A) (e)(f) 447,760 5,213 Sector Re V, Ltd., Variable Rate Notes, 12/1/20 (144A) (e)(f) 189,021 1,711 Sector Re V, Ltd., Variable Rate Notes, 3/1/20 (144A) (e)(f) 4,458 12,500 Sector Re V, Ltd., Variable Rate Notes, 3/1/20 (144A) (e)(f) 265,288 2,000,000 Shenandoah 2017-1 Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 7/7/17 (e)(f) 1,940,800 2,000,000 Silverton Re, Ltd., Variable Rate Notes, 9/18/19 (144A) (e)(f) 2,000,000 1,000,000 Silverton Re, Ltd., Variable Rate Notes, 9/18/17 (144A) (e)(f) 24,700 1,700,000 Silverton Re, Ltd., Variable Rate Notes, 9/18/18 (144A) (e)(f) 1,943,440 1,300,000 St. Andrews Segregated Account (Artex SAC Ltd.), Variable Rate Notes, 1/22/16 (e)(f) 25,610 2,000,000 St. Andrews Segregated Account (Artex SAC Ltd.), Variance Rate Notes, 2/1/18 (e)(f) 2,331,200 500,000 5.10 Ursa Re, Ltd., Floating Rate Note, 9/21/18 (Cat Bond) (144A) 509,500 3,500,000 N/A Ursa Re, Ltd., Floating Rate Note, 12/10/19 (Cat Bond) (144A) 3,502,100 4,000,000 Versutus 2016, Class A-1, Variable Rate Notes, 11/30/20 (e)(f) 4,393,200 2,500,000 Versutus Ltd., Series 2015-A, Variable Rate Notes, 12/31/2017 (e)(f) 64,000 500,000 2.92 Vitality Re IV, Ltd., Floating Rate Note, 1/9/17 (Cat Bond) (144A) 499,600 1,750,000 2.01 Vitality Re V, Ltd., Floating Rate Note, 1/7/19 (Cat Bond) (144A) 1,735,825 2,900,000 2.47 Vitality Re VII, Ltd., Floating Rate Note, 1/7/20 (Cat Bond) (144A) 2,901,160 1,000,000 2.76 Vitality Re VII, Ltd., Floating Rate Note, 1/7/20 (Cat Bond) (144A) 1,012,800 --------------- $ 168,528,867 --------------- Total Insurance $ 251,389,302 --------------------------------------------------------------------------------------------------- REAL ESTATE -- 1.4% Diversified REIT -- 0.6% 1,475,000 DCT Industrial Operating Partnership LP, 4.5%, 10/15/23 $ 1,497,172 2,175,000 Duke Realty LP, 3.625%, 4/15/23 2,209,315 7,560,000 Duke Realty LP, 3.75%, 12/1/24 7,658,703 9,500,000 Essex Portfolio LP, 3.5%, 4/1/25 9,356,588 3,985,000 Ventas Realty LP, 3.125%, 6/15/23 3,911,931 --------------- $ 24,633,709 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 46 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Office REIT -- 0.3% 2,681,000 Alexandria Real Estate Equities, Inc., 2.75%, 1/15/20 $ 2,674,812 1,093,000 Alexandria Real Estate Equities, Inc., 3.9%, 6/15/23 1,109,635 1,350,000 Alexandria Real Estate Equities, Inc., 3.95%, 1/15/27 1,344,030 3,415,000 Alexandria Real Estate Equities, Inc., 4.6%, 4/1/22 3,612,838 2,032,000 Highwoods Realty LP, 3.2%, 6/15/21 2,039,516 3,390,000 Highwoods Realty LP, 3.625%, 1/15/23 3,352,195 --------------- $ 14,133,026 --------------------------------------------------------------------------------------------------- Health Care REIT -- 0.3% 4,905,000 Healthcare Realty Trust, Inc., 3.875%, 5/1/25 $ 4,836,536 605,000 Healthcare Realty Trust, Inc., 5.75%, 1/15/21 664,928 6,805,000 Healthcare Trust of America Holdings LP, 3.5%, 8/1/26 6,503,069 --------------- $ 12,004,533 --------------------------------------------------------------------------------------------------- Residential REIT -- 0.2% 9,260,000 UDR, Inc., 4.0%, 10/1/25 $ 9,478,471 --------------- Total Real Estate $ 60,249,739 --------------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 0.8% Data Processing & Outsourced Services -- 0.2% 3,000,000 Cardtronics, Inc., 5.125%, 8/1/22 $ 3,022,500 4,550,000 Visa, Inc., 2.2%, 12/14/20 4,564,146 --------------- $ 7,586,646 --------------------------------------------------------------------------------------------------- Application Software -- 0.2% 8,560,000 Adobe Systems, Inc., 3.25%, 2/1/25 $ 8,564,160 --------------------------------------------------------------------------------------------------- Systems Software -- 0.4% 5,225,000 Microsoft Corp., 2.0%, 8/8/23 $ 4,994,071 10,600,000 Oracle Corp., 2.5%, 5/15/22 10,526,383 --------------- $ 15,520,454 --------------- Total Software & Services $ 31,671,260 --------------------------------------------------------------------------------------------------- TECHNOLOGY HARDWARE & EQUIPMENT -- 0.6% Communications Equipment -- 0.1% 3,840,000 Brocade Communications Systems, Inc., 4.625%, 1/15/23 $ 3,801,600 --------------------------------------------------------------------------------------------------- Computer Hardware Storage & Peripherals -- 0.2% 4,600,000 NCR Corp., 4.625%, 2/15/21 $ 4,682,800 1,425,000 NCR Corp., 6.375%, 12/15/23 1,531,875 --------------- $ 6,214,675 --------------------------------------------------------------------------------------------------- Electronic Components -- 0.2% 8,412,000 Amphenol Corp., 3.125%, 9/15/21 $ 8,542,150 --------------------------------------------------------------------------------------------------- Electronic Manufacturing Services -- 0.1% 5,780,000 Flex, Ltd., 4.75%, 6/15/25 $ 6,115,361 --------------- Total Technology Hardware & Equipment $ 24,673,786 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 47 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT -- 0.3% Semiconductors -- 0.3% 11,075,000 Intel Corp., 4.8%, 10/1/41 $ 12,191,659 --------------- Total Semiconductors & Semiconductor Equipment $ 12,191,659 --------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 1.4% Integrated Telecommunication Services -- 1.1% 6,200,000 AT&T, Inc., 3.8%, 3/15/22 $ 6,355,862 9,690,000 AT&T, Inc., 3.95%, 1/15/25 9,706,783 2,250,000 AT&T, Inc., 4.75%, 5/15/46 2,131,693 1,445,000 Frontier Communications Corp., 10.5%, 9/15/22 1,519,128 4,300,000 Frontier Communications Corp., 7.125%, 1/15/23 3,891,500 130,000 Frontier Communications Corp., 8.875%, 9/15/20 138,450 4,800,000 GTP Acquisition Partners I LLC, 2.35%, 6/15/45 (144A) 4,677,792 2,750,000 Telefonica Emisiones SAU, 6.221%, 7/3/17 2,811,716 1,500,000 Unison Ground Lease Funding LLC, 2.981%, 3/16/43 (144A) 1,467,568 5,100,000 Verizon Communications, Inc., 5.15%, 9/15/23 5,639,289 7,254,000 Verizon Communications, Inc., 6.55%, 9/15/43 9,060,079 --------------- $ 47,399,860 --------------------------------------------------------------------------------------------------- Wireless Telecommunication Services -- 0.3% 2,200,000 Crown Castle Towers LLC, 4.883%, 8/15/20 (144A) $ 2,342,716 1,625,000 Crown Castle Towers LLC, 6.113%, 1/15/20 (144A) 1,760,624 3,100,000 SBA Tower Trust, 2.877%, 7/15/21 (144A) 3,073,588 3,585,000 T-Mobile USA, Inc., 6.0%, 4/15/24 3,777,694 --------------- $ 10,954,622 --------------- Total Telecommunication Services $ 58,354,482 --------------------------------------------------------------------------------------------------- UTILITIES -- 2.6% Electric Utilities -- 1.9% 980,000 Commonwealth Edison Co., 6.15%, 9/15/17 $ 1,012,207 4,250,000 Electricite de France SA, 6.0%, 1/22/14 (144A) 4,123,388 2,150,000 5.25 Electricite de France SA, Floating Rate Note (Perpetual) (144A) 2,021,000 3,365,000 Enel Finance International NV, 5.125%, 10/7/19 (144A) 3,597,098 2,320,000 8.13 Enel S.p.A., Floating Rate Note, 9/24/73 (144A) 2,639,000 4,570,000 Exelon Corp., 2.85%, 6/15/20 4,618,785 507,799 FPL Energy American Wind LLC, 6.639%, 6/20/23 (144A) 520,494 4,655,000 Iberdrola International BV, 6.75%, 7/15/36 5,693,400 2,725,000 Indiana Michigan Power Co., 4.55%, 3/15/46 2,826,294 5,450,000 Israel Electric Corp., Ltd., 5.0%, 11/12/24 5,671,106 1,925,000 Israel Electric Corp., Ltd., 7.25%, 1/15/19 (144A) 2,078,792 The accompanying notes are an integral part of these financial statements. 48 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Electric Utilities -- (continued) 610,000 Israel Electric Corp., Ltd., 9.375%, 1/28/20 (144A) $ 721,356 910,000 Nevada Power Co., 6.5%, 8/1/18 978,516 6,536,000 NextEra Energy Capital Holdings, Inc., 2.3%, 4/1/19 6,585,752 368,865 OrCal Geothermal, Inc., 6.21%, 12/30/20 (144A) 363,332 8,540,000 PPL Capital Funding, Inc., 3.1%, 5/15/26 8,170,030 2,690,000 Public Service Co. of New Mexico, 7.95%, 5/15/18 2,903,995 4,871,380 Southern California Edison Co., 1.845%, 2/1/22 4,792,094 5,720,000 6.25 Southern California Edison Co., Floating Rate Note (Perpetual) 6,342,050 10,800,000 Southwestern Electric Power Co., 3.9%, 4/1/45 10,059,606 5,251,000 Talen Energy Supply LLC, 6.5%, 6/1/25 4,056,398 --------------- $ 79,774,693 --------------------------------------------------------------------------------------------------- Gas Utilities -- 0.2% 2,215,000 AmeriGas Partners LP, 5.5%, 5/20/25 $ 2,237,150 2,125,000 DCP Midstream Operating LP, 5.6%, 4/1/44 1,939,062 2,113,073 Nakilat, Inc., 6.267%, 12/31/33 (144A) 2,430,034 --------------- $ 6,606,246 --------------------------------------------------------------------------------------------------- Multi-Utilities -- 0.4% 8,385,000 Consolidated Edison Co. of New York, Inc., 4.625%, 12/1/54 $ 8,796,385 5,055,000 New York State Electric & Gas Corp., 6.15%, 12/15/17 (144A) 5,251,377 163,937 Ormat Funding Corp., 8.25%, 12/30/20 162,297 2,632,143 San Diego Gas & Electric Co., 1.914%, 2/1/22 2,599,799 --------------- $ 16,809,858 --------------------------------------------------------------------------------------------------- Independent Power Producers & Energy Traders -- 0.1% 496,003 Alta Wind Holdings LLC, 7.0%, 6/30/35 (144A) $ 541,176 1,106,934 Kiowa Power Partners LLC, 5.737%, 3/30/21 (144A) 1,159,793 3,295,000 NRG Energy, Inc., 6.625%, 3/15/23 3,303,238 750,000 NRG Energy, Inc., 7.25%, 5/15/26 (144A) 746,250 182,000 NRG Energy, Inc., 7.875%, 5/15/21 189,735 --------------- $ 5,940,192 --------------- Total Utilities $ 109,130,989 --------------------------------------------------------------------------------------------------- TOTAL CORPORATE BONDS (Cost $1,489,743,266) $ 1,508,317,783 --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- 37.3% 293,894 Fannie Mae, 2.5%, 12/1/42 $ 281,112 2,955,434 Fannie Mae, 2.5%, 2/1/43 2,826,861 2,735,282 Fannie Mae, 2.5%, 7/1/30 2,743,495 1,642,420 Fannie Mae, 2.5%, 7/1/30 1,646,909 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 49 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,605,603 Fannie Mae, 2.5%, 7/1/30 $ 1,610,427 9,860,000 Fannie Mae, 3.0%, 1/18/17 (TBA) 9,795,060 3,900,000 Fannie Mae, 3.0%, 1/23/17 (TBA) 4,002,070 3,532,641 Fannie Mae, 3.0%, 10/1/30 3,631,051 9,852,140 Fannie Mae, 3.0%, 10/1/46 9,798,092 9,996,929 Fannie Mae, 3.0%, 11/1/46 9,942,086 1,558,382 Fannie Mae, 3.0%, 12/1/42 1,557,939 2,826,759 Fannie Mae, 3.0%, 2/1/43 2,825,953 1,129,114 Fannie Mae, 3.0%, 3/1/45 1,123,498 8,809,102 Fannie Mae, 3.0%, 5/1/30 9,047,627 8,063,308 Fannie Mae, 3.0%, 5/1/31 8,298,888 10,904,051 Fannie Mae, 3.0%, 5/1/43 10,900,933 784,302 Fannie Mae, 3.0%, 5/1/43 784,078 1,144,752 Fannie Mae, 3.0%, 5/1/46 1,140,523 713,547 Fannie Mae, 3.0%, 5/1/46 712,238 7,881,598 Fannie Mae, 3.0%, 6/1/45 7,856,353 2,507,740 Fannie Mae, 3.0%, 7/1/30 2,575,643 759,242 Fannie Mae, 3.0%, 7/1/43 759,026 19,003,330 Fannie Mae, 3.0%, 8/1/42 18,997,922 1,817,476 Fannie Mae, 3.0%, 8/1/43 1,816,959 4,414,211 Fannie Mae, 3.0%, 9/1/28 4,540,916 5,255,862 Fannie Mae, 3.0%, 9/1/42 5,254,366 5,117,912 Fannie Mae, 3.0%, 9/1/43 5,116,454 5,263,149 Fannie Mae, 3.0%, 9/1/46 5,234,276 8,611,349 Fannie Mae, 3.5%, 1/1/46 8,832,880 6,993,450 Fannie Mae, 3.5%, 1/1/46 7,173,353 136,205,000 Fannie Mae, 3.5%, 1/18/17 (TBA) 139,599,487 663,188 Fannie Mae, 3.5%, 10/1/41 684,057 1,861,178 Fannie Mae, 3.5%, 10/1/45 1,911,170 1,119,784 Fannie Mae, 3.5%, 10/1/46 1,149,138 622,544 Fannie Mae, 3.5%, 10/1/46 639,440 1,345,138 Fannie Mae, 3.5%, 11/1/40 1,387,127 285,879 Fannie Mae, 3.5%, 11/1/42 294,703 14,103,225 Fannie Mae, 3.5%, 11/1/45 14,554,201 1,238,221 Fannie Mae, 3.5%, 11/1/46 1,270,681 1,348,136 Fannie Mae, 3.5%, 12/1/26 1,406,736 672,208 Fannie Mae, 3.5%, 12/1/42 693,357 635,283 Fannie Mae, 3.5%, 12/1/42 655,243 5,695,060 Fannie Mae, 3.5%, 12/1/45 5,841,818 3,227,285 Fannie Mae, 3.5%, 12/1/45 3,310,188 2,832,030 Fannie Mae, 3.5%, 12/1/45 2,904,957 2,533,087 Fannie Mae, 3.5%, 2/1/29 2,639,742 The accompanying notes are an integral part of these financial statements. 50 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 6,521,321 Fannie Mae, 3.5%, 2/1/44 $ 6,717,527 6,103,909 Fannie Mae, 3.5%, 2/1/46 6,260,950 3,654,115 Fannie Mae, 3.5%, 2/1/46 3,747,893 2,316,190 Fannie Mae, 3.5%, 3/1/46 2,376,051 964,428 Fannie Mae, 3.5%, 4/1/26 1,006,050 8,232,844 Fannie Mae, 3.5%, 4/1/45 8,444,348 4,921,748 Fannie Mae, 3.5%, 4/1/46 5,048,179 2,996,114 Fannie Mae, 3.5%, 5/1/46 3,082,899 3,284,521 Fannie Mae, 3.5%, 6/1/28 3,427,213 3,393,356 Fannie Mae, 3.5%, 7/1/42 3,499,448 3,878,673 Fannie Mae, 3.5%, 7/1/45 3,978,383 12,975,660 Fannie Mae, 3.5%, 7/1/46 13,311,790 3,675,851 Fannie Mae, 3.5%, 8/1/42 3,790,210 9,424,082 Fannie Mae, 3.5%, 8/1/45 9,728,849 3,304,123 Fannie Mae, 3.5%, 8/1/45 3,389,006 2,284,161 Fannie Mae, 3.5%, 8/1/45 2,342,703 9,409,281 Fannie Mae, 3.5%, 8/1/46 9,653,020 548,111 Fannie Mae, 3.5%, 9/1/26 572,702 3,506,257 Fannie Mae, 3.5%, 9/1/44 3,598,636 9,288,903 Fannie Mae, 3.5%, 9/1/45 9,528,709 5,938,556 Fannie Mae, 3.5%, 9/1/45 6,090,739 9,712,458 Fannie Mae, 3.5%, 9/1/46 9,964,053 1,208,282 Fannie Mae, 3.763%, 12/1/20 1,275,285 3,802,199 Fannie Mae, 4.0%, 1/1/42 3,999,973 470,611 Fannie Mae, 4.0%, 1/1/42 495,435 150,493 Fannie Mae, 4.0%, 1/1/44 158,190 533,994 Fannie Mae, 4.0%, 1/1/45 561,568 229,059 Fannie Mae, 4.0%, 1/1/45 240,891 110,488 Fannie Mae, 4.0%, 1/1/45 116,199 3,060,871 Fannie Mae, 4.0%, 1/1/46 3,220,504 41,570,000 Fannie Mae, 4.0%, 1/18/17 (TBA) 43,702,898 1,883,065 Fannie Mae, 4.0%, 10/1/41 1,987,186 6,348,617 Fannie Mae, 4.0%, 10/1/45 6,679,197 5,868,504 Fannie Mae, 4.0%, 10/1/45 6,174,041 3,779,600 Fannie Mae, 4.0%, 10/1/45 3,976,460 6,919,703 Fannie Mae, 4.0%, 11/1/44 7,276,095 333,156 Fannie Mae, 4.0%, 11/1/44 350,370 170,368 Fannie Mae, 4.0%, 11/1/44 179,142 118,193 Fannie Mae, 4.0%, 11/1/44 124,319 4,851,455 Fannie Mae, 4.0%, 11/1/45 5,104,380 118,690 Fannie Mae, 4.0%, 11/1/45 124,842 1,466,822 Fannie Mae, 4.0%, 12/1/40 1,559,511 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 51 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,490,133 Fannie Mae, 4.0%, 12/1/41 $ 1,573,623 4,990,406 Fannie Mae, 4.0%, 12/1/43 5,283,845 562,175 Fannie Mae, 4.0%, 12/1/44 591,273 66,927 Fannie Mae, 4.0%, 12/1/44 70,383 7,510,306 Fannie Mae, 4.0%, 2/1/42 7,914,222 3,023,052 Fannie Mae, 4.0%, 2/1/42 3,189,901 7,060,313 Fannie Mae, 4.0%, 2/1/44 7,422,734 526,674 Fannie Mae, 4.0%, 2/1/45 553,810 252,870 Fannie Mae, 4.0%, 2/1/45 266,023 54,107 Fannie Mae, 4.0%, 2/1/45 56,905 7,677,057 Fannie Mae, 4.0%, 2/1/46 8,091,945 1,400,795 Fannie Mae, 4.0%, 3/1/42 1,480,436 384,436 Fannie Mae, 4.0%, 4/1/25 406,127 3,286,710 Fannie Mae, 4.0%, 4/1/39 3,469,219 1,305,147 Fannie Mae, 4.0%, 4/1/41 1,378,334 904,419 Fannie Mae, 4.0%, 4/1/41 957,379 3,130,225 Fannie Mae, 4.0%, 4/1/42 3,305,620 730,544 Fannie Mae, 4.0%, 4/1/42 771,012 359,059 Fannie Mae, 4.0%, 4/1/42 377,657 1,905,295 Fannie Mae, 4.0%, 4/1/46 2,004,912 1,044,988 Fannie Mae, 4.0%, 5/1/41 1,103,290 7,608,221 Fannie Mae, 4.0%, 5/1/46 8,005,491 534,180 Fannie Mae, 4.0%, 6/1/42 562,114 173,399 Fannie Mae, 4.0%, 6/1/42 182,749 158,447 Fannie Mae, 4.0%, 6/1/44 166,593 110,975 Fannie Mae, 4.0%, 6/1/44 116,662 7,362,409 Fannie Mae, 4.0%, 6/1/46 7,747,358 9,029 Fannie Mae, 4.0%, 7/1/18 9,290 4,280,388 Fannie Mae, 4.0%, 7/1/42 4,531,591 231,763 Fannie Mae, 4.0%, 7/1/42 244,617 6,783,244 Fannie Mae, 4.0%, 7/1/44 7,132,098 412,763 Fannie Mae, 4.0%, 7/1/44 434,086 7,525,984 Fannie Mae, 4.0%, 7/1/46 7,919,887 9,735,214 Fannie Mae, 4.0%, 8/1/42 10,282,677 5,501,646 Fannie Mae, 4.0%, 8/1/44 5,786,526 1,758,564 Fannie Mae, 4.0%, 8/1/44 1,849,217 306,242 Fannie Mae, 4.0%, 8/1/44 322,069 302,932 Fannie Mae, 4.0%, 8/1/44 318,517 3,904,239 Fannie Mae, 4.0%, 8/1/45 4,125,413 7,662,378 Fannie Mae, 4.0%, 8/1/46 8,063,422 7,389,551 Fannie Mae, 4.0%, 8/1/46 7,776,411 36,592 Fannie Mae, 4.0%, 9/1/20 37,696 The accompanying notes are an integral part of these financial statements. 52 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 7,208,586 Fannie Mae, 4.0%, 9/1/43 $ 7,577,263 8,694,095 Fannie Mae, 4.0%, 9/1/44 9,171,406 526,366 Fannie Mae, 4.0%, 9/1/44 553,451 486,875 Fannie Mae, 4.0%, 9/1/44 512,030 52,017 Fannie Mae, 4.0%, 9/1/44 54,697 6,476,233 Fannie Mae, 4.5%, 1/1/42 6,982,153 4,844,212 Fannie Mae, 4.5%, 1/1/42 5,213,534 7,076,073 Fannie Mae, 4.5%, 1/1/44 7,610,660 228,636 Fannie Mae, 4.5%, 10/1/35 246,890 121,637 Fannie Mae, 4.5%, 10/1/35 130,827 217,405 Fannie Mae, 4.5%, 11/1/20 225,961 15,740 Fannie Mae, 4.5%, 11/1/20 16,251 2,164,044 Fannie Mae, 4.5%, 11/1/40 2,332,064 214,032 Fannie Mae, 4.5%, 12/1/40 231,453 9,500,490 Fannie Mae, 4.5%, 12/1/43 10,218,238 7,094,399 Fannie Mae, 4.5%, 12/1/43 7,630,370 3,880,811 Fannie Mae, 4.5%, 12/1/43 4,209,555 805,846 Fannie Mae, 4.5%, 2/1/41 869,460 291,219 Fannie Mae, 4.5%, 2/1/44 313,220 1,929,239 Fannie Mae, 4.5%, 4/1/41 2,079,958 3,537,432 Fannie Mae, 4.5%, 5/1/41 3,813,593 2,719,716 Fannie Mae, 4.5%, 5/1/41 2,930,454 99,504 Fannie Mae, 4.5%, 5/1/41 107,116 1,484,782 Fannie Mae, 4.5%, 7/1/41 1,600,665 1,442,141 Fannie Mae, 4.5%, 7/1/41 1,555,652 1,370,931 Fannie Mae, 4.5%, 7/1/41 1,475,807 1,069,351 Fannie Mae, 4.5%, 8/1/40 1,154,734 599,155 Fannie Mae, 4.5%, 8/1/40 645,878 126,768 Fannie Mae, 5.0%, 1/1/20 129,735 53,357 Fannie Mae, 5.0%, 1/1/20 55,208 209,399 Fannie Mae, 5.0%, 10/1/20 217,959 219,362 Fannie Mae, 5.0%, 10/1/34 235,704 24,377 Fannie Mae, 5.0%, 2/1/20 24,948 167,870 Fannie Mae, 5.0%, 2/1/22 179,192 10,846 Fannie Mae, 5.0%, 2/1/22 11,100 940,418 Fannie Mae, 5.0%, 2/1/39 1,031,588 3,365,647 Fannie Mae, 5.0%, 2/1/41 3,674,567 13,965,399 Fannie Mae, 5.0%, 2/1/45 15,267,119 80,438 Fannie Mae, 5.0%, 3/1/23 85,706 352,960 Fannie Mae, 5.0%, 5/1/23 376,867 774,269 Fannie Mae, 5.0%, 6/1/40 845,498 707,281 Fannie Mae, 5.0%, 6/1/40 773,252 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 53 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 158,796 Fannie Mae, 5.0%, 7/1/34 $ 169,809 1,087,893 Fannie Mae, 5.0%, 7/1/40 1,188,003 798,077 Fannie Mae, 5.0%, 7/1/40 871,493 552,537 Fannie Mae, 5.0%, 7/1/40 603,231 33,366 Fannie Mae, 5.0%, 8/1/18 34,147 33,371 Fannie Mae, 5.5%, 12/1/17 33,727 360,043 Fannie Mae, 5.5%, 3/1/36 403,148 161,687 Fannie Mae, 5.5%, 5/1/36 180,685 24,067 Fannie Mae, 5.5%, 6/1/33 26,730 201,076 Fannie Mae, 5.5%, 6/1/36 224,379 97,544 Fannie Mae, 5.5%, 7/1/33 109,363 664,100 Fannie Mae, 5.5%, 7/1/34 744,862 141,629 Fannie Mae, 5.5%, 9/1/19 146,248 56,305 Fannie Mae, 5.72%, 11/1/28 58,188 38,444 Fannie Mae, 5.72%, 6/1/29 38,815 27,414 Fannie Mae, 5.9%, 11/1/27 27,567 82,247 Fannie Mae, 5.9%, 4/1/28 86,164 4,224 Fannie Mae, 6.0%, 1/1/32 4,839 56,467 Fannie Mae, 6.0%, 10/1/32 64,774 14,443 Fannie Mae, 6.0%, 10/1/34 16,457 87,213 Fannie Mae, 6.0%, 10/1/35 98,749 30,396 Fannie Mae, 6.0%, 11/1/33 34,791 251,746 Fannie Mae, 6.0%, 11/1/34 286,940 11,922 Fannie Mae, 6.0%, 11/1/34 13,640 200,109 Fannie Mae, 6.0%, 12/1/35 226,901 29,750 Fannie Mae, 6.0%, 12/1/37 33,685 16,962 Fannie Mae, 6.0%, 2/1/32 19,202 8,643 Fannie Mae, 6.0%, 2/1/33 9,780 10,199 Fannie Mae, 6.0%, 2/1/35 11,643 4,549 Fannie Mae, 6.0%, 2/1/35 5,195 6,478 Fannie Mae, 6.0%, 3/1/32 7,415 81,789 Fannie Mae, 6.0%, 3/1/33 93,748 91,128 Fannie Mae, 6.0%, 4/1/33 103,784 197,307 Fannie Mae, 6.0%, 4/1/35 226,086 32,272 Fannie Mae, 6.0%, 5/1/35 36,518 339,595 Fannie Mae, 6.0%, 6/1/38 389,297 340,046 Fannie Mae, 6.0%, 7/1/33 386,171 188,405 Fannie Mae, 6.0%, 7/1/33 215,795 60,948 Fannie Mae, 6.0%, 7/1/38 69,008 3,993 Fannie Mae, 6.0%, 8/1/32 4,572 138,925 Fannie Mae, 6.0%, 8/1/34 159,597 The accompanying notes are an integral part of these financial statements. 54 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,045 Fannie Mae, 6.0%, 9/1/29 $ 1,195 498 Fannie Mae, 6.0%, 9/1/32 570 93,557 Fannie Mae, 6.0%, 9/1/34 106,193 43,547 Fannie Mae, 6.0%, 9/1/34 49,757 28,720 Fannie Mae, 6.0%, 9/1/34 32,772 9,207 Fannie Mae, 6.0%, 9/1/34 10,500 2,557 Fannie Mae, 6.5%, 1/1/31 2,892 8,158 Fannie Mae, 6.5%, 10/1/31 9,230 71,512 Fannie Mae, 6.5%, 10/1/32 80,906 136,622 Fannie Mae, 6.5%, 11/1/37 156,347 37,161 Fannie Mae, 6.5%, 11/1/47 40,932 128,807 Fannie Mae, 6.5%, 12/1/31 145,728 4,738 Fannie Mae, 6.5%, 2/1/32 5,360 60,255 Fannie Mae, 6.5%, 3/1/32 68,170 2,049 Fannie Mae, 6.5%, 4/1/31 2,319 5,008 Fannie Mae, 6.5%, 5/1/31 5,666 71,142 Fannie Mae, 6.5%, 6/1/31 80,488 7,922 Fannie Mae, 6.5%, 7/1/29 8,963 104,660 Fannie Mae, 6.5%, 7/1/32 118,409 29,231 Fannie Mae, 6.5%, 7/1/34 33,071 8,815 Fannie Mae, 6.5%, 8/1/31 9,973 7,877 Fannie Mae, 6.5%, 9/1/31 8,912 3,947 Fannie Mae, 6.5%, 9/1/31 4,465 18,871 Fannie Mae, 7.0%, 1/1/32 22,305 7,029 Fannie Mae, 7.0%, 12/1/30 7,864 706 Fannie Mae, 7.0%, 12/1/30 747 24,691 Fannie Mae, 7.0%, 12/1/31 26,238 8,516 Fannie Mae, 7.0%, 4/1/31 10,055 9,937 Fannie Mae, 7.0%, 9/1/31 11,686 389,601 Federal Home Loan Mortgage Corp., 2.5%, 1/1/30 391,110 229,452 Federal Home Loan Mortgage Corp., 2.5%, 4/1/30 230,335 19,815,000 Federal Home Loan Mortgage Corp., 3.0%, 1/18/17 (TBA) 19,675,788 3,474,417 Federal Home Loan Mortgage Corp., 3.0%, 10/1/29 3,568,644 1,463,438 Federal Home Loan Mortgage Corp., 3.0%, 11/1/30 1,504,376 7,830,432 Federal Home Loan Mortgage Corp., 3.0%, 11/1/42 7,827,242 2,258,467 Federal Home Loan Mortgage Corp., 3.0%, 2/1/43 2,257,547 2,623,940 Federal Home Loan Mortgage Corp., 3.0%, 5/1/43 2,620,703 1,961,252 Federal Home Loan Mortgage Corp., 3.0%, 5/1/45 1,950,428 5,552,956 Federal Home Loan Mortgage Corp., 3.0%, 6/1/46 5,523,148 3,515,918 Federal Home Loan Mortgage Corp., 3.0%, 8/1/29 3,616,507 1,442,492 Federal Home Loan Mortgage Corp., 3.0%, 8/1/45 1,433,918 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 55 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,111,220 Federal Home Loan Mortgage Corp., 3.0%, 9/1/42 $ 1,110,767 4,386,443 Federal Home Loan Mortgage Corp., 3.0%, 9/1/46 4,360,176 2,903,440 Federal Home Loan Mortgage Corp., 3.5%, 10/1/44 2,976,653 8,762,396 Federal Home Loan Mortgage Corp., 3.5%, 10/1/45 8,978,878 3,286,774 Federal Home Loan Mortgage Corp., 3.5%, 10/1/45 3,378,325 1,848,598 Federal Home Loan Mortgage Corp., 3.5%, 11/1/28 1,943,761 146,659 Federal Home Loan Mortgage Corp., 3.5%, 11/1/44 150,276 8,951,938 Federal Home Loan Mortgage Corp., 3.5%, 11/1/45 9,184,353 7,771,283 Federal Home Loan Mortgage Corp., 3.5%, 12/1/44 7,963,032 349,140 Federal Home Loan Mortgage Corp., 3.5%, 3/1/26 364,697 3,751,479 Federal Home Loan Mortgage Corp., 3.5%, 3/1/45 3,844,249 4,587,016 Federal Home Loan Mortgage Corp., 3.5%, 3/1/46 4,700,957 1,904,673 Federal Home Loan Mortgage Corp., 3.5%, 4/1/42 1,961,521 932,629 Federal Home Loan Mortgage Corp., 3.5%, 4/1/45 955,696 7,531,825 Federal Home Loan Mortgage Corp., 3.5%, 5/1/46 7,721,356 8,339,350 Federal Home Loan Mortgage Corp., 3.5%, 7/1/44 8,544,866 249,985 Federal Home Loan Mortgage Corp., 3.5%, 7/1/45 257,080 3,288,775 Federal Home Loan Mortgage Corp., 3.5%, 8/1/43 3,385,860 950,811 Federal Home Loan Mortgage Corp., 3.5%, 8/1/44 975,156 11,265,503 Federal Home Loan Mortgage Corp., 3.5%, 8/1/46 11,572,923 701,986 Federal Home Loan Mortgage Corp., 3.5%, 9/1/44 721,816 2,078,887 Federal Home Loan Mortgage Corp., 4.0%, 1/1/44 2,183,697 316,699 Federal Home Loan Mortgage Corp., 4.0%, 10/1/46 333,318 11,356,835 Federal Home Loan Mortgage Corp., 4.0%, 11/1/41 12,073,825 127,245 Federal Home Loan Mortgage Corp., 4.0%, 11/1/42 133,760 1,902,177 Federal Home Loan Mortgage Corp., 4.0%, 12/1/44 1,998,837 6,580,308 Federal Home Loan Mortgage Corp., 4.0%, 12/1/45 6,915,718 618,586 Federal Home Loan Mortgage Corp., 4.0%, 2/1/44 653,562 6,790,847 Federal Home Loan Mortgage Corp., 4.0%, 3/1/46 7,137,387 1,768,949 Federal Home Loan Mortgage Corp., 4.0%, 4/1/45 1,858,894 6,130,234 Federal Home Loan Mortgage Corp., 4.0%, 5/1/44 6,438,353 608,503 Federal Home Loan Mortgage Corp., 4.0%, 5/1/46 639,661 286,432 Federal Home Loan Mortgage Corp., 4.0%, 5/1/46 301,108 411,848 Federal Home Loan Mortgage Corp., 4.0%, 6/1/42 432,937 5,665,211 Federal Home Loan Mortgage Corp., 4.0%, 6/1/44 5,950,910 5,326,485 Federal Home Loan Mortgage Corp., 4.0%, 6/1/46 5,604,337 153,392 Federal Home Loan Mortgage Corp., 4.0%, 7/1/42 162,004 8,188,985 Federal Home Loan Mortgage Corp., 4.0%, 7/1/44 8,602,830 2,030,091 Federal Home Loan Mortgage Corp., 4.0%, 7/1/44 2,144,322 1,665,236 Federal Home Loan Mortgage Corp., 4.0%, 7/1/44 1,755,605 1,312,010 Federal Home Loan Mortgage Corp., 4.0%, 7/1/44 1,385,588 8,150,509 Federal Home Loan Mortgage Corp., 4.0%, 9/1/44 8,592,514 3,309,481 Federal Home Loan Mortgage Corp., 4.0%, 9/1/44 3,476,706 The accompanying notes are an integral part of these financial statements. 56 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 210,687 Federal Home Loan Mortgage Corp., 4.5%, 10/1/20 $ 221,087 3,488,433 Federal Home Loan Mortgage Corp., 4.5%, 11/1/40 3,756,537 224,587 Federal Home Loan Mortgage Corp., 4.5%, 11/1/43 241,405 87,424 Federal Home Loan Mortgage Corp., 4.5%, 3/1/20 90,756 5,066,020 Federal Home Loan Mortgage Corp., 4.5%, 3/1/42 5,439,032 2,067,015 Federal Home Loan Mortgage Corp., 4.5%, 3/1/42 2,224,576 562,145 Federal Home Loan Mortgage Corp., 5.0%, 10/1/20 588,455 378,812 Federal Home Loan Mortgage Corp., 5.0%, 10/1/38 412,368 13,381 Federal Home Loan Mortgage Corp., 5.0%, 11/1/34 14,649 17,079 Federal Home Loan Mortgage Corp., 5.0%, 12/1/21 18,118 167,541 Federal Home Loan Mortgage Corp., 5.0%, 6/1/35 182,365 389,722 Federal Home Loan Mortgage Corp., 5.0%, 9/1/38 424,208 11,802 Federal Home Loan Mortgage Corp., 5.5%, 1/1/34 13,074 113,159 Federal Home Loan Mortgage Corp., 5.5%, 11/1/34 127,206 22,767 Federal Home Loan Mortgage Corp., 5.5%, 11/1/34 25,564 32,456 Federal Home Loan Mortgage Corp., 5.5%, 11/1/35 36,410 98,546 Federal Home Loan Mortgage Corp., 5.5%, 12/1/18 100,782 1,328,298 Federal Home Loan Mortgage Corp., 5.5%, 6/1/41 1,483,069 133,854 Federal Home Loan Mortgage Corp., 5.5%, 8/1/35 148,262 234,470 Federal Home Loan Mortgage Corp., 5.5%, 9/1/33 263,605 100,339 Federal Home Loan Mortgage Corp., 6.0%, 1/1/33 114,745 48,076 Federal Home Loan Mortgage Corp., 6.0%, 1/1/33 54,312 36,184 Federal Home Loan Mortgage Corp., 6.0%, 1/1/34 40,878 31,830 Federal Home Loan Mortgage Corp., 6.0%, 1/1/34 36,418 87,582 Federal Home Loan Mortgage Corp., 6.0%, 1/1/38 99,210 34,889 Federal Home Loan Mortgage Corp., 6.0%, 11/1/33 39,415 16,372 Federal Home Loan Mortgage Corp., 6.0%, 11/1/33 18,495 121,828 Federal Home Loan Mortgage Corp., 6.0%, 12/1/33 137,633 116,371 Federal Home Loan Mortgage Corp., 6.0%, 12/1/33 131,467 9,048 Federal Home Loan Mortgage Corp., 6.0%, 12/1/33 10,222 41,186 Federal Home Loan Mortgage Corp., 6.0%, 12/1/36 46,847 54,316 Federal Home Loan Mortgage Corp., 6.0%, 2/1/33 62,335 4,707 Federal Home Loan Mortgage Corp., 6.0%, 2/1/33 5,394 163,943 Federal Home Loan Mortgage Corp., 6.0%, 3/1/33 187,852 37,095 Federal Home Loan Mortgage Corp., 6.0%, 3/1/33 41,907 34,088 Federal Home Loan Mortgage Corp., 6.0%, 4/1/35 38,511 196,017 Federal Home Loan Mortgage Corp., 6.0%, 4/1/36 221,446 5,252 Federal Home Loan Mortgage Corp., 6.0%, 5/1/17 5,273 468,118 Federal Home Loan Mortgage Corp., 6.0%, 5/1/34 533,300 144,559 Federal Home Loan Mortgage Corp., 6.0%, 5/1/34 164,219 109,547 Federal Home Loan Mortgage Corp., 6.0%, 6/1/35 123,759 85,826 Federal Home Loan Mortgage Corp., 6.0%, 6/1/35 96,960 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 57 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 52,686 Federal Home Loan Mortgage Corp., 6.0%, 7/1/36 $ 59,521 13,965 Federal Home Loan Mortgage Corp., 6.0%, 7/1/36 15,881 99,902 Federal Home Loan Mortgage Corp., 6.0%, 7/1/38 113,712 5,449 Federal Home Loan Mortgage Corp., 6.0%, 8/1/18 6,156 95,159 Federal Home Loan Mortgage Corp., 6.0%, 8/1/34 107,504 114,754 Federal Home Loan Mortgage Corp., 6.0%, 9/1/33 131,290 161 Federal Home Loan Mortgage Corp., 6.5%, 1/1/31 182 258 Federal Home Loan Mortgage Corp., 6.5%, 1/1/33 292 38,847 Federal Home Loan Mortgage Corp., 6.5%, 10/1/33 45,302 337 Federal Home Loan Mortgage Corp., 6.5%, 11/1/30 381 3,451 Federal Home Loan Mortgage Corp., 6.5%, 2/1/33 3,898 5,542 Federal Home Loan Mortgage Corp., 6.5%, 3/1/31 6,259 487 Federal Home Loan Mortgage Corp., 6.5%, 3/1/31 550 7,991 Federal Home Loan Mortgage Corp., 6.5%, 5/1/31 9,026 5,278 Federal Home Loan Mortgage Corp., 6.5%, 5/1/31 5,961 207 Federal Home Loan Mortgage Corp., 6.5%, 6/1/32 234 11,386 Federal Home Loan Mortgage Corp., 6.5%, 7/1/32 12,944 4,068 Federal Home Loan Mortgage Corp., 6.5%, 8/1/31 4,595 793 Federal Home Loan Mortgage Corp., 6.5%, 8/1/31 908 74,515 Federal Home Loan Mortgage Corp., 7.0%, 10/1/46 84,254 2,862 Federal Home Loan Mortgage Corp., 7.0%, 11/1/30 3,359 3,337 Federal Home Loan Mortgage Corp., 7.0%, 6/1/31 3,347 12,099 Federal Home Loan Mortgage Corp., 7.0%, 8/1/22 12,136 93,140 Federal Home Loan Mortgage Corp., 7.0%, 9/1/22 98,762 563,848 Federal National Mortgage Association, 3.0%, 12/1/21 579,830 1,556,906 Federal National Mortgage Association, 3.0%, 4/1/31 1,599,063 7,712,798 Federal National Mortgage Association, 3.5%, 7/1/46 7,912,476 6,533,327 Federal National Mortgage Association, 4.0%, 10/1/45 6,872,920 341,866 Federal National Mortgage Association, 4.0%, 11/1/34 363,296 899,840 Federal National Mortgage Association, 5.0%, 8/1/40 983,666 888,277 Government National Mortgage Association I, 3.5%, 1/15/44 930,955 13,838,852 Government National Mortgage Association I, 3.5%, 1/15/45 14,400,642 30,710,000 Government National Mortgage Association I, 3.5%, 1/24/17 (TBA) 31,932,344 The accompanying notes are an integral part of these financial statements. 58 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 9,291,711 Government National Mortgage Association I, 3.5%, 7/15/42 $ 9,691,894 92,996 Government National Mortgage Association I, 4.0%, 1/15/41 98,796 26,408 Government National Mortgage Association I, 4.0%, 1/15/41 28,096 2,865,254 Government National Mortgage Association I, 4.0%, 1/15/45 3,043,998 2,034,922 Government National Mortgage Association I, 4.0%, 1/15/45 2,160,050 1,837,458 Government National Mortgage Association I, 4.0%, 1/15/45 1,950,735 533,355 Government National Mortgage Association I, 4.0%, 1/15/45 570,033 8,045 Government National Mortgage Association I, 4.0%, 10/15/40 8,572 7,281 Government National Mortgage Association I, 4.0%, 10/15/41 7,733 5,630 Government National Mortgage Association I, 4.0%, 10/15/41 5,979 142,446 Government National Mortgage Association I, 4.0%, 10/15/44 151,297 41,810 Government National Mortgage Association I, 4.0%, 11/15/40 44,410 11,926 Government National Mortgage Association I, 4.0%, 11/15/40 12,671 5,739 Government National Mortgage Association I, 4.0%, 11/15/41 6,107 4,285 Government National Mortgage Association I, 4.0%, 11/15/41 4,548 26,119 Government National Mortgage Association I, 4.0%, 11/15/43 27,890 671,894 Government National Mortgage Association I, 4.0%, 11/15/44 713,815 7,960 Government National Mortgage Association I, 4.0%, 12/15/41 8,480 2,626,678 Government National Mortgage Association I, 4.0%, 12/15/44 2,791,210 10,507 Government National Mortgage Association I, 4.0%, 2/15/41 11,197 218,219 Government National Mortgage Association I, 4.0%, 2/15/42 231,830 33,288 Government National Mortgage Association I, 4.0%, 2/15/42 35,467 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 59 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 2,553,801 Government National Mortgage Association I, 4.0%, 2/15/45 $ 2,712,677 1,494,433 Government National Mortgage Association I, 4.0%, 2/15/45 1,587,043 4,977,774 Government National Mortgage Association I, 4.0%, 3/15/44 5,286,254 1,146,100 Government National Mortgage Association I, 4.0%, 3/15/44 1,217,270 505,504 Government National Mortgage Association I, 4.0%, 3/15/44 536,700 16,237 Government National Mortgage Association I, 4.0%, 3/15/44 17,245 3,330,554 Government National Mortgage Association I, 4.0%, 3/15/45 3,539,237 248,339 Government National Mortgage Association I, 4.0%, 3/15/45 263,724 3,383,710 Government National Mortgage Association I, 4.0%, 4/15/44 3,593,169 38,337 Government National Mortgage Association I, 4.0%, 4/15/44 40,727 9,660 Government National Mortgage Association I, 4.0%, 4/15/44 10,259 7,879 Government National Mortgage Association I, 4.0%, 5/15/39 8,369 2,512,036 Government National Mortgage Association I, 4.0%, 5/15/45 2,668,779 5,224 Government National Mortgage Association I, 4.0%, 6/15/39 5,547 71,003 Government National Mortgage Association I, 4.0%, 6/15/41 75,421 177,776 Government National Mortgage Association I, 4.0%, 7/15/41 189,006 873,842 Government National Mortgage Association I, 4.0%, 7/15/45 929,305 286,614 Government National Mortgage Association I, 4.0%, 8/15/40 304,489 8,939 Government National Mortgage Association I, 4.0%, 8/15/40 9,524 1,418,439 Government National Mortgage Association I, 4.0%, 8/15/43 1,506,544 523,522 Government National Mortgage Association I, 4.0%, 8/15/44 556,098 750,304 Government National Mortgage Association I, 4.0%, 8/15/45 800,032 99,090 Government National Mortgage Association I, 4.0%, 9/15/40 105,311 The accompanying notes are an integral part of these financial statements. 60 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 8,004 Government National Mortgage Association I, 4.0%, 9/15/40 $ 8,528 527,199 Government National Mortgage Association I, 4.0%, 9/15/41 559,488 4,765 Government National Mortgage Association I, 4.0%, 9/15/41 5,062 3,387,769 Government National Mortgage Association I, 4.0%, 9/15/44 3,598,297 864,686 Government National Mortgage Association I, 4.0%, 9/15/44 918,233 455,559 Government National Mortgage Association I, 4.0%, 9/15/44 483,889 359,531 Government National Mortgage Association I, 4.0%, 9/15/44 381,920 71,887 Government National Mortgage Association I, 4.0%, 9/15/44 76,365 445,267 Government National Mortgage Association I, 4.5%, 1/15/40 487,267 188,857 Government National Mortgage Association I, 4.5%, 10/15/33 205,867 161,752 Government National Mortgage Association I, 4.5%, 10/15/33 175,133 132,748 Government National Mortgage Association I, 4.5%, 10/15/35 143,946 17,241 Government National Mortgage Association I, 4.5%, 12/15/19 17,950 1,069,813 Government National Mortgage Association I, 4.5%, 12/15/39 1,161,298 35,621 Government National Mortgage Association I, 4.5%, 2/15/34 38,717 59,577 Government National Mortgage Association I, 4.5%, 3/15/35 64,463 16,386 Government National Mortgage Association I, 4.5%, 3/15/35 17,733 8,712 Government National Mortgage Association I, 4.5%, 4/15/18 8,924 37,260 Government National Mortgage Association I, 4.5%, 4/15/20 39,046 206,229 Government National Mortgage Association I, 4.5%, 4/15/35 224,739 21,225 Government National Mortgage Association I, 4.5%, 4/15/35 22,972 116,010 Government National Mortgage Association I, 4.5%, 4/15/38 125,621 563,415 Government National Mortgage Association I, 4.5%, 4/15/41 609,889 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 61 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,175,714 Government National Mortgage Association I, 4.5%, 5/15/41 $ 1,272,681 26,580 Government National Mortgage Association I, 4.5%, 6/15/19 27,471 224,265 Government National Mortgage Association I, 4.5%, 6/15/25 237,136 1,068,375 Government National Mortgage Association I, 4.5%, 6/15/41 1,158,757 80,315 Government National Mortgage Association I, 4.5%, 7/15/33 87,402 395,308 Government National Mortgage Association I, 4.5%, 7/15/41 428,120 6,144 Government National Mortgage Association I, 4.5%, 8/15/19 6,367 1,122,758 Government National Mortgage Association I, 4.5%, 8/15/41 1,215,186 216,904 Government National Mortgage Association I, 4.5%, 9/15/33 238,220 20,617 Government National Mortgage Association I, 4.5%, 9/15/35 22,305 270,139 Government National Mortgage Association I, 4.5%, 9/15/40 294,158 49,579 Government National Mortgage Association I, 5.0%, 10/15/18 51,912 31,919 Government National Mortgage Association I, 5.0%, 2/15/19 33,562 96,956 Government National Mortgage Association I, 5.0%, 4/15/34 106,468 448,248 Government National Mortgage Association I, 5.0%, 4/15/35 500,895 53,522 Government National Mortgage Association I, 5.0%, 7/15/19 56,293 628 Government National Mortgage Association I, 5.0%, 7/15/19 658 92,273 Government National Mortgage Association I, 5.0%, 7/15/33 101,974 226,741 Government National Mortgage Association I, 5.0%, 7/15/40 249,265 79,083 Government National Mortgage Association I, 5.0%, 9/15/33 87,497 52,054 Government National Mortgage Association I, 5.5%, 1/15/29 58,066 137,335 Government National Mortgage Association I, 5.5%, 1/15/35 155,223 The accompanying notes are an integral part of these financial statements. 62 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 20,219 Government National Mortgage Association I, 5.5%, 10/15/17 $ 20,390 8,553 Government National Mortgage Association I, 5.5%, 10/15/17 8,624 33,796 Government National Mortgage Association I, 5.5%, 10/15/19 34,870 71,312 Government National Mortgage Association I, 5.5%, 10/15/33 80,284 62,973 Government National Mortgage Association I, 5.5%, 10/15/33 71,439 49,001 Government National Mortgage Association I, 5.5%, 10/15/34 55,378 188,062 Government National Mortgage Association I, 5.5%, 10/15/35 212,610 96,145 Government National Mortgage Association I, 5.5%, 10/15/35 107,250 19,991 Government National Mortgage Association I, 5.5%, 11/15/18 20,424 180,628 Government National Mortgage Association I, 5.5%, 11/15/19 186,710 401,314 Government National Mortgage Association I, 5.5%, 11/15/34 448,464 11,319 Government National Mortgage Association I, 5.5%, 12/15/18 11,558 43,688 Government National Mortgage Association I, 5.5%, 2/15/18 44,210 35,920 Government National Mortgage Association I, 5.5%, 2/15/18 36,390 38,990 Government National Mortgage Association I, 5.5%, 2/15/35 43,509 31,422 Government National Mortgage Association I, 5.5%, 2/15/35 35,051 43,855 Government National Mortgage Association I, 5.5%, 2/15/37 49,337 10,966 Government National Mortgage Association I, 5.5%, 4/15/19 11,188 1,135 Government National Mortgage Association I, 5.5%, 4/15/19 1,166 37,442 Government National Mortgage Association I, 5.5%, 4/15/31 41,766 11,364 Government National Mortgage Association I, 5.5%, 6/15/18 11,488 12,590 Government National Mortgage Association I, 5.5%, 6/15/33 14,221 66,012 Government National Mortgage Association I, 5.5%, 6/15/35 73,664 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 63 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 73,856 Government National Mortgage Association I, 5.5%, 7/15/33 $ 83,424 71,432 Government National Mortgage Association I, 5.5%, 7/15/33 80,676 364,391 Government National Mortgage Association I, 5.5%, 7/15/34 410,089 471,154 Government National Mortgage Association I, 5.5%, 7/15/35 547,061 83,091 Government National Mortgage Association I, 5.5%, 8/15/19 85,388 82,461 Government National Mortgage Association I, 5.5%, 8/15/19 84,957 178,898 Government National Mortgage Association I, 5.5%, 8/15/33 202,180 32,882 Government National Mortgage Association I, 5.5%, 8/15/33 37,057 22,163 Government National Mortgage Association I, 5.5%, 8/15/33 25,034 90,928 Government National Mortgage Association I, 5.5%, 9/15/19 93,717 115,998 Government National Mortgage Association I, 5.5%, 9/15/33 129,395 63,251 Government National Mortgage Association I, 5.5%, 9/15/33 71,200 16,376 Government National Mortgage Association I, 5.72%, 4/15/29 18,373 54 Government National Mortgage Association I, 6.0%, 1/15/17 54 7,109 Government National Mortgage Association I, 6.0%, 1/15/19 7,163 14,432 Government National Mortgage Association I, 6.0%, 1/15/24 16,361 174,117 Government National Mortgage Association I, 6.0%, 1/15/33 201,707 35,119 Government National Mortgage Association I, 6.0%, 1/15/33 40,469 35,435 Government National Mortgage Association I, 6.0%, 1/15/33 40,186 7,324 Government National Mortgage Association I, 6.0%, 10/15/28 8,395 40,839 Government National Mortgage Association I, 6.0%, 10/15/32 47,454 35,112 Government National Mortgage Association I, 6.0%, 10/15/32 39,821 11,395 Government National Mortgage Association I, 6.0%, 10/15/32 12,917 The accompanying notes are an integral part of these financial statements. 64 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 40,717 Government National Mortgage Association I, 6.0%, 10/15/33 $ 46,158 313,361 Government National Mortgage Association I, 6.0%, 10/15/34 360,797 83,034 Government National Mortgage Association I, 6.0%, 10/15/34 96,005 64,808 Government National Mortgage Association I, 6.0%, 10/15/34 73,616 125,782 Government National Mortgage Association I, 6.0%, 10/15/36 144,794 31,514 Government National Mortgage Association I, 6.0%, 11/15/31 36,546 7,330 Government National Mortgage Association I, 6.0%, 11/15/32 8,311 6,666 Government National Mortgage Association I, 6.0%, 11/15/32 7,558 132,592 Government National Mortgage Association I, 6.0%, 11/15/33 150,982 130,672 Government National Mortgage Association I, 6.0%, 11/15/34 151,466 43,036 Government National Mortgage Association I, 6.0%, 11/15/37 48,787 151,498 Government National Mortgage Association I, 6.0%, 12/15/23 171,607 400,902 Government National Mortgage Association I, 6.0%, 12/15/32 465,054 221,304 Government National Mortgage Association I, 6.0%, 12/15/32 251,215 200,600 Government National Mortgage Association I, 6.0%, 12/15/32 227,733 143,576 Government National Mortgage Association I, 6.0%, 12/15/32 162,780 87,495 Government National Mortgage Association I, 6.0%, 12/15/32 99,768 18,453 Government National Mortgage Association I, 6.0%, 12/15/32 21,399 14,709 Government National Mortgage Association I, 6.0%, 12/15/32 16,949 103,561 Government National Mortgage Association I, 6.0%, 2/15/29 120,127 66,878 Government National Mortgage Association I, 6.0%, 2/15/29 77,696 146,341 Government National Mortgage Association I, 6.0%, 2/15/33 171,943 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 65 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 98,075 Government National Mortgage Association I, 6.0%, 2/15/33 $ 111,729 85,399 Government National Mortgage Association I, 6.0%, 2/15/33 99,034 34,801 Government National Mortgage Association I, 6.0%, 2/15/33 40,145 25,767 Government National Mortgage Association I, 6.0%, 2/15/33 29,221 2,119 Government National Mortgage Association I, 6.0%, 3/15/17 2,121 369 Government National Mortgage Association I, 6.0%, 3/15/17 370 24,180 Government National Mortgage Association I, 6.0%, 3/15/19 24,542 1,926 Government National Mortgage Association I, 6.0%, 3/15/32 2,234 389,533 Government National Mortgage Association I, 6.0%, 3/15/33 462,293 260,271 Government National Mortgage Association I, 6.0%, 3/15/33 301,281 175,320 Government National Mortgage Association I, 6.0%, 3/15/33 198,749 154,440 Government National Mortgage Association I, 6.0%, 3/15/33 179,127 120,708 Government National Mortgage Association I, 6.0%, 3/15/33 139,783 99,164 Government National Mortgage Association I, 6.0%, 3/15/33 115,016 54,426 Government National Mortgage Association I, 6.0%, 3/15/33 62,010 43,907 Government National Mortgage Association I, 6.0%, 3/15/33 50,851 182,525 Government National Mortgage Association I, 6.0%, 3/15/34 216,285 998 Government National Mortgage Association I, 6.0%, 4/15/18 1,000 46,099 Government National Mortgage Association I, 6.0%, 4/15/28 53,159 45,527 Government National Mortgage Association I, 6.0%, 4/15/33 52,027 32,082 Government National Mortgage Association I, 6.0%, 4/15/33 36,369 17,661 Government National Mortgage Association I, 6.0%, 4/15/33 20,029 3,709 Government National Mortgage Association I, 6.0%, 5/15/17 3,720 The accompanying notes are an integral part of these financial statements. 66 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,846 Government National Mortgage Association I, 6.0%, 5/15/17 $ 1,848 152,019 Government National Mortgage Association I, 6.0%, 5/15/33 177,427 18,729 Government National Mortgage Association I, 6.0%, 5/15/33 21,232 365 Government National Mortgage Association I, 6.0%, 6/15/17 366 109,427 Government National Mortgage Association I, 6.0%, 6/15/31 124,197 11,986 Government National Mortgage Association I, 6.0%, 6/15/33 13,898 66,209 Government National Mortgage Association I, 6.0%, 6/15/34 76,807 7,121 Government National Mortgage Association I, 6.0%, 8/15/32 8,267 132,121 Government National Mortgage Association I, 6.0%, 8/15/34 149,776 37,008 Government National Mortgage Association I, 6.0%, 8/15/34 42,064 249,796 Government National Mortgage Association I, 6.0%, 8/15/36 287,312 70,550 Government National Mortgage Association I, 6.0%, 8/15/38 79,978 33,535 Government National Mortgage Association I, 6.0%, 9/15/19 34,087 212,923 Government National Mortgage Association I, 6.0%, 9/15/28 247,546 236,929 Government National Mortgage Association I, 6.0%, 9/15/32 268,947 92,920 Government National Mortgage Association I, 6.0%, 9/15/32 105,338 60,696 Government National Mortgage Association I, 6.0%, 9/15/32 69,571 58,042 Government National Mortgage Association I, 6.0%, 9/15/33 67,303 17,413 Government National Mortgage Association I, 6.0%, 9/15/33 20,031 16,292 Government National Mortgage Association I, 6.0%, 9/15/33 18,469 158,605 Government National Mortgage Association I, 6.0%, 9/15/34 184,027 66,012 Government National Mortgage Association I, 6.0%, 9/15/34 75,212 26,933 Government National Mortgage Association I, 6.0%, 9/15/34 31,245 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 67 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 818,561 Government National Mortgage Association I, 6.0%, 9/15/35 $ 947,972 23,714 Government National Mortgage Association I, 6.5%, 1/15/29 27,088 90,025 Government National Mortgage Association I, 6.5%, 1/15/32 102,833 27,108 Government National Mortgage Association I, 6.5%, 1/15/32 30,964 374,992 Government National Mortgage Association I, 6.5%, 1/15/33 435,177 3,596 Government National Mortgage Association I, 6.5%, 1/15/33 4,115 8,860 Government National Mortgage Association I, 6.5%, 1/15/34 10,121 558 Government National Mortgage Association I, 6.5%, 1/15/35 599 25,346 Government National Mortgage Association I, 6.5%, 10/15/24 28,376 16,688 Government National Mortgage Association I, 6.5%, 10/15/28 19,062 4,129 Government National Mortgage Association I, 6.5%, 10/15/28 4,717 83,834 Government National Mortgage Association I, 6.5%, 10/15/31 95,761 27,716 Government National Mortgage Association I, 6.5%, 10/15/31 31,659 7,450 Government National Mortgage Association I, 6.5%, 10/15/31 8,510 103,556 Government National Mortgage Association I, 6.5%, 10/15/32 118,288 2,040 Government National Mortgage Association I, 6.5%, 10/15/33 2,330 44,282 Government National Mortgage Association I, 6.5%, 11/15/31 50,582 5,113 Government National Mortgage Association I, 6.5%, 11/15/31 5,840 57,597 Government National Mortgage Association I, 6.5%, 11/15/32 67,593 359,067 Government National Mortgage Association I, 6.5%, 12/15/32 419,491 8,464 Government National Mortgage Association I, 6.5%, 2/15/28 9,668 20,206 Government National Mortgage Association I, 6.5%, 2/15/29 23,080 7,377 Government National Mortgage Association I, 6.5%, 2/15/29 8,427 The accompanying notes are an integral part of these financial statements. 68 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,125 Government National Mortgage Association I, 6.5%, 2/15/29 $ 1,285 42,306 Government National Mortgage Association I, 6.5%, 2/15/32 49,064 29,514 Government National Mortgage Association I, 6.5%, 2/15/32 33,713 19,106 Government National Mortgage Association I, 6.5%, 2/15/32 22,319 16,786 Government National Mortgage Association I, 6.5%, 2/15/32 19,547 9,879 Government National Mortgage Association I, 6.5%, 2/15/32 11,285 8,036 Government National Mortgage Association I, 6.5%, 2/15/34 9,180 82,676 Government National Mortgage Association I, 6.5%, 3/15/29 94,438 65,422 Government National Mortgage Association I, 6.5%, 3/15/29 74,730 13,595 Government National Mortgage Association I, 6.5%, 3/15/29 15,529 8,585 Government National Mortgage Association I, 6.5%, 3/15/29 9,806 5,159 Government National Mortgage Association I, 6.5%, 3/15/31 5,893 83,199 Government National Mortgage Association I, 6.5%, 3/15/32 95,036 15,913 Government National Mortgage Association I, 6.5%, 3/15/32 18,177 536 Government National Mortgage Association I, 6.5%, 4/15/17 537 37,632 Government National Mortgage Association I, 6.5%, 4/15/28 42,986 8,312 Government National Mortgage Association I, 6.5%, 4/15/28 9,495 64,960 Government National Mortgage Association I, 6.5%, 4/15/31 74,202 71,738 Government National Mortgage Association I, 6.5%, 4/15/32 83,585 13,479 Government National Mortgage Association I, 6.5%, 4/15/32 15,397 9,478 Government National Mortgage Association I, 6.5%, 4/15/32 10,827 7,048 Government National Mortgage Association I, 6.5%, 4/15/32 8,050 23,461 Government National Mortgage Association I, 6.5%, 4/15/33 26,799 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 69 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 40,697 Government National Mortgage Association I, 6.5%, 4/15/35 $ 46,487 64,349 Government National Mortgage Association I, 6.5%, 5/15/29 73,669 4,747 Government National Mortgage Association I, 6.5%, 5/15/29 5,422 3,391 Government National Mortgage Association I, 6.5%, 5/15/29 3,874 39,134 Government National Mortgage Association I, 6.5%, 5/15/31 44,702 18,283 Government National Mortgage Association I, 6.5%, 5/15/31 21,434 16,926 Government National Mortgage Association I, 6.5%, 5/15/31 19,611 15,255 Government National Mortgage Association I, 6.5%, 5/15/32 17,778 11,575 Government National Mortgage Association I, 6.5%, 5/15/32 13,222 5,780 Government National Mortgage Association I, 6.5%, 5/15/32 6,603 4,694 Government National Mortgage Association I, 6.5%, 5/15/32 5,361 31,360 Government National Mortgage Association I, 6.5%, 5/15/33 35,822 2,764 Government National Mortgage Association I, 6.5%, 6/15/17 2,769 9,313 Government National Mortgage Association I, 6.5%, 6/15/28 10,762 25,850 Government National Mortgage Association I, 6.5%, 6/15/29 29,527 7,413 Government National Mortgage Association I, 6.5%, 6/15/31 8,467 13,690 Government National Mortgage Association I, 6.5%, 6/15/32 15,638 13,166 Government National Mortgage Association I, 6.5%, 6/15/32 15,039 10,329 Government National Mortgage Association I, 6.5%, 6/15/32 11,798 112,394 Government National Mortgage Association I, 6.5%, 6/15/34 128,385 6,539 Government National Mortgage Association I, 6.5%, 6/15/35 7,469 24,736 Government National Mortgage Association I, 6.5%, 7/15/31 28,255 136,358 Government National Mortgage Association I, 6.5%, 7/15/32 159,623 The accompanying notes are an integral part of these financial statements. 70 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 30,167 Government National Mortgage Association I, 6.5%, 7/15/32 $ 34,459 10,188 Government National Mortgage Association I, 6.5%, 7/15/32 11,638 8,939 Government National Mortgage Association I, 6.5%, 7/15/32 10,211 64,694 Government National Mortgage Association I, 6.5%, 7/15/35 73,898 39,785 Government National Mortgage Association I, 6.5%, 7/15/35 45,445 7,087 Government National Mortgage Association I, 6.5%, 8/15/28 8,096 51,051 Government National Mortgage Association I, 6.5%, 8/15/31 58,314 53,678 Government National Mortgage Association I, 6.5%, 8/15/32 61,315 41,156 Government National Mortgage Association I, 6.5%, 8/15/32 47,814 3,837 Government National Mortgage Association I, 6.5%, 8/15/32 4,383 18,645 Government National Mortgage Association I, 6.5%, 9/15/31 21,298 43,021 Government National Mortgage Association I, 6.5%, 9/15/32 49,142 39,924 Government National Mortgage Association I, 6.5%, 9/15/32 45,603 18,829 Government National Mortgage Association I, 6.5%, 9/15/32 21,508 4,045 Government National Mortgage Association I, 6.5%, 9/15/34 4,621 5,705 Government National Mortgage Association I, 6.75%, 4/15/26 6,517 18,002 Government National Mortgage Association I, 7.0%, 1/15/28 19,816 43,665 Government National Mortgage Association I, 7.0%, 1/15/31 44,293 6,912 Government National Mortgage Association I, 7.0%, 10/15/31 7,139 9,683 Government National Mortgage Association I, 7.0%, 11/15/26 11,120 50,194 Government National Mortgage Association I, 7.0%, 11/15/28 59,103 15,964 Government National Mortgage Association I, 7.0%, 11/15/28 18,496 63,998 Government National Mortgage Association I, 7.0%, 11/15/29 71,297 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 71 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 8,304 Government National Mortgage Association I, 7.0%, 11/15/31 $ 8,732 37,953 Government National Mortgage Association I, 7.0%, 12/15/30 44,803 39,216 Government National Mortgage Association I, 7.0%, 12/15/30 40,068 10,452 Government National Mortgage Association I, 7.0%, 12/15/30 11,501 3,699 Government National Mortgage Association I, 7.0%, 12/15/30 3,906 19,618 Government National Mortgage Association I, 7.0%, 2/15/28 21,388 13,135 Government National Mortgage Association I, 7.0%, 3/15/28 13,501 10,520 Government National Mortgage Association I, 7.0%, 3/15/31 10,961 54,369 Government National Mortgage Association I, 7.0%, 3/15/32 60,091 12,793 Government National Mortgage Association I, 7.0%, 4/15/28 13,911 26,784 Government National Mortgage Association I, 7.0%, 4/15/29 29,264 23,070 Government National Mortgage Association I, 7.0%, 4/15/29 23,919 7,188 Government National Mortgage Association I, 7.0%, 4/15/31 7,383 45,920 Government National Mortgage Association I, 7.0%, 4/15/32 51,119 37,985 Government National Mortgage Association I, 7.0%, 5/15/29 39,978 8,276 Government National Mortgage Association I, 7.0%, 5/15/31 8,730 82,105 Government National Mortgage Association I, 7.0%, 5/15/32 99,138 21,556 Government National Mortgage Association I, 7.0%, 6/15/27 24,854 4,449 Government National Mortgage Association I, 7.0%, 6/15/29 4,463 29,366 Government National Mortgage Association I, 7.0%, 6/15/31 34,586 26,495 Government National Mortgage Association I, 7.0%, 7/15/25 29,600 17,685 Government National Mortgage Association I, 7.0%, 7/15/28 19,405 5,725 Government National Mortgage Association I, 7.0%, 7/15/28 5,743 The accompanying notes are an integral part of these financial statements. 72 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 11,932 Government National Mortgage Association I, 7.0%, 7/15/29 $ 13,481 3,432 Government National Mortgage Association I, 7.0%, 7/15/31 4,019 20,401 Government National Mortgage Association I, 7.0%, 8/15/23 21,973 1,363 Government National Mortgage Association I, 7.0%, 8/15/28 1,550 155,320 Government National Mortgage Association I, 7.0%, 8/15/31 185,947 60,855 Government National Mortgage Association I, 7.0%, 9/15/24 68,501 35,006 Government National Mortgage Association I, 7.0%, 9/15/31 38,700 12,908 Government National Mortgage Association I, 7.0%, 9/15/31 13,693 35,605 Government National Mortgage Association I, 7.5%, 10/15/23 39,007 49,035 Government National Mortgage Association I, 7.5%, 10/15/27 55,372 12,777 Government National Mortgage Association I, 7.5%, 10/15/29 14,270 6,029 Government National Mortgage Association I, 7.5%, 10/15/29 6,315 4,095 Government National Mortgage Association I, 7.5%, 12/15/25 4,241 44,580 Government National Mortgage Association I, 7.5%, 12/15/31 46,960 1,708 Government National Mortgage Association I, 7.5%, 2/15/26 1,778 14,878 Government National Mortgage Association I, 7.5%, 2/15/27 16,454 16,108 Government National Mortgage Association I, 7.5%, 2/15/31 16,705 14,582 Government National Mortgage Association I, 7.5%, 2/15/31 14,803 8,430 Government National Mortgage Association I, 7.5%, 3/15/23 9,061 35,659 Government National Mortgage Association I, 7.5%, 3/15/27 42,075 7,464 Government National Mortgage Association I, 7.5%, 3/15/31 7,737 1,540 Government National Mortgage Association I, 7.5%, 6/15/24 1,593 16,359 Government National Mortgage Association I, 7.5%, 6/15/29 18,280 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 73 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 10,252 Government National Mortgage Association I, 7.5%, 8/15/25 $ 10,515 17,415 Government National Mortgage Association I, 7.5%, 8/15/29 18,359 2,814 Government National Mortgage Association I, 7.5%, 8/15/29 2,880 950 Government National Mortgage Association I, 7.5%, 8/15/29 953 5,334 Government National Mortgage Association I, 7.5%, 9/15/25 5,880 1,894 Government National Mortgage Association I, 7.5%, 9/15/25 1,900 19,274 Government National Mortgage Association I, 7.5%, 9/15/29 19,342 2,255 Government National Mortgage Association I, 7.75%, 2/15/30 2,300 19,282 Government National Mortgage Association I, 8.25%, 5/15/20 20,324 1,712 Government National Mortgage Association I, 8.5%, 8/15/21 1,719 5,763 Government National Mortgage Association I, 9.0%, 1/15/20 5,849 890 Government National Mortgage Association I, 9.0%, 12/15/19 947 1,933 Government National Mortgage Association I, 9.0%, 6/15/22 2,001 210 Government National Mortgage Association I, 9.0%, 9/15/21 216 4,391,128 Government National Mortgage Association II, 3.0%, 8/20/46 4,452,466 13,818,331 Government National Mortgage Association II, 3.0%, 9/20/46 14,011,352 7,253,368 Government National Mortgage Association II, 3.5%, 1/20/46 7,548,116 907,570 Government National Mortgage Association II, 3.5%, 3/20/45 944,985 1,761,558 Government National Mortgage Association II, 3.5%, 3/20/46 1,842,522 1,567,835 Government National Mortgage Association II, 3.5%, 4/20/45 1,634,110 1,197,036 Government National Mortgage Association II, 3.5%, 4/20/45 1,245,675 523,331 Government National Mortgage Association II, 3.5%, 4/20/45 545,129 4,630,202 Government National Mortgage Association II, 3.5%, 8/20/45 4,818,157 2,427,390 Government National Mortgage Association II, 4.0%, 10/20/44 2,580,023 The accompanying notes are an integral part of these financial statements. 74 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 10,247,157 Government National Mortgage Association II, 4.0%, 10/20/46 $ 10,895,782 10,223,843 Government National Mortgage Association II, 4.0%, 7/20/44 10,866,711 278,102 Government National Mortgage Association II, 4.0%, 9/20/44 295,589 299,839 Government National Mortgage Association II, 4.5%, 1/20/35 322,713 96,663 Government National Mortgage Association II, 4.5%, 12/20/34 104,081 50,200 Government National Mortgage Association II, 4.5%, 3/20/35 54,017 1,546,730 Government National Mortgage Association II, 4.5%, 9/20/41 1,667,047 21,457 Government National Mortgage Association II, 5.0%, 1/20/20 22,620 53,870 Government National Mortgage Association II, 5.0%, 12/20/18 55,688 27,342 Government National Mortgage Association II, 5.0%, 2/20/19 28,702 172,957 Government National Mortgage Association II, 5.5%, 10/20/19 178,225 147,506 Government National Mortgage Association II, 5.5%, 10/20/37 163,573 209,304 Government National Mortgage Association II, 5.5%, 3/20/34 240,338 185,652 Government National Mortgage Association II, 5.5%, 4/20/34 208,401 148,672 Government National Mortgage Association II, 5.75%, 6/20/33 164,185 26,894 Government National Mortgage Association II, 5.9%, 1/20/28 29,848 46,057 Government National Mortgage Association II, 5.9%, 11/20/27 51,095 86,059 Government National Mortgage Association II, 5.9%, 7/20/28 94,844 94,428 Government National Mortgage Association II, 6.0%, 1/20/33 110,084 20,599 Government National Mortgage Association II, 6.0%, 10/20/31 23,965 105,822 Government National Mortgage Association II, 6.0%, 10/20/33 123,141 22,199 Government National Mortgage Association II, 6.0%, 12/20/18 22,485 59,273 Government National Mortgage Association II, 6.0%, 6/20/34 68,962 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 75 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 1,492 Government National Mortgage Association II, 6.0%, 7/20/17 $ 1,500 9,797 Government National Mortgage Association II, 6.0%, 7/20/19 9,876 86,113 Government National Mortgage Association II, 6.45%, 1/20/33 98,112 45,474 Government National Mortgage Association II, 6.45%, 11/20/32 51,795 48,830 Government National Mortgage Association II, 6.45%, 7/20/32 55,619 25,289 Government National Mortgage Association II, 6.5%, 1/20/24 27,357 46,274 Government National Mortgage Association II, 6.5%, 10/20/32 54,241 2,157 Government National Mortgage Association II, 6.5%, 2/20/29 2,485 866 Government National Mortgage Association II, 6.5%, 3/20/29 997 61,774 Government National Mortgage Association II, 6.5%, 3/20/34 72,762 27,016 Government National Mortgage Association II, 6.5%, 4/20/29 30,644 14,136 Government National Mortgage Association II, 6.5%, 4/20/31 16,482 9,951 Government National Mortgage Association II, 6.5%, 6/20/31 11,537 45,209 Government National Mortgage Association II, 6.5%, 8/20/28 51,440 72,428 Government National Mortgage Association II, 7.0%, 1/20/29 85,204 10,996 Government National Mortgage Association II, 7.0%, 1/20/31 12,833 70,065 Government National Mortgage Association II, 7.0%, 11/20/28 82,162 10,526 Government National Mortgage Association II, 7.0%, 11/20/31 12,370 2,089 Government National Mortgage Association II, 7.0%, 12/20/30 2,498 6,983 Government National Mortgage Association II, 7.0%, 2/20/29 8,025 5,390 Government National Mortgage Association II, 7.0%, 3/20/31 6,305 9,731 Government National Mortgage Association II, 7.0%, 5/20/26 11,086 21,776 Government National Mortgage Association II, 7.0%, 6/20/28 25,584 The accompanying notes are an integral part of these financial statements. 76 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- (continued) 27,063 Government National Mortgage Association II, 7.0%, 7/20/31 $ 32,205 20,817 Government National Mortgage Association II, 7.0%, 8/20/27 24,341 6,777 Government National Mortgage Association II, 7.5%, 12/20/30 8,166 11,139 Government National Mortgage Association II, 7.5%, 5/20/30 13,538 3,389 Government National Mortgage Association II, 7.5%, 6/20/30 3,948 9,307 Government National Mortgage Association II, 7.5%, 7/20/30 10,528 12,429 Government National Mortgage Association II, 7.5%, 8/20/30 15,107 42 Government National Mortgage Association II, 8.0%, 5/20/25 47 2,476 Government National Mortgage Association II, 9.0%, 11/20/24 2,487 2,397 Government National Mortgage Association II, 9.0%, 3/20/22 2,407 336 Government National Mortgage Association II, 9.0%, 4/20/22 337 433 Government National Mortgage Association II, 9.0%, 9/20/21 434 17,425 Government National Mortgage Association, 6.5%, 3/15/29 19,904 968,184 Tennessee Valley Authority, 4.929%, 1/15/21 1,036,379 147,025,000 U.S. Treasury Bills, 1/12/17 (c) 147,010,284 30,720,000 U.S. Treasury Bills, 1/5/17 (c) 30,719,386 2,500,000 U.S. Treasury Bonds, 4.25%, 5/15/39 3,035,255 6,865,000 U.S. Treasury Bonds, 4.375%, 11/15/39 8,474,520 1,600,000 U.S. Treasury Bonds, 4.375%, 5/15/40 1,976,813 62,762,044 U.S. Treasury Inflation Indexed Bonds, 0.75%, 2/15/45 59,055,381 71,642,843 U.S. Treasury Inflation Indexed Bonds, 1.0%, 2/15/46 71,945,605 1,500,000 U.S. Treasury Notes, 0.625%, 5/31/17 1,500,117 1,500,000 U.S. Treasury Notes, 1.125%, 1/15/19 1,497,129 5,200,000 U.S. Treasury Notes, 1.875%, 8/31/17 5,238,189 5,400,000 U.S. Treasury Notes, 2.625%, 11/15/20 5,581,408 --------------- $ 1,555,944,926 --------------------------------------------------------------------------------------------------- TOTAL U.S. GOVERNMENT AND AGENCY OBLIGATIONS (Cost $1,565,358,269) $ 1,555,944,926 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 77 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- FOREIGN GOVERNMENT BONDS -- 0.1% 4,550,000 Africa Finance Corp., 4.375%, 4/29/20 (144A) $ 4,656,925 1,075,000 Provincia de Cordoba, 7.125%, 6/10/21 (144A) 1,104,562 --------------------------------------------------------------------------------------------------- TOTAL FOREIGN GOVERNMENT BONDS (Cost $5,594,472) $ 5,761,487 --------------------------------------------------------------------------------------------------- MUNICIPAL BONDS -- 1.2% Municipal Development -- 0.1% 4,500,000 New Jersey Economic Development Authority, 2/15/18 (c) $ 4,396,095 --------------------------------------------------------------------------------------------------- Municipal Education -- 0.0%+ 525,000 Amherst College, 3.794%, 11/1/42 $ 508,015 --------------------------------------------------------------------------------------------------- Municipal General -- 0.3% 4,075,000 JobsOhio Beverage System, 3.985%, 1/1/29 $ 4,303,282 1,035,000 JobsOhio Beverage System, 4.532%, 1/1/35 1,117,200 2,325,000 Virginia Commonwealth Transportation Board, 4.0%, 5/15/31 2,471,405 2,335,000 Virginia Commonwealth Transportation Board, 4.0%, 5/15/32 2,472,532 --------------- $ 15,268,529 --------------------------------------------------------------------------------------------------- Higher Municipal Education -- 0.4% 1,025,000 Baylor University, 4.313%, 3/1/42 $ 1,035,270 7,425,000 Massachusetts Development Finance Agency, Harvard University-Series A, 5.0%, 7/15/40 9,380,968 1,100,000 Massachusetts Institute of Technology, 5.6%, 7/1/11 1,333,333 1,900,000 The George Washington University, 1.827%, 9/15/17 1,906,549 3,100,000 University of Virginia, Green Bond Series A, 5.0%, 4/1/45 3,537,968 --------------- $ 17,194,088 --------------------------------------------------------------------------------------------------- Municipal Medical -- 0.1% 1,765,000 Ohio Higher Educational Facility Commission, 5.0%, 1/1/42 $ 1,943,336 --------------------------------------------------------------------------------------------------- Municipal School District -- 0.1% 2,800,000 Frisco Independent School District, 4.0%, 8/15/40 $ 2,872,240 1,750,000 Frisco Independent School District, 4.0%, 8/15/45 1,787,730 --------------- $ 6,603,306 --------------------------------------------------------------------------------------------------- Municipal Transportation -- 0.1% 600,000 Port Authority of New York & New Jersey, 4.458%, 10/1/62 $ 601,998 1,000,000 Texas Transportation Commission State Highway Fund, 5.0%, 4/1/33 1,142,750 2,830,000 Virginia Commonwealth Transportation Board, 3.0%, 5/15/39 2,500,956 --------------- $ 4,245,704 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 78 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Municipal Obligation -- 0.1% 3,150,000 State of Texas, 4.0%, 10/1/44 $ 3,255,998 1,600,000 State of Washington, 5.0%, 7/1/30 1,855,776 --------------- $ 5,111,774 --------------------------------------------------------------------------------------------------- TOTAL MUNICIPAL BONDS (Cost $48,629,341) $ 48,423,401 --------------------------------------------------------------------------------------------------- SENIOR FLOATING RATE LOAN INTERESTS -- 3.2%** ENERGY -- 0.1% Oil & Gas Refining & Marketing -- 0.0%+ 569,261 3.52 Pilot Travel Centers LLC, 2016 Refinancing Tranche B Term Loan, 5/18/23 $ 574,420 --------------------------------------------------------------------------------------------------- Oil & Gas Storage & Transportation -- 0.1% 1,904,228 6.25 Gulf Finance LLC, Tranche B Term Loan, 8/17/23 $ 1,923,270 --------------- Total Energy $ 2,497,690 --------------------------------------------------------------------------------------------------- MATERIALS -- 0.1% Commodity Chemicals -- 0.0%+ 755,108 4.50 Tronox Pigments Holland BV, New Term Loan, 3/19/20 $ 758,197 --------------------------------------------------------------------------------------------------- Specialty Chemicals -- 0.1% 164,825 3.75 Huntsman International LLC, 2015 Extended Term B Dollar Loan, 4/19/19 $ 165,787 805,860 5.00 MacDermid, Inc., Tranche B-4 Term Loan, 10/13/23 816,716 598,500 5.25 OMNOVA Solutions, Inc., Term B-2 Loan, 8/17/23 609,722 391,974 2.88 WR Grace & Co-Conn, U.S. Term Loan, 1/23/21 394,816 --------------- $ 1,987,041 --------------------------------------------------------------------------------------------------- Construction Materials -- 0.0%+ 104,280 4.25 CeramTec Acquisition Corp., Initial Dollar Term B-2 Loan, 8/30/20 $ 105,258 278,570 4.25 CeramTec GmbH, Dollar Term B-3 Loan, 8/30/20 281,182 920,537 4.25 CeramTec Service GmbH, Initial Dollar Term B-1 Loan, 8/30/20 929,167 --------------- $ 1,315,607 --------------------------------------------------------------------------------------------------- Metal & Glass Containers -- 0.0%+ 762,456 4.75 BWAY Holding Co., Initial Term Loan (2016), 8/14/23 $ 766,649 --------------------------------------------------------------------------------------------------- Aluminum -- 0.0%+ 689,500 4.02 Novelis, Inc., Initial Term Loan, 5/28/22 $ 693,994 --------------------------------------------------------------------------------------------------- Diversified Metals & Mining -- 0.0%+ 125,209 3.75 Fortescue Metals Group, Ltd., Bank Loan, 6/30/19 $ 125,616 --------------- Total Materials $ 5,647,104 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 79 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 0.4% Aerospace & Defense -- 0.1% 2,351,468 3.50 DigitalGlobe, Inc., Term Loan, 12/22/23 $ 2,372,044 1,432,316 5.75 The SI Organization, Inc., Term Loan (First Lien), 11/19/19 1,451,115 --------------- $ 3,823,159 --------------------------------------------------------------------------------------------------- Building Products -- 0.1% 1,575,667 4.25 NCI Building Systems, Inc., Tranche B Term Loan, 6/24/19 $ 1,578,621 1,966,314 4.25 Unifrax Corp., New Term B Loan, 12/31/19 1,963,243 --------------- $ 3,541,864 --------------------------------------------------------------------------------------------------- Electrical Components & Equipment -- 0.1% 1,100,000 4.25 Dell International LLC, Term B Loan, 6/2/23 $ 1,120,052 2,012,396 3.25 Southwire Co., Term Loan, 1/31/21 2,025,813 471,578 5.00 Sybil Software LLC, Initial Dollar Term Loan, 8/3/22 478,416 --------------- $ 3,624,281 --------------------------------------------------------------------------------------------------- Construction & Farm Machinery & Heavy Trucks -- 0.0%+ 744,361 6.50 Navistar, Inc., Tranche B Term Loan, 8/17/17 $ 755,061 --------------------------------------------------------------------------------------------------- Industrial Machinery -- 0.1% 3,460,697 5.00 NN, Inc., Tranche B Term Loan, 10/19/22 $ 3,476,378 --------------------------------------------------------------------------------------------------- Trading Companies & Distributors -- 0.0%+ 597,000 5.25 Nexeo Solutions LLC, Initial Term Loan, 5/17/23 $ 602,970 489,048 3.75 WESCO Distribution, Inc., Tranche B-1 Loan, 12/12/19 490,577 --------------- $ 1,093,547 --------------- Total Capital Goods $ 16,314,290 --------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.0%+ Security & Alarm Services -- 0.0%+ 780,508 4.00 Garda World Security Corp., Term B Loan, 11/1/20 $ 782,785 199,665 4.00 Garda World Security Corp., Term B Loan, 11/8/20 200,247 --------------- $ 983,032 --------------- Total Commercial Services & Supplies $ 983,032 --------------------------------------------------------------------------------------------------- TRANSPORTATION -- 0.0%+ Airlines -- 0.0%+ 792,000 3.25 Delta Air Lines, Inc., Term Loan (First Lien), 8/24/22 $ 801,900 --------------------------------------------------------------------------------------------------- Marine -- 0.0%+ 308,737 5.25 Navios Maritime Partners LP, Term Loan, 6/27/18 $ 300,247 --------------- Total Transportation $ 1,102,147 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 80 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- AUTOMOBILES & COMPONENTS -- 0.3% Auto Parts & Equipment -- 0.2% 635,186 3.26 Allison Transmission, Inc., Term B-3 Loan, 8/23/19 $ 644,431 1,203,132 5.75 Electrical Components International, Inc., Loan, 4/17/21 1,209,147 1,400,834 4.75 Federal-Mogul Corp., Tranche C Term, 4/15/21 1,389,452 4,493,250 3.75 MPG Holdco I, Inc., Tranche B-1 Term Loan (2015), 10/20/21 4,511,034 1,763,150 4.50 TI Group Automotive Systems LLC, Initial US Term Loan, 6/25/22 1,789,598 --------------- $ 9,543,662 --------------------------------------------------------------------------------------------------- Tires & Rubber -- 0.0%+ 1,396,667 3.75 The Goodyear Tire & Rubber Co., Term Loan (Second Lien), 3/27/19 $ 1,412,554 --------------------------------------------------------------------------------------------------- Automobile Manufacturers -- 0.1% 2,190,335 3.50 Chrysler Group LLC, Term Loan B, 5/24/17 $ 2,198,822 --------------- Total Automobiles & Components $ 13,155,038 --------------------------------------------------------------------------------------------------- CONSUMER DURABLES & APPAREL -- 0.0%+ Apparel, Accessories & Luxury Goods -- 0.0%+ 374,853 3.25 Hanesbrands, Inc., New Term B Loan, 4/15/22 $ 378,367 --------------------------------------------------------------------------------------------------- Footwear -- 0.0%+ 895,494 3.25 Regal Cinemas Corp., Refinancing Term Loan, 4/1/22 $ 901,091 --------------- Total Consumer Durables & Apparel $ 1,279,458 --------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.2% Casinos & Gaming -- 0.1% 110,167 3.84 Pinnacle Entertainment, Inc., Term B Facility Loan, 3/30/23 $ 110,901 4,263,000 6.00 Scientific Games, Initial Term B-2, 10/1/21 4,320,094 --------------- $ 4,430,995 --------------------------------------------------------------------------------------------------- Leisure Facilities -- 0.0%+ 598,500 6.00 L.A. Fitness International, LLC, Tranche B Term Loan (First Lien), 4/25/20 $ 599,921 1,292,915 3.09 Six Flags Theme Parks, Inc., Tranche B Term Loan, 6/30/22 1,305,642 --------------- $ 1,905,563 --------------------------------------------------------------------------------------------------- Restaurants -- 0.0%+ 358,806 3.75 Burger King BC ULC, Term B-2 Loan, 12/12/21 $ 362,319 --------------------------------------------------------------------------------------------------- Education Services -- 0.1% 576,689 3.50 Bright Horizons Family Solutions LLC (f.k.a. Bright Horizons Family Solutions, Inc.), Effective Date Incremental Term Loan, 11/3/23 $ 582,216 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 81 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Education Services -- (continued) 992,443 4.00 Houghton Mifflin Harcourt Publishers, Inc., Term Loan, 5/11/21 $ 947,783 992,366 5.00 Nord Anglia Education, Initial Term Loan, 3/31/21 1,009,113 --------------- $ 2,539,112 --------------------------------------------------------------------------------------------------- Specialized Consumer Services -- 0.0%+ 245,565 5.25 GENEX Holdings, Inc., Term B Loan (First Lien), 5/22/21 $ 244,645 --------------- Total Consumer Services $ 9,482,634 --------------------------------------------------------------------------------------------------- MEDIA -- 0.3% Advertising -- 0.0%+ 1,043,471 6.75 Affinion Group, Inc., Tranche B Term Loan, 4/30/18 $ 1,039,015 --------------------------------------------------------------------------------------------------- Broadcasting -- 0.1% 2,218,283 4.00 Univision Communications, Inc., Replacement First-Lien Term Loan (C-4), 3/1/20 $ 2,231,377 --------------------------------------------------------------------------------------------------- Cable & Satellite -- 0.1% 1,664,625 3.02 Charter Communications Operating LLC, Term F Loan, 1/1/21 $ 1,672,254 720,343 3.75 Intelsat Jackson Holdings SA, Tranche B-2 Term Loan, 6/30/19 698,604 --------------- $ 2,370,858 --------------------------------------------------------------------------------------------------- Movies & Entertainment -- 0.1% 408,365 5.00 CDS US Intermediate Holdings, Inc., Initial Term Loan (First Lien), 6/25/22 $ 412,550 2,074,800 3.31 Live Nation Entertainment, Inc., Term B-2 Loan, 10/27/23 2,098,142 3,195,445 3.75 Rovi Solutions Corp., Term B Loan, 7/2/21 3,224,738 --------------- $ 5,735,430 --------------------------------------------------------------------------------------------------- Publishing -- 0.0%+ 1,442,009 3.38 MTL Publishing LLC, Term B-4 Loan, 8/20/22 $ 1,452,644 --------------- Total Media $ 12,829,324 --------------------------------------------------------------------------------------------------- RETAILING -- 0.1% General Merchandise Stores -- 0.0%+ 151,515 3.25 Dollar Tree, Inc., Term B-3 Loan, 7/6/22 $ 153,093 --------------------------------------------------------------------------------------------------- Specialty Stores -- 0.0%+ 1,149,756 4.00 PetSmart, Inc., Tranche B-2 Loan, 3/10/22 $ 1,155,439 --------------------------------------------------------------------------------------------------- Automotive Retail -- 0.1% 1,381,665 3.59 Cooper-Standard Automotive, Inc., Additional Term B-1 Loan, 10/28/23 $ 1,399,800 1,008,250 4.50 CWGS Group LLC, Term Loan, 11/3/23 1,018,018 --------------- $ 2,417,818 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 82 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Homefurnishing Retail -- 0.0%+ 1,667,477 4.50 Serta Simmons Bedding LLC, Initial Term Loan (Second Lien), 10/21/23 $ 1,684,152 --------------- Total Retailing $ 5,410,502 --------------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 0.2% Agricultural Products -- 0.1% 1,967,900 3.25 Darling International, Inc., Term B USD Loan, 12/19/20 $ 1,986,965 --------------------------------------------------------------------------------------------------- Packaged Foods & Meats -- 0.1% 3,552,767 4.00 JBS USA LUX SA, 2015 Incremental Term Loan, 9/18/22 $ 3,586,814 1,887,433 5.29 Keurig Green Mountain, Inc., Term B USD Loan, 2/10/23 1,920,054 20,755 3.39 Pinnacle Foods Finance LLC, Tranche G Term Loan, 4/29/20 20,955 --------------- $ 5,527,823 --------------- Total Food, Beverage & Tobacco $ 7,514,788 --------------------------------------------------------------------------------------------------- HOUSEHOLD & PERSONAL PRODUCTS -- 0.0%+ Personal Products -- 0.0%+ 738,150 4.37 Revlon Consumer Products Corp., Initial Term B Loan, 7/22/23 $ 746,085 508,911 5.00 The Nature's Bounty Co., Dollar Term B Loan, 4/27/23 513,841 --------------- $ 1,259,926 --------------- Total Household & Personal Products $ 1,259,926 --------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.4% Health Care Supplies -- 0.1% 2,877,067 5.00 Kinetic Concepts, Inc., Dollar Term F Loan, 11/30/20 $ 2,889,294 --------------------------------------------------------------------------------------------------- Health Care Services -- 0.0%+ 916,345 4.25 Alliance HealthCare Services, Inc., Initial Term Loan, 6/3/19 $ 907,182 182,835 6.50 Ardent Legacy Acquisitions, Inc., Term Loan, 7/31/21 182,949 247,336 3.50 DaVita HealthCare Partners, Inc., Tranche B Loan (First Lien), 6/19/21 250,222 --------------- $ 1,340,353 --------------------------------------------------------------------------------------------------- Health Care Facilities -- 0.2% 504,481 4.16 CHS, Incremental 2018 Term F Loan, 12/31/18 $ 497,307 1,069,174 3.59 CHS, Incremental 2019 Term G Loan, 12/31/19 1,038,268 1,967,265 4.00 CHS, Incremental 2021 Term H Loan, 1/27/21 1,906,491 1,722,196 4.02 HCA, Inc., Tranche B-6 Term Loan, 3/8/23 1,744,126 The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 83 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Health Care Facilities -- (continued) 629,507 3.52 HCA, Inc., Tranche B-7 Term Loan, 2/5/24 $ 637,095 544,420 4.25 Kindred Healthcare, Inc., Tranche B Loan (First Lien), 4/10/21 544,874 1,166,188 6.01 Select Medical Corp., Series F Tranche B Term Loan, 3/4/21 1,189,511 1,737,710 5.00 Vizient, Inc., Term B-2 Loan, 2/11/23 1,767,395 --------------- $ 9,325,067 --------------------------------------------------------------------------------------------------- Health Care Technology -- 0.1% 1,582,961 3.50 Quintiles IMS, Inc., Term B Dollar Loan, 3/17/21 $ 1,596,812 --------------- Total Health Care Equipment & Services $ 15,151,526 --------------------------------------------------------------------------------------------------- PHARMACEUTICALS, BIOTECHNOLOGY & LIFE SCIENCES -- 0.2% Biotechnology -- 0.0%+ 734,655 3.50 Alkermes, Inc., 2021 Term Loan, 9/25/19 $ 737,869 --------------------------------------------------------------------------------------------------- Pharmaceuticals -- 0.1% 1,633,500 5.25 Concordia Healthcare Corp., Initial Dollar Term Loan, 10/20/21 $ 1,283,830 379,275 3.71 Grifols Worldwide Operations USA, Inc., U.S. Tranche B Term Loam, 4/1/21 382,375 841,349 3.34 Mallinckrodt International Finance SA, Initial Term B Loan, 3/6/21 844,579 1,330,279 3.18 RPI Finance Trust, Term B-5 Term Loan, 10/5/22 1,346,789 512,927 5.25 Valeant Pharmaceuticals International, Inc., Series C-2 Tranche B Term Loan, 12/11/19 513,034 935,882 5.50 Valeant Pharmaceuticals, Series F-1, 3/11/22 938,047 --------------- $ 5,308,654 --------------------------------------------------------------------------------------------------- Life Sciences Tools & Services -- 0.1% 1,243,703 6.01 Albany Molecular Research, Inc., Term Loan, 7/14/21 $ 1,260,804 1,405,016 3.75 Catalent Pharma Solutions, Dollar Term Loan, 5/20/21 1,417,164 --------------- $ 2,677,968 --------------- Total Pharmaceuticals, Biotechnology & Life Sciences $ 8,724,491 --------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 0.1% Other Diversified Financial Services -- 0.0%+ 426,452 4.75 Builders FirstSource, Inc., Initial Term Loan, 7/31/22 $ 430,770 1,209,268 3.64 Fly Funding II Sarl, Loan, 8/9/19 1,221,361 --------------- $ 1,652,131 --------------------------------------------------------------------------------------------------- Specialized Finance -- 0.1% 218,734 3.70 Avago Technologies Cayman Holdings, Ltd., Term B-3 Loan, 2/1/23 $ 222,084 The accompanying notes are an integral part of these financial statements. 84 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- Specialized Finance -- (continued) 1,469,790 3.50 Trans Union LLC, 2016 Incremental Term B-2 Commitment, 4/9/21 $ 1,481,995 --------------- $ 1,704,079 --------------- Total Diversified Financials $ 3,356,210 --------------------------------------------------------------------------------------------------- INSURANCE -- 0.2% Insurance Brokers -- 0.2% 1,146,613 4.50 NFP Corp., Term Loan B, 12/9/23 $ 1,159,274 1,143,690 4.50 National Financial Partners Corp., Tranche B Term Loan (First Lien), 7/1/20 1,150,005 4,490,177 4.25 USI Insurance Services LLC, Term B Loan, 12/30/19 4,513,561 --------------- $ 6,822,840 --------------- Total Insurance $ 6,822,840 --------------------------------------------------------------------------------------------------- REAL ESTATE -- 0.1% Retail REIT -- 0.0%+ 992,443 4.25 DTZ US Borrower LLC, 2015-1 Additional Term Loan (First Lien), 11/4/21 $ 997,509 --------------------------------------------------------------------------------------------------- Specialized REIT -- 0.1% 1,633,469 5.00 Communications Sales & Leasing, Inc., Term Loan, 10/16/22 $ 1,654,704 --------------- Total Real Estate $ 2,652,213 --------------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 0.1% IT Consulting & Other Services -- 0.0%+ 478,681 3.27 NXP B.V. (NXP Funding LLC), Tranche F Loan, 12/7/20 $ 481,822 412,366 7.00 TaxAct, Inc., Initial Term Loan, 12/31/22 415,458 --------------- $ 897,280 --------------------------------------------------------------------------------------------------- Data Processing & Outsourced Services -- 0.1% 217,563 3.76 First Data Corp., 2021C New Dollar Term Loan, 3/24/21 $ 220,341 1,282,811 3.76 First Data Corp., 2022C New Dollar Term Loan, 7/10/22 1,298,525 --------------- $ 1,518,866 --------------------------------------------------------------------------------------------------- Application Software -- 0.0%+ 350,000 6.25 STG-Fairway Acquisitions, Inc., Term Loan (First Lien), 6/30/22 $ 342,125 --------------- Total Software & Services $ 2,758,271 --------------------------------------------------------------------------------------------------- TECHNOLOGY HARDWARE & EQUIPMENT -- 0.0%+ Communications Equipment -- 0.0%+ 1,117,223 3.75 Ciena Corp., Term Loan, 7/15/19 $ 1,124,206 105,957 3.31 CommScope, Inc., Tranche 4 Term Loan, 1/14/18 106,520 --------------- $ 1,230,726 --------------- Total Technology Hardware & Equipment $ 1,230,726 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 85 Schedule of Investments | 12/31/16 (unaudited) (continued) --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- SEMICONDUCTORS & SEMICONDUCTOR EQUIPMENT -- 0.1% Semiconductor Equipment -- 0.0%+ 1,107,338 3.09 Sensata Technologies BV, Sixth Amendment Term Loan, 10/14/21 $ 1,116,248 --------------------------------------------------------------------------------------------------- Semiconductors -- 0.1% 396,957 3.75 Microsemi Corp., Closing Date Term B Loan, 12/17/22 $ 401,547 1,720,688 3.90 On Semiconductor Corp., Term Loan (First Lien), 3/31/23 1,743,390 --------------- $ 2,144,937 --------------- Total Semiconductors & Semiconductor Equipment $ 3,261,185 --------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 0.1% Integrated Telecommunication Services -- 0.1% 1,143,313 4.00 Cincinnati Bell, Inc., Tranche B Term Loan, 9/10/20 $ 1,149,148 1,193,429 4.68 GCI Holdings, Inc., New Term B Loan (2016), 2/2/22 1,195,666 --------------- $ 2,344,814 --------------------------------------------------------------------------------------------------- Wireless Telecommunication Services -- 0.0%+ 1,853,687 3.88 Altice US Finance I Corp., 2016 Refinancing Term Loan, 10/25/24 $ 1,878,016 --------------- Total Telecommunication Services $ 4,222,830 --------------------------------------------------------------------------------------------------- UTILITIES -- 0.2% Electric Utilities -- 0.1% 1,674,351 3.09 Calpine Construction Finance Co. LP, Term B-1 Loan, 5/3/20 $ 1,676,444 947,747 5.00 TPF II Power, LLC, Term Loan, 10/2/21 957,698 415,194 5.00 Vistra Operations Co., LLC, Initial Term C Loan, 8/4/23 420,968 1,820,466 5.00 Vistra Operations Co., LLC, Initial Term Loan, 8/4/23 1,837,533 --------------- $ 4,892,643 --------------------------------------------------------------------------------------------------- Independent Power Producers & Energy Traders -- 0.1% 1,000,000 5.00 Dynegy, Inc., Term Loan, 6/27/23 $ 1,013,929 291,025 4.00 Dynegy, Inc., Tranche B-2 Term Loan, 4/23/20 292,510 1,299,116 3.50 NRG Energy, Inc., Term Loan, 6/30/23 1,314,138 --------------- $ 2,620,577 --------------- Total Utilities $ 7,513,220 --------------------------------------------------------------------------------------------------- TOTAL SENIOR FLOATING RATE LOAN INTERESTS (Cost $130,462,286) $ 133,169,445 --------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 86 Pioneer Bond Fund | Semiannual Report | 12/31/16 --------------------------------------------------------------------------------------------------- Principal Floating Amount ($) Rate (b) Value --------------------------------------------------------------------------------------------------- TEMPORARY CASH INVESTMENTS -- 1.6% Repurchase Agreements -- 1.0% 19,210,000 $19,210,000 ScotiaBank, 0.50%, dated 12/30/16 plus accrued interest on 1/3/17 collateralized by the following $15,114,900 Freddie Mac Giant, 2.5%, 6/1/31 $4,295,385 Federal National Mortgage Association (ARM), 2.688%, 6/1/42 $185,004 Government National Mortgage Association, 2.0%, 3/20/42 $ 19,210,000 22,120,000 $22,120,000 RBC Capital Markets LLC, 0.43%, dated 12/30/16 plus accrued interest on 1/3/17 collateralized by the following: $293,345 Freddie Mac Giant, 3.0% -- 3.5%, 12/1/46 $8,946,268 Federal Home Loan Mortgage Corp., 2.758% -- 3.352%, 1/1/37-9/1/41 $2,631,995 Federal National Mortgage Association (ARM), 2.638% -- 3.71%, 1/1/41 -- 5/1/41 $8,159,025 Federal National Mortgage Association, 3.5% -- 4.0%, 5/1/44-12/1/46 $2,531,767 Government National Mortgage Association, 3.5%, 9/20/46 22,120,000 --------------- $ 41,330,000 --------------------------------------------------------------------------------------------------- Commercial Paper -- 0.1% 5,250,000 Prudential Funding Corp., Commercial Paper, 1/3/17 (c) $ 5,249,733 --------------------------------------------------------------------------------------------------- Certificates of Deposit -- 0.5% 10,186,000 1.16 Skandinaviska Enskilda Banken, Floating Rate Note, 12/24/17 $ 10,194,778 10,600,000 1.26 Sumitomo Mitsui, Floating Rate Note, 11/1/16 10,608,118 --------------- $ 20,802,896 --------------------------------------------------------------------------------------------------- TOTAL TEMPORARY CASH INVESTMENTS (Cost $67,365,848) $ 67,382,629 --------------------------------------------------------------------------------------------------- TOTAL INVESTMENT IN SECURITIES -- 104.4% (Cost $4,360,409,143) (a) $ 4,360,258,690 --------------------------------------------------------------------------------------------------- OTHER ASSETS & LIABILITIES -- (4.4)% $ (182,939,014) --------------------------------------------------------------------------------------------------- NET ASSETS -- 100.0% $ 4,177,319,676 =================================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 87 Schedule of Investments | 12/31/16 (unaudited) (continued) REIT Real Estate Investment Trust. + Rounds to less than 0.01%. (Perpetual) Security with no stated maturity date. (ARM) Adjustable Rate Mortgage. (Cat Bond) Catastrophe or event linked bond. At December 31, 2016 the value of these securities amounted to $102,631,190 or 2.5% of net assets. See Notes to Financial Statements -- 1F. REMICS Real Estate Mortgage Investment Conduits. (Step) Bond issued with an initial coupon rate which converts to a higher rate at a later date. (TBA) "To Be Announced" Securities. (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 30, 2016, the value of these securities amounted to $1,189,245,074 or 28.5% of net assets. ** Senior floating rate loan interests in which the Fund invests generally pay interest at rates that are periodically redetermined by reference to a base lending rate plus a premium. These base lending rates are generally (i) the lending rate offered by one or more major European banks, such as LIBOR (London InterBank Offered Rate), (ii) the prime rate offered by one or more major U.S. banks, (iii) the rate of a certificate of deposit or (iv) other base lending rates used by commercial lenders. The rate shown is the coupon rate at period end. (a) At December 31, 2016, the net unrealized depreciation on investments based on cost for federal income tax purposes of $4,366,718,399 was as follows: Aggregate gross unrealized appreciation for all investments in which there is an excess of value over tax cost $ 45,472,089 Aggregate gross unrealized depreciation for all investments in which there is an excess of tax cost over value (51,931,798) ------------ Net unrealized depreciation $ (6,459,709) ============ (b) Debt obligation with a variable interest rate. Rate shown is rate at end of period. (c) Security issued with a zero coupon. Income is earned through accretion of discount. (d) Security is valued using fair value methods (other than prices supplied by independent pricing services or broker-dealers). See Notes to Financial Statements -- Note 1A. (e) Structured reinsurance investment. At December 31, 2016, the value of these securities amounted to $65,897,677 or 1.6% of net assets. See Notes to Financial Statements -- Note 1F. (f) Rate to be determined. Purchases and sales of securities (excluding temporary cash investments) for the six months ended December 31, 2016 were as follows: -------------------------------------------------------------------- Purchases Sales -------------------------------------------------------------------- Long-Term U.S. Government Securities $280,906,435 $117,953,650 Other Long-Term Securities 726,264,381 831,740,759 The accompanying notes are an integral part of these financial statements. 88 Pioneer Bond Fund | Semiannual Report | 12/31/16 The Fund is permitted to engage in purchase and sale transactions ("cross trades") with certain funds and accounts for which Pioneer Investment Management, Inc. 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, 2016, the Fund engaged in purchases and sales pursuant to these procedures amounting to $91,277,110 and $7,937,725, respectively, resulting in a net realized gain (loss) of $94,838. Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below. Level 1 - quoted prices in active markets for identical securities. Level 2 - other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk, etc.) See Notes to Financial Statements -- Note 1A. Level 3 - significant unobservable inputs (including the Fund's own assumptions in determining fair value of investments) See Notes to Financial Statements -- Note 1A. The following is a summary of the inputs used as of December 31, 2016, in valuing the Fund's assets: ------------------------------------------------------------------------------------------------- Level 1 Level 2 Level 3 Total ------------------------------------------------------------------------------------------------- Convertible Preferred Stock $24,268,924 $ -- $ -- $ 24,268,924 Asset Backed Securities -- 175,735,744 -- 175,735,744 Collateralized Mortgage Obligations -- 841,254,351 -- 841,254,351 Corporate Bonds Diversified Financials Other Diversified Financial Services -- 13,613,533 1,246,369 14,859,902 Insurance Reinsurance -- 89,865,080 71,161,687 161,026,767 All Other Corporate Bonds -- 1,332,431,114 -- 1,332,431,114 U.S. Government Agency Obligations -- 1,555,944,926 -- 1,555,944,926 Foreign Government Bonds -- 5,761,487 -- 5,761,487 Municipal Bonds -- 48,423,401 -- 48,423,401 Senior Floating Rate Loan Interests -- 133,169,445 -- 133,169,445 Commercial Paper -- 5,249,733 -- 5,249,733 Repurchase Agreements -- 41,330,000 -- 41,330,000 Certificates of Deposit -- 20,802,896 -- 20,802,896 ------------------------------------------------------------------------------------------------- Total $24,268,924 $ 4,263,581,710 $72,408,056 $4,360,258,690 ================================================================================================= Other Financial Instruments Net unrealized depreciation on Futures Contracts $ 4,182,036 $ -- $ -- $ 4,182,036 ------------------------------------------------------------------------------------------------- Total Other Financial Instruments $ 4,182,036 $ -- $ -- $ 4,182,036 ================================================================================================= The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 89 Schedule of Investments | 12/31/16 (unaudited) (continued) Following is a reconciliation of assets using significant unobservable inputs (Level 3): -------------------------------------------------------------------------------- Corporate Bonds -------------------------------------------------------------------------------- Balance as of 6/30/16 $61,501,798 Realized gain (loss)(1) 2,055 Change in unrealized appreciation (depreciation)(2) 3,995,894 Net purchases 13,770,962 Net sales(3) (6,862,653) Transfers in between Level 3* -- -------------------------------------------------------------------------------- Balance as of 12/31/16 $72,408,056 ================================================================================ (1) Realized gain (loss) on these securities is included in the net realized gain (loss) from investments in the Statement of Operations. (2) Unrealized appreciation (depreciation) on these securities is included in the change in unrealized appreciation (depreciation) on investments in the Statement of Operations. (3) Amount represents return of capital on Insurance-Linked Securities. * Transfers are calculated on the beginning of period values. During the six months ended December 31, 2016, there were no transfers between Levels 1, 2 and 3. Net change in unrealized appreciation (depreciation) of investments still held as of 12/31/16 $4,152,059 ---------- The accompanying notes are an integral part of these financial statements. 90 Pioneer Bond Fund | Semiannual Report | 12/31/16 Statement of Assets and Liabilities | 12/31/16 (unaudited) ASSETS: Investment in securities (cost $4,360,409,143) $4,360,258,690 Cash 77,793,497 Restricted cash* 5,901,702 Receivables -- Investment securities sold 42,147,538 Fund shares sold 28,726,511 Interest 23,329,645 Due from Pioneer Investment Management, Inc. 496,794 Futures receivable 252,171 Other assets 136,116 -------------------------------------------------------------------------------------- Total Assets $4,539,042,664 ====================================================================================== LIABILITIES: Payables -- Investment securities purchased $ 314,955,098 Fund shares repurchased 40,349,127 Dividends 3,610,574 Variation margin on futures contracts 1,077,313 Due to affiliates 186,186 Accrued expenses 1,544,690 -------------------------------------------------------------------------------------- Total Liabilities $ 361,722,988 ====================================================================================== NET ASSETS: Paid-in capital $4,190,362,655 Distributions in excess of net investment income (10,813,572) Accumulated net realized loss on investments and futures contracts (6,260,990) Net unrealized depreciation on investments (150,453) Net unrealized appreciation on futures contracts 4,182,036 -------------------------------------------------------------------------------------- Net Assets $4,177,319,676 ====================================================================================== NET ASSET VALUE PER SHARE: (No par value, unlimited number of shares authorized) Class A (based on $1,186,677,093/123,323,737 shares) $ 9.62 Class C (based on $119,281,758/12,537,376 shares) $ 9.51 Class K (based on $388,716,491/40,412,269 shares) $ 9.62 Class R (based on $166,500,268/17,147,913 shares) $ 9.71 Class Y (based on $2,316,144,066/242,989,033 shares) $ 9.53 MAXIMUM OFFERING PRICE: Class A ($9.62 / 95.5% ) $ 10.07 ====================================================================================== * Represents restricted cash deposited at the counterparty for derivative contracts. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 91 Statement of Operations (unaudited) For the Six Months Ended 12/31/16 INVESTMENT INCOME: Interest $ 67,087,296 Dividends 525,931 --------------------------------------------------------------------------------------------- Total investment income $ 67,613,227 ============================================================================================= EXPENSES: Management fees $ 8,233,886 Transfer agent fees Class A 1,660,615 Class C 73,912 Class K 1,071 Class R 220,347 Class Y 1,482,420 Distribution fees Class A 1,503,083 Class C 664,537 Class R 408,885 Shareholder communications expense 33,198 Administrative expense 655,988 Custodian fees 145,565 Registration fees 187,272 Professional fees 92,480 Printing expense 34,027 Fees and expenses of nonaffiliated Trustees 93,263 Miscellaneous 243,271 --------------------------------------------------------------------------------------------- Total expenses $ 15,733,820 Less fees waived and expenses reimbursed by Pioneer Investment Management, Inc. (1,270,433) --------------------------------------------------------------------------------------------- Net expenses $ 14,463,387 --------------------------------------------------------------------------------------------- Net investment income $ 53,149,840 --------------------------------------------------------------------------------------------- REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS AND FUTURES CONTRACTS: Net realized gain (loss) on: Investments $ 16,284,783 Futures contracts 10,339,991 $ 26,624,774 --------------------------------------------------------------------------------------------- Change in net unrealized appreciation (depreciation) on: Investments $ (95,375,043) Futures contracts 21,484,834 $ (73,890,209) --------------------------------------------------------------------------------------------- Net realized and unrealized gain (loss) on investments and futures contracts $ (47,265,435) --------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 5,884,405 ============================================================================================= The accompanying notes are an integral part of these financial statements. 92 Pioneer Bond Fund | Semiannual Report | 12/31/16 Statements of Changes in Net Assets --------------------------------------------------------------------------------------------- Six Months Ended 12/31/16 Year Ended (unaudited) 6/30/16 --------------------------------------------------------------------------------------------- FROM OPERATIONS: Net investment income $ 53,149,840 $ 93,820,785 Net realized gain (loss) on investments, futures contracts and swap contracts 26,624,774 (6,243,404) Change in net unrealized appreciation (depreciation) on investments, futures contracts and swap contracts (73,890,209) 59,491,707 --------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 5,884,405 $ 147,069,088 --------------------------------------------------------------------------------------------- DISTRIBUTIONS TO SHAREOWNERS: Net investment income: Class A ($0.15 and $0.27 per share, respectively) $ (18,747,182) $ (30,130,801) Class C ($0.12 and $0.20 per share, respectively) (1,576,036) (2,503,533) Class K ($0.17 and $0.31 per share, respectively) (6,533,751) (8,577,930) Class R ($0.14 and $0.25 per share, respectively) (2,354,580) (3,514,545) Class Y ($0.17 and $0.29 per share, respectively) (38,436,789) (56,701,826) Class Z* ($0.00 and $0.03 per share, respectively) -- (184,669) Net realized gains Class A ($0.00 and $0.02 per share, respectively) -- (2,297,989) Class C ($0.00 and $0.02 per share, respectively) -- (256,680) Class K ($0.00 and $0.02 per share, respectively) -- (632,921) Class R ($0.00 and $0.02 per share, respectively) -- (289,802) Class Y ($0.00 and $0.02 per share, respectively) -- (3,842,000) --------------------------------------------------------------------------------------------- Total distributions to shareowners $ (67,648,338) $ (108,932,696) --------------------------------------------------------------------------------------------- FROM FUND SHARE TRANSACTIONS Net proceeds from sale or exchange of shares $ 860,272,534 $ 1,673,600,863 Shares issued in reorganization -- 103,289,215 Reinvestment of distributions 51,996,631 82,738,583 Cost of shares repurchased (618,312,826) (1,113,066,216) --------------------------------------------------------------------------------------------- Net increase in net assets resulting from Fund share transactions $ 293,956,339 $ 746,562,445 --------------------------------------------------------------------------------------------- Net increase in net assets $ 232,192,406 $ 784,698,837 NET ASSETS: Beginning of period $3,945,127,270 $ 3,160,428,433 --------------------------------------------------------------------------------------------- End of period $4,177,319,676 $ 3,945,127,270 --------------------------------------------------------------------------------------------- Undistributed (distributions in excess of) net investment income $ (10,813,572) $ 3,684,926 ============================================================================================= * Class Z shares converted to Class Y shares on August 7, 2015. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 93 Statements of Changes in Net Assets (continued) ------------------------------------------------------------------------------------------------ Six Months Six Months Ended Ended 12/31/16 12/31/16 Year Ended Year Ended Shares Amount 6/30/16 6/30/16 (unaudited) (unaudited) Shares Amount ------------------------------------------------------------------------------------------------ Class A Shares sold 19,966,849 $ 195,120,799 39,520,516 $ 381,082,323 Shares issued in reorganization -- -- 8,687,202 83,223,137 Reinvestment of distributions 1,357,929 13,239,826 2,429,101 23,363,971 Less shares repurchased (18,636,607) (181,842,109) (37,895,940) (364,153,575) ------------------------------------------------------------------------------------------------ Net increase 2,688,171 $ 26,518,516 12,740,879 $ 123,515,856 ================================================================================================ Class C Shares sold 969,095 $ 9,373,937 3,590,552 $ 34,068,700 Shares issued in reorganization -- -- 1,566,042 14,846,083 Reinvestment of distributions 103,476 997,416 171,403 1,630,270 Less shares repurchased (2,444,041) (23,466,959) (3,349,111) (31,797,823) ------------------------------------------------------------------------------------------------ Net increase (decrease) (1,371,470) $ (13,095,606) 1,978,886 $ 18,747,230 ================================================================================================ Class K Shares sold 9,898,567 $ 96,741,440 22,645,768 $ 217,799,806 Reinvestment of distributions 330,413 3,219,513 418,685 4,026,426 Less shares repurchased (4,658,204) (45,514,447) (6,730,820) (64,517,198) ------------------------------------------------------------------------------------------------ Net increase 5,570,776 $ 54,446,506 16,333,633 $ 157,309,034 ================================================================================================ Class R Shares sold 3,117,023 $ 30,693,371 7,857,134 $ 76,161,586 Reinvestment of distributions 190,141 1,870,389 332,632 3,227,431 Less shares repurchased (2,002,845) (19,733,775) (4,303,242) (41,715,627) ------------------------------------------------------------------------------------------------ Net increase 1,304,319 $ 12,829,985 3,886,524 $ 37,673,390 ================================================================================================ Class Y Shares sold 54,744,846 $ 528,342,987 101,127,077 $ 963,277,766 Shares issued in reorganization -- -- 550,053 5,219,995 Reinvestment of distributions 3,382,380 32,669,487 5,283,365 50,341,027 Less shares repurchased (36,019,368) (347,755,536) (57,493,210) (547,987,984) ------------------------------------------------------------------------------------------------ Net increase 22,107,858 $ 213,256,938 49,467,285 $ 470,850,804 ================================================================================================ Class Z* Shares sold -- $ -- 125,036 $ 1,210,682 Reinvestment of distributions -- -- 15,392 149,458 Less shares repurchased -- -- (6,477,629) (62,894,009) ------------------------------------------------------------------------------------------------ Net decrease -- $ -- (6,337,201) $ (61,533,869) ================================================================================================ * Class Z shares converted to Class Y shares on August 7, 2015. The accompanying notes are an integral part of these financial statements. 94 Pioneer Bond Fund | Semiannual Report | 12/31/16 Financial Highlights ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/16 Ended Ended Ended Ended Ended (unaudited) 6/30/16 6/30/15 6/30/14 6/30/13 6/30/12 ------------------------------------------------------------------------------------------------------------------------------------ Class A Net asset value, beginning of period $ 9.76 $ 9.68 $ 9.88 $ 9.67 $ 9.73 $ 9.66 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.12(a) $ 0.25(a) $ 0.27 $ 0.35 $ 0.38 $ 0.42 Net realized and unrealized gain (loss) on investments (0.11) 0.12 (0.14) 0.24 (0.07) 0.13 ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 0.01 $ 0.37 $ 0.13 $ 0.59 $ 0.31 $ 0.55 ------------------------------------------------------------------------------------------------------------------------------------ Distribution to shareowners: Net investment income $ (0.15) $ (0.27) $ (0.29) $ (0.38) $ (0.37) $ (0.43) Net realized gain -- (0.02) (0.04) -- -- (0.05) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.15) $ (0.29) $ (0.33) $ (0.38) $ (0.37) $ (0.48) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ (0.14) $ 0.08 $ (0.20) $ 0.21 $ (0.06) $ 0.07 ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.62 $ 9.76 $ 9.68 $ 9.88 $ 9.67 $ 9.73 ==================================================================================================================================== Total return* 0.13% 3.93% 1.32% 6.19% 3.21% 5.91% Ratio of net expenses to average net assets 0.85%** 0.85% 0.85% 0.85% 0.85% 0.85% Ratio of net investment income (loss) to average net assets 2.43%** 2.58% 2.68% 3.52% 3.77% 4.35% Portfolio turnover rate 48%** 43% 81% 41% 28% 21% Net assets, end of period (in thousands) $1,186,677 $1,177,941 $1,044,659 $706,962 $565,569 $453,772 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 1.00%** 0.98% 0.93% 1.00% 1.01% 1.03% Net investment income (loss) to average net assets 2.29%** 2.45% 2.60% 3.37% 3.61% 4.17% ==================================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. ** Annualized. (a) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 95 Financial Highlights (continued) ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/16 Ended Ended Ended Ended Ended (unaudited) 6/30/16 6/30/15 6/30/14 6/30/13 6/30/12 ------------------------------------------------------------------------------------------------------------------------------------ Class C Net asset value, beginning of period $ 9.66 $ 9.57 $ 9.77 $ 9.57 $ 9.63 $ 9.55 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.08(a) $ 0.17(a) $ 0.19 $ 0.26 $ 0.29 $ 0.33 Net realized and unrealized gain (loss) on investments (0.11) 0.14 (0.14) 0.23 (0.06) 0.15 ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ (0.03) $ 0.31 $ 0.05 $ 0.49 $ 0.23 $ 0.48 ------------------------------------------------------------------------------------------------------------------------------------ Distribution to shareowners: Net investment income $ (0.12) $ (0.20) $ (0.21) $ (0.29) $ (0.29) $ (0.35) Net realized gain -- (0.02) (0.04) -- -- (0.05) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.12) $ (0.22) $ (0.25) $ (0.29) $ (0.29) $ (0.40) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ (0.15) $ 0.09 $ (0.20) $ 0.20 $ (0.06) $ 0.08 ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.51 $ 9.66 $ 9.57 $ 9.77 $ 9.57 $ 9.63 ==================================================================================================================================== Total return* (0.35)% 3.28% 0.49% 5.20% 2.33% 5.12% Ratio of net expenses to average net assets 1.59%** 1.60% 1.63% 1.73% 1.72% 1.73% Ratio of net investment income (loss) to average net assets 1.69%** 1.84% 1.89% 2.69% 2.93% 3.47% Portfolio turnover rate 48%** 43% 81% 41% 28% 21% Net assets, end of period (in thousands) $ 119,282 $ 134,299 $ 114,222 $ 73,224 $ 87,763 $ 93,737 ==================================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. Total return would be reduced if sales charges were taken into account. ** Annualized. (a) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 96 Pioneer Bond Fund | Semiannual Report | 12/31/16 ----------------------------------------------------------------------------------------------------------------------------- Six Months Ended Year Year Year 12/20/12 12/31/16 Ended Ended Ended to (unaudited) 6/30/16 6/30/15 6/30/14 6/30/13 ----------------------------------------------------------------------------------------------------------------------------- Class K Net asset value, beginning of period $ 9.76 $ 9.68 $ 9.87 $ 9.67 $ 9.94 ----------------------------------------------------------------------------------------------------------------------------- Increase (decrease) from investment operations: Net investment income (loss) $ 0.14(b) $ 0.29(b) $ 0.30 $ 0.40 $ 0.20 Net realized and unrealized gain (loss) on investments (0.11) 0.12 (0.13) 0.20 (0.26) ----------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) from investment operations $ 0.03 $ 0.41 $ 0.17 $ 0.60 $ (0.06) ----------------------------------------------------------------------------------------------------------------------------- Distribution to shareowners: Net investment income $ (0.17) $ (0.31) $ (0.32) $ (0.40) $ (0.21) Net realized gain -- (0.02) (0.04) -- -- ----------------------------------------------------------------------------------------------------------------------------- Total distributions $ (0.17) $ (0.33) $ (0.36) $ (0.40) $ (0.21) ----------------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ (0.14) $ 0.08 $ (0.19) $ 0.20 $ (0.27) ----------------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.62 $ 9.76 $ 9.68 $ 9.87 $ 9.67 ============================================================================================================================= Total return* 0.32% 4.32% 1.80% 6.37% (0.61)%(a) Ratio of net expenses to average net assets 0.47%** 0.47% 0.47% 0.56% 0.57%** Ratio of net investment income (loss) to average net assets 2.81%** 2.98% 3.03% 3.59% 3.86%** Portfolio turnover rate 48%** 43% 81% 41% 28% Net assets, end of period (in thousands) $ 388,716 $ 340,096 $ 179,135 $ 4,398 $ 10 ============================================================================================================================= * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. ** Annualized. (a) Not Annualized. (b) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 97 Financial Highlights (continued) ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/16 Ended Ended Ended Ended Ended (unaudited) 6/30/16 6/30/15 6/30/14 6/30/13 6/30/12 ------------------------------------------------------------------------------------------------------------------------------------ Class R Net asset value, beginning of period $ 9.85 $ 9.77 $ 9.97 $ 9.76 $ 9.82 $ 9.74 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.11(a) $ 0.23(a) $ 0.25 $ 0.32 $ 0.34 $ 0.39 Net realized and unrealized gain (loss) on investments (0.11) 0.12 (0.15) 0.23 (0.06) 0.14 ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ -- $ 0.35 $ 0.10 $ 0.55 $ 0.28 $ 0.53 ------------------------------------------------------------------------------------------------------------------------------------ Distribution to shareowners: Net investment income $ (0.14) $ (0.25) $ (0.26) $ (0.34) $ (0.34) $ (0.40) Net realized gain -- (0.02) (0.04) -- -- (0.05) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.14) $ (0.27) $ (0.30) $ (0.34) $ (0.34) $ (0.45) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ (0.14) $ 0.08 $ (0.20) $ 0.21 $ (0.06) $ 0.08 ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.71 $ 9.85 $ 9.77 $ 9.97 $ 9.76 $ 9.82 ==================================================================================================================================== Total return* 0.02% 3.66% 1.06% 5.75% 2.80% 5.58% Ratio of net expenses to average net assets 1.10%** 1.10% 1.10% 1.25% 1.25% 1.25% Ratio of net investment income (loss) to average net assets 2.18%** 2.33% 2.43% 3.12% 3.36% 3.94% Portfolio turnover rate 48%** 43% 81% 41% 28% 21% Net assets, end of period (in thousands) $ 166,500 $ 156,110 $ 116,815 $ 48,264 $ 31,169 $ 23,892 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 1.24%** 1.21% 1.21% 1.32% 1.35% 1.35% Net investment income (loss) to average net assets 2.04%** 2.22% 2.32% 3.05% 3.26% 3.84% ==================================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. ** Annualized. (a) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. 98 Pioneer Bond Fund | Semiannual Report | 12/31/16 ------------------------------------------------------------------------------------------------------------------------------------ Six Months Ended Year Year Year Year Year 12/31/16 Ended Ended Ended Ended Ended (unaudited) 6/30/16 6/30/15 6/30/14 6/30/13 6/30/12 ------------------------------------------------------------------------------------------------------------------------------------ Class Y Net asset value, beginning of period $ 9.67 $ 9.59 $ 9.79 $ 9.58 $ 9.65 $ 9.57 ------------------------------------------------------------------------------------------------------------------------------------ Increase (decrease) from investment operations: Net investment income (loss) $ 0.13(a) $ 0.27(a) $ 0.30 $ 0.36 $ 0.39 $ 0.44 Net realized and unrealized gain (loss) on investments (0.10) 0.12 (0.15) 0.24 (0.07) 0.14 ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) from investment operations $ 0.03 $ 0.39 $ 0.15 $ 0.60 $ 0.32 $ 0.58 ------------------------------------------------------------------------------------------------------------------------------------ Distribution to shareowners: Net investment income $ (0.17) $ (0.29) $ (0.31) $ (0.39) $ (0.39) $ (0.45) Net realized gain -- (0.02) (0.04) -- -- (0.05) ------------------------------------------------------------------------------------------------------------------------------------ Total distributions $ (0.17) $ (0.31) $ (0.35) $ (0.39) $ (0.39) $ (0.50) ------------------------------------------------------------------------------------------------------------------------------------ Net increase (decrease) in net asset value $ (0.14) $ 0.08 $ (0.20) $ 0.21 $ (0.07) $ 0.08 ------------------------------------------------------------------------------------------------------------------------------------ Net asset value, end of period $ 9.53 $ 9.67 $ 9.59 $ 9.79 $ 9.58 $ 9.65 ==================================================================================================================================== Total return* 0.26% 4.22% 1.59% 6.41% 3.34% 6.27% Ratio of net expenses to average net assets 0.58%** 0.58% 0.58% 0.66% 0.66% 0.65% Ratio of net investment income (loss) to average net assets 2.70%** 2.85% 2.95% 3.72% 3.97% 4.55% Portfolio turnover rate 48%** 43% 81% 41% 28% 21% Net assets, end of period (in thousands) $2,316,144 $2,136,681 $1,644,161 $871,801 $916,182 $847,072 Ratios with no waiver of fees and assumption of expenses by PIM and no reduction for fees paid indirectly: Total expenses to average net assets 0.60%** 0.59% 0.58% 0.66% 0.66% 0.65% Net investment income (loss) to average net assets 2.68%** 2.84% 2.95% 3.72% 3.97% 4.55% ==================================================================================================================================== * Assumes initial investment at net asset value at the beginning of each period, reinvestment of all distributions and the complete redemption of the investment at net asset value at the end of each period. ** Annualized. (a) The per share data presented above is based on the average shares outstanding for the period presented. The accompanying notes are an integral part of these financial statements. Pioneer Bond Fund | Semiannual Report | 12/31/16 99 Notes to Financial Statements | 12/31/16 (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. Class Z shares were converted to Class Y shares on August 7, 2015. Each class of shares represents an interest in the same portfolio of investments of the Fund and has identical rights (based on relative net asset values) to assets and liquidation proceeds. Share classes can bear different rates of class-specific fees and expenses such as transfer agent and distribution fees. Differences in class-specific fees and expenses will result in differences in net investment income and, therefore, the payment of different dividends from net investment income earned by each class. The Amended and Restated Declaration of Trust of the Fund gives the Board of Trustees the flexibility to specify either per-share voting or dollar-weighted voting when submitting matters for shareholder approval. Under per-share voting, each share of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a shareholder's voting power is determined not by the number of shares owned, but by the dollar value of the shares on the record date. Each share class has exclusive voting rights with respect to matters affecting only that class, including with respect to the distribution plan for that class. There is no distribution plan for Class K or Class Y shares. The Fund's financial statements have been prepared in conformity with U.S. generally accepted accounting principles (U.S. GAAP) that require the management of the Fund to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of income, expenses and gains and losses on investments during the reporting period. Actual results could differ from those estimates. The Fund is an investment company and follows investment company accounting and reporting guidance under U.S. GAAP. The following is a summary of significant accounting policies followed by the Fund in the preparation of its financial statements: 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. 100 Pioneer Bond Fund | Semiannual Report | 12/31/16 Fixed income securities are valued by using prices supplied by independent pricing services, which consider such factors as market prices, market events, quotations from one or more brokers, Treasury spreads, yields, maturities and ratings, or may use a pricing matrix or other fair value methods or techniques to provide an estimated value of the security or instrument. A pricing matrix is a means of valuing a debt security on the basis of current market prices for other debt securities, historical trading patterns in the market for fixed income securities and/or other factors. Non-U.S. debt securities that are listed on an exchange will be valued at the bid price obtained from an independent third party pricing service. When independent third party pricing services are unable to supply prices, or when prices or market quotations are considered to be unreliable, the value of that security may be determined using quotations from one or more broker-dealers. Loan interests are valued in accordance with guidelines established by the Board of Trustees at the mean between the last available bid and asked prices from one or more brokers or dealers as obtained from Loan Pricing Corporation, an independent third party pricing service. If price information is not available from Loan Pricing Corporation, or if the price information is deemed to be unreliable, price information will be obtained from an alternative loan interest pricing service. If no reliable price quotes are available from either the primary or alternative pricing service, broker quotes will be solicited. Event-linked bonds or catastrophe bonds are valued at the bid price obtained from an independent third party pricing service. Other insurance linked securities (including sidecars, collateralized reinsurance and industry loss warranties) may be valued at the bid price obtained from an independent pricing service, or through a third party using a pricing matrix, insurance industry valuation models, or other fair value methods or techniques to provide an estimated value of the instrument. 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. Swap contracts, including interest rate swaps, caps and floors (other than centrally cleared swap contracts) are valued at the dealer quotations obtained from reputable International Swap Dealer association members. Centrally cleared swaps are valued at the daily settlement price provided by the central clearing counterparty. Pioneer Bond Fund | Semiannual Report | 12/31/16 101 Futures contracts are generally valued at the closing settlement price established by the exchange on which they are traded. Repurchase agreements are valued at par. Cash may include overnight time deposits at approved financial institutions. Securities or loan interests for which independent pricing services or broker-dealers are unable to supply prices or for which market prices and/or quotations are not readily available or are considered to be unreliable are valued by a fair valuation team comprised of certain personnel of Pioneer Investment Management, Inc. (PIM), the Fund's investment adviser and a wholly owned indirect subsidiary of UniCredit S.p.A. (UniCredit), pursuant to procedures adopted by the Fund's Board of Trustees. PIM's fair valuation team uses fair value methods approved by the Valuation Committee of the Board of Trustees. PIM's fair valuation team is responsible for monitoring developments that may impact fair valued securities and for discussing and assessing fair values on an ongoing basis, and at least quarterly, with the Valuation Committee of the Board of Trustees. Inputs used when applying fair value methods to value a security may include credit ratings, the financial condition of the company, current market conditions and comparable securities. The Fund may use fair value methods 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, 2016, one security was valued using fair value methods (in addition to securities valued using prices supplied by independent pricing services, broker-dealers or using a third party insurance industry pricing model) representing less than 0.1% of net assets. B. Investment Income and Transactions Principal amounts of mortgage-backed securities, asset-backed securities and corporate bonds 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. 102 Pioneer Bond Fund | Semiannual Report | 12/31/16 Dividend income is recorded on the ex-dividend date, except that certain dividends from foreign securities where the ex-dividend date may have passed are recorded as soon as the Fund becomes aware of the ex-dividend data in the exercise of reasonable diligence. Interest income, including interest on income bearing cash accounts, is recorded on the accrual basis. Dividend and interest income are reported net of unrecoverable foreign taxes withheld at the applicable country rates. Security transactions are recorded as of trade date. Gains and losses on sales of investments are calculated on the identified cost method for both financial reporting and federal income tax purposes. C. Federal Income Taxes It is the Fund's policy to comply with the requirements of the Internal Revenue Code applicable to regulated investment companies and to distribute all of its net taxable income and net realized capital gains, if any, to its shareowners. Therefore, no provision for federal income taxes is required. As of June 30, 2016, the Fund did not accrue any interest or penalties with respect to uncertain tax positions, which, if applicable, would be recorded as an income tax expense in the Statement of Operations. Tax returns filed within the prior three years remain subject to examination by Federal and State tax authorities. The amount and character of income and capital gain distributions to shareowners are determined in accordance with federal income tax rules, which may differ from U.S. GAAP. Distributions in excess of net investment income or net realized gains are temporary overdistributions for financial statement purposes resulting from differences in the recognition or classification of income or distributions for financial statement and tax purposes. Capital accounts within the financial statements are adjusted for permanent book/tax differences to reflect tax character, but are not adjusted for temporary differences. 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, 2016 was as follows: --------------------------------------------------------------------------- 2016 --------------------------------------------------------------------------- Distributions paid from: Ordinary income $101,613,304 Long-term capital gain 7,319,392 --------------------------------------------------------------------------- Total $108,932,696 =========================================================================== Pioneer Bond Fund | Semiannual Report | 12/31/16 103 The following shows the components of distributable earnings on a federal income tax basis at June 30, 2016: --------------------------------------------------------------------------- 2016 --------------------------------------------------------------------------- Distributable earnings: Undistributed ordinary income $ 8,887,736 Capital Loss Carryforward (47,095,232) Current year dividends payable (1,986,884) Net unrealized appreciation 88,915,334 --------------------------------------------------------------------------- Total $ 48,720,954 =========================================================================== 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, the tax treatment of premium and amortization and the mark-to-market of futures contracts. D. Fund Shares The Fund records sales and repurchases of its shares as of trade date. Pioneer Funds Distributor, Inc. (PFD), the principal underwriter for the Fund and a wholly owned indirect subsidiary of UniCredit S.p.A. (UniCredit), earned $34,894 in underwriting commissions on the sale of Class A shares during the six months ended December 31, 2016. E. Class Allocations Income, common expenses, and realized and unrealized gains and losses are calculated at the Fund level and allocated daily to each class of shares based on its respective percentage of adjusted net assets at the beginning of the day. Distribution fees are calculated based on the average daily net asset value attributable to Class A, Class C, and Class R shares of the Fund, respectively (see Note 4). Class K and Class Y shares do not pay distribution fees. All expenses and fees paid to the Fund's transfer agent, for its services are allocated among the classes of shares based on the number of accounts in each class and the ratable allocation of related out-of-pocket expenses (see Note 3). 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. 104 Pioneer Bond Fund | Semiannual Report | 12/31/16 F. Insurance-Linked Securities (ILS) The Fund invests in event-linked bonds. Event-linked bonds are floating rate debt obligations for which the return of principal and the payment of interest are contingent on the non-occurrence of a pre-defined "trigger" event, such as a hurricane or an earthquake of a specific magnitude. The trigger event's magnitude may be based on losses to a company or industry, industry indexes or readings of scientific instruments, or may be based on specified actual losses. If a trigger event, as defined within the terms of an event-linked bond occurs, the Fund may lose a portion or all of its accrued interest and/or principal invested in such event-linked bond. The Fund is entitled to receive principal and interest payments so long as no trigger event occurs of the description and magnitude specified by the instrument. In addition to the specified trigger events, event-linked bonds may expose the Fund to other risks, including but not limited to issuer (credit) default, adverse regulatory or jurisdictional interpretations and adverse tax consequences. The Fund's investments in ILS may include special purpose vehicles ("SPVs") or similar instruments structured to comprise a portion of a reinsurer's catastrophe-oriented business, known as quota share instruments (sometimes referred to as reinsurance sidecars), or to provide reinsurance relating to specific risks to insurance or reinsurance companies through a collateralized instrument, known as collateralized reinsurance. Structured reinsurance investments also may include industry loss warranties ("ILWs"). A traditional ILW takes the form of a bilateral reinsurance contract, but there are also products that take the form of derivatives, collateralized structures, or exchange traded instruments. Structured reinsurance investments, including quota share instruments, collateralized reinsurance investments and ILWs, generally are subject to the same risks as event-linked bonds. In addition, where the instruments are based on the performance of underlying reinsurance contracts, the Fund has limited transparency into the individual underlying contracts and therefore must rely upon the risk assessment and sound underwriting practices of the issuer. Accordingly, it may be more difficult for PIM to fully evaluate the underlying risk profile of the Fund's structured reinsurance investments and therefore the Fund's assets are placed at greater risk of loss than if PIM had more complete information. Structured reinsurance instruments generally will be considered illiquid securities by the Fund. These securities may be difficult to purchase, sell or unwind. Illiquid securities also may be difficult to value. If the Fund is forced to sell an illiquid asset, the Fund may be forced to sell at a loss. Pioneer Bond Fund | Semiannual Report | 12/31/16 105 G. Risks Interest rates in the U.S. recently have been historically low, so the Fund faces a heightened risk that interest rates may rise. A general rise in interest rates may cause investors to move out of fixed income securities on a large scale, which could adversely affect the price and liquidity of fixed income securities and could also result in increased redemptions from the Fund. At times, the Fund's investments may represent industries or industry sectors that are interrelated or have common risks, making the Fund more susceptible to any economic, political, or regulatory developments or other risks affecting those industries and sectors. The Fund's prospectus contains unaudited information regarding the Fund's principal risks. Please refer to that document when considering the Fund's principal risks. H. 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, 2016 was $5,985,450 and is included in "Restricted Cash" in the Statement of Assets and Liabilities. Subsequent payments for futures contracts ("variation margin") are paid or received by the Fund, depending on the daily fluctuation in the value of the contracts, and are recorded by the Fund as unrealized appreciation or depreciation. When the contract is closed, the Fund realizes a 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. The use of futures contracts are subject to market risk, interest rate risk and currency exchange rate risk. Changes in value of the contracts may not directly correlate to the changes in value of the underlying securities. The average value of contracts open during the six months ended December 31, 2016 was $(623,080,913). 106 Pioneer Bond Fund | Semiannual Report | 12/31/16 At December 31, 2016, open futures contracts were as follows: -------------------------------------------------------------------------------------------- Number of Contracts Unrealized Long/ Settlement Appreciation Description Counterparty (Short) Month Value (Depreciation) -------------------------------------------------------------------------------------------- U.S. Long Bond (CBT) Citibank NA 451 3/17 $ 67,945,969 $ (325,569) U.S. Ultra Bond (CBT) Citibank NA 204 3/17 32,691,000 580,942 U.S. 10 Year Ultra Bond (CBT) Citibank NA 598 3/17 80,169,375 (109,437) U.S. 10 Year Note (CBT) Citibank NA (5,731) 3/17 (712,255,844) 3,959,144 U.S. 2 Year Note (CBT) Citibank NA 745 3/17 161,432,188 (32,731) U.S. 5 Year Note (CBT) Citibank NA (216) 3/17 (25,415,438) 109,687 -------------------------------------------------------------------------------------------- Total $(395,432,750) $4,182,036 ============================================================================================ 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 subcustodian of the Fund. PIM is responsible for determining that the value of the collateral remains at least equal to the repurchase price. In the event of a default by the counterparty, the Fund is entitled to sell the securities, but the Fund may not be able to sell them for the price at which they were purchased, thus causing a loss to the Fund. Additionally, if the counterparty becomes insolvent, there is some risk that the Fund will not have a right to the securities, or the immediate right to sell the securities. Open repurchase agreements at December 31, 2016 are listed at the end of the Schedule of Investments. J. Credit Default Swap Agreements A credit default swap is a contract between a buyer of protection and a seller of protection against a pre-defined credit event on an underlying reference obligation, which may be a single security or a basket or index of securities. The Fund may sell or buy credit default swap contracts to seek to increase the 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 Pioneer Bond Fund | Semiannual Report | 12/31/16 107 in a loss to the Fund. In return, the Fund would receive from the counterparty a periodic stream of payments during the term of the contract provided that no event of default occurred. The maximum exposure of loss to the seller would be the notional value of the credit default swaps outstanding. If no default occurs, the Fund would keep the stream of payments and would have no payment obligation. The Fund may also buy credit default swap contracts in order to hedge against the risk of default of debt securities, in which case the Fund would function as the counterparty referenced above. When the Fund enters into a credit default swap contract, the protection buyer makes an upfront or periodic payment to the protection seller in exchange for the right to receive a contingent payment. An upfront payment made by the Fund, as the protection buyer, is recorded as an asset in the Statement of Assets and Liabilities. Periodic payments received or paid by the Fund are recorded as realized gains or losses in the Statement of Operations. Credit default swap contracts are marked-to-market daily using valuations supplied by independent sources and the change in value, if any, is recorded as unrealized appreciation or depreciation in the Statement of Assets and Liabilities. Payments received or made as a result of a credit event or upon termination of the contract are recognized, net of the appropriate amount of the upfront payment, as realized gains or losses in the Statement of Operations. Credit default swap contracts involving the sale of protection may involve greater risks than if the Fund had invested in the referenced debt instrument directly. Credit default swap contracts are subject to general market risk, liquidity risk, counterparty risk and credit risk. If the Fund is a protection buyer and no credit event occurs, it will lose its investment. If the Fund is a protection seller and a credit event occurs, the value of the referenced debt instrument received by the Fund, together with the periodic payments received, may be less than the amount the Fund pays to the protection buyer, resulting in a loss to the Fund. Certain swap contracts that are cleared through a central clearinghouse are referred to as centrally cleared swaps. All payments made or received by the Fund are pursuant to a centrally cleared swap contract with the central clearing party rather than the original counterparty. Upon entering into a centrally cleared swap contract, the Fund is required to make an initial margin deposit, either in cash or in securities. The daily change in value on open centrally cleared contracts is recorded as variation margin on centrally cleared swaps on the Statement of Assets and Liabilities. There were no open credit default swap contracts as of December 31, 2016. The average value of swap contracts open during the six months ended December 31, 2016 was $51,498. 108 Pioneer Bond Fund | Semiannual Report | 12/31/16 2. Management Agreement PIM, a wholly owned indirect subsidiary of UniCredit, manages the Fund's portfolio. Management fees are calculated daily at the annual rate of 0.40% of the Fund's average daily net assets. For the six months ended December 31, 2016, the effective management fee (excluding waivers and/or assumption of expenses) was equal to 0.40% of the Fund's average daily net assets. PIM has contractually agreed to limit ordinary operating expenses to the extent required to reduce Fund expenses to 0.85%, 1.10%, and 0.58% 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, 2016 are reflected on the Statement of Operations. These expense limitations are in effect through November 1, 2018. There can be no assurance that PIM will extend the expense limitation agreement for a class of shares beyond the dates referred to above. In addition, under the management and administration agreements, certain other services and costs, including accounting, regulatory reporting, and insurance premiums, are paid by the Fund as administrative reimbursements. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $145,346 in management fees, administrative costs and certain other reimbursements payable to PIM at December 31, 2016. 3. Transfer Agent Boston Financial Data Services serves as the transfer agent to the Fund at negotiated rates. Transfer agent fees and payables shown on the Statement of Operations and the Statement of Assets and Liabilities, respectively, include sub-transfer agent expenses incurred through the Fund's omnibus relationship contracts. In addition, the Fund reimbursed the transfer agent for out-of-pocket expenses incurred by the transfer agent related to shareholder communications activities such as proxy and statement mailings, outgoing phone calls and omnibus relationship contracts. For the six months ended December 31, 2016, such out-of-pocket expenses by class of shares were as follows: -------------------------------------------------------------------------------- Shareholder Communications: -------------------------------------------------------------------------------- Class A $ 8,781 Class C 5,239 Class K 1,608 Class R 68 Class Y 17,502 -------------------------------------------------------------------------------- Total $33,198 ================================================================================ Pioneer Bond Fund | Semiannual Report | 12/31/16 109 4. Distribution and Service Plans The Fund has adopted a Distribution Plan pursuant to Rule 12b-1 of the Investment Company Act of 1940 with respect to its Class A, Class C and Class R shares. Pursuant to the Plan, the Fund pays PFD 0.25% of the average daily net assets attributable to Class A shares as compensation for personal services and/or account maintenance services or distribution services with regard to Class A shares. Pursuant to the Plan, the Fund also pays PFD 1.00% of the average daily net assets attributable to Class C shares. The fee for Class C shares consists of a 0.25% service fee and a 0.75% distribution fee paid as compensation for personal services and/or account maintenance services or distribution services with regard to Class C shares. Pursuant to the Plan, the Fund further pays PFD 0.50% of the average daily net assets attributable to Class R shares for distribution services. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $41,040 in distribution fees payable to PFD at December 31, 2016. The Fund also has adopted a separate service plan for Class R shares (Service Plan). The Service Plan authorizes the Fund to pay securities dealers, plan administrators or other service organizations that agree to provide certain services to retirement plans or plan participants holding shares of the Fund a service fee of up to 0.25% of the Fund's average daily net assets attributable to Class R shares held by such plans. In addition, redemptions of each class of shares (except Class K, Class R and Class Y shares) may be subject to a contingent deferred sales charge (CDSC). A CDSC of 1.00% may be imposed on redemptions of certain net asset value purchases of Class A shares within 12 months of purchase. Redemptions of Class C shares within 12 months of purchase are subject to a CDSC of 1.00%, based on the lower of cost or market value of shares being redeemed. Shares purchased as part of an exchange remain subject to any CDSC that applied to the original purchase of those shares. There is no CDSC for Class R or Class Y shares. Proceeds from the CDSC are paid to PFD. For the six months ended December 31, 2016, CDSC in the amount of $5,263 were paid to PFD. 5. Line of Credit Facility The Fund, along with certain other funds in the Pioneer Family of Funds (the Funds), participates in a committed, unsecured revolving line of credit facility. Borrowings are used solely for temporary or emergency purposes. The Fund may borrow up to the lesser of the amount available under the facility or the limits set for borrowing by the Fund's prospectus and the 1940 Act. The credit facility in effect until February 9, 2016 was in the amount of $240 million. As of February 10, 2016, the facility is in the amount of $220 million. Under such facility, depending on the type of loan, interest on borrowings is payable at the London Interbank Offered Rate (LIBOR) plus 0.85% on an annualized basis, or 110 Pioneer Bond Fund | Semiannual Report | 12/31/16 the alternate base rate, which is the greater of (a) the facility's administrative agent's daily announced prime rate on the borrowing date, (b) 2% plus the federal funds rate on the borrowing date and (c) 2% plus the overnight eurodollar rate on the borrowing date. The Funds pay an annual commitment fee to participate in the credit facility. The commitment fee is allocated among participating Funds based on an allocation schedule set forth in the credit agreement. During the six months ended December 31, 2016, the Fund had no borrowings under the credit agreement. 6. Additional Disclosures about Derivative Instruments and Hedging Activities: The Fund's use of derivatives subjects it to the following risks: Interest rate risk relates to the fluctuations in the value of interest-bearing securities due to changes in the prevailing levels of market interest rates. Credit risk relates to the ability of the issuer of a financial instrument to make further principal or interest payments on an obligation or commitment that it has to the Fund. Foreign exchange rate risk relates to fluctuations in the value of an asset or liability due to changes in currency exchange rates. Equity risk relates to the fluctuations in the value of financial instruments as a result of changes in market prices (other than those arising from interest rate risk or foreign exchange risk), whether caused by factors specific to an individual investment, its issuer, or all factors affecting all instruments traded in a market or market segment. Commodity risk relates to the risk that the value of a commodity or commodity index will fluctuate based on increases or decreases in the commodities market and factors specific to a particular industry or commodity. The fair value of open derivative instruments (not considered to be hedging instruments for accounting disclosure purposes) by risk exposure at December 31, 2016 was as follows: -------------------------------------------------------------------------------------------------- Foreign Statement of Assets Interest Exchange Equity Commodity and Liabilities Rate Risk Credit Risk Rate Risk Risk Risk -------------------------------------------------------------------------------------------------- Assets Net unrealized appreciation on futures contracts* $4,182,036 $ -- $ -- $ -- $ -- -------------------------------------------------------------------------------------------------- Total Value $4,182,036 $ -- $ -- $ -- $ -- ================================================================================================== * Reflects net unrealized appreciation/depreciation of futures contracts (see Note 1H). The current day's variation margin is disclosed on the Statement of Assets and Liabilities. Pioneer Bond Fund | Semiannual Report | 12/31/16 111 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, 2016 was as follows: -------------------------------------------------------------------------------- Foreign Statement of Interest Credit Exchange Equity Commodity Operations Rate Risk Risk Rate Risk Risk Risk -------------------------------------------------------------------------------- Net realized gain (loss) Futures contracts $ 10,339,991 $ -- $ -- $ -- $ -- -------------------------------------------------------------------------------- Total Value $ 10,339,991 $ -- $ -- $ -- $ -- ================================================================================ Change in net unrealized appreciation (depreciation) on Futures contracts $(21,484,834) $ -- $ -- $ -- $ -- -------------------------------------------------------------------------------- Total Value $(21,484,834) $ -- $ -- $ -- $ -- ================================================================================ 7. Reorganization Information On March 18, 2016 ("Closing Date"), Pioneer Government Income Fund (the "predecessor fund") was reorganized into the Fund. The purpose of this transaction was to combine two funds (managed by PIM) with similar investment objectives. This tax-free reorganization was accomplished by exchanging the assets and liabilities of the predecessor fund for shares of the Fund. Shareowners holding Class A, Class C and Class Y of the predecessor fund received Class A, Class C and Class Y shares of the Fund, respectively, in the reorganization. The investment portfolio of the predecessor fund, with an aggregate value of $100,781,776 and an identified cost of $96,686,438 at March 18, 2016, was the principal asset acquired by the Fund. For financial reporting purposes, assets received and shares issued by the Fund were recorded at net asset value, however, the cost basis of the investments received from the predecessor fund was carried forward to align ongoing reporting of the Fund's realized and unrealized gains and losses with amounts distributable to shareowners for tax reporting purposes. 112 Pioneer Bond Fund | Semiannual Report | 12/31/16 The following charts shows the details of the reorganization as of the Closing Date: ------------------------------------------------------------------------------------------- Pioneer Government Income Fund Pioneer Bond Fund Pioneer Bond Fund (Pre-Reorganization) (Pre-Reorganization) (Post-Reorganization) ------------------------------------------------------------------------------------------- Net Assets Class A $ 83,223,137 $1,052,667,521 $1,135,890,658 Class C 14,846,083 117,661,581 132,507,664 Class K -- 311,330,352 311,330,352 Class R -- 146,651,259 146,651,259 Class Y 5,219,995 1,927,283,548 1,932,503,543 ------------------------------------------------------------------------------------------- Total Net Assets $103,289,215 $3,555,594,261 $3,658,883,476 ------------------------------------------------------------------------------------------- Shares Outstanding Class A 8,893,098 109,849,580 118,536,782 Class C 1,584,984 12,417,206 13,983,248 Class K -- 32,499,467 32,499,467 Class R -- 15,165,715 15,165,715 Class Y 558,355 203,011,669 203,561,722 -------------------------------------------------------------------------------------------- Shares issued Exchange Ratio in reorganization -------------------------------------------------------------------------------------------- Class A 0.9768 8,687,202 Class C 0.9880 1,566,042 Class Y 0.9851 550,053 -------------------------------------------------------------------------------------------- Unrealized Appreciation on Accumulated Gain Closing Date (Loss) on Closing Date -------------------------------------------------------------------------------------------- Fund $11,796,814 $ 818,031 Predecessor Fund 4,095,338 (9,616,481) Assuming the Reorganization had been completed on July 1, 2015, the pro-forma results of operations for the fiscal six months ended December 31, 2016, were as follows: Net Investment income (loss) $ 95,529,990 Net realized and unrealized gain (loss) 51,270,329 -------------------------------------------------------------------------------- Change in net assets resulting from operations $146,800,319 -------------------------------------------------------------------------------- Because the combined investment portfolios have been managed as a single integrated portfolio since the reorganization was completed, it is not practical to separate the amounts of revenue and earnings of the Fund that have been included in the Statements of Operations since the Reorganization was consummated. Pioneer Bond Fund | Semiannual Report | 12/31/16 113 ADDITIONAL INFORMATION Pioneer Investment Management, Inc. (the "Adviser"), the Fund's investment adviser, is currently an indirect, wholly owned subsidiary of UniCredit S.p.A. ("UniCredit"). On December 12, 2016, UniCredit announced that it has entered into a binding agreement for the sale of its Pioneer Investments business, which includes the Adviser, to Amundi (the "Transaction"). Amundi is headquartered in Paris, France, and, as of September 30, 2016, had more than $1.1 trillion in assets under management worldwide. The closing of the Transaction is expected to happen in 2017, subject to certain regulatory and antitrust approvals, and other conditions. Under the Investment Company Act of 1940, the closing of the Transaction will cause the Fund's current investment advisory agreement with the Adviser to terminate. Accordingly, the Fund's Board of Trustees will be asked to approve a new investment advisory agreement for the Fund. If approved by the Board, the Fund's new investment advisory agreement will be submitted to the shareholders of the Fund for their approval. 114 Pioneer Bond Fund | Semiannual Report | 12/31/16 Approval of Investment Advisory Agreement Pioneer Investment Management, Inc. (PIM) serves as the investment adviser to Pioneer Bond Fund (the Fund) pursuant to an investment advisory agreement between PIM and the Fund. In order for PIM to remain the investment adviser of the Fund, the Trustees of the Fund must determine annually whether to renew the investment advisory agreement for the Fund. The contract review process began in January 2016 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 2016 and May 2016. 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 advisory agreement. In March 2016, 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 advisory agreement, and reviewed and discussed the qualifications of the investment management teams, as well as the level of investment by the Fund's portfolio managers in the Fund. In May 2016, the Trustees, among other things, reviewed the Fund's management fee and total expense ratios, the financial statements of PIM and its parent companies, the profitability analyses provided by PIM, and possible economies of scale. The Trustees also reviewed the profitability of the institutional business of PIM and PIM's affiliate, Pioneer Institutional Asset Management, Inc. (together with PIM, "Pioneer"), as compared to that of PIM's fund management business, and considered the differences between the fees and expenses of the Fund and the fees and expenses of Pioneer's institutional accounts, as well as the different services provided by PIM to the Fund and by Pioneer to the institutional accounts. The Trustees further considered contract review materials in July and September 2016. At a meeting held on September 13, 2016, based on their evaluation of the information provided by PIM and third parties, the Trustees of the Fund, including the Independent Trustees voting separately, unanimously approved the renewal of the investment advisory agreement for another year. In approving the renewal of the investment advisory agreement, the Trustees considered various factors that they determined were relevant, including the factors described below. The Trustees did not identify any single factor as the controlling factor in determining to approve the renewal of the agreement. Pioneer Bond Fund | Semiannual Report | 12/31/16 115 Nature, Extent and Quality of Services The Trustees considered the nature, extent and quality of the services that had been provided by PIM to the Fund, taking into account the investment objective and strategy of the Fund. The Trustees also reviewed PIM's investment approach for the Fund and its research process. The Trustees considered the resources of PIM and the personnel of PIM who provide investment management services to the Fund. They also reviewed the amount of non-Fund assets managed by the portfolio managers of the Fund. The Trustees considered the non-investment resources and personnel of PIM involved in PIM's services to the Fund, including PIM's compliance and legal resources and personnel. The Trustees noted the substantial attention and high priority given by PIM's senior management to the Pioneer fund complex. The Trustees considered that PIM supervises and monitors the performance of the Fund's service providers and provides the Fund with personnel (including Fund officers) and other resources that are necessary for the Fund's business management and operations. The Trustees also considered that, as administrator, PIM is responsible for the administration of the Fund's business and other affairs. The Trustees considered the fees paid to PIM 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 PIM to the Fund were satisfactory and consistent with the terms of the investment advisory agreement. Performance of the Fund In considering the Fund's performance, the Trustees regularly review and discuss throughout the year data prepared by PIM and information comparing the Fund's performance with the performance of its peer group of funds as classified by each of Morningstar, Inc. (Morningstar) and Lipper, and with the performance of the Fund's benchmark index. They also discuss the Fund's performance with PIM on a regular basis. The Trustees' regular reviews and discussions were factored into the Trustees' deliberations concerning the renewal of the advisory agreement. Management Fee and Expenses The Trustees considered information showing the fees and expenses of the Fund in comparison to the management fees and expense ratios of its peer group of funds as classified by Morningstar and also to the expense ratios of a peer group of funds selected on the basis of criteria determined by the Independent Trustees for this purpose using data provided by Strategic Insight Mutual Fund Research and Consulting, LLC (Strategic Insight), an independent third party. In all quintile rankings referred to below, first quintile is most favorable to the Fund's shareowners. 116 Pioneer Bond Fund | Semiannual Report | 12/31/16 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 peer group for the comparable period. The Trustees also considered the breakpoints in the management fee schedule 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 third quintile relative to its Morningstar peer group and in the third quintile relative to its Strategic Insight peer group, in each case for the comparable period. The Trustees considered that the expense ratio of the Fund's Class Y shares for the most recent fiscal year was in the third quintile relative to its Morningstar peer group and in the third quintile relative to its Strategic Insight peer group, in each case for the comparable period. The Trustees noted that PIM was waiving fees and/or reimbursing expenses in order to limit the ordinary operating expenses of the Fund. The Trustees considered the impact of transfer agency, sub-transfer agency, and other non-management fee expenses on the expense ratios of the Fund. The Trustees noted that they separately review the Fund's transfer agency, sub-transfer agency and intermediary arrangements and that the results of the most recent such review were considered in the consideration of the Fund's expense ratio. The Trustees reviewed management fees charged by Pioneer to institutional and other clients, including publicly offered European funds sponsored by affiliates of Pioneer, unaffiliated U.S. registered investment companies (in a sub-advisory capacity), and unaffiliated foreign and domestic separate accounts. The Trustees also considered PIM's costs in providing services to the Fund and Pioneer'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 Pioneer's client accounts, the Trustees took into account the respective demands, resources and complexity associated with the Fund and 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 advisory agreement with the Fund, PIM 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 different entrepreneurial risks associated with PIM's management of the Fund and Pioneer's management of the other client accounts. The Trustees concluded that the management fee payable by the Fund to PIM was reasonable in relation to the nature and quality of the services provided by PIM to the Fund. Pioneer Bond Fund | Semiannual Report | 12/31/16 117 Profitability The Trustees considered information provided by PIM regarding the profitability of PIM with respect to the advisory services provided by PIM to the Fund, including the methodology used by PIM in allocating certain of its costs to the management of the Fund. The Trustees also considered PIM's profit margin in connection with the overall operation of the Fund. They further reviewed the financial results, including the profit margins, realized by PIM and its affiliates from non-fund businesses. The Trustees considered PIM's profit margins with respect to the Fund in comparison to the limited industry data available and noted that the profitability of any adviser was affected by numerous factors, including its organizational structure and method for allocating expenses. The Trustees concluded that PIM's profitability with respect to the management of the Fund was not unreasonable. Economies of Scale The Trustees considered PIM's views relating to economies of scale in connection with the Pioneer Funds as fund assets grow and the extent to which any such economies of scale are shared with funds 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 PIM in research and analytical capabilities and PIM's commitment and resource allocation to the Fund. The Trustees noted that profitability also may be an indicator of the availability of any economies of scale, although profitability may vary for other reasons including reductions in expenses. The Trustees concluded that economies of scale, if any, were being appropriately shared with the Funds. Other Benefits The Trustees considered the other benefits to PIM from its relationship with the Fund. The Trustees considered the character and amount of fees paid by the Fund, other than under the investment advisory agreement, for services provided by PIM and its affiliates. The Trustees further considered the revenues and profitability of PIM's businesses other than the fund business. Pioneer is the principal U.S. asset management business of Pioneer Global Asset Management, the worldwide asset management business of UniCredit Group, which manages over $150 billion in assets (including the Funds). Pioneer and the Funds receive reciprocal intangible benefits from the relationship, including mutual brand recognition and, for the Funds, direct and indirect access to the resources of a large global asset manager. The Trustees concluded that any such benefits received by Pioneer as a result of its 118 Pioneer Bond Fund | Semiannual Report | 12/31/16 relationship with the Funds were reasonable and their consideration of the advisory agreement between the Fund and PIM and the fees thereunder were unaffected by Pioneer's possible receipt of any such intangible benefits. Conclusion After consideration of the factors described above as well as other factors, the Trustees, including all of the Independent Trustees, concluded that the investment advisory agreement between PIM and the Fund, including the fees payable thereunder, was fair and reasonable and voted to approve the proposed renewal of the investment advisory agreement for the Fund. Pioneer Bond Fund | Semiannual Report | 12/31/16 119 Trustees, Officers and Service Providers Trustees Advisory Trustee Thomas J. Perna, Chairman Lorraine H. Monchak* David R. Bock Benjamin M. Friedman Officers Margaret B.W. Graham Lisa M. Jones, President and Chief Marguerite A. Piret Executive Officer Fred J. Ricciardi Mark E. Bradley, Treasurer and Kenneth J. Taubes Chief Financial Officer Christopher J. Kelley, Secretary and Chief Legal Officer Investment Adviser and Administrator Pioneer Investment Management, Inc. Custodian and Sub-Administrator Brown Brothers Harriman & Co. Principal Underwriter Pioneer Funds Distributor, Inc. Legal Counsel Morgan, Lewis & Bockius LLP Shareowner Services and Transfer Agent Boston Financial Data Services, Inc. Proxy Voting Policies and Procedures of the Fund are available without charge, upon request, by calling our toll free number (1-800-225-6292). Information regarding how the Fund voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is publicly available to shareowners at us.pioneerinvestments.com. This information is also available on the Securities and Exchange Commission's web site at www.sec.gov. * Ms. Monchak is a non-voting Advisory Trustee. 120 Pioneer Bond Fund | Semiannual Report | 12/31/16 This page for your notes. Pioneer Bond Fund | Semiannual Report | 12/31/16 121 This page for your notes. 122 Pioneer Bond Fund | Semiannual Report | 12/31/16 This page for your notes. Pioneer Bond Fund | Semiannual Report | 12/31/16 123 This page for your notes. 124 Pioneer Bond Fund | Semiannual Report | 12/31/16 How to Contact Pioneer We are pleased to offer a variety of convenient ways for you to contact us for assistance or information. Call us for: -------------------------------------------------------------------------------- Account Information, including existing accounts, new accounts, prospectuses, applications and service forms 1-800-225-6292 FactFone(SM) for automated fund yields, prices, account information and transactions 1-800-225-4321 Retirement plans information 1-800-622-0176 Write to us: -------------------------------------------------------------------------------- Pioneer Funds P.O. Box 55014 Boston, Massachusetts 02205-5014 Our toll-free fax 1-800-225-4240 Our internet e-mail address ask.pioneer@pioneerinvestments.com (for general questions about Pioneer only) Visit our web site: us.pioneerinvestments.com This report must be preceded or accompanied by a prospectus. The Fund files a complete schedule of investments with the Securities and Exchange Commission for the first and third quarters for each fiscal year on Form N-Q. Shareholders may view the filed Form N-Q by visiting the Commission's web site at http://www.sec.gov. The filed form may also be viewed and copied at the Commission's Public Reference Room in Washington, DC. Information regarding the operations of the Public Reference Room may be obtained by calling 1-800-SEC-0330. [LOGO] PIONEER Investments(R) Pioneer Investment Management, Inc. 60 State Street Boston, MA 02109 us.pioneerinvestments.com Securities offered through Pioneer Funds Distributor, Inc. 60 State Street, Boston, MA 02109 Underwriter of Pioneer Mutual Funds, Member SIPC (C) 2017 Pioneer Investments 18633-11-0217 ITEM 2. CODE OF ETHICS. (a) Disclose whether, as of the end of the period covered by the report, the registrant has adopted a code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party. If the registrant has not adopted such a code of ethics, explain why it has not done so. The registrant has adopted, as of the end of the period covered by this report, a code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer and controller. (b) For purposes of this Item, the term "code of ethics" means written standards that are reasonably designed to deter wrongdoing and to promote: (1) Honest and ethical conduct, including the ethical handling of actual or apparent conflicts of interest between personal and professional relationships; (2) Full, fair, accurate, timely, and understandable disclosure in reports and documents that a registrant files with, or submits to, the Commission and in other public communications made by the registrant; (3) Compliance with applicable governmental laws, rules, and regulations; (4) The prompt internal reporting of violations of the code to an appropriate person or persons identified in the code; and (5) Accountability for adherence to the code. (c) The registrant must briefly describe the nature of any amendment, during the period covered by the report, to a provision of its code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party, and that relates to any element of the code of ethics definition enumerated in paragraph (b) of this Item. The registrant must file a copy of any such amendment as an exhibit pursuant to Item 10(a), unless the registrant has elected to satisfy paragraph (f) of this Item by posting its code of ethics on its website pursuant to paragraph (f)(2) of this Item, or by undertaking to provide its code of ethics to any person without charge, upon request, pursuant to paragraph (f)(3) of this Item. The registrant has made no amendments to the code of ethics during the period covered by this report. (d) If the registrant has, during the period covered by the report, granted a waiver, including an implicit waiver, from a provision of the code of ethics to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party, that relates to one or more of the items set forth in paragraph (b) of this Item, the registrant must briefly describe the nature of the waiver, the name of the person to whom the waiver was granted, and the date of the waiver. Not applicable. (e) If the registrant intends to satisfy the disclosure requirement under paragraph (c) or (d) of this Item regarding an amendment to, or a waiver from, a provision of its code of ethics that applies to the registrant's principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions and that relates to any element of the code of ethics definition enumerated in paragraph (b) of this Item by posting such information on its Internet website, disclose the registrant's Internet address and such intention. Not applicable. (f) The registrant must: (1) File with the Commission, pursuant to Item 12(a)(1), a copy of its code of ethics that applies to the registrant's principal executive officer,principal financial officer, principal accounting officer or controller, or persons performing similar functions, as an exhibit to its annual report on this Form N-CSR (see attachment); (2) Post the text of such code of ethics on its Internet website and disclose, in its most recent report on this Form N-CSR, its Internet address and the fact that it has posted such code of ethics on its Internet website; or (3) Undertake in its most recent report on this Form N-CSR to provide to any person without charge, upon request, a copy of such code of ethics and explain the manner in which such request may be made. 	See Item 10(2) ITEM 3. AUDIT COMMITTEE FINANCIAL EXPERT. (a) (1) Disclose that the registrant's board of trustees has determined that the registrant either: (i) Has at least one audit committee financial expert serving on its audit committee; or (ii) Does not have an audit committee financial expert serving on its audit committee. The registrant's Board of Trustees has determined that the registrant has at least one audit committee financial expert. (2) If the registrant provides the disclosure required by paragraph (a)(1)(i) of this Item, it must disclose the name of the audit committee financial expert and whether that person is "independent." In order to be considered "independent" for purposes of this Item, a member of an audit committee may not, other than in his or her capacity as a member of the audit committee, the board of trustees, or any other board committee: (i) Accept directly or indirectly any consulting, advisory, or other compensatory fee from the issuer; or (ii) Be an "interested person" of the investment company as defined in Section 2(a)(19) of the Act (15 U.S.C. 80a-2(a)(19)). Ms. Marguerite A. Piret, an independent trustee, is such an audit committee financial expert. (3) If the registrant provides the disclosure required by paragraph (a)(1) (ii) of this Item, it must explain why it does not have an audit committee financial expert. Not applicable. ITEM 4. PRINCIPAL ACCOUNTANT FEES AND SERVICES. (a) Disclose, under the caption AUDIT FEES, the aggregate fees billed for each of the last two fiscal years for professional services rendered by the principal accountant for the audit of the registrant's annual financial statements or services that are normally provided by the accountant in connection with statutory and regulatory filings or engagements for those fiscal years. 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 Pioneer Investment Management, Inc ("PIM"), the audit committee and the independent auditors. The Funds recognize that a Fund's independent auditors: 1) possess knowledge of the Funds, 2) are able to incorporate certain services into the scope of the audit, thereby avoiding redundant work, cost and disruption of Fund personnel and processes, and 3) have expertise that has value to the Funds. As a result, there are situations where it is desirable to use the Fund's independent auditors for services in addition to the annual audit and where the potential for conflicts of interests are minimal. Consequently, this policy, which is intended to comply with Rule 210.2-01(C)(7), sets forth guidelines and procedures to be followed by the Funds when retaining the independent audit firm to perform audit, audit-related tax and other services under those circumstances, while also maintaining independence. Approval of a service in accordance with this policy for a Fund shall also constitute approval for any other Fund whose pre-approval is required pursuant to Rule 210.2-01(c)(7)(ii). In addition to the procedures set forth in this policy, any non-audit services that may be provided consistently with Rule 210.2-01 may be approved by the Audit Committee itself and any pre-approval that may be waived in accordance with Rule 210.2-01(c)(7)(i)(C) is hereby waived. Selection of a Fund's independent auditors and their compensation shall be determined by the Audit Committee and shall not be subject to this policy. SECTION II - POLICY ---------------- -------------------------------- ------------------------------------------------- SERVICE SERVICE CATEGORY DESCRIPTION SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES CATEGORY ---------------- -------------------------------- ------------------------------------------------- I. AUDIT Services that are directly o Accounting research assistance SERVICES related to performing the o SEC consultation, registration independent audit of the Funds statements, and reporting o Tax accrual related matters o Implementation of new accounting standards o Compliance letters (e.g. rating agency letters) o Regulatory reviews and assistance regarding financial matters o Semi-annual reviews (if requested) o Comfort letters for closed end offerings ---------------- -------------------------------- ------------------------------------------------- II. Services which are not o AICPA attest and agreed-upon procedures AUDIT-RELATED prohibited under Rule o Technology control assessments SERVICES 210.2-01(C)(4) (the "Rule") o Financial reporting control assessments and are related extensions of o Enterprise security architecture the audit services support the assessment audit, or use the knowledge/expertise gained from the audit procedures as a foundation to complete the project. In most cases, if the Audit-Related Services are not performed by the Audit firm, the scope of the Audit Services would likely increase. The Services are typically well-defined and governed by accounting professional standards (AICPA, SEC, etc.) ---------------- -------------------------------- ------------------------------------------------- ------------------------------------- ------------------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------- ------------------------------------ o "One-time" pre-approval o A summary of all such for the audit period for all services and related fees pre-approved specific service reported at each regularly subcategories. Approval of the scheduled Audit Committee independent auditors as meeting. auditors for a Fund shall constitute pre approval for these services. ------------------------------------- ------------------------------------ o "One-time" pre-approval o A summary of all such for the fund fiscal year within services and related fees a specified dollar limit (including comparison to for all pre-approved specified dollar limits) specific service subcategories reported quarterly. o Specific approval is needed to exceed the pre-approved dollar limit for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for Audit-Related Services not denoted as "pre-approved", or to add a specific service subcategory as "pre-approved" ------------------------------------- ------------------------------------ SECTION III - POLICY DETAIL, CONTINUED ----------------------- --------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES DESCRIPTION ----------------------- --------------------------- ----------------------------------------------- III. TAX SERVICES Services which are not o Tax planning and support prohibited by the Rule, o Tax controversy assistance if an officer of the Fund o Tax compliance, tax returns, excise determines that using the tax returns and support Fund's auditor to provide o Tax opinions these services creates significant synergy in the form of efficiency, minimized disruption, or the ability to maintain a desired level of confidentiality. ----------------------- --------------------------- ----------------------------------------------- ------------------------------------- ------------------------- AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------- ------------------------- ------------------------------------- ------------------------- o "One-time" pre-approval o A summary of for the fund fiscal year all such services and within a specified dollar limit related fees 				 (including comparison 			 to specified dollar 			 limits) reported 			 quarterly. o Specific approval is needed to exceed the pre-approved dollar limits for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for tax services not denoted as pre-approved, or to add a specific service subcategory as "pre-approved" ------------------------------------- ------------------------- SECTION III - POLICY DETAIL, CONTINUED ----------------------- --------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES DESCRIPTION ----------------------- --------------------------- ----------------------------------------------- IV. OTHER SERVICES Services which are not o Business Risk Management support prohibited by the Rule, o Other control and regulatory A. SYNERGISTIC, if an officer of the Fund compliance projects UNIQUE QUALIFICATIONS determines that using the Fund's auditor to provide these services creates significant synergy in the form of efficiency, minimized disruption, the ability to maintain a desired level of confidentiality, or where the Fund's auditors posses unique or superior qualifications to provide these services, resulting in superior value and results for the Fund. ----------------------- --------------------------- ----------------------------------------------- --------------------------------------- ------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------- -------------------------- o "One-time" pre-approval o A summary of for the fund fiscal year within all such services and a specified dollar limit related fees 			 (including comparison 			 to specified dollar 				 limits) reported quarterly. o Specific approval is needed to exceed the pre-approved dollar limits for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for "Synergistic" or "Unique Qualifications" Other Services not denoted as pre-approved to the left, or to add a specific service subcategory as "pre-approved" ------------------------------------- -------------------------- SECTION III - POLICY DETAIL, CONTINUED ----------------------- ------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PROHIBITED SERVICE SUBCATEGORIES DESCRIPTION ----------------------- ------------------------- ----------------------------------------------- PROHIBITED SERVICES Services which result 1. Bookkeeping or other services in the auditors losing related to the accounting records or independence status financial statements of the audit under the Rule. client* 2. Financial information systems design and implementation* 3. Appraisal or valuation services, fairness* opinions, or contribution-in-kind reports 4. Actuarial services (i.e., setting actuarial reserves versus actuarial audit work)* 5. Internal audit outsourcing services* 6. Management functions or human resources 7. Broker or dealer, investment advisor, or investment banking services 8. Legal services and expert services unrelated to the audit 9. Any other service that the Public Company Accounting Oversight Board determines, by regulation, is impermissible ----------------------- ------------------------- ----------------------------------------------- ------------------------------------------- ------------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------------- ------------------------------ o These services are not to be o A summary of all performed with the exception of the(*) services and related services that may be permitted fees reported at each if they would not be subject to audit regularly scheduled procedures at the audit client (as Audit Committee meeting defined in rule 2-01(f)(4)) level will serve as continual the firm providing the service. confirmation that has 				 not provided any restricted services. ------------------------------------------- ------------------------------ -------------------------------------------------------------------------------- GENERAL AUDIT COMMITTEE APPROVAL POLICY: o For all projects, the officers of the Funds and the Fund's auditors will each make an assessment to determine that any proposed projects will not impair independence. o Potential services will be classified into the four non-restricted service categories and the "Approval of Audit, Audit-Related, Tax and Other Services" Policy above will be applied. Any services outside the specific pre-approved service subcategories set forth above must be specifically approved by the Audit Committee. o At least quarterly, the Audit Committee shall review a report summarizing the services by service category, including fees, provided by the Audit firm as set forth in the above policy. -------------------------------------------------------------------------------- (2) Disclose the percentage of services described in each of paragraphs (b) through (d) of this Item that were approved by the audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X. 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. The registrant's principal executive officer and principal financial officer, however, voluntarily are reporting the following information: In August of 2006 the registrant's investment adviser enhanced its internal procedures for reporting performance information required to be included in prospectuses. Those enhancements involved additional internal controls over the appropriateness of performance data generated for this purpose. Such enhancements were made following an internal review which identified prospectuses relating to certain classes of shares of a limited number of registrants where, inadvertently, performance information not reflecting the deduction of applicable sales charges was included. Those prospectuses were revised, and the revised prospectuses were distributed to shareholders. ITEM 12. EXHIBITS. (a) File the exhibits listed below as part of this Form. Letter or number the exhibits in the sequence indicated. (1) Any code of ethics, or amendment thereto, that is the subject of the disclosure required by Item 2, to the extent that the registrant intends to satisfy the Item 2 requirements through filing of an exhibit. (2) A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2(a) under the Act (17 CFR 270.30a-2(a)) , exactly as set forth below: Filed herewith. SIGNATURES [See General Instruction F] Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized. (Registrant) Pioneer Bond Fund By (Signature and Title)* /s/ Lisa M. Jones Lisa M. Jones, President & Chief Executive Officer Date March 1, 2017 Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated. By (Signature and Title)* /s/ Lisa M. Jones Lisa M. Jones, President & Chief Executive Officer Date March 1, 2017 By (Signature and Title)* /s/ Mark E. Bradley Mark E. Bradley, Treasurer & Chief Accounting & Financial Officer Date March 1, 2017 * Print the name and title of each signing officer under his or her signature.