OMB APPROVAL OMB Number: 3235-0570 Expires: August 31, 2013 Estimated average burden hours per response.....18.9 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 811-21558 Pioneer Short Term Income 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: August 31 Date of reporting period: September 1, 2009 through August 31, 2010 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 SHAREOWNERS. Pioneer Short Term Income Fund - -------------------------------------------------------------------------------- Annual Report | August 31, 2010 - -------------------------------------------------------------------------------- Ticker Symbols: Class A STABX Class B STBBX Class C PSHCX Class Y PSHYX [LOGO] PIONEER Investments(R) visit us: pioneerinvestments.com Table of Contents Letter to Shareowners 2 Portfolio Management Discussion 4 Portfolio Summary 8 Prices and Distributions 9 Performance Update 10 Comparing Ongoing Fund Expenses 14 Schedule of Investments 16 Financial Statements 42 Notes to Financial Statements 50 Report of Independent Registered Public Accounting Firm 60 Trustees, Officers and Service Providers 62 Pioneer Short Term Income Fund | Annual Report | 8/31/10 1 President's Letter Dear Shareowner, Stock and bond markets around the globe have begun to recover over the past year from one of their most tumultuous periods in history. This is a welcome relief, and we are generally optimistic about the prospects for the economy going forward. Still, challenges remain. Unemployment is high; consumer demand and loan growth are weak; and housing has not returned to normal. At Pioneer, we have long advocated the benefits of investing for the long term. This strategy has generally performed well for many investors. Those who remained invested in the market during the downturn have most likely seen their portfolios start to recover over the past year, as the Dow Jones Industrial Average climbed back from the depressed levels we saw in early 2009. Many bond investors have similarly seen a strong rebound, with a broad-based recovery occurring across many different fixed-income asset classes. The riskiest asset classes, such as high-yield bonds, outperformed other fixed-income asset classes during most of 2009. At Pioneer, we are not changing the approach to investing that we have used for more than 80 years. We remain focused on company fundamentals and risk management. Our investment process is based on careful research into individual companies, quantitative analysis, and active portfolio management. This three-pillared process, which we apply to each of our portfolios, is supported by an integrated team approach and is designed to carefully balance risk and reward. While we see potential opportunities for making money in many corners of the markets around the globe, it takes research and experience to separate solid investment opportunities from speculation. Following this difficult period, many investors are rethinking their approach to investing and risk management. Some are questioning whether the basic investment principles they were taught in the past are still useful in today's markets. Complicating matters is that financial markets remain unpredictable. Our advice, as always, is to work closely with a trusted financial advisor to discuss your goals and work together to develop an investment strategy that meets your individual needs. There is no single best strategy that works for every investor. 2 Pioneer Short Term Income Fund | Annual Report | 8/31/10 We invite you to learn more about Pioneer and our time-tested approach to investing by consulting with your financial advisor or visiting us online at www.pioneerinvestments.com. We greatly appreciate your trust in us and we thank you for investing with Pioneer. Sincerely, /s/ Daniel K. Kingsbury Daniel K. Kingsbury President and CEO Pioneer Investment Management USA, Inc. 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 the opinion of Fund management as of the date of this report. These statements should not be relied upon for any other purposes. Past performance is no guarantee of future results, and there is no guarantee that market forecasts discussed will be realized. Pioneer Short Term Income Fund | Annual Report | 8/31/10 3 Portfolio Management Discussion | 8/31/10 In the following interview, portfolio managers Richard Schlanger and Charles Melchreit discuss the factors that influenced Pioneer Short Term Income Fund's performance over the 12-month period ended August 31, 2010. Q Can you describe the market environment for fixed-income investors over the 12-month period ended August 31, 2010? A As the period opened in September of 2009, the credit markets continued to show signs of stabilizing. The improved sentiment was supported by ongoing signs of economic recovery, albeit a recovery aided by a number of government stimulus programs. The fourth quarter of 2009 saw U.S. gross domestic product (GDP) growth come in at a robust 5.7%. Optimism over renewed overall growth was tempered, however, by weak employment data, as hiring remained low and unemployment hovered near 10%. Entering 2010, the markets were roiled by a series of concerns. The prospect of defaults on debt instruments issued by Dubai and Greece triggered worries over sovereign debt in the eurozone. The sovereign debt concerns soon spread across much of southern Europe, and in April 2010 both Greece and Spain lost their AAA debt ratings. In addition, signs of slowing growth in China raised concerns about the sustainability of the global economic recovery, while weaker-than-hoped-for economic data in the U.S. led to fear of a "double-dip" recession. The result was a jittery market characterized by sporadic flights into Treasury bonds as investors reacted defensively to even mixed economic news. Given concerns over unemployment and moderate inflation, the Federal Reserve Board (the Fed) kept the target for its benchmark short-term interest rate at between 0% and 0.25% for the entire 12-month period. With short-term rates anchored by the Fed, the trend shifted towards a flattening of the Treasury yield curve in the one- to five-year range, as investors sought incremental yield. The two-year Treasury yield fell by 50 basis points (0.50%), from 0.97% to 0.47%, while the five-year yield fell 106 basis points (1.06%), from 2.39% to 1.33%. Despite an uncertain backdrop, the overall trend for credit-sensitive sectors was upward over the full 12 months ended August 31, 2010. For the full period, credit spreads (the incremental yields offered by lower-quality versus higher-quality fixed-income instruments) narrowed as investors sought incremental yield in a low-rate environment. 4 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Q How did the Fund perform in that environment over the 12 months ended August 31, 2010? A The Fund's Class A shares had a total return of 7.19% at net asset value over the 12 months ended August 31, 2010, while the Fund's benchmark, the Barclays Capital One- to Three-Year Government/Credit Index, returned 3.40%. Over the same 12-month period, the average return of the 248 mutual funds in Lipper's Short Investment-Grade Debt Funds category was 5.40%. As of August 31, 2010, the Fund's 30-day SEC yield was 1.99%. The total return and SEC yield numbers are for Class A shares and do not include the impact of any sales charge paid. Q Can you review the Fund's principal investment strategies and what affect they had on performance during the 12 months ended August 31, 2010? A We continued to follow a disciplined investment process based on identifying relative value among fixed-income sectors and carefully evaluating the risk/reward profile of individual issues. The Fund's largest exposure in terms of sector weighting during the period was in mortgage-related issues. Within mortgage-related securities, we trimmed the Fund's holdings of issues that benefited from government efforts to enhance market liquidity, such as those backed by Ginnie Mae, Fannie Mae and Freddie Mac, in anticipation of the Fed's removing its support for those instruments. In turn, we purchased non-agency collateralized mortgage obligations that we believed were attractively valued. We also maintained significant exposure in the Fund's portfolio to commercial mortgage-backed securities and asset- backed securities (such as issues backed by home equity loans). All of those sectors outperformed agency pass-through securities over the 12 months ended August 31, 2010. Over the 12-month period we made significant purchases of new corporate debt issues in order to take advantage of the higher yields being offered in that space, compared with issues traded in the secondary market. Within corporates, we took the portfolio's credit quality slightly downward early in the period on signs that the economic backdrop was improving, adding to the Fund's holdings of bonds rated BBB and BB. That worked out well for the Fund as credit spreads narrowed for much of the 12 months ended August 31, 2010. With respect to industry sectors, the Fund had significantly overweight exposure to financials for much of the period; financials outperformed the broader corporate market as bank profits were supported by a steep yield curve. Late in the 12-month period, we trimmed the Fund's lower-rated corporate exposure as valuations became less attractive relative to other areas of the bond market, investing the proceeds principally in government agency-backed issues. We also reduced the Fund's overweight to corporate financial issues as the yield curve flattened. Pioneer Short Term Income Fund | Annual Report | 8/31/10 5 The Fund had very little exposure to U.S. Treasury issues, reflecting our view that Treasuries, while viewed by many investors as a safe haven, have not been valued attractively versus credit-sensitive sectors given their negative real yields. That move helped the Fund's performance, as shorter-term Treasuries underperformed their credit sector counterparts in an environment of narrowing credit spreads. At the end of the period on August 31, 2010, mortgage-related and asset- backed securities accounted for 47% of Fund assets. The Fund's corporate holdings represented 26% of assets at August 31, 2010, while U.S. Treasury and Agency issues represented 20% of assets. The remaining roughly 7% of Fund assets was held in cash in the form of overnight repurchase agreements. The Fund's overall duration (a standard measure of price sensitivity to changes in market interest rates) at August 31, 2010, was 1.4 years, compared with 1.9 years for the Barclays Capital One- to Three-Year Government/ Credit Index. The Fund's lower overall duration was a modest constraint on performance returns during a period of falling rates. The Fund's yield curve positioning, however, more than made up for the duration lag, as the Fund had significant exposure to issues in the five-year range, which outperformed the two-year area of the yield curve in the falling rate environment. Q What is your assessment of the current climate for fixed-income investing? A Given the weak global backdrop, high unemployment rate and moderate inflation, we expect the Fed to leave short-term rates near zero for some time going forward. As a short-term fund, we typically focus holdings on issues with maturities ranging from overnight commercial paper to the five- year range. With the yield curve from zero- to five-years still relatively steep, we expect for now to maintain the Fund's somewhat "barbelled" positioning, with substantial exposure to five-year issues balanced by a position in short-term paper. That posture helps position the Fund to garner the incremental income available out on the yield curve while maintaining an overall duration and interest rate sensitivity that is consistent with the Fund's guidelines. In addition, by minimizing exposure to issues in the two-to-three year range of the yield curve, the Fund would be positioned to protect against any upside surprise in economic growth numbers that could lead to market speculation that the Fed will have its hand on interest rates forced by inflation fears. In addition to Fed policy, we will be monitoring the impact on the markets of the upcoming mid-term election cycle, in particular the debate with respect to taxation levels. At the same time, as we take note of macroeconomic factors with the potential to affect the markets, we will remain principally focused on adding value to the Fund through individual security selection. While the yield advantage provided by corporate issues has narrowed, we continue to see opportunities there to add yield to the Fund in a 6 Pioneer Short Term Income Fund | Annual Report | 8/31/10 low rate environment. We will be monitoring the companies in the Fund's portfolio closely and focusing strongly on making sure that the Fund is getting paid for any credit risk it assumes. As always, we will seek to provide a high level of current income while reducing the impact of interest rate changes on the Fund's share price. We believe our focus on income and relative share price stability continues to make the Fund an attractive investment for appropriate investors in the current, low-interest-rate environment. Please refer to the Schedule of Investments on pages 16-41 for a full listing of Fund securities. When interest rates rise, the prices of fixed-income securities in the Fund will generally fall. Conversely, when interest rates fall, the prices of fixed-income securities in the Fund will generally rise. Investments in the Fund are subject to possible loss due to the financial failure of the issuers of the underlying securities and their inability to meet their debt obligations. These risks may increase share price volatility. Prepayment risk is the chance that mortgage-backed bonds will be paid off early if falling interest rates prompt homeowners to refinance their mortgages. 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 associated with falling interest rates. 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. Investing in foreign and/or emerging markets securities involves risks relating to interest rates, currency exchange rates, economic, and political conditions. At times, the Fund's investments may represent industries or industry sectors that are interrelated or have common risks, making it more susceptible to any economic, political, or regulatory developments or other risks affecting those industries and sectors. Past performance is not a guarantee of future results, and there is no guarantee that market forecasts discussed will be realized. 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 the opinion of Fund management as of the date of this report. These statements should not be relied upon for any other purposes. Pioneer Short Term Income Fund | Annual Report | 8/31/10 7 Portfolio Summary | 8/31/10 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 29.2% U.S. Corporate Bonds 23.9% Collateralized Mortgage Obligations 23.8% Asset Backed Securities 12.3% Temporary Cash Investments 8.4% Senior Floating Rate Loans 1.7% Municipal Bonds 0.5% Foreign Government Bonds 0.1% Convertible Corporate Bonds 0.1% Portfolio Quality - -------------------------------------------------------------------------------- (As a percentage of total investment portfolio; based on S&P ratings) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] A 8.7% AA 7.7% AAA 0.8% B & Lower 3.2% BB 3.4% BBB 12.7% Commercial Paper 6.9% Treasury/Agency 56.6% 10 Largest Holdings - -------------------------------------------------------------------------------- (As a percentage of total long-term holdings)* 1. U.S. Treasury Notes, 1.0%, 7/31/11 6.41% - -------------------------------------------------------------------------------- 2. U.S. Treasury Notes, 2.5%, 4/30/15 5.68 - -------------------------------------------------------------------------------- 3. U.S. Treasury Notes, 0.875%, 5/31/11 2.80 - -------------------------------------------------------------------------------- 4. Fannie Mae Grantor Trust, Floating Rate Note, 10/25/40 2.11 - -------------------------------------------------------------------------------- 5. U.S. Treasury Notes, 1.875%, 6/15/12 2.04 - -------------------------------------------------------------------------------- 6. Residential Accreditation Loans, Inc., 5.0%, 8/25/18 1.63 - -------------------------------------------------------------------------------- 7. U.S. Treasury Notes, 1.5%, 7/15/12 1.62 - -------------------------------------------------------------------------------- 8. New Century Home Equity Loan 2005-4 A2B, Floating Rate Note, 9/25/35 1.37 - -------------------------------------------------------------------------------- 9. Fannie Mae, 5.0%, 5/15/29 1.26 - -------------------------------------------------------------------------------- 10. Government National Mortgage Association, 2.351%, 6/16/50 1.02 - -------------------------------------------------------------------------------- * This list excludes temporary cash investments and derivative instruments. The portfolio is actively managed and current holdings may be different. The holdings listed should not be considered recommendations to buy or sell any security listed. 8 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Prices and Distributions | 8/31/10 Net Asset Value per Share - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Class 8/31/10 8/31/09 - -------------------------------------------------------------------------------- A $9.75 $9.40 - -------------------------------------------------------------------------------- B $9.75 $9.39 - -------------------------------------------------------------------------------- C $9.73 $9.38 - -------------------------------------------------------------------------------- Y $9.74 $9.38 - -------------------------------------------------------------------------------- Distributions per Share: 9/1/09-8/31/10 - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Net Investment Short-Term Long-Term Class Income Capital Gains Capital Gains - -------------------------------------------------------------------------------- A $0.3160 $ -- $ -- - -------------------------------------------------------------------------------- B $0.2298 $ -- $ -- - -------------------------------------------------------------------------------- C $0.2361 $ -- $ -- - -------------------------------------------------------------------------------- Y $0.3453 $ -- $ -- - -------------------------------------------------------------------------------- Pioneer Short Term Income Fund | Annual Report | 8/31/10 9 Performance Update | 8/31/10 Class A Shares Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Pioneer Short Term Income Fund at public offering price, compared to that of the Barclays Capital One- to Three-Year Government/Credit Index. Average Annual Total Returns (As of August 31, 2010) - -------------------------------------------------------------------------------- Net Asset Public Offering Period Value (NAV) Price (POP) - -------------------------------------------------------------------------------- Life-of-Class (7/8/04) 3.60% 3.17% 5 Years 4.05 3.53 1 Year 7.19 4.52 - -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated December 31, 2009) - -------------------------------------------------------------------------------- Gross Net - -------------------------------------------------------------------------------- 1.15% 0.90% - -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Barclays Capital Pioneer Short Term One- to Three-Year Income Fund Government/Credit Index ----------- ----------------------- 7/04 9,745 10,000 8/04 9,805 10,078 8/05 9,933 10,218 8/06 10,170 10,534 8/07 10,645 11,104 8/08 10,877 11,754 8/09 11,301 12,361 8/10 12,114 12,781 Call 1-800-225-6292 or visit www.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. POP returns reflect deduction of maximum 2.50% sales charge. NAV 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 net expense ratio reflects contractual expense limitations currently in effect through 1/1/12 for Class A shares. There can be no assurance that Pioneer will extend the expense limitations 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. The Barclays Capital One- to Three-Year Government/Credit Index measures the performance of the short-term (1 to 3 years) government and investment-grade corporate bond markets. Index returns are calculated monthly, assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. You cannot invest directly in an index. 10 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Performance Update | 8/31/10 Class B Shares Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Pioneer Short Term Income Fund, compared to that of the Barclays Capital One- to Three-Year Government/Credit Index. Average Annual Total Returns (As of August 31, 2010) - -------------------------------------------------------------------------------- If If Period Held Redeemed - -------------------------------------------------------------------------------- Life-of-Class (7/8/04) 2.70% 2.70% 5 Years 3.14 3.14 1 Year 6.35 4.35 - -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated December 31, 2009) - -------------------------------------------------------------------------------- Gross Net - -------------------------------------------------------------------------------- 1.95% 1.80% - -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Barclays Capital Pioneer Short Term One- to Three-Year Income Fund Government/Credit Index ----------- ----------------------- 7/04 10,000 10,000 8/04 10,052 10,078 8/05 10,108 10,218 8/06 10,265 10,534 8/07 10,639 11,104 8/08 10,762 11,754 8/09 11,092 12,361 8/10 11,796 12,781 Call 1-800-225-6292 or visit www.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 B shares reflect the deduction of the maximum applicable contingent deferred sales charge (CDSC). The maximum CDSC is 2.0% and declines over three years. "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 net expense ratio reflects contractual expense limitations currently in effect through 1/1/11 for Class B shares. There can be no assurance that Pioneer will extend the expense limitations beyond such time. Please see the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. The Barclays Capital One- to Three-Year Government/Credit Index measures the performance of the short-term (1 to 3 years) government and investment-grade corporate bond markets. Index returns are calculated monthly, assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. You cannot invest directly in an index. Pioneer Short Term Income Fund | Annual Report | 8/31/10 11 Performance Update | 8/31/10 Class C Shares Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Pioneer Short Term Income Fund, compared to that of the Barclays Capital One- to Three-Year Government/Credit Index. Average Annual Total Returns (As of August 31, 2010) - -------------------------------------------------------------------------------- If If Period Held Redeemed - -------------------------------------------------------------------------------- Life-of-Class (7/8/04) 2.75% 2.75% 5 Years 3.18 3.18 1 Year 6.32 6.32 - -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated December 31, 2009) - -------------------------------------------------------------------------------- Gross Net - -------------------------------------------------------------------------------- 1.79% 1.79% - -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Barclays Capital Pioneer Short Term One- to Three-Year Income Fund Government/Credit Index ----------- ----------------------- 7/04 10,000 10,000 8/04 10,052 10,078 8/05 10,111 10,218 8/06 10,260 10,534 8/07 10,648 11,104 8/08 10,781 11,754 8/09 11,121 12,361 8/10 11,823 12,781 Call 1-800-225-6292 or visit www.pioneerinvestments.com for the most recent month-end performance results. Current performance may be lower or higher than the performance data quoted. The performance data quoted represents past performance, which is no guarantee of future results. Investment return and principal value will fluctuate, and shares, when redeemed, may be worth more or less than their original cost. Class C shares held for less than one year are also subject to a 1% contingent deferred sales charge (CDSC). "If Held" results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The net expense ratio reflects contractual expense limitations currently in effect through 1/1/11 for Class C shares. There can be no assurance that Pioneer will extend the expense limitations 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. The Barclays Capital One- to Three-Year Government/Credit Index measures the performance of the short-term (1 to 3 years) government and investment-grade corporate bond markets. Index returns are calculated monthly, assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. You cannot invest directly in an index. 12 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Performance Update | 8/31/10 Class Y Shares Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $5 million investment made in Pioneer Short Term Income Fund, compared to that of the Barclays Capital One- to Three-Year Government/Credit Index. Average Annual Total Returns (As of August 31, 2010) - -------------------------------------------------------------------------------- If If Period Held Redeemed - -------------------------------------------------------------------------------- Life-of-Class (7/8/04) 3.94% 3.94% 5 Years 4.36 4.36 1 Year 7.64 7.64 - -------------------------------------------------------------------------------- Expense Ratio (Per prospectus dated December 31, 2009) - -------------------------------------------------------------------------------- Gross Net - -------------------------------------------------------------------------------- 0.63% 0.63% - -------------------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $5,000,000 Investment Barclays Capital Pioneer Short Term One- to Three-Year Income Fund Government/Credit Index ----------- ----------------------- 7/04 5,000,000 5,000,000 8/04 5,031,883 5,039,143 8/05 5,125,561 5,109,065 8/06 5,265,685 5,266,787 8/07 5,527,035 5,552,160 8/08 5,662,589 5,876,896 8/09 5,895,518 6,180,639 8/10 6,345,978 6,390,515 Call 1-800-225-6292 or visit www.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 contractual expense limitations currently in effect through 1/1/11 for Class Y shares. There can be no assurance that Pioneer will extend the expense limitations beyond such time. Please see the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. The Barclays Capital One- to Three-Year Government/Credit Index measures the performance of the short-term (1 to 3 years) government and investment-grade corporate bond markets. Index returns are calculated monthly, assume reinvestment of dividends and, unlike Fund returns, do not reflect any fees, expenses or sales charges. You cannot invest directly in an index. Pioneer Short Term Income Fund | Annual Report | 8/31/10 13 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 Short Term Income Fund Based on actual returns from March 1, 2010 through August 31, 2010. - ------------------------------------------------------------------------------------- Share Class A B C Y - ------------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 $1,000.00 Value on 3/1/10 - ------------------------------------------------------------------------------------- Ending Account Value $1,028.89 $1,024.27 $1,024.77 $1,030.54 on 8/31/10 - ------------------------------------------------------------------------------------- Expenses Paid $ 4.60 $ 9.18 $ 8.68 $ 2.92 During Period* - ------------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.90%, 1.80%, 1.70%, and 0.57% for Class A, Class B, Class C 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). 14 Pioneer Short Term Income Fund | Annual Report | 8/31/10 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 Short Term Income Fund Based on a hypothetical 5% return per year before expenses, reflecting the period from March 1, 2010 through August 31, 2010. - ------------------------------------------------------------------------------------- Share Class A B C Y - ------------------------------------------------------------------------------------- Beginning Account $1,000.00 $1,000.00 $1,000.00 $1,000.00 Value on 3/1/10 - ------------------------------------------------------------------------------------- Ending Account Value $1,020.67 $1,016.13 $1,016.64 $1,022.33 on 8/31/10 - ------------------------------------------------------------------------------------- Expenses Paid $ 4.58 $ 9.15 $ 8.64 $ 2.91 During Period* - ------------------------------------------------------------------------------------- * Expenses are equal to the Fund's annualized expense ratio of 0.90%, 1.80%, 1.70%, and 0.57% for Class A, Class B, Class C 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 Short Term Income Fund | Annual Report | 8/31/10 15 Schedule of Investments | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value CONVERTIBLE CORPORATE BOND -- 0.1% BANKS -- 0.1% Regional Banks -- 0.1% 140,000 A/A3 National City Corp., 4.0%, 2/1/11 $ 141,575 - --------------------------------------------------------------------------------------------------------- TOTAL CONVERTIBLE CORPORATE BOND (Cost $140,374) $ 141,575 - --------------------------------------------------------------------------------------------------------- ASSET BACKED SECURITIES -- 12.4% MATERIALS -- 0.9% Aluminum -- 0.4% 731,740 0.89 AAA/Aaa Bayview Financial Acquisition, Floating Rate Note, 5/28/44 $ 654,581 371,484 0.62 AAA/Aaa Bayview Financial Acquisition, Floating Rate Note, 8/28/44 340,104 ------------ $ 994,685 - --------------------------------------------------------------------------------------------------------- Steel -- 0.5% 295,099 0.46 AAA/Aaa Ameriquest Mortgage Securities, Floating Rate Note, 5/25/35 $ 289,036 266,517 0.46 AAA/Aaa Ameriquest Mortgage Securities, Floating Rate Note, 8/25/35 254,490 990,096 0.73 AA+/Aa3 Nomura Home Equity Loan, Inc., Floating Rate Note, 5/25/35 956,559 6,889 0.38 AAA/Aaa Nomura Home Equity Trust, Inc., Floating Rate Note, 3/25/36 6,882 ------------ $ 1,506,967 ------------ Total Materials $ 2,501,652 - --------------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.3% Restaurants -- 0.3% 250,000 BB+/Baa3 Dunkin Brands Master Finance LLC, 5.779%, 6/20/31 $ 247,948 685,000 BB-/Ba3 Dunkin Brands Master Finance LLC, 8.28%, 6/20/31 (144A) 637,797 ------------ $ 885,745 ------------ Total Consumer Services $ 885,745 - --------------------------------------------------------------------------------------------------------- FOOD & DRUG RETAILING -- 0.1% Food Retail -- 0.1% 215,000 BBB-/Baa3 Dominos Pizza Master Issuer LLC, 5.261%, 4/25/37 $ 209,051 200,000 BB/Aaa Dominos Pizza Master Issuer LLC, 7.629%, 4/25/37 178,522 ------------ $ 387,573 ------------ Total Food & Drug Retailing $ 387,573 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 16 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value BANKS -- 3.8% Diversified Banks -- 0.0% 35,427 0.35 AAA/Aa1 Wells Fargo Home Equity, Floating Rate Note, 4/25/37 $ 34,367 - --------------------------------------------------------------------------------------------------------- Thrifts & Mortgage Finance -- 3.8% 162,302 0.51 A+/Aa1 ACE 2005-HE7 A2C, Floating Rate Note, 11/25/35 $ 160,908 232,088 0.39 AA/Aa2 ACE Securities Corp., Floating Rate Note, 5/25/36 231,140 683,280 AA/Aa2 Bear Stearns Asset Backed Securities, 0.8271%, 6/25/35 641,952 268,310 0.37 AA/A1 Bear Stearns Asset Backed Securities, Floating Rate Note, 12/25/36 260,198 584,500 4.89 AAA/Aaa Bear Stearns Asset Backed Securities, Inc., Floating Rate Note, 6/25/43 535,517 266,889 0.41 AAA/Aaa Bear Stearns Asset Backed Securities, Inc., Floating Rate Note, 8/25/36 265,607 347,228 0.31 AAA/Baa1 Carrington Mortgage Loan Trust, Floating Rate Note, 1/25/37 330,545 353,291 0.49 AAA/Aa1 Carrington Mortgage Loan Trust, Floating Rate Note, 12/25/35 346,744 197,076 0.67 AA+/Aa1 Citigroup Mortgage Loan Trust, Floating Rate Note, 7/25/35 188,750 78,594 0.31 AAA/Baa2 Countrywide Asset Backed Certificates, Floating Rate Note, 5/25/47 78,065 358,505 0.80 B-/Baa2 Countrywide Asset Backed Certificates, Floating Rate Note, 4/25/32 168,419 1,226,306 0.77 A+/Ba2 Countrywide Asset-Backed Certificates, Floating Rate Note, 5/25/29 1,135,327 330,000 0.63 AAA/Baa2 Countrywide Asset-Backed Certificates, Floating Rate Note, 1/25/36 296,629 580,529 0.31 A/Ba1 Countrywide Asset-Backed Certificates, Floating Rate Note, 7/25/37 561,431 270,492 0.28 AAA/Ba2 Countrywide Asset-Backed Certificates, Floating Rate Note, 12/25/35 265,775 319,899 5.56 AAA/A2 CRMSI 2006-2 A3, Floating Rate Note, 9/25/36 323,103 239,000 5.68 B+/Ba1 CWL 2006-15 A2, Floating Rate Note, 10/25/46 227,702 350,000 0.79 AA+/A1 GSAA Trust, Floating Rate Note, 6/25/35 326,070 112,702 0.66 A/A2 GSAMP Trust, Floating Rate Note, 3/25/35 108,148 58,741 0.60 AAA/Aaa GSAMP, Trust Floating Rate Note, 8/25/36 57,121 631,199 A+/Ba3 HEMT 2004-6 M2, 5.321%, 4/25/35 432,256 637,496 AAA/Aaa LEAF II Receivables, 3.45%, 11/20/12 635,775 466,215 BB/Baa3 Local Insight Media Finance LLC, 5.88%, 10/23/37 223,783 The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 17 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Thrifts & Mortgage Finance -- (continued) 54,856 0.27 AAA/A1 Morgan Stanley ABS Capital, Inc., Floating Rate Note, 10/25/36 $ 54,726 466,885 0.38 A/Aa3 Option One Mortgage Loan Trust, Floating Rate Note, 2/25/38 455,298 27,806 0.32 BBB+/Baa2 Option One Mortgage Trust, Floating Rate Note, 5/25/37 26,755 190,751 0.71 AA+/Aaa Ownit Mortgage Loan Asset Back, Floating Rate Note, 3/25/36 190,313 761,886 AA/Aa2 Popular ABS Mortgage Pass Through Trust, 5.181%, 9/25/34 600,168 541,125 0.58 AAA/Aaa RAAC Series, Floating Rate Note, 6/25/35 527,426 240,000 0.67 AA+/A3 RASC 2005-KS7 M1, Floating Rate Note, 8/25/35 197,729 159,562 0.28 AA+/Aaa SASC 2006-BC2 A2, Floating Rate Note, 9/25/36 155,459 116,968 1.21 BBB/Aa2 SAST 2002-1 M1, Floating Rate Note, 1/25/32 67,599 228,241 0.29 AAA/A2 Soundview Home Equity Loan, Floating Rate Note, 8/25/37 226,519 ------------ $ 10,302,957 ------------ Total Banks $ 10,337,324 - --------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 3.7% Asset Management & Custody Banks -- 0.3% 191,032 NR/Aaa Freddie Mac Reference, 4.75%, 7/15/15 $ 193,178 568,807 0.65 BB+/B3 SPSAC 1998-1 A1, Floating Rate Note, 3/25/28 330,119 ------------ $ 523,297 - --------------------------------------------------------------------------------------------------------- Consumer Finance -- 0.5% 289,623 AA/Baa1 RFMS2 2003-HI1 M1, 5.27%, 4/25/28 $ 246,290 1,156,886 0.49 AA+/A3 Specialty Underwriting & Residual, Floating Rate Note, 9/25/36 1,133,426 ------------ $ 1,379,716 - --------------------------------------------------------------------------------------------------------- Diversified Financial Services -- 0.3% 58,048 A/Aaa Asset Backed Securities Corp., 1.93838%, 8/15/32 $ 58,057 159,044 AA/NR DT Auto Owner Trust, 5.92%, 10/15/15 159,647 250,000 AA/A1 Home Equity Asset Trust, 0.76875%, 8/25/35 237,937 461,154 0.33 AAA/Aaa JP Morgan Mortgage Acquisition, Floating Rate Note, 8/25/36 460,115 ------------ $ 915,756 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 18 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Specialized Finance -- 2.6% 706,777 0.59 AAA/Aaa Aegis Asset Backed Securities, Floating Rate Note, 9/25/34 $ 638,700 630,241 0.53 AA+/A1 Aegis Asset Backed Securities, Floating Rate Note, 3/25/12 557,841 1,020,274 AAA/Aaa Conseco Finance, Inc., 7.05%, 4/15/32 1,080,756 207,951 6.69 AAA/Aaa Conseco Finance, Inc., Floating Rate Note, 11/15/32 212,056 620,175 5.32 NR/Baa1 Irwin Home Equity Corp., Floating Rate Note, 6/25/35 601,877 69,814 AA+/Aa1 Master Asset Backed Security Trust, 0.67375%, 5/25/35 67,195 122,670 0.61 AAA/Aaa New Century Home Equity Loan, Floating Rate Note, 3/25/35 116,356 3,587,380 0.53 AAA/Aa2 New Century Home Equity Loan Trust, Floating Rate Note, 9/25/35 3,451,418 380,000 0.63 AAA/Aaa SLMA 2004-10 A6B, Floating Rate Note, 4/27/26 379,240 ------------ $ 7,105,439 ------------ Total Diversified Financials $ 9,924,208 - --------------------------------------------------------------------------------------------------------- GOVERNMENT -- 3.6% 473,604 AAA/Aaa Fannie Mae Benchmark Remic, 5.45%, 12/25/20 $ 516,772 435,000 NR/NR Fannie Mae Grantor Trust, 5.503%, 9/25/11 455,226 1,640,159 4.48 AAA/Aaa Fannie Mae Grantor Trust, Floating Rate Note, 7/25/43 1,743,871 5,123,781 4.54 NR/Aa1 Fannie Mae Grantor Trust, Floating Rate Note, 10/25/40 5,295,007 1,734,739 6.00 AAA/Aaa Fannie Mae Whole Loan, Floating Rate Note, 7/25/42 1,754,515 ------------ $ 9,765,391 ------------ Total Government $ 9,765,391 - --------------------------------------------------------------------------------------------------------- TOTAL ASSET BACKED SECURITIES (Cost $34,775,232) $ 33,801,893 - --------------------------------------------------------------------------------------------------------- COLLATERALIZED MORTGAGE OBLIGATIONS -- 24.1% BANKS -- 10.5% Thrifts & Mortgage Finance -- 10.5% 336,180 NR/Aaa ABN Amro Mortgage Corp., 4.75%, 5/25/18 $ 338,537 10,205 AAA/Aaa CDMC 2003-2P A3, 5.45%, 11/25/19 10,255 1,474,829 AAA/Aaa Cendant Mortgage Corp., 6.25%, 3/25/32 1,469,962 The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 19 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Thrifts & Mortgage Finance -- (continued) 799,215 AAA/Aaa Cendant Mortgage Corp., 6.25%, 6/25/32 $ 828,995 732,926 6.48 NR/Aaa Chase Commercial Mortgage Securities Corp., Floating Rate Note, 2/12/16 745,019 297,236 AAA/Aaa Citigroup Commercial Mortgage, 4.639%, 5/15/43 304,763 747,238 5.92 AAA/Aaa Citigroup Commercial Mortgage, Floating Rate Note, 3/15/49 757,636 578,615 AAA/Aaa CMLTI 2003-UP3 A1, 7.0%, 9/25/33 592,232 297,118 3.56 CCC/NR CMLTI 2005-1 2A1A, Floating Rate Note, 4/25/35 173,108 502,861 NR/NR CMLTI 2005-9 2SX2, 5.5%, 11/25/35 64,685 97,531 1.18 NR/Aaa CMOT 44 F, Floating Rate Note, 7/1/18 98,347 605,236 0.71 AAA/Aa3 Countrywide Alternative Loan Trust, Floating Rate Note, 9/25/34 559,675 2,078,861 AAA/NA Countrywide Home Loans, Inc., 5.5%, 10/25/32 2,150,272 204,123 AAA/Aaa Downey Savings & Loan, 0.83625%, 7/19/44 144,879 496,197 AAA/Aaa GECMC 2005-C1 A2, 4.353%, 6/10/48 502,345 552,443 AAA/Aaa GS Mortgage Securities Corp., II, 4.602%, 8/10/38 555,721 75,063 2.03 CC/Ca Impac Cmb Trust, Floating Rate Note, 11/25/34 23,089 2,109,000 0.87 AAA/Aa2 Impac Cmb Trust, Floating Rate Note, 9/25/34 1,539,614 24,032 AAA/Aaa JP Morgan Chase Commercial Mortgage, 4.79%, 10/15/42 24,024 81,598 4.33 B+/B1 JP Morgan Mortgage Trust, Floating Rate Note, 11/25/35 77,558 257,730 NR/B3 JP Morgan Mortgage Trust, 6.0%, 8/25/36 27,072 593,259 AAA/Aaa JPMCC 2004-CB8 A1A, 4.158%, 1/12/39 607,995 81,096 AAA/Aaa JPMCC 2004-CB8 A2, 3.837%, 1/12/39 81,438 625,516 0.75 A+/B2 LBSBC 2005- 2 A M2, Floating Rate Note, 9/25/30 142,305 424,570 AAA/Aa1 LBSBC 2007- 2 A1, 5.57%, 3/25/37 400,174 2,500,000 AAA/Aa2 LBUBS 2001-C2 C, 6.975%, 9/15/34 2,548,966 390,925 AAA/Aaa LBUBS 2005-C2 A2, 4.81%, 4/15/30 391,071 25,823 AAA/NR LB-UBS Commercial Mortgage, 6.058%, 6/15/20 25,869 495,176 AAA/Aaa LB-UBS Commercial Mortgage, 4.201%, 12/15/29 498,785 568,748 AAA/Aaa LB-UBS Commercial Mortgage, 6.51%, 12/15/26 570,135 The accompanying notes are an integral part of these financial statements. 20 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Thrifts & Mortgage Finance -- (continued) 326,589 AAA/NR Master Alternative Loans Trust, 4.5%, 1/25/15 $ 320,653 566,039 6.73 BBB/NR Master Seasoned Securities Trust, Floating Rate Note, 9/25/32 586,911 84,510 AAA/Aaa Merrill Lynch Mortgage Trust, 4.556%, 6/12/43 86,917 374,755 5.44 AAA/Aaa Merrill Lynch/Countrywide Communities, Floating Rate Note, 3/12/11 378,669 330,943 0.49 AAA/Aaa MLCC Mortgage Investors, Inc., Floating Rate Note, 4/25/29 307,690 1,440,147 BBB/Baa1 RAAC Series, 6.0%, 1/25/32 1,481,306 1,157,506 6.24 BB+/Aaa Residential Asset Mortgage Products, Inc., Floating Rate Note, 5/25/18 1,139,958 310,082 0.46 BBB/Aa3 SAMI 2007-AR4 A1, Floating Rate Note, 9/25/47 306,067 237,565 0.59 AAA/Aaa SEMT 2004-10 A2, Floating Rate Note, 11/20/34 202,058 766,936 AAA/B1 SEMT 2005-1 A2, 5.8325%, 2/20/35 624,349 866,239 4.27 CCC/Ba1 Structured Asset Mortgage Investments, Inc., Floating Rate Note, 5/25/45 473,756 258,745 2.63 AAA/Aaa Thornburg Mortgage Securities, Inc., Floating Rate Note, 3/25/44 246,130 1,555,892 0.60 AAA/Aa2 Thornburg Mortgage Securities, Inc., Floating Rate Note, 9/25/34 1,457,404 43,120 AAA/NR Wachovia Bank Commercial Mortgage, 4.516%, 5/15/44 43,108 400,000 AAA/Aaa Wachovia Bank Commercial Mortgage, 4.957%, 8/15/35 404,303 426,912 AAA/Aaa Wachovia Bank Commercial Mortgage, 5.416%, 1/15/45 431,956 109,646,343 0.02 AAA/Aaa Wachovia Bank Commercial Mortgage Trust, Floating Rate Note, 6/15/45 148,231 1,600,141 NR/Baa1 Wells Fargo Mortgage Backed Securities, 4.75%, 4/25/20 1,636,453 256,977 AAA/A1 Wells Fargo Mortgage Backed Securities, 5.0%, 11/25/36 261,591 288,767 AAA/Baa1 Wells Fargo Mortgage Backed Securities, 5.5%, 5/25/35 294,038 172,731 2.96 AAA/Aa1 Wells Fargo Mortgage Backed Securities, Floating Rate Note, 10/25/35 169,093 32,000 4.72 AAA/Aaa Wells Fargo Mortgage Backed Securities, Floating Rate Note, 6/25/34 31,869 400,127 3.25 AAA/Aaa Wells Fargo Mortgage Backed Securities, Floating Rate Note, 9/25/34 393,372 The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 21 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Thrifts & Mortgage Finance -- (continued) 173,925 4.56 AAA/Aaa WFMBS 2003-N-1A1, Floating Rate Note, 12/25/33 $ 174,973 525,000 4.76 AAA/Aaa WFMBS 2004-L A6, Floating Rate Note, 7/25/34 532,274 ------------ $ 28,387,655 ------------ Total Banks $ 28,387,655 - --------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 7.0% Diversified Financial Services -- 6.5% 1,549,843 5.01 AAA/Aaa American Home Mortgage Investment Corp., Floating Rate Note, 10/25/34 $ 1,414,405 1,262,582 0.53 A-/Ba2 American Home Mortgage Investment Corp., Floating Rate Note, 11/25/45 823,774 596,736 NR/Aaa Bank of America Mortgage, 3.614%, 11/25/33 565,828 406,373 2.92 AAA/Aaa Bank of America Mortgage, Floating Rate Note, 7/25/33 391,565 1,503,212 3.59 AAA/Aaa Bank of America Mortgage, Floating Rate Note, 9/25/33 1,472,491 337,826 2.94 NR/Ba3 Bank of America Mortgage Securities, Floating Rate Note, 5/25/35 319,783 364,087 AAA/NR Bank of America Mortgage Securities, Inc., 5.0%, 8/25/33 364,682 205,237 0.97 A+/Aaa Bear Stearns Alt-A Trust, Floating Rate Note, 11/25/34 169,936 1,543,515 AAA/NR Citicorp Mortgage Securities, Inc., 4.75%, 8/25/34 1,557,896 707,498 AAA/NR Citicorp Mortgage Securities, Inc., 5.5%, 12/25/33 710,300 420,155 NR/A2 Citicorp Mortgage Securities, Inc., 5.5%, 3/25/35 429,322 42,626 3.12 AAA/WR First Horizon Mortgage Pass-Through Trust, Floating Rate Note, 12/27/32 42,266 89,640 2.84 AAA/Aaa First Horizon Mortgage Pass-Through Trust, Floating Rate Note, 2/25/34 90,532 568,238 AAA/Aaa Morgan Stanley DW, 4.25%, 12/13/41 582,833 2,970,178 CCC/Caa3 RALI 2005-QA10 A41, 5.7412%, 9/25/35 2,042,274 378,823 AAA/A1 Residential Accreditation Loans, Inc., 4.5%, 4/25/34 370,131 307,066 0.81 AAA/Aa2 Residential Accreditation Loans, Inc., Floating Rate Note, 1/25/34 287,928 761,675 0.81 AAA/Aa2 Residential Accreditation Loans, Inc., Floating Rate Note, 10/25/17 735,898 3,945,241 NR/Aaa Residential Accreditation Loans, Inc., 5.0%, 8/25/18 4,079,975 The accompanying notes are an integral part of these financial statements. 22 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Diversified Financial Services -- (continued) 850,458 AAA/Aaa Residential Accreditation Loans, Inc., 5.75%, 10/25/33 $ 854,898 132,426 NR/NR Vericrest Opportunity Loan Trust, 4.25%, 5/25/39 132,095 ------------ $ 17,438,812 - --------------------------------------------------------------------------------------------------------- Investment Banking & Brokerage -- 0.4% 160,367 5.46 NR/Aaa Bear Stearns Commercial Mortgage, Floating Rate Note, 4/12/38 $ 162,363 939,326 5.56 AA+/Aaa Lehman Brothers, Floating Rate Note, 9/15/21 (144A) 857,079 ------------ $ 1,019,442 - --------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.1% 495,425 0.33 A/A1 Indymac Index Mortgage Loan Trust, Floating Rate Note, 2/25/37 $ 477,022 ------------ Total Diversified Financials $ 18,935,276 - --------------------------------------------------------------------------------------------------------- REAL ESTATE -- 1.6% Mortgage Real Estate Investment Trust -- 1.6% 772,902 AAA/Aaa Credit Suisse First Boston Mortgage Security, 6.51%, 2/15/34 $ 775,435 436,455 AAA/Aaa Credit Suisse First Boston Mortgage Security, 7.5%, 5/25/32 450,317 383,822 1.58 AA+/Aa2 Credit Suisse First Boston Mortgage Security, Floating Rate Note, 12/25/33 365,842 2,227,628 AAA/Aaa Credit Suisse First Boston Mortgage Security, 7.13%, 11/15/30 2,246,295 218,833 1.75 AA+/WR Credit Suisse First Boston Mortgage Security, Floating Rate Note, 8/25/33 205,715 109,146 1.38 CC/B3 Credit Suisse First Boston Mortgage Security, Floating Rate Note, 9/25/34 23,396 265,447 AAA/NA CSFB 2004-C2 A1, 3.819%, 5/15/36 268,498 ------------ $ 4,335,498 ------------ Total Real Estate $ 4,335,498 - --------------------------------------------------------------------------------------------------------- GOVERNMENT -- 5.0% 3,000,000 AAA/Aaa Fannie Mae, 5.0%, 5/15/29 $ 3,152,364 287,745 AAA/Aaa Fannie Mae, 5.69%, 1/25/32 301,135 411,496 AAA/Aaa Fannie Mae, 6.0%, 6/25/29 449,174 250,850 AAA/Aaa Federal Home Loan Mortgage Association, 5.0%, 6/25/28 256,444 711 AAA/Aaa Federal Home Loan Mortgage Association, 6.0%, 4/25/36 723 384,948 NR/NR Federal National Mortgage Association, 5.5%, 4/25/30 393,859 The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 23 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Government -- (continued) 415,408 AAA/Aaa Freddie Mac, 4.5%, 8/15/17 $ 433,281 809,944 AAA/Aaa Freddie Mac, 5.5%, 10/15/35 884,969 370,395 NR/Aa1 Freddie Mac, 3.25%, 6/15/17 379,782 1,368,997 AAA/Aaa Freddie Mac, 3.4%, 7/1/19 1,402,282 1,744,082 NR/Aa1 Freddie Mac, 4.0%, 6/15/22 1,830,048 694,861 NR/NR Freddie Mac, 4.5%, 10/15/27 704,897 208,774 AAA/Aa1 Freddie Mac, 5.0%, 8/15/31 215,732 1,500,000 NR/Aa1 Freddie Mac, 5.0%, 11/15/28 1,570,395 750,000 AAA/Aa1 Freddie Mac, 6.0%, 5/15/30 764,654 225,706 AAA/Aaa Freddie Mac, 6.0%, 4/15/27 227,069 63,525 AAA/Aaa Freddie Mac, 4.0%, 12/15/12 64,740 9,249 AAA/Aaa Freddie Mac, 4.0%, 4/15/22 9,305 70,961 AAA/Aaa Freddie Mac, 5.5%, 6/15/32 72,053 70,961 AAA/Aaa Freddie Mac, 6.0%, 6/15/32 71,991 62,245 AAA/Aaa Freddie Mac, 6.1%, 9/15/18 62,664 398,681 AAA/A2 GSR Mortgage Loan Trust, 4.1408%, 6/25/34 389,568 ------------ $ 13,637,129 ------------ Total Government $ 13,637,129 - --------------------------------------------------------------------------------------------------------- TOTAL COLLATERALIZED MORTGAGE OBLIGATIONS (Cost $68,334,030) $ 65,295,558 - --------------------------------------------------------------------------------------------------------- CORPORATE BONDS -- 24.2% ENERGY -- 2.9% Integrated Oil & Gas -- 0.2% 500,000 A/A2 BP Capital Markets Plc, 3.125%, 3/10/12 $ 500,864 - --------------------------------------------------------------------------------------------------------- Oil & Gas Equipment & Services -- 0.8% 500,000 3.52 NR/NR Sevan Marine ASA, Floating Rate Note, 5/14/13 (144A) $ 411,250 2,500,000 11.99 NA/NA Sevan Marine ASA, Floating Rate Note, 10/24/12 (144A) 395,964 500,000 BBB/Baa1 Weatherford International, Inc., 5.95%, 6/15/12 534,210 650,000 BBB/Baa1 Weatherford International, Inc., 6.625%, 11/15/11 682,554 ------------ $ 2,023,978 - --------------------------------------------------------------------------------------------------------- Oil & Gas Exploration & Production -- 0.6% 250,000 A/Aa2 Ras Laffan LNG 3 Co., Ltd., 4.5%, 9/30/12 (144A) $ 263,229 250,000 A/Aa2 Ras Laffan LNG 3 Co., Ltd., 5.5%, 9/30/14 (144A) 276,215 The accompanying notes are an integral part of these financial statements. 24 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Oil & Gas Exploration & Production -- (continued) 1,000,000 BBB-/Baa2 TNK-BP Finance SA, 7.5%, 3/13/13 (144A) $ 1,075,000 ------------ $ 1,614,444 - --------------------------------------------------------------------------------------------------------- Oil & Gas Refining & Marketing -- 0.9% 1,500,000 BBB/Baa2 Premcor Refining Group, Inc., 6.125%, 5/1/11 $ 1,536,680 1,000,000 BBB-/Baa3 Sunoco, Inc., 6.75%, 4/1/11 1,025,079 ------------ $ 2,561,759 - --------------------------------------------------------------------------------------------------------- Oil & Gas Storage & Transportation -- 0.4% 250,000 BBB-/Baa3 NGPL Pipeco LLC, 6.514%, 12/15/12 (144A) $ 262,590 750,000 BBB-/Baa3 Williams Partners LP, 3.8%, 2/15/15 784,655 ------------ $ 1,047,245 ------------ Total Energy $ 7,748,290 - --------------------------------------------------------------------------------------------------------- MATERIALS -- 0.4% Industrial Gases -- 0.2% 500,000 BBB/Baa3 Airgas, Inc., 2.85%, 10/1/13 $ 509,406 - --------------------------------------------------------------------------------------------------------- Specialty Chemicals -- 0.2% 536,000 BBB-/Baa3 Cytec Industries, Inc., 4.6%, 7/1/13 $ 566,829 ------------ Total Materials $ 1,076,235 - --------------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 1.2% Industrial Conglomerates -- 0.4% 465,000 A/A2 Cargill, Inc., 5.2%, 1/22/13 (144A) $ 504,900 500,000 BBB-/Baa2 Tyco Electronics Group SA, 6.0%, 10/1/12 541,349 ------------ $ 1,046,249 - --------------------------------------------------------------------------------------------------------- Industrial Machinery -- 0.2% 500,000 BBB+/Baa1 Ingersoll-Rand Global Holding, 9.5%, 4/15/14 $ 619,703 - --------------------------------------------------------------------------------------------------------- Trading Companies & Distributors -- 0.6% 440,000 BBB/Baa1 GATX Corp., 4.75%, 10/1/12 $ 462,953 1,000,000 BBB-/Baa2 Glencore Funding LLC, 6.0%, 4/15/14 (144A) 1,033,005 ------------ $ 1,495,958 ------------ Total Capital Goods $ 3,161,910 - --------------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.2% Environmental & Facilities Services -- 0.1% 306,000 BBB/Baa3 Allied Waste North America, Inc., 5.75%, 2/15/11 $ 311,898 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 25 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Office Services & Supplies -- 0.1% 350,000 BBB+/A1 Pitney Bowes, Inc., 4.625%, 10/1/12 $ 367,394 ------------ Total Commercial Services & Supplies $ 679,292 - --------------------------------------------------------------------------------------------------------- AUTOMOBILES & COMPONENTS -- 0.6% Automobile Manufacturers -- 0.6% 500,000 BBB+/A3 Daimler Chrysler NA Holding Corp., 5.875%, 3/15/11 $ 513,471 1,000,000 BBB-/Baa3 Hyundai Motor Manufacturer, Ltd., 4.5%, 4/15/15 1,029,733 100,000 BBB/Baa2 Nissan Motor Acceptance Corp., 4.5%, 1/30/15 (144A) 106,229 ------------ $ 1,649,433 ------------ Total Automobiles & Components $ 1,649,433 - --------------------------------------------------------------------------------------------------------- CONSUMER DURABLES & APPAREL -- 0.7% Home Furnishings -- 0.1% 252,000 BB+/Ba2 Mohawk Industries, Inc., 6.5%, 1/15/11 $ 254,520 - --------------------------------------------------------------------------------------------------------- Household Appliances -- 0.2% 500,000 BBB-/Baa3 Whirlpool Corp., 5.5%, 3/1/13 $ 537,186 - --------------------------------------------------------------------------------------------------------- Housewares & Specialties -- 0.4% 1,000,000 BBB-/Baa3 Fortune Brands, Inc., 3.0%, 6/1/12 $ 1,013,848 ------------ Total Consumer Durables & Apparel $ 1,805,554 - --------------------------------------------------------------------------------------------------------- MEDIA -- 0.3% Broadcasting -- 0.3% 750,000 BBB-/Baa2 Discovery Communications LLC, 3.7%, 6/1/15 $ 788,978 ------------ Total Media $ 788,978 - --------------------------------------------------------------------------------------------------------- FOOD, BEVERAGE & TOBACCO -- 1.0% Brewers -- 0.4% 1,000,000 BBB+/Baa2 Anheuser-Busch InBev Worldwide, Inc., 2.5%, 3/26/13 $ 1,016,438 - --------------------------------------------------------------------------------------------------------- Packaged Foods & Meats -- 0.4% 1,000,000 BBB/Baa2 WM Wrigley Jr Co., 3.05%, 6/28/13 $ 1,026,406 - --------------------------------------------------------------------------------------------------------- Soft Drinks -- 0.2% 500,000 A-/Aa3 Pepsico, Inc., 5.15%, 5/15/12 $ 535,437 ------------ Total Food, Beverage & Tobacco $ 2,578,281 - --------------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.6% Health Care Facilities -- 0.1% 300,000 BB+/Baa3 Universal Health Services, Inc., 6.75%, 11/15/11 $ 313,133 - --------------------------------------------------------------------------------------------------------- Health Care Services -- 0.3% 1,000,000 BBB/Baa3 Express Scripts, Inc., 5.25%, 6/15/12 $ 1,066,777 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 26 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Managed Health Care -- 0.2% 500,000 A-/Baa1 Wellpoint, Inc., 5.0%, 1/15/11 $ 507,546 ------------ Total Health Care Equipment & Services $ 1,887,456 - --------------------------------------------------------------------------------------------------------- PHARMACEUTICALS & BIOTECHNOLOGY -- 1.1% Biotechnology -- 0.5% 900,000 BBB+/Baa3 Biogen Idec, Inc., 6.0%, 3/1/13 $ 984,637 285,000 A-/Baa2 Genzyme Corp., 3.625%, 6/15/15 302,804 ------------ $ 1,287,441 - --------------------------------------------------------------------------------------------------------- Life Sciences Tools & Services -- 0.4% 750,000 BBB-/Ba1 Life Technologies Co., 3.375%, 3/1/13 $ 771,644 475,000 A-/Baa1 Thermo Fisher Scientific, Inc., 2.15%, 12/28/12 483,809 ------------ $ 1,255,453 - --------------------------------------------------------------------------------------------------------- Pharmaceuticals -- 0.2% 500,000 AA/A1 Abbott Laboratories, Inc., 5.15%, 11/30/12 $ 548,278 ------------ Total Pharmaceuticals & Biotechnology $ 3,091,172 - --------------------------------------------------------------------------------------------------------- BANKS -- 3.7% Diversified Banks -- 2.8% 300,000 BB+/Ba1 Alfa Div Pymt Rights Finance, Inc., 7.23563%, 12/15/11 (144A) $ 284,997 1,500,000 AA-/Aa3 Barclays Bank Plc, 2.5%, 1/23/13 1,527,339 1,000,000 1.05 AA/Aa2 HSBC Bank Plc, Floating Rate Note, 8/12/13 (144A) 998,770 2,000,000 AAA/Aaa International Bank for Reconstruction, Inc., 1.25%, 6/15/12 2,010,150 1,000,000 1.33 AA/Aa2 Santander US Debt SA, Floating Rate Note, 3/30/12 (144A) 985,300 500,000 A/A3 Standard Chartered Plc, 3.85%, 4/27/15 (144A) 516,963 820,000 A+/A2 Wachovia Corp., 5.25%, 8/1/14 884,515 250,000 AA-/A1 Wells Fargo Co., 4.375%, 1/31/13 266,624 ------------ $ 7,474,658 - --------------------------------------------------------------------------------------------------------- Regional Banks -- 0.9% 300,000 BBB+/A2 American Express Bank FSB, 5.5%, 4/16/13 $ 326,233 500,000 A/A1 BB&T Corp., 5.7%, 4/30/14 560,520 500,000 A-/A2 KeyBank NA, 5.5%, 9/17/12 532,993 275,000 BBB+/A3 KeyBank NA, 5.8%, 7/1/14 300,211 500,000 BBB+/Baa1 KeyCorp, 3.75%, 8/13/15 505,453 The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 27 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Regional Banks -- (continued) 215,000 BBB+/Baa1 Keycorp, 6.5%, 5/14/13 $ 235,454 ------------ $ 2,460,864 ------------ Total Banks $ 9,935,522 - --------------------------------------------------------------------------------------------------------- DIVERSIFIED FINANCIALS -- 5.7% Asset Management & Custody Banks -- 0.1% 300,000 AA-/A1 Franklin Resources, Inc., 3.125%, 5/20/15 $ 315,240 - --------------------------------------------------------------------------------------------------------- Consumer Finance -- 0.9% 476,000 0.38 BBB+/A2 American Express Credit Corp., Floating Rate Note, 2/24/12 $ 472,301 380,000 A+/A1 American Honda Finance Corp., 6.7%, 10/1/13 (144A) 434,468 500,000 A+/A1 American Honda Finance Corp., 2.375%, 3/18/13 510,772 900,000 A+/A1 American Honda Finance Corp., 5.125%, 12/15/10 911,336 100,000 AAA/Aaa John Deere Capital Corp., 2.875%, 6/19/12 104,010 ------------ $ 2,432,887 - --------------------------------------------------------------------------------------------------------- Diversified Financial Services -- 3.7% 500,000 BBB+/A2 American Express, Inc., 5.25%, 11/21/11 $ 517,878 250,000 6.66 BB+/NR Caelus Re II, Ltd., Floating Rate Note, 5/24/13 248,200 1,000,000 A-/Baa1 Citigroup, Inc., 5.0%, 9/15/14 1,027,506 250,000 2.90 A/A3 Citigroup, Inc., Floating Rate Note, 3/16/12 245,664 500,000 NR/A2 Crown Castle Towers LLC, 3.214%, 8/15/15 (144A) 506,281 1,000,000 BBB/Baa1 GATX Corp., 5.5%, 2/15/12 1,040,807 800,000 AA+/Aa2 General Electric Capital Corp., 4.0%, 2/15/12 826,650 1,000,000 AA+/Aa2 General Electric Capital Corp., 1.101%, 12/20/13 978,727 1,000,000 AA+/Aa2 General Electric Capital Corp., 5.5%, 11/15/11 1,007,695 50,000 AA+/Aa2 General Electric Capital Corp., 5.5%, 4/28/11 51,586 500,000 0.96 A+/Aa3 JP Morgan Chase & Co., Floating Rate Note, 2/26/13 500,859 2,000,000 AAA/Aaa JPMorgan Chase & Co., 1.65%, 2/23/11 2,011,832 100,000 AAA/Aaa JPMorgan Chase & Co., 3.125%, 12/1/11 103,349 250,000 BB+/NR Lodestone Re, Ltd., 0.0%, 5/17/13 (144A) 245,100 The accompanying notes are an integral part of these financial statements. 28 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Diversified Financial Services -- (continued) 577,449 BBB/Baa2 Power Receivables Finance LLC, 6.29%, 1/1/12 (144A) $ 577,738 250,000 6.76 BB/NR Residential Reinsurance 2010, Ltd., Floating Rate Note, 6/6/13 (144A) 249,425 ------------ $ 10,139,297 - --------------------------------------------------------------------------------------------------------- Investment Banking & Brokerage -- 0.8% 340,000 A/A1 Goldman Sachs Group, Inc., 3.7%, 8/1/15 $ 344,197 500,000 A/A2 Merrill Lynch & Co., 5.45%, 2/5/13 533,702 500,000 A/A2 Morgan Stanley & Co., 5.0%, 8/31/25 494,460 800,000 2.88 A/A2 Morgan Stanley & Co., Floating Rate Note, 5/14/13 808,147 ------------ $ 2,180,506 - --------------------------------------------------------------------------------------------------------- Specialized Finance -- 0.2% 500,000 A/A2 National Rural Utilities Corp., 5.4%, 10/15/13 $ 550,755 ------------ Total Diversified Financials $ 15,618,685 - --------------------------------------------------------------------------------------------------------- INSURANCE -- 1.4% Life & Health Insurance -- 0.7% 500,000 A-/NR Jefferson-Pilot Corp., 4.75%, 1/30/14 $ 528,160 250,000 A-/Baa2 Lincoln National Corp., 4.3%, 6/15/15 263,497 500,000 BBB/A3 Principal Financial Group, Inc., 7.875%, 5/15/14 591,614 500,000 A/Baa2 Prudential Financial, Inc., 5.1%, 9/20/14 543,442 ------------ $ 1,926,713 - --------------------------------------------------------------------------------------------------------- Multi-Line Insurance -- 0.2% 50,000 AA-/A1 Allstate Life Global, Inc., 5.375%, 4/30/13 $ 55,197 500,000 AA-/Aa3 Metropolitan Life Global Funding, Inc., 2.875%, 9/17/12 513,210 ------------ $ 568,407 - --------------------------------------------------------------------------------------------------------- Reinsurance -- 0.5% 500,000 7.19 BB+/NR Blue Fin, Ltd., Floating Rate Note, 4/10/12 $ 476,850 250,000 5.81 BB+/A2 Foundation Re III, Ltd., Floating Rate Note, 2/3/14 244,125 250,000 12.03 NR/B3 Globecat, Ltd., Cat Bond, Floating Rate Note, 1/2/13 (144A) 231,300 250,000 10.25 BB-/NR Mystic Re, Ltd., Floating Rate Note, 6/7/11 250,725 ------------ $ 1,203,000 ------------ Total Insurance $ 3,698,120 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 29 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value REAL ESTATE -- 1.5% Diversified Real Estate Activities -- 0.1% 350,000 A-/A2 Westfield Group, Inc., 5.4%, 10/1/12 $ 375,690 - --------------------------------------------------------------------------------------------------------- Diversified Real Estate Investment Trust -- 0.4% 685,000 BBB+/Baa1 Dexus Finance Pty, Ltd., 7.125%, 10/15/14 $ 752,083 350,000 BBB/Baa2 Digital Realty Trust, 4.5%, 7/15/15 (144A) 354,429 ------------ $ 1,106,512 - --------------------------------------------------------------------------------------------------------- Office Real Estate Investment Trust -- 0.2% 385,000 BBB/Baa2 Mack-Cali Realty LP, 5.125%, 2/15/14 $ 408,237 - --------------------------------------------------------------------------------------------------------- Retail Real Estate Investment Trust -- 0.5% 500,000 BB/Baa3 Developers Diversified Realty, 5.375%, 10/15/12 $ 499,351 773,000 A-/A3 Simon Property Group LP, 5.0%, 3/1/12 803,602 ------------ $ 1,302,953 - --------------------------------------------------------------------------------------------------------- Specialized Real Estate Investment Trust -- 0.3% 780,000 BBB/Baa2 Hospitality Properties Trust, Inc., 7.875%, 8/15/14 $ 874,841 ------------ Total Real Estate $ 4,068,233 - --------------------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 0.2% Internet Software & Services -- 0.2% 550,000 NR/A2 GTP Towers Issuer LLC, 4.436%, 2/15/15 (144A) $ 555,535 ------------ Total Software & Services $ 555,535 - --------------------------------------------------------------------------------------------------------- TECHNOLOGY HARDWARE & EQUIPMENT -- 0.9% Communications Equipment -- 0.0% 50,000 A+/A1 Cisco Systems Inc., 5.25%, 2/22/11 $ 51,107 - --------------------------------------------------------------------------------------------------------- Electronic Equipment & Instruments -- 0.5% 500,000 BBB-/Baa3 Agilent Technologies, Inc., 2.5%, 7/15/13 $ 508,765 620,000 BBB-/NR Agilent Technologies, Inc., 5.5%, 9/14/15 694,597 ------------ $ 1,203,362 - --------------------------------------------------------------------------------------------------------- Office Electronics -- 0.4% 500,000 BBB-/Baa2 Xerox Corp., 5.5%, 5/15/12 $ 533,565 500,000 BBB-/Baa2 Xerox Corp., 6.875%, 8/15/11 525,080 ------------ $ 1,058,645 ------------ Total Technology Hardware & Equipment $ 2,313,114 - --------------------------------------------------------------------------------------------------------- SEMICONDUCTORS -- 0.3% 750,000 BBB/Baa1 Maxim Integrated Products, Inc., 3.45%, 6/14/13 $ 770,740 ------------ Total Semiconductors $ 770,740 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 30 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value TELECOMMUNICATION SERVICES -- 0.6% Integrated Telecommunication Services -- 0.6% 750,000 BBB/Baa2 Telecom Italia Capital SA, 4.95%, 9/30/14 (b) $ 788,299 720,000 BBB/Baa2 Telecom Italia Capital, SA, 4.875%, 10/1/10 722,322 ------------ $ 1,510,621 ------------ Total Telecommunication Services $ 1,510,621 - --------------------------------------------------------------------------------------------------------- UTILITIES -- 0.9% Electric Utilities -- 0.9% 1,000,000 BBB+/Baa1 FPL Group Capital, Inc., 2.55%, 11/15/13 $ 1,022,987 1,000,000 A-/A3 Iberdrola Finance Ireland, Ltd., 3.8%, 9/11/14 (144A) 1,020,903 500,000 BBB+/Baa1 Midamerican Energy Holdings Co., 3.15%, 7/15/12 517,141 ------------ $ 2,561,031 ------------ Total Utilities $ 2,561,031 - --------------------------------------------------------------------------------------------------------- TOTAL CORPORATE BONDS (Cost $63,435,139) $ 65,498,202 - --------------------------------------------------------------------------------------------------------- U.S. GOVERNMENT AND AGENCY OBLIGATIONS -- 29.4% 106,615 AAA/WR Federal Home Loan Bank, 4.84%, 1/25/12 $ 112,292 415,794 AAA/Aaa Federal Home Loan Mortgage Corp., 4.5%, 9/1/12 430,420 545,447 AAA/Aaa Federal Home Loan Mortgage Corp., 5.0%, 9/1/11 - 2/1/21 575,356 444,175 AAA/Aaa Federal Home Loan Mortgage Corp., 5.505%, 12/1/31 457,051 10,928 AAA/Aaa Federal Home Loan Mortgage Corp., 5.79%, 11/1/31 11,350 136,319 AAA/Aaa Federal Home Loan Mortgage Corp., 6.064%, 11/1/40 138,328 783,831 AAA/Aaa Federal Home Loan Mortgage Corp., 6.134%, 10/1/31 819,072 13,988 AAA/Aaa Federal Home Loan Mortgage Corp., 6.303%, 7/1/18 14,618 642,921 AAA/Aaa Federal Home Loan Mortgage Corp., 6.44%, 10/1/36 684,834 76,028 AAA/Aaa Federal Home Loan Mortgage Corp., 6.5%, 3/1/11 - 6/1/17 81,432 7,349 AAA/Aaa Federal Home Loan Mortgage Corp., 6.533%, 11/1/25 7,670 The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 31 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value U.S. Government and Agency Obligations -- (continued) 3,759 AAA/Aaa Federal Home Loan Mortgage Corp., 6.571%, 4/1/29 $ 3,910 4,079 AAA/Aaa Federal Home Loan Mortgage Corp., 6.837%, 4/1/28 4,268 10,538 AAA/Aaa Federal Home Loan Mortgage Corp., 6.985%, 5/1/25 11,103 4,739 AAA/Aaa Federal Home Loan Mortgage Corp., 7.035%, 4/1/29 4,855 5,881 AAA/Aaa Federal Home Loan Mortgage Corp., 7.142%, 1/1/28 6,148 184,242 AAA/Aaa Federal Home Loan Mortgage Corp., 7.245%, 8/1/31 193,037 1,740 AAA/Aaa Federal Home Loan Mortgage Corp., 7.25%, 8/1/31 1,795 221,346 AAA/Aaa Federal Home Loan Mortgage Corp., 7.3%, 10/1/32 229,573 120,113 AAA/Aaa Federal Home Loan Mortgage Corp., 7.393%, 11/1/24 120,665 23,370 AAA/Aaa Federal Home Loan Mortgage Corp., 7.484%, 2/1/27 24,524 51,905 AAA/Aaa Federal Home Loan Mortgage Corp., 7.652%, 4/1/25 54,225 75,136 AAA/Aaa Federal Home Loan Mortgage Corp., 7.680%, 1/1/25 75,707 2,686 AAA/Aaa Federal Home Loan Mortgage Corp., 7.936%, 2/1/33 2,813 1,980,339 AAA/Aaa Federal National Mortgage Association, 4.0%, 5/1/24 2,082,013 3,633,239 AAA/Aaa Federal National Mortgage Association, 4.5%, 7/1/19 3,869,729 254,355 AAA/Aaa Federal National Mortgage Association, 5.0%, 7/1/15 265,973 121,798 AAA/Aaa Federal National Mortgage Association, 5.469%, 7/1/36 127,865 859,974 AAA/Aaa Federal National Mortgage Association, 5.5%, 1/1/12 - 12/1/35 924,960 2,374,982 AAA/Aaa Federal National Mortgage Association, 6.0%, 2/1/24 - 1/1/39 2,562,590 546,467 AAA/Aaa Federal National Mortgage Association, 6.339%, 12/1/36 569,786 958,781 AAA/Aaa Federal National Mortgage Association, 6.5%, 8/1/13 - 7/1/32 1,058,835 1,189,513 AAA/Aaa Federal National Mortgage Association, 7.0%, 5/1/12 - 1/1/36 1,303,521 96,082 AAA/Aaa Federal National Mortgage Association, 7.243%, 12/1/28 100,496 The accompanying notes are an integral part of these financial statements. 32 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value U.S. Government and Agency Obligations -- (continued) 102,890 AAA/Aaa Federal National Mortgage Association, 7.405%, 10/1/29 $ 106,554 248,457 AAA/Aaa Federal National Mortgage Association, 7.586%, 10/1/29 260,074 107,016 AAA/Aaa Federal National Mortgage Association, 8.0%, 4/1/14 114,373 17,964,010 AAA/Aa1 Government National Mortgage Association, 1.524, 2/16/52 1,231,573 2,500,000 NR/NR Government National Mortgage Association, 2.351%, 6/16/50 2,549,023 1,000,000 AAA/Aaa Government National Mortgage Association, 3.025%, 2/16/30 1,041,045 501,357 AAA/Aa1 Government National Mortgage Association, 3.084%, 4/16/22 510,251 121,095 AAA/Aa1 Government National Mortgage Association, 4.009%, 5/16/37 128,583 350,000 AAA/Aa1 Government National Mortgage Association, 4.549%, 6/16/28 374,773 1,892,065 AAA/Aaa Government National Mortgage Association, 6.0%, 5/20/13 - 11/15/36 2,058,195 1,023,011 NR/Aaa Government National Mortgage Association, 6.269%, 10/16/27 1,080,499 248,142 AAA/Aaa Government National Mortgage Association, 6.5%, 5/15/31 - 10/15/37 275,061 25,303 AAA/Aaa Government National Mortgage Association, 7.0%, 11/15/13 26,884 298,051 AAA/Aaa Government National Mortgage Association, 7.5%, 8/15/11 - 10/15/36 330,845 17,330,998 0.71 NR/NR Government National Mortgage Association, Floating Rate Note, 11/16/51 778,117 512,357 4.65 AAA/Aaa Government National Mortgage Association, Floating Rate Note, 6/16/31 524,758 7,000,000 AAA/Aaa U.S. Treasury Notes, 0.875%, 5/31/11 7,032,816 16,000,000 AAA/Aaa U.S. Treasury Notes, 1.0%, 7/31/11 16,104,368 4,000,000 AAA/Aaa U.S. Treasury Notes, 1.5%, 7/15/12 4,079,844 2,000,000 AAA/Aaa U.S. Treasury Notes, 1.7%, 9/15/12 2,049,922 5,000,000 AAA/Aaa U.S. Treasury Notes, 1.875%, 6/15/12 5,127,735 13,500,000 NR/Aaa U.S. Treasury Notes, 2.5%, 4/30/15 14,273,091 1,000,000 NR/Aaa U.S. Treasury Notes, 1.0%, 10/31/11 1,007,500 2,000,000 AAA/Aaa U.S. Treasury Notes, 1.375%, 9/15/12 2,035,311 ------------ $ 80,032,009 - --------------------------------------------------------------------------------------------------------- TOTAL U.S. GOVERNMENT AND AGENCY OBLIGATIONS (Cost $78,338,389) $ 80,032,009 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 33 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value FOREIGN GOVERNMENT BOND -- 0.1% 250,000 A/A1 Korea Development Bank, 5.3%, 1/17/13 $ 266,107 - --------------------------------------------------------------------------------------------------------- TOTAL FOREIGN GOVERNMENT BOND (Cost $249,643) $ 266,107 - --------------------------------------------------------------------------------------------------------- MUNICIPAL BONDS -- 0.5% Municipal General -- 0.5% 500,000 AA/Aa1 OH INFRA-TXB-2-BABS, 3.0%, 6/15/15 $ 516,255 760,000 A+/A1 State of Illinois, 3.321%, 1/1/13 756,952 ------------ $ 1,273,207 - --------------------------------------------------------------------------------------------------------- TOTAL MUNICIPAL BONDS (Cost $1,270,131) $ 1,273,207 - --------------------------------------------------------------------------------------------------------- SENIOR FLOATING RATE LOAN INTERESTS -- 1.8%** MATERIALS -- 0.3% Metal & Glass Containers -- 0.2% 228,571 5.50 B+/Ba3 BWAY Holding Co., B Term Loan, 6/16/17 $ 229,144 153,396 6.75 B+/B2 Graham Packaging Co., Term C Loan, 4/5/14 154,807 16,233 2.58 B+/B2 Graham Packaging Co., Term B Loan, 10/7/11 16,217 21,429 5.50 B+/Ba3 ICL Industrial Containers, Inc., C Term Loan, 6/16/17 21,482 ------------ $ 421,650 - --------------------------------------------------------------------------------------------------------- Paper Packaging -- 0.1% 263,115 3.28 BB/Ba2 Graphic Packaging International, Inc., Incremental Term Loan, 5/16/14 $ 259,267 ------------ Total Materials $ 680,917 - --------------------------------------------------------------------------------------------------------- CAPITAL GOODS -- 0.1% Aerospace & Defense -- 0.1% 350,000 4.50 NR/NR Triumph Group, Inc., U.S. Term II Loan, 6/16/16 $ 351,969 ------------ Total Capital Goods $ 351,969 - --------------------------------------------------------------------------------------------------------- COMMERCIAL SERVICES & SUPPLIES -- 0.1% Environmental & Facilities Services -- 0.1% 194,975 2.28 D/B2 Synagro Technologies, Inc., 1st Lien Term Loan, 4/2/14 $ 165,891 ------------ Total Commercial Services & Supplies $ 165,891 - --------------------------------------------------------------------------------------------------------- CONSUMER SERVICES -- 0.0% Casinos & Gaming -- 0.0% 16,583 3.05 NR/NR Gateway Casinos & Entertainment, Delayed Draw Term Loan, 9/30/14 (e) $ 16,169 The accompanying notes are an integral part of these financial statements. 34 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Casinos & Gaming -- (continued) 81,875 3.05 NR/NR Gateway Casinos & Entertainment, Inc., Term Advance Loan, 9/30/14 (e) $ 79,828 ------------ $ 95,997 ------------ Total Consumer Services $ 95,997 - --------------------------------------------------------------------------------------------------------- MEDIA -- 0.3% Movies & Entertainment -- 0.3% 482,500 5.25 NR/NR Christie/AIX Inc., Term Loan, 4/29/16 $ 479,484 199,500 4.50 B+/NR Live Nation Entertainment, Inc., Term B Loan, 11/7/16 196,092 ------------ $ 675,576 ------------ Total Media $ 675,576 - --------------------------------------------------------------------------------------------------------- RETAILING -- 0.1% Automotive Retail -- 0.1% 250,000 6.00 NR/NR Autotrader Com, Inc., Tranche B Term Loan, 6/14/16 $ 250,781 ------------ Total Retailing $ 250,781 - --------------------------------------------------------------------------------------------------------- HEALTH CARE EQUIPMENT & SERVICES -- 0.3% Health Care Facilities -- 0.2% 18,633 2.55 BB -/Ba3 CHS/Community Health Systems, Inc., Delayed Draw Term Loan, 7/25/14 $ 17,605 363,172 2.55 BB -/Ba3 CHS/Community Health Systems, Inc., Funded Term Loan, 7/25/14 343,135 66,511 2.18 B +/Ba2 Psychiatric Solutions, Inc., Term Loan, 7/1/12 66,137 21,375 3.64 B +/Ba2 Sun Health Care, Inc., Term Loan, 4/19/14 20,894 12,680 4.33 B +/Ba2 Sun Health Care, Inc., Synthetic LC Loan, 4/19/14 12,394 ------------ $ 460,165 - --------------------------------------------------------------------------------------------------------- Health Care Services -- 0.0% 238,578 6.00 B B/Ba3 RehabCare Group, Inc., Term Loan B, 11/24/15 $ 236,550 - --------------------------------------------------------------------------------------------------------- Health Care Supplies -- 0.1% 198,199 3.51 B B-/B1 Bausch & Lomb, Inc., Parent Term Loan, 4/24/15 $ 190,384 48,004 3.51 B B-/B1 Bausch & Lomb, Inc., Delayed Draw Term Loan, 4/24/15 46,111 ------------ $ 236,495 ------------ Total Health Care Equipment & Services $ 933,210 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 35 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value DIVERSIFIED FINANCIALS -- 0.1% Investment Banking & Brokerage -- 0.1% 149,625 5.25 B+/Ba3 LPL Holdings, Inc., 2017 Term Loan, 6/28/17 $ 148,877 ------------ Total Diversified Financials $ 148,877 - --------------------------------------------------------------------------------------------------------- SOFTWARE & SERVICES -- 0.2% Data Processing & Outsourced Services -- 0.1% 250,000 5.25 BBB-/Ba1 Fidelity National Information Services, Inc., Term B Loan, 7/18/16 $ 251,741 - --------------------------------------------------------------------------------------------------------- IT Consulting & Other Services -- 0.1% 389,899 2.04 BB/Ba3 Sungard Data Systems, Inc., Tranche A U.S. Term Loan, 2/28/14 $ 373,328 ------------ Total Software & Services $ 625,069 - --------------------------------------------------------------------------------------------------------- TELECOMMUNICATION SERVICES -- 0.3% Integrated Telecommunication Services -- 0.3% 344,138 6.50 BB/Ba3 Cincinnati Bell, Inc., Tranche B Term Loan, 6/11/17 $ 342,632 40,048 3.27 NR/NR Telesat Canada, Inc., U.S. Term II Loan, 10/31/14 38,824 466,240 3.27 NR/NR Telesat Canada, Inc., U.S. Term I Loan, 10/31/14 451,993 ------------ $ 833,449 ------------ Total Telecommunication Services $ 833,449 - --------------------------------------------------------------------------------------------------------- TOTAL SENIOR FLOATING RATE LOAN INTERESTS (Cost $4,715,756) $ 4,761,736 - --------------------------------------------------------------------------------------------------------- TEMPORARY CASH INVESTMENTS -- 8.5% REPURCHASE AGREEMENTS -- 8.3% 4,500,000 Bank of America, Inc., 0.25%, dated 8/31/10, repurchase price of $4,500,000 plus accrued interest on 9/1/10 collateralized by the following: $3,379,652 Freddie Mac Giant, 5.5%, 8/1/25 $1,210,348 Federal National Mortgage Association, 4.5%, 3/1/40 $ 4,500,000 4,500,000 BNP Paribas SA, 0.25%, dated 8/31/10, repurchase price of $4,500,000 plus accrued interest on 9/1/10 collateralized by $4,590,000 Freddie Mac Giant, 4.0 - 5.5%, 8/1/25 - 3/1/40 4,500,000 The accompanying notes are an integral part of these financial statements. 36 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Repurchase Agreements -- (continued) 4,500,000 Deutsche Bank Securities, Inc, 0.25%, dated 7/31/10, repurchase price of $4,500,000 plus accrued interest on 9/1/10 collateralized by $4,590,000 Freddie Mac Giant, 4.0%, 8/1/40 $ 4,500,000 4,500,000 JPMorgan Securities, Inc., 0.24%, dated 8/31/10, repurchase price of $4,500,000 plus accrued interest on 9/1/10 collateralized by $4,590,118 Federal National Mortgage Association, 4.5%, 7/1/39 4,500,000 4,500,000 SG Americas Securities LLC, 0.25%, dated 8/31/10, repurchase price of $4,500,000 plus accrued interest on 9/1/10 collateralized by $4,590,002 U.S. Treasury Note, 0.75%, 11/30/11 4,500,000 ------------ Total Repurchase Agreements $ 22,500,000 - --------------------------------------------------------------------------------------------------------- SECURITIES LENDING COLLATERAL -- 0.2% (c) Certificates of Deposit: 15,886 Bank of Nova Scotia, 0.47%, 9/7/10 $ 15,886 11,120 BBVA Group NY, 0.51%, 7/26/11 11,120 15,886 BNP Paribas Bank NY, 0.38%, 11/8/10 15,886 7,943 DNB Nor Bank ASA NY, 0.27%, 11/10/10 7,943 15,886 Nordea NY, 0.50%, 12/10/10 15,886 15,886 RoboBank Netherland NV NY, 0.44%, 8/8/11 15,886 15,886 Royal Bank of Canada NY, 0.26%, 1/21/11 15,886 15,886 SocGen NY, 0.34%, 11/10/10 15,886 7,943 Svenska NY, 0.275%, 11/12/10 7,943 ------------ $ 122,322 - --------------------------------------------------------------------------------------------------------- Commercial Paper: 9,531 American Honda Finance, 0.33%, 5/4/11 $ 9,531 6,394 American Honda Finance, 1.29%, 6/20/11 6,394 5,848 Australia & New Zealand Banking Group, 1.04%, 8/4/11 5,848 7,551 Caterpillar Financial Services Corp., 1.29%, 6/24/11 7,551 17,474 CBA, 0.56%, 1/3/11 17,474 3,176 CHARFD, 0.38%, 10/15/10 3,176 11,110 CHARFD, 0.31%, 12/14/10 11,110 6,351 CLIPPR, 0.45%, 10/8/10 6,351 9,525 CLIPPR, 0.28%, 12/1/10 9,525 The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 37 Schedule of Investments | 8/31/10 (continued) Floating S&P/Moody's Principal Rate (d) Ratings Amount ($) (unaudited) (unaudited) Value Commercial Paper: -- (continued) 9,531 CLIPPR, 0.45%, 9/1/10 $ 9,531 5,128 FAIRPP, 0.30%, 11/9/10 5,128 6,350 FASCO, 0.27%, 12/1/10 6,350 7,307 FASCO, 0.45%, 9/9/10 7,307 7,943 FASCO, 0.46%, 9/2/10 7,943 15,888 Federal Home Loan Bank, 0.37%, 6/1/11 15,888 7,942 GE Corp., 0.548%, 1/26/11 7,942 1,587 General Electric Capital Corp., 0.61%, 6/6/11 1,587 1,732 General Electric Capital Corp., 0.59%, 10/6/10 1,732 1,720 General Electric Capital Corp., 0.62%, 10/21/10 1,720 13,426 JPMorgan Chase & Co., 0.89%, 09/24/10 13,426 7,942 RANGER, 0.25%, 9/13/10 7,942 12,701 SANTANDER, 0.43%, 10/22/10 12,701 3,176 SRCPP, 0.38%, 10/12/10 3,176 4,764 STRAIT, 0.36%, 10/4/10 4,764 7,939 TBLLC, 0.38%, 10/12/10 7,939 7,942 TBLLC, 0.24%, 9/10/10 7,942 15,886 Toyota Motor Credit Corp., 0.29%, 1/10/11 15,886 15,877 VARFUN, 0.35%, 10/25/10 15,877 9,532 Wachovia, 0.69%, 3/22/11 9,532 15,886 Westpac, 0.50%, 7/29/11 15,886 6,354 WFC, 0.61%, 12/2/10 6,354 ------------ $ 263,513 - --------------------------------------------------------------------------------------------------------- Tri-party Repurchase Agreements: 29,139 Barclays Capital Markets, 0.24%, 9/1/10 $ 29,139 39,714 Deutsche Bank Securities, Inc., 0.24%, 9/1/10 39,714 15,886 HSBC Bank USA NA, 0.24%, 9/1/10 15,886 31,771 RBS Securities, Inc., 0.25%, 9/1/10 31,771 ------------ $ 116,510 - --------------------------------------------------------------------------------------------------------- Shares - --------------------------------------------------------------------------------------------------------- Money Market Mutual Funds 15,883 Blackrock Liquidity Temporary Cash Fund $ 15,883 15,886 Dreyfus Preferred Money Market Fund 15,886 15,886 Fidelity Prime Money Market Fund 15,886 ------------ $ 47,655 ------------ Total Securities Lending Collateral $ 550,000 - --------------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 38 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Shares Value TOTAL TEMPORARY CASH INVESTMENTS (Cost $23,050,000) $ 23,050,000 - --------------------------------------------------------------------------------------------------------- TOTAL INVESTMENT IN SECURITIES -- 101.1% (Cost $274,308,694) (a) $274,120,287 - --------------------------------------------------------------------------------------------------------- OTHER ASSETS AND LIABILITIES -- (1.1)% $ (3,114,349) - --------------------------------------------------------------------------------------------------------- TOTAL NET ASSETS -- 100.0% $271,005,938 ========================================================================================================= NR Not rated by either S&P or Moody's. WR Withdrawn rating. (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 August 31, 2010, the value of these securities amounted to $12,784,480 or 4.7% of total 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 United States banks, (iii) the certificate of deposit or (iv) other base lending rates used by commercial lenders. The rate shown is the coupon rate at period end. (a) At August 31, 2010, the net unrealized loss on investments based on cost for federal income tax purposes of $274,615,248 was as follows: Aggregate gross unrealized gain for all investments in which there is an excess of value over tax cost $5,098,089 Aggregate gross unrealized loss for all investments in which there is an excess of tax cost over value (5,593,050) ---------- Net unrealized loss $ (494,961) ========== (b) At August 31, 2010, the following security was out on loan: - -------------------------------------------------------------------------------- Principal Amount ($) Security Value - -------------------------------------------------------------------------------- 500,000 Telecom Italia Capital SA, 4.95%, 9/30/14 $525,533 ================================================================================ (c) Securities lending collateral is managed by Credit Suisse AG, New York Branch. (d) Debt obligation with a variable interest rate. Rate shown is rate at end of period. (e) Security is in default and is non-income producing. The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 39 Schedule of Investments | 8/31/10 (continued) Purchases and sales of securities (excluding temporary cash investments) for the year ended August 31, 2010 were as follows: - -------------------------------------------------------------------------------- Purchases Sales - -------------------------------------------------------------------------------- Long-Term U.S. Government $ 66,465,073 $23,793,411 - -------------------------------------------------------------------------------- Other Long-Term Securities $128,329,880 $49,567,645 - -------------------------------------------------------------------------------- Various inputs are used in determining the value of the Fund's investments. These inputs are summarized in the three broad levels listed below. Highest priority is given to Level 1 inputs and lowest priority is given to Level 3. 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.) Level 3 -- significant unobservable inputs (including the Fund's own assumptions in determining fair value of investments) The following is a summary of the inputs used as of August 31, 2010, in valuing the Fund's assets: - -------------------------------------------------------------------------------------------------------- Level 1 Level 2 Level 3 Total - -------------------------------------------------------------------------------------------------------- Convertible Corporate Bonds $ -- $ 141,575 $ -- $ 141,575 Asset Backed Securities -- 33,801,893 -- 33,801,893 Collateralized Mortgage Obligations -- 64,895,384 -- 64,895,384 Collateralized Mortgage Obligations (Banks) -- -- 400,174 400,174 Corporate Bonds -- 65,498,202 -- 65,498,202 U.S. Government Agency Obligations -- 80,032,009 -- 80,032,009 Foreign Government Bonds -- 266,107 -- 266,107 Municipal Bonds -- 1,273,207 -- 1,273,207 Senior Floating Rate Loan Interests -- 4,761,736 -- 4,761,736 Temporary Cash Investments -- 23,002,345 -- 23,002,345 Money Market Mutual Funds 47,655 -- -- 47,655 - -------------------------------------------------------------------------------------------------------- Total $47,655 $273,672,458 $400,174 $274,120,287 ======================================================================================================== The accompanying notes are an integral part of these financial statements. 40 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Following is a reconciliation of assets using significant unobservable inputs (Level 3): - --------------------------------------------------------------------------------------------- Asset Backed Collateralized Securities Mortgage Obligations - --------------------------------------------------------------------------------------------- Balance as of 8/31/09 $ 287,229 $ 693,277 Realized gain (loss)(1) 70 -- Change in unrealized appreciation (depreciation)(2) (82,709) (293,103) Net purchases (sales) -- -- Transfers in and out of Level 3* (204,590) -- - --------------------------------------------------------------------------------------------- Balance as of 8/31/10 $ -- $ 400,174 ============================================================================================= 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 gain (loss) on investments in the Statement of Operations. * Transfers are calculated on the beginning of period values. Net change in unrealized appreciation (depreciation) of investments still held as of 8/31/10 $282,885 -------- The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 41 Statement of Assets and Liabilities | 8/31/10 ASSETS: Investment in securities (including securities loaned of $525,533) (cost $274,308,694) $274,120,287 Foreign currencies, at value (cost $16,771) 15,894 Receivables -- Paydown 107,625 Fund shares sold 1,753,117 Forward foreign currency portfolio hedge contracts, open -- net 25,439 Dividends and interest 1,408,039 Due from Pioneer Investment Management, Inc. 75,564 Other 36,857 - -------------------------------------------------------------------------------------- Total assets $277,542,822 - -------------------------------------------------------------------------------------- LIABILITIES: Payables -- Investment securities purchased $ 3,562,276 Fund shares repurchased 733,624 Dividends 272,571 Forward foreign currency settlement contracts, net 2,061 Upon return of securities loaned 550,000 Due to bank 1,312,513 Due to affiliates 32,110 Accrued expenses 71,729 - -------------------------------------------------------------------------------------- Total liabilities $ 6,536,884 - -------------------------------------------------------------------------------------- NET ASSETS: Paid-in capital $279,379,917 Distributions in excess of net investment income (59,804) Accumulated net realized loss on investments and foreign currency transactions (8,148,166) Net unrealized loss on investments (188,407) Net unrealized gain on forward foreign currency contracts and other assets and liabilities denominated in foreign currencies 22,398 - -------------------------------------------------------------------------------------- Total net assets $271,005,938 ====================================================================================== NET ASSET VALUE PER SHARE: (No par value, unlimited number of shares authorized) Class A (based on $130,523,772/13,386,231 shares) $ 9.75 Class B (based on $4,821,574/494,600 shares) $ 9.75 Class C (based on $20,507,219/2,107,110 shares) $ 9.73 Class Y (based on $115,153,373/11,822,496 shares) $ 9.74 MAXIMUM OFFERING PRICE: Class A ($9.75 [divided by] 97.5%) $ 10.00 ====================================================================================== The accompanying notes are an integral part of these financial statements. 42 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Statement of Operations For the Year Ended 8/31/10 INVESTMENT INCOME: Interest $7,178,388 Income from securities loaned, net 902 - ------------------------------------------------------------------------------------------------------ Total investment income $ 7,179,290 - ------------------------------------------------------------------------------------------------------ EXPENSES: Management fees $ 724,050 Transfer agent fees and expenses Class A 85,492 Class B 14,428 Class C 15,023 Class Y 1,411 Distribution fees Class A 127,883 Class B 58,907 Class C 141,785 Shareholder communications expense 48,215 Administrative reimbursements 56,874 Custodian fees 15,267 Registration fees 72,209 Professional fees 66,332 Printing expense 44,457 Fees and expenses of nonaffiliated trustees 5,629 Miscellaneous 45,912 - ------------------------------------------------------------------------------------------------------ Total expenses $ 1,523,874 Less fees waived and expenses reimbursed by Pioneer Investment Management, Inc. (87,662) - ------------------------------------------------------------------------------------------------------ Net expenses $ 1,436,212 - ------------------------------------------------------------------------------------------------------ Net investment income $ 5,743,078 - ------------------------------------------------------------------------------------------------------ REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS, AND FOREIGN CURRENCY TRANSACTIONS: Net realized loss on: Investments $ (381,921) Forward foreign currency contracts and other assets and liabilities denominated in foreign currencies (21,760) $ (403,681) - ------------------------------------------------------------------------------------------------------ Change in net unrealized gain on: Investments $6,972,512 Forward foreign currency contracts and other assets and liabilities denominated in foreign currencies 36,009 $ 7,008,521 - ------------------------------------------------------------------------------------------------------ Net gain on investments and foreign currency transactions $ 6,604,840 - ------------------------------------------------------------------------------------------------------ Net increase in net assets resulting from operations $12,347,918 ====================================================================================================== The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 43 Statements of Changes in Net Assets For the Years Ended 8/31/10 and 8/31/09, respectively - -------------------------------------------------------------------------------------------------- Year Ended Year Ended 8/31/10 8/31/09 - -------------------------------------------------------------------------------------------------- FROM OPERATIONS: Net investment income $ 5,743,078 $ 4,938,682 Net realized loss on investments and foreign currency transactions (403,681) (126,966) Change in net unrealized gain (loss) on investments and foreign currency transactions 7,008,521 (1,870,045) - -------------------------------------------------------------------------------------------------- Net increase in net assets resulting from operations $ 12,347,918 $ 2,941,671 - -------------------------------------------------------------------------------------------------- DISTRIBUTIONS TO SHAREOWNERS: Net investment income: Class A ($0.32 and $0.46 per share, respectively) $ (1,529,659) $ (705,053) Class B ($0.23 and $0.38 per share, respectively) (144,001) (273,250) Class C ($0.24 and $0.39 per share, respectively) (336,754) (261,030) Class Y ($0.35 and $0.49 per share, respectively) (3,945,313) (5,053,655) - -------------------------------------------------------------------------------------------------- Total distributions to shareowners $ (5,955,727) $ (6,292,988) - -------------------------------------------------------------------------------------------------- FROM FUND SHARE TRANSACTIONS: Net proceeds from sale of shares $194,603,188 $ 51,674,970 Shares issued in reorganization -- 2,948,475 Reinvestment of distributions 1,588,208 3,962,554 Cost of shares repurchased (63,622,492) (76,403,252) - -------------------------------------------------------------------------------------------------- Net increase (decrease) in net assets resulting from Fund share transactions $132,568,904 $(17,817,253) - -------------------------------------------------------------------------------------------------- Net increase (decrease) in net assets $138,961,095 $(21,168,570) NET ASSETS: Beginning of year 132,044,843 153,213,413 - -------------------------------------------------------------------------------------------------- End of year $271,005,938 $132,044,843 - -------------------------------------------------------------------------------------------------- Distributions in excess of net investment income $ (392,698) $ (55,067) - -------------------------------------------------------------------------------------------------- The accompanying notes are an integral part of these financial statements. 44 Pioneer Short Term Income Fund | Annual Report | 8/31/10 - ------------------------------------------------------------------------------------------------------- '10 Shares '10 Amount '09 Shares '09 Amount - ------------------------------------------------------------------------------------------------------- Class A Shares sold 16,135,157 $155,975,673 1,481,394 $ 13,487,157 Shares issued in reorganization -- -- 310,760 2,815,490 Reinvestment of distributions 105,459 1,018,000 62,043 564,408 Less shares repurchased (4,933,375) (47,613,013) (1,088,825) (9,952,183) - ------------------------------------------------------------------------------------------------------- Net increase 11,307,241 $109,380,660 765,372 $ 6,914,872 ======================================================================================================= Class B Shares sold 165,531 $ 1,583,923 322,005 $ 2,956,123 Reinvestment of distributions 12,250 117,431 20,043 181,876 Less shares repurchased (383,974) (3,683,579) (356,583) (3,254,647) - ------------------------------------------------------------------------------------------------------- Net decrease (206,193) $ (1,982,225) (14,535) $ (116,648) ======================================================================================================= Class C Shares sold 1,686,258 $ 16,169,023 973,568 $ 8,938,734 Reinvestment of distributions 26,006 249,635 16,344 148,199 Less shares repurchased (516,830) (4,957,407) (440,687) (3,972,471) - ------------------------------------------------------------------------------------------------------- Net increase 1,195,434 $ 11,461,251 549,225 $ 5,114,462 ======================================================================================================= Class Y Shares sold 2,190,445 $ 20,874,569 2,855,292 $ 26,292,956 Shares issued in reorganization -- -- 14,694 132,985 Reinvestment of distributions 21,180 203,142 339,487 3,068,071 Less shares repurchased (764,432) (7,368,493) (6,550,393) (59,223,951) - ------------------------------------------------------------------------------------------------------- Net increase (decrease) 1,447,193 $ 13,709,218 (3,340,920) $(29,729,939) ======================================================================================================= The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 45 Financial Highlights - --------------------------------------------------------------------------------------------------------- Year Ended Year Ended 8/31/10 8/31/09 - --------------------------------------------------------------------------------------------------------- Class A Net asset value, beginning of period $ 9.40 $ 9.52 - --------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.31 $ 0.37 Net realized and unrealized gain (loss) on investments and foreign currency transactions 0.36 (0.03) - --------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.67 $ 0.34 Distributions to shareowners: Net investment income (0.32) (0.46) - --------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.35 $ (0.12) - --------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.75 $ 9.40 ========================================================================================================= Total return* 7.19% 3.90% Ratio of net expenses to average net assets+ 0.90% 0.90% Ratio of net investment income to average net assets+ 2.78% 3.59% Portfolio turnover rate 42% 43% Net assets, end of period (in thousands) $130,524 $19,544 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 1.06% 1.15% Net investment income 2.61% 3.35% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 0.90% 0.90% Net investment income 2.78% 3.59% ========================================================================================================= - ----------------------------------------------------------------------------------------------------------------------- Year Ended Year Ended Year Ended 8/31/08 8/31/07 8/31/06 - ----------------------------------------------------------------------------------------------------------------------- Class A Net asset value, beginning of period $ 9.76 $ 9.75 $ 9.84 - ----------------------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.45 $ 0.43 $ 0.29 Net realized and unrealized gain (loss) on investments and foreign currency transactions (0.24) 0.02 (0.06) - ----------------------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.21 $ 0.45 $ 0.23 Distributions to shareowners: Net investment income (0.45) (0.44) (0.32) - ----------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ (0.24) $ 0.01 $ (0.09) - ----------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.52 $ 9.76 $ 9.75 ======================================================================================================================= Total return* 2.18% 4.68% 2.38% Ratio of net expenses to average net assets+ 0.91% 0.91% 0.90% Ratio of net investment income to average net assets+ 4.60% 4.27% 3.05% Portfolio turnover rate 34% 78% 81% Net assets, end of period (in thousands) $12,499 $13,184 $21,701 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 1.00% 1.00% 0.99% Net investment income 4.51% 4.18% 2.96% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 0.90% 0.90% 0.90% Net investment income 4.61% 4.28% 3.05% ======================================================================================================================= * 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. + Ratio with no reduction for fees paid indirectly. The accompanying notes are an integral part of these financial statements. 46 Pioneer Short Term Income Fund | Annual Report | 8/31/10 - --------------------------------------------------------------------------------------------------------- Year Ended Year Ended 8/31/10 8/31/09 - --------------------------------------------------------------------------------------------------------- Class B Net asset value, beginning of period $ 9.39 $ 9.50 - --------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.22 $ 0.28 Net realized and unrealized gain (loss) on investments and foreign currency transactions 0.37 (0.01) - --------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.59 $ 0.27 Distributions to shareowners: Net investment income (0.23) (0.38) - --------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.36 $(0.11) - --------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.75 $ 9.39 ========================================================================================================= Total return* 6.35% 3.06% Ratio of net expenses to average net assets+ 1.80% 1.80% Ratio of net investment income to average net assets+ 2.37% 3.15% Portfolio turnover rate 42% 43% Net assets, end of period (in thousands) $4,822 $6,582 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 1.88% 1.95% Net investment income 2.29% 3.00% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 1.80% 1.80% Net investment income 2.37% 3.15% ========================================================================================================= - ----------------------------------------------------------------------------------------------------------------------- Year Ended Year Ended Year Ended 8/31/08 8/31/07 8/31/06 - ----------------------------------------------------------------------------------------------------------------------- Class B Net asset value, beginning of period $ 9.75 $ 9.75 $ 9.84 - ----------------------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.36 $ 0.34 $ 0.20 Net realized and unrealized gain (loss) on investments and foreign currency transactions (0.25) 0.01 (0.05) - ----------------------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.11 $ 0.35 $ 0.15 Distributions to shareowners: Net investment income (0.36) (0.35) (0.24) - ----------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $(0.25) $ -- $ (0.09) - ----------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.50 $ 9.75 $ 9.75 ======================================================================================================================= Total return* 1.16% 3.64% 1.56% Ratio of net expenses to average net assets+ 1.80% 1.82% 1.80% Ratio of net investment income to average net assets+ 3.72% 3.37% 2.14% Portfolio turnover rate 34% 78% 81% Net assets, end of period (in thousands) $6,798 $8,969 $14,959 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 1.85% 1.88% 1.82% Net investment income 3.67% 3.31% 2.12% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 1.80% 1.80% 1.80% Net investment income 3.72% 3.39% 2.14% ======================================================================================================================= * 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. + Ratio with no reduction for fees paid indirectly. The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 47 Financial Highlights (continued) - ---------------------------------------------------------------------------------------------------------- Year Ended Year Ended 8/31/10 8/31/09 - ---------------------------------------------------------------------------------------------------------- Class C Net asset value, beginning of period $ 9.38 $ 9.49 - ---------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.23 $ 0.29 Net realized and unrealized gain (loss) on investments and foreign currency transactions 0.36 (0.01) - ---------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.59 $ 0.28 Distributions to shareowners: Net investment income (0.24) (0.39) - ---------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.35 $(0.11) - ---------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.73 $ 9.38 ========================================================================================================== Total return* 6.32% 3.14% Ratio of net expenses to average net assets+ 1.70% 1.79% Ratio of net investment income to average net assets+ 2.27% 2.74% Portfolio turnover rate 42% 43% Net assets, end of period (in thousands) $20,507 $8,549 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 1.70% 1.79% Net investment income 2.27% 2.74% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 1.70% 1.79% Net investment income 2.27% 2.74% ========================================================================================================== - ---------------------------------------------------------------------------------------------------------------------- Year Ended Year Ended Year Ended 8/31/08 8/31/07 8/31/06 - ---------------------------------------------------------------------------------------------------------------------- Class C Net asset value, beginning of period $ 9.74 $ 9.73 $ 9.82 - ---------------------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.37 $ 0.35 $ 0.21 Net realized and unrealized gain (loss) on investments and foreign currency transactions (0.25) 0.01 (0.07) - ---------------------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.12 $ 0.36 $ 0.14 Distributions to shareowners: Net investment income (0.37) (0.35) (0.23) - ---------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $(0.25) $ 0.01 $(0.09) - ---------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.49 $ 9.74 $ 9.73 ====================================================================================================================== Total return* 1.25% 3.79% 1.47% Ratio of net expenses to average net assets+ 1.73% 1.72% 1.78% Ratio of net investment income to average net assets+ 3.77% 3.45% 2.16% Portfolio turnover rate 34% 78% 81% Net assets, end of period (in thousands) $3,441 $2,879 $5,964 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 1.73% 1.72% 1.78% Net investment income 3.77% 3.45% 2.16% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 1.73% 1.71% 1.78% Net investment income 3.77% 3.46% 2.16% ====================================================================================================================== * 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. + Ratio with no reduction for fees paid indirectly. The accompanying notes are an integral part of these financial statements. 48 Pioneer Short Term Income Fund | Annual Report | 8/31/10 - --------------------------------------------------------------------------------------------------------- Year Ended Year Ended 8/31/10 8/31/09 - --------------------------------------------------------------------------------------------------------- Class Y Net asset value, beginning of period $ 9.38 $ 9.51 - --------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.34 $ 0.40 Net realized and unrealized gain (loss) on investments and foreign currency transactions 0.37 (0.04) - --------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.71 $ 0.36 Distributions to shareowners: Net investment income (0.35) (0.49) - --------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ 0.36 $ (0.13) - --------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.74 $ 9.38 ========================================================================================================= Total return* 7.64% 4.11% Ratio of net expenses to average net assets+ 0.57% 0.63% Ratio of net investment income to average net assets+ 3.52% 4.36% Portfolio turnover rate 42% 43% Net assets, end of period (in thousands) $115,153 $97,370 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 0.57% 0.63% Net investment income 3.52% 4.36% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 0.57% 0.63% Net investment income 3.52% 4.36% ========================================================================================================= - ----------------------------------------------------------------------------------------------------------------------- Year Ended Year Ended Year Ended 8/31/08 8/31/07 8/31/06 - ----------------------------------------------------------------------------------------------------------------------- Class Y Net asset value, beginning of period $ 9.76 $ 9.76 $ 9.85 - ----------------------------------------------------------------------------------------------------------------------- Increase from investment operations: Net investment income $ 0.48 $ 0.45 $ 0.32 Net realized and unrealized gain (loss) on investments and foreign currency transactions (0.24) 0.02 (0.06) - ----------------------------------------------------------------------------------------------------------------------- Net increase from investment operations $ 0.24 $ 0.47 $ 0.26 Distributions to shareowners: Net investment income (0.49) (0.47) (0.35) - ----------------------------------------------------------------------------------------------------------------------- Net increase (decrease) in net asset value $ (0.25) $ -- $ (0.09) - ----------------------------------------------------------------------------------------------------------------------- Net asset value, end of period $ 9.51 $ 9.76 $ 9.76 ======================================================================================================================= Total return* 2.45% 4.96% 2.73% Ratio of net expenses to average net assets+ 0.55% 0.53% 0.53% Ratio of net investment income to average net assets+ 4.98% 4.68% 3.37% Portfolio turnover rate 34% 78% 81% Net assets, end of period (in thousands) $130,475 $189,724 $148,514 Ratios with no waiver of fees and assumption of expenses by the Adviser and no reduction for fees paid indirectly: Net expenses 0.55% 0.53% 0.53% Net investment income 4.98% 4.68% 3.37% Ratios with waiver of fees and assumption of expenses by the Adviser and reduction for fees paid indirectly: Net expenses 0.55% 0.53% 0.53% Net investment income 4.98% 4.68% 3.37% ======================================================================================================================= * 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. + Ratio with no reduction for fees paid indirectly. The accompanying notes are an integral part of these financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 49 Notes to Financial Statements | 8/31/10 1. Organization and Significant Accounting Policies Pioneer Short Term Income Fund (the Fund) is a Delaware statutory trust registered under the Investment Company Act of 1940 as a diversified, open-end management investment company. The investment objective of the Fund is to seek a high level of current income to the extent consistent with a relatively high level of stability of principal. The Fund offers three classes of shares designated as Class A, Class C, and Class Y shares. Effective as of the close of business on December 31, 2009, Class B shares are no longer offered to new or existing shareholders, except that dividends and/or capital gain distributions may continue to be reinvested in Class B shares, and shareholders may exchange their Class B shares for Class B shares of other Pioneer funds, as permitted by existing exchange privileges. 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 the flexibility to specify either per-share voting or dollar-weighted voting when submitting matters for shareholder approval. Under per-share voting, each share of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a shareholder's voting power is determined not by the number of shares owned, but by the dollar value of the shares on the record date. Each share class has exclusive voting rights with respect to matters affecting only that class, including with respect to the distribution plan for that class. There is no distribution plan for Class Y shares. Class B shares convert to Class A shares approximately eight years after the date of purchase. When interest rates rise, the prices of fixed-income securities in the Fund will generally fall. Conversely, when interest rates fall, the prices of fixed-income securities in the Fund will generally rise. Investments in the Fund are subject to possible loss due to the financial failure of underlying issuers and their inability to meet their debt obligations. 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. The Fund's financial statements have been prepared in conformity with U.S. generally accepted accounting principles that require the management of the Fund to, among other things, make estimates and assumptions that affect the 50 Pioneer Short Term Income Fund | Annual Report | 8/31/10 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 year. Actual results could differ from those estimates. The following is a summary of significant accounting policies followed by the Fund in the preparation of its financial statements, which are consistent with those policies generally accepted in the investment company industry: A. Security Valuation Security transactions are recorded as of trade date. 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. Senior floating rate loan interests (senior loans) 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. Senior loans for which no reliable price quotes are available will be valued by Loan Pricing Corporation through the use of pricing matrices to determine valuations. Fixed income securities with remaining maturity of more than sixty days are valued at 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. Valuations may be supplemented by dealers and other sources, as required. Securities for which independent pricing services 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 using fair value methods pursuant to procedures adopted by the Board of Trustees. 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. Thus, the valuation of the Fund's securities may differ from exchange prices. At August 31, 2010, one security, representing 0.1% of total net assets was valued using fair value methods (other than securities valued using prices supplied by independent pricing services). Inputs used in the valuation of a security using fair value methods include credit ratings, the financial condition of the company, current market conditions and comparable securities. Short-term fixed income securities with remaining maturities of sixty days or less generally are valued at amortized cost. Money market mutual funds are valued at net asset value. Principal amounts of mortgage-backed securities are adjusted for monthly paydowns. Premiums and discounts related to certain mortgage-backed securities are amortized or accreted in proportion to the monthly paydowns. Pioneer Short Term Income Fund | Annual Report | 8/31/10 51 All discounts/premiums on debt securities are accreted/amortized for financial reporting purposes over the life of the respective securities, and such accretion/amortization is included in interest income. Interest income, including interest on income bearing cash accounts, is recorded on the accrual basis, net of unrecoverable foreign taxes withheld at the applicable country rates. Gains and losses on sales of investments are calculated on the identified cost method for both financial reporting and federal income tax purposes. B. Foreign Currency Translation The books and records of the Fund are maintained in U.S. dollars. Amounts denominated in foreign currencies are translated into U.S. dollars using current exchange rates. Net realized gains and losses on foreign currency transactions, if any, represent, among other things, the net realized gains and losses on foreign currency contracts, disposition of foreign currencies and the difference between the amount of income accrued and the U.S. dollars actually received. Further, the effects of changes in foreign currency exchange rates on investments are not segregated in the statement of operations from the effects of changes in market price of those securities but are included with the net realized and unrealized gain or loss on investments. C. Forward Foreign Currency Contracts The Fund may enter into forward foreign currency contracts (contracts) for the purchase or sale of a specific foreign currency at a fixed price on a future date. All contracts are marked to market daily at the applicable exchange rates, and any resulting unrealized gains or losses are recorded in the Fund's financial statements. The Fund records realized gains and losses at the time a portfolio hedge is offset by entry into a closing transaction or extinguished by delivery of the currency. Risks may arise upon entering into these contracts from the potential inability of counterparties to meet the terms of the contract and from unanticipated movements in the value of foreign currencies relative to the U.S. dollar (see Note 6). D. Federal Income Taxes It is the Fund's policy to comply with the requirements of the Internal Revenue Code applicable to regulated investment companies and to distribute all of its taxable income and net realized capital gains, if any, to its shareowners. Therefore, no federal income tax provision is required. Tax years for the prior three fiscal years remain subject to examination by tax authorities. The amounts and characterizations of distributions to shareowners for financial reporting purposes are determined in accordance with federal 52 Pioneer Short Term Income Fund | Annual Report | 8/31/10 income tax rules. Therefore, the sources of the Fund's distributions may be shown in the accompanying financial statements as from or in excess of net investment income or as from net realized gain on investment transactions, or as from paid-in capital, depending on the type of book/tax differences that may exist. At August 31, 2010, The fund had a net capital loss carryforward of $7,622,625, of which, the following amounts will expire between 2011 and 2018 if not utilized: $124 in 2011, $1,200,645 in 2012, $628,614 in 2013, $975,752 in 2014, $2,520,831 in 2015, $667,204 in 2016, $566,527 in 2017 and $1,062,928 in 2018. The Fund has elected to defer $212,581 in capital losses recognized between November 1, 2009 and August 31, 2010 to its fiscal year ending August 31, 2011. At August 31, 2010, the Fund has reclassified $207,912 to increase distributions in excess of net investment income and $207,912 to increase accumulated net realized loss and foreign currency transactions, to reflect permanent book/tax differences. The reclassification has no impact on the net assets of the Fund and presents the Fund's capital accounts on a tax basis. The tax character of distributions paid during the years ended August 31, 2010 and August 31, 2009 were as follows: - -------------------------------------------------------------------------------- 2010 2009 - -------------------------------------------------------------------------------- Distributions paid from: Ordinary income $5,955,727 $6,292,988 - -------------------------------------------------------------------------------- Total $5,955,727 $6,292,988 ================================================================================ The following shows the components of distributable earnings on a federal income tax basis at August 31, 2010: - -------------------------------------------------------------------------------- 2010 - -------------------------------------------------------------------------------- Distributable earnings: Undistributed ordinary income $ 229,740 Capital loss carryforward (7,622,625) Current year post-October loss deferred (212,581) Current year dividend payable (272,571) Unrealized depreciation (495,942) - -------------------------------------------------------------------------------- Total $(8,373,979) ================================================================================ The difference between book-basis and tax-basis unrealized depreciation is attributable to the tax treatment of premium and amortization, the mark-to-market of foreign currency contracts, adjustments relating to catastrophe bonds and interest on defaulted bonds. Pioneer Short Term Income Fund | Annual Report | 8/31/10 53 E. Fund Shares The Fund records sales and repurchases of its shares as of trade date. Pioneer Funds Distributor, Inc. (PFD), the principal underwriter for the Fund and a wholly owned indirect subsidiary of UniCredit S.p.A. (UniCredit), earned approximately $5,546 in underwriting commissions on the sale of Class A shares for the year ended August 31, 2010. F. Class Allocations Income, common expenses, and realized and unrealized gains and losses are calculated at the Fund level and allocated daily to each class of shares based on its respective percentage of adjusted net assets at the beginning of the day. Distribution fees are calculated based on the average daily net asset value attributable to Class A, Class B, and Class C shares of the Fund, respectively (see Note 4). Class Y shares do not pay distribution fees. All expenses and fees paid to the transfer agent, Pioneer Investment Management Shareholder Services, Inc. (PIMSS), 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 B, Class C and Class Y shares can reflect different transfer agent and distribution expense rates. G. Repurchase Agreements With respect to repurchase agreements entered into by the Fund, the value of the underlying securities (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. The Fund's investment adviser, Pioneer Investment Management, Inc. (PIM), is responsible for determining that the value of the collateral remains at least equal to the repurchase price. H. Securities Lending The Fund lends securities in its portfolio to certain broker-dealers or other institutional investors. When entering into a securities loan transaction, the Fund typically receives cash collateral from the borrower equal to at least the fair value of the securities loaned, which is invested in temporary investments. Credit Suisse AG, New York Branch, as the Fund's securities lending 54 Pioneer Short Term Income Fund | Annual Report | 8/31/10 agent, manages the Fund's securities lending collateral. The income earned on the investment of collateral is shared with the borrower and the lending agent in payment of any rebate due to the borrower with respect to the securities loan, and in compensation for the lending agent's services to the Fund. The Fund also continues to receive payments in lieu of dividends or interest on the securities loaned. Gain or loss on the fair value of the loaned securities that may occur during the term of the loan will be for the account of the Fund. The amount of the collateral is required to be adjusted daily to reflect any price fluctuation in the fair value of the loaned securities. If the required market value of the collateral is less than the fair value of the loaned securities, the borrower is required to deliver additional collateral for the account of the Fund prior to the close of business on that day. The Fund has the right, under the lending agreement, to terminate the loan and recover the securities from the borrower with prior notice. The Fund is required to return the cash collateral to the borrower and could suffer a loss if the value of the collateral, as invested, has declined. 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. PIM has contractually agreed to limit ordinary operating expenses to the extent required to reduce Fund expenses to 0.90%, 1.80%, 1.80% and 0.79% of the average daily net assets attributable to Class A, Class B, Class C and Class Y shares, respectively. These expense limitations are in effect through January 1, 2012 for Class A shares, through January 1, 2011 for Class B and Class C shares and through June 1, 2012 for Class Y shares. 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 $3,196 in management fees, administrative costs and certain other reimbursements payable to PIM at August 31, 2010. 3. Transfer Agent PIMSS, a wholly owned indirect subsidiary of UniCredit, provides substantially all transfer agent and shareowner services to the Fund at negotiated rates. Pioneer Short Term Income Fund | Annual Report | 8/31/10 55 In addition, the Fund reimburses PIMSS for out-of-pocket expenses incurred by PIMSS related to shareholder communications activities such as proxy and statement mailings, outgoing phone calls and omnibus relationship contracts. For the year ended August 31, 2010, such out-of-pocket expenses by class of shares were as follows: - -------------------------------------------------------------------------------- Shareholder Communications: - -------------------------------------------------------------------------------- Class A $40,365 Class B 3,373 Class C 3,702 Class Y 775 - -------------------------------------------------------------------------------- Total $48,215 ================================================================================ Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $27,333 in transfer agent fees and out-of-pocket reimbursements payable to PIMSS at August 31, 2010. 4. Distribution Plan The Fund has adopted a Distribution Plan pursuant to Rule 12b-1 of the Investment Company Act of 1940 with respect to its Class A, Class B and Class C shares. Pursuant to the Plan, the Fund pays PFD 0.25% of the average daily net assets attributable to Class A shares as compensation for personal services and/or account maintenance services or distribution services with regard to Class A shares. Pursuant to the Plan, the Fund also pays PFD 1.00% of the average daily net assets attributable to Class B and Class C shares. The fee for Class B and 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 B and Class C shares. Included in "Due to affiliates" reflected on the Statement of Assets and Liabilities is $1,581 in distribution fees payable to PFD at August 31, 2010. In addition, redemptions of each class of shares (except Class Y shares) may be subject to a contingent deferred sales charge (CDSC). A CDSC of 1.00% may be imposed on redemptions of certain net asset value purchases of Class A shares within 18 months of purchase (within 12 months for purchases made on or after April 1, 2009). Class B shares that are redeemed within three years of purchase are subject to a CDSC at declining rates beginning at 2.00%, based on the lower of cost or market value of shares being redeemed. Redemptions of Class C shares within one year of purchase are subject to a CDSC of 1.00%, based on the lower of cost or market value of shares being redeemed. Shares purchased as part of an exchange remain subject to any CDSC that applied to the original purchase of those shares. There is no CDSC for Class Y shares. Proceeds from the CDSCs are paid to PFD. For the year ended August 31, 2010, CDSCs in the amount of $17,181 were paid to PFD. 56 Pioneer Short Term Income Fund | Annual Report | 8/31/10 5. Expense Offset Arrangements The Fund has entered into certain expense offset arrangements with PIMSS, resulting in a reduction in the Fund's total expenses due to interest earned on cash held by PIMSS. For the year ended August 31, 2010, the Fund's expenses were not reduced under such arrangements. 6. Forward Foreign Currency Contracts At August 31, 2010, the Fund had entered into various forward foreign currency contracts that obligate the Fund to deliver or take delivery of currencies at specified future maturity dates. Alternatively, prior to the settlement date of a forward foreign currency contract, the Fund may close out such contract by entering into an offsetting contract. At August 31, 2010, the Fund's gross forward currency settlement contracts receivable and payable were $384,085 and $386,147, respectively, resulting in a net payable of $2,061. The average number of contracts open during the year ended August 31, 2010 was 2,898,077. Open portfolio hedges at August 31, 2010 were as follows: - ----------------------------------------------------------------------------------------------- Net Net Contracts to In Exchange Settlement Unrealized Currency deliver For Date Value Gain - ----------------------------------------------------------------------------------------------- NOK (Norwegian Krone) (2,425,000) $383,946 12/31/10 $(381,443) $ 2,503 NOK (Norwegian Krone) (2,525,000) $422,659 9/3/10 $(399,723) $22,936 7. Reorganization Information On May 8, 2009, beneficial owners of Regions Morgan Keegan Select Limited Maturity Fixed Income Fund approved a proposed Agreement and Plan of Reorganization that provided for the reorganization listed below. This tax-free reorganization was accomplished on May 15, 2009 ("Closing Date"), by exchanging the assets and stated liabilities of Regions Morgan Keegan Select Limited Maturity Fixed Income Fund for shares of Pioneer Short Term Income Fund. Shareholders holding Class A, Class C and Class I shares of Regions Morgan Keegan Select Limited Maturity Fixed Income Fund received Class A, Class A and Class Y shares, respectively, of Pioneer Short Term Income Fund in the reorganization. The following charts show the details of the reorganization as of that Closing Date: Pioneer Short Term Income Fund | Annual Report | 8/31/10 57 - -------------------------------------------------------------------------------------------------- Regions Morgan Pioneer Pioneer Short Term Keegan Limited Maturity Short Term Income Fund Fixed Income Fund Income Fund (Pre-Reorganization) (Pre-Reorganization) (Post-Reorganization) - -------------------------------------------------------------------------------------------------- Net Assets Class A $14,463,249 $2,568,326 $ 17,278,739* Class B $ 6,457,009 $ -- $ 6,457,009 Class C $ 6,717,464 $ 247,164 $ 6,717,464* Class Y/I $70,142,312 $ 132,985 $ 70,275,297 - -------------------------------------------------------------------------------------------------- Total Net Assets $97,780,034 $2,948,475 $100,728,509 - -------------------------------------------------------------------------------------------------- Shares Outstanding Class A 1,596,197 340,313 1,906,957* Class B 713,308 -- 713,308 Class C 742,845 32,753 742,845* Class Y/I 7,751,275 17,619 7,765,969 Shares Issued in Reorganization Class A 310,760 Class Y 14,694 - -------------------------------------------------------------------------------------------------- Unrealized Accumulated Depreciation On Gain On Closing Date Closing Date - -------------------------------------------------------------------------------------------------- Regions Morgan Keegan Select Limited Maturity Fixed Income Fund $ (189,329) $ 16,539 - -------------------------------------------------------------------------------------------------- * On Closing Date, Class C shares of Regions Morgan Keegan Select Limited Maturity Fixed Income Fund were exchanged for Class A shares of Pioneer Short Term Income Fund. 8. Additional Disclosures about Derivative Instruments and Hedging Activities: Fair values of derivative instruments as of August 31, 2010 were as follows: - ---------------------------------------------------------------------------------------------- Derivatives Not Accounted For As Hedging Instruments Under Accounting Codification Standards (ASC) 815 (formerly FASB Statement 133) Asset Derivatives 2010 Liabilities Derivatives 2010 - ---------------------------------------------------------------------------------------------- Balance Sheet Fair Balance Sheet Fair Location Value Location Value - ---------------------------------------------------------------------------------------------- Foreign Exchange Contracts Receivables $25,439 Payables $2,061 - ---------------------------------------------------------------------------------------------- Total $25,439 $2,061 - ---------------------------------------------------------------------------------------------- 58 Pioneer Short Term Income Fund | Annual Report | 8/31/10 The effect of derivative instruments on the Statement of Operations for the year ended August 31, 2010 was as follows: - ----------------------------------------------------------------------------------------------------- Derivatives Not Accounted For As Change in Hedging Instruments Location of Gain Realized Gain Unrealized Under Accounting or (Loss) On or (Loss) Gain or (Loss) Codification Standards Derivatives on Derivatives on Derivatives (ASC) 815 (formerly Recognized Recognized Recognized FASB Statement 133) in Income in Income in Income - ----------------------------------------------------------------------------------------------------- Foreign Exchange Net realized loss on forward foreign $(21,760) Contracts currency contracts and other assets and liabilities denominated in foreign currencies Foreign Exchange Change in unrealized gain (loss) on $36,009 Contracts forward foreign currency contracts and other assets and liabilities denominated in foreign currencies 9. Subsequent Events In preparing these financial statements, PIM has evaluated the impact of all events and transactions for potential recognition or disclosure and has determined that there were no subsequent events requiring recognition or disclosure in the financial statements. Pioneer Short Term Income Fund | Annual Report | 8/31/10 59 Report of Independent Registered Public Accounting Firm To the Trustees and Shareholders of Pioneer Short Term Income Fund: - -------------------------------------------------------------------------------- We have audited the accompanying statement of assets and liabilities of Pioneer Short Term Income Fund (the Fund), including the schedule of investments, as of August 31, 2010, and the related statement of operations for the year then ended, the statements of changes in net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended. These financial statements and financial highlights are the responsibility of the Fund's management. Our responsibility is to express an opinion on these financial statements and financial highlights based on our audits. We conducted our audits in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements and financial highlights are free of material misstatement. We were not engaged to perform an audit of the Fund's internal control over financial reporting. Our audits included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the Fund's internal control over financial reporting. Accordingly, we express no such opinion. An audit also includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements and financial highlights, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. Our procedures included confirmation of securities owned as of August 31, 2010, by correspondence with the custodian, brokers and agent banks or by other appropriate auditing procedures where replies from brokers and agent banks were not received. We believe that our audits provide a reasonable basis for our opinion. In our opinion, the financial statements and financial highlights referred to above present fairly, in all material respects, the financial position of Pioneer Short Term Income Fund at August 31, 2010, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended, and the financial highlights for each of the five years in the period then ended, in conformity with U.S. generally accepted accounting principles. /s/ Ernst & Young LLP Boston, Massachusetts October 26, 2010 60 Pioneer Short Term Income Fund | Annual Report | 8/31/10 ADDITIONAL INFORMATION (unaudited) The percentages of the Fund's ordinary income distributions that are exempt from nonresident alien (NRA) tax withholding resulting from qualified interest income and qualified short term gains were 90.83% and 0.0%, respectively. Pioneer Short Term Income Fund | Annual Report | 8/31/10 61 Trustees, Officers and Service Providers Investment Adviser Pioneer Investment Management, Inc. Custodian Brown Brothers Harriman & Co. Independent Registered Public Accounting Firm Ernst & Young LLP Principal Underwriter Pioneer Funds Distributor, Inc. Legal Counsel Bingham McCutchen LLP Shareowner Services and Transfer Agent Pioneer Investment Management Shareholder Services, Inc. Trustees and Officers The Fund's Trustees and officers are listed below, together with their principal occupations during at least the past five years. Trustees who are interested persons of the Fund within the meaning of the 1940 Act are referred to as Interested Trustees. Trustees who are not interested persons of the Fund are referred to as Independent Trustees. Each of the Trustees serves as a Trustee of each of the 58 U.S. registered investment portfolios for which Pioneer serves as investment adviser (the "Pioneer Funds"). The address for all Trustees and all officers of the Fund is 60 State Street, Boston, Massachusetts 02109. 62 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Interested Trustees - -------------------------------------------------------------------------------- Position Held Length of Service Name and Age with the Fund and Term of Office - -------------------------------------------------------------------------------- John F. Cogan, Jr. (84)* Chairman of the Board, Trustee since 2004. Trustee and President Serves until a successor trustee is elected or ear- lier retirement or removal. - -------------------------------------------------------------------------------- Daniel K. Kingsbury (52)* Trustee and Executive Trustee since 2008. Vice President Serves until a successor trustee is elected or ear- lier retirement or removal. - -------------------------------------------------------------------------------- - ------------------------------------------------------------------------------------------------------------------------- Other Directorships Name and Age Principal Occupation(s) Held by Trustee - ------------------------------------------------------------------------------------------------------------------------- John F. Cogan, Jr. (84)* Non-Executive Chairman and a Director of Pioneer Investment Man- None agement USA Inc. ("PIM-USA"); Chairman and a Director of Pioneer; Chairman and Director of Pioneer Institutional Asset Management, Inc. (since 2006); Director of Pioneer Alternative Investment Manage- ment Limited (Dublin); President and a Director of Pioneer Alternative Investment Management (Bermuda) Limited and affiliated funds; Deputy Chairman and a Director of Pioneer Global Asset Management S.p.A. ("PGAM") (until April 2010); Director of PIOGLOBAL Real Estate Investment Fund (Russia) (until June 2006); Director of Nano-C, Inc. (since 2003); Director of Cole Management Inc. (since 2004); Director of Fiduciary Counseling, Inc.; President and Director of Pioneer Funds Distributor, Inc. ("PFD") (until May 2006); President of all of the Pioneer Funds; and Of Counsel, Wilmer Cutler Pickering Hale and Dorr LLP - ------------------------------------------------------------------------------------------------------------------------- Daniel K. Kingsbury (52)* Director, CEO and President of PIM-USA (since February 2007); None Director and President of Pioneer and Pioneer Institutional Asset Management, Inc. (since February 2007); Executive Vice President of all of the Pioneer Funds (since March 2007); Director of PGAM (2007-2010); Head of New Europe Division, PGAM (2000-2005); Head of New Markets Division, PGAM (2005-2007) - ------------------------------------------------------------------------------------------------------------------------- * Mr. Cogan and Mr. Kingsbury are Interested Trustees because they are officers or directors of the Fund's investment adviser and certain of its affiliates. Pioneer Short Term Income Fund | Annual Report | 8/31/10 63 Independent Trustees - ------------------------------------------------------------------- Position Held Length of Service Name and Age with the Fund and Term of Office - ------------------------------------------------------------------- David R. Bock (66) Trustee Trustee since 2005. Serves until a successor trustee is elected or ear- lier retirement or removal. - ------------------------------------------------------------------- - ---------------------------------------------------------------------------------------------------------------------------------- Other Directorships Name and Age Principal Occupation(s) Held by Trustee - ---------------------------------------------------------------------------------------------------------------------------------- David R. Bock (66) Interim Chief Executive Officer, Oxford Analytica, Inc. (privately-held Director of Enterprise Commu- research and consulting company) (2010 - present); Managing Part- nity Investment, Inc. (privately- ner, Federal City Capital Advisors (corporate advisory services com- held affordable housing finance pany) (1997-2004 and 2008-present); Executive Vice President and company) (1985 - present); Chief Financial Officer, I-trax, Inc. (publicly traded health care services Director of Oxford Analytica, company) (2004-2007); Executive Vice President and Chief Financial Inc. (2008 - present); Director Officer, Pedestal Inc. (internet-based mortgage trading company) of New York Mortgage Trust (2000-2002) (publicly-traded mortgage REIT) (2004-2009) - ---------------------------------------------------------------------------------------------------------------------------------- 64 Pioneer Short Term Income Fund | Annual Report | 8/31/10 - ------------------------------------------------------------------ Position Held Length of Service Name and Age with the Fund and Term of Office - ------------------------------------------------------------------ Mary K. Bush (62) Trustee Trustee since 2004. Serves until a successor trustee is elected or ear- lier retirement or removal. - ------------------------------------------------------------------ - ---------------------------------------------------------------------------------------------------------------------------------- Other Directorships Name and Age Principal Occupation(s) Held by Trustee - ---------------------------------------------------------------------------------------------------------------------------------- Mary K. Bush (62) President, Bush International, LLC (international financial advisory Director of Marriott Interna- firm) (1991 - present); Managing Director, Federal Housing Finance tional, Inc. (2008 - present); Board (oversight of Federal Home Loan Bank system) (1989 - 1991); Director of Discover Financial Vice President and Head of International Finance, Federal National Services (credit card issuer and Mortgage Association (1988 - 1989); U.S. Alternate Executive Direc- electronic payment services) tor, International Monetary Fund (1984 - 1988); Executive Assistant (2007 - present); Former Direc- to Deputy Secretary of the U.S. Treasury, U.S. Treasury Department tor of Briggs & Stratton Co. (1982 - 1984); Vice President and Team Leader in Corporate Bank- (engine manufacturer) ing, Bankers Trust Co. (1976 - 1982) (2004 - 2009); Director of UAL Corporation (airline holding company) (2006 - present); Director of ManTech Interna- tional Corporation (national security, defense, and intelli- gence technology firm) (2006 - present); Member, Board of Governors, Investment Company Institute (2007 - present); Former Direc- tor of Brady Corporation (2000 - 2007); Former Director of Mortgage Guaranty Insurance Corporation (1991 - 2006); Former Director of Millennium Chemicals, Inc. (commodity chemicals) (2002 - 2005); Former Director, R.J. Reynolds Tobacco Holdings, Inc. (tobacco) (1999 - 2005); Former Director of Texaco, Inc. (1997 - 2001) - ---------------------------------------------------------------------------------------------------------------------------------- Pioneer Short Term Income Fund | Annual Report | 8/31/10 65 Independent Trustees (continued) - ------------------------------------------------------------------------- Position Held Length of Service Name and Age with the Fund and Term of Office - ------------------------------------------------------------------------- Benjamin M. Friedman (65) Trustee Trustee since 2008. Serves until a successor trustee is elected or ear- lier retirement or removal. - ------------------------------------------------------------------------- Margaret B.W. Graham (63) Trustee Trustee since 2004. Serves until a successor trustee is elected or ear- lier retirement or removal. - ------------------------------------------------------------------------- Thomas J. Perna (59) Trustee Trustee since 2006. Serves until a successor trustee is elected or ear- lier retirement or removal. - ------------------------------------------------------------------------- Marguerite A. Piret (62) Trustee Trustee since 2004. Serves until a successor trustee is elected or ear- lier retirement or removal. - ------------------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------------------- Other Directorships Name and Age Principal Occupation(s) Held by Trustee - ----------------------------------------------------------------------------------------------------------------------------------- Benjamin M. Friedman (65) William Joseph Maier Professor of Political Economy, Harvard Univer- Trustee, Mellon Institutional sity (1972 - present) Funds Investment Trust and Mellon Institutional Funds Mas- ter Portfolio (oversaw 17 portfo- lios in fund complex) (1989 - 2008) - ----------------------------------------------------------------------------------------------------------------------------------- Margaret B.W. Graham (63) Founding Director, Vice-President and Corporate Secretary, The None Winthrop Group, Inc. (consulting firm) (1982 - present); Desautels Faculty of Management, McGill University (1999 - present); and Man- ager of Research Operations and Organizational Learning, Xerox PARC, Xerox's Advance Research Center (1990 - 1994) - ----------------------------------------------------------------------------------------------------------------------------------- Thomas J. Perna (59) Chairman and Chief Executive Officer, Quadriserv, Inc. (technology Director, Broadridge Financial products for securities lending industry) (2008 - present); Private Solutions, Inc. (investor com- investor (2004 - 2008); and Senior Executive Vice President, The munications and securities Bank of New York (financial and securities services) (1986 - 2004) processing provider for financial services industry) (2009 - present); Director, Quadriserv, Inc. (2005 - present) - ----------------------------------------------------------------------------------------------------------------------------------- Marguerite A. Piret (62) President and Chief Executive Officer, Newbury, Piret & Company, Inc. Director of New America High (investment banking firm) (1981 - present) Income Fund, Inc. (closed-end investment company) (2004 - present); Member, Board of Governors, Investment Company Institute (2000 - 2006) - ----------------------------------------------------------------------------------------------------------------------------------- 66 Pioneer Short Term Income Fund | Annual Report | 8/31/10 Fund Officers - -------------------------------------------------------------------------------- Position Held Length of Service Name and Age with the Fund and Term of Office - -------------------------------------------------------------------------------- Christopher J. Kelley (45) Secretary Since 2010. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- Carol B. Hannigan (49) Assistant Secretary Since 2010. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- Thomas Reyes (47) Assistant Secretary Since 2010. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- Mark E. Bradley (50) Treasurer Since 2008. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- Luis I. Presutti (45) Assistant Treasurer Since 2004. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- Gary Sullivan (52) Assistant Treasurer Since 2004. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------------------------------------------------- Other Directorships Name and Age Principal Occupation(s) Held by Officer - -------------------------------------------------------------------------------------------------------------------------- Christopher J. Kelley (45) Vice President and Associate General Counsel of Pioneer since Janu- None ary 2008 and Secretary of all of the Pioneer Funds since June 2010; Assistant Secretary of all of the Pioneer Funds from September 2003 to May 2010; Vice President and Senior Counsel of Pioneer from July 2002 to December 2007 - -------------------------------------------------------------------------------------------------------------------------- Carol B. Hannigan (49) Fund Governance Director of Pioneer since December 2006 and None Assistant Secretary of all the Pioneer Funds since June 2010; Man- ager -- Fund Governance of Pioneer from December 2003 to Novem- ber 2006; Senior Paralegal of Pioneer from January 2000 to Novem- ber 2003 - -------------------------------------------------------------------------------------------------------------------------- Thomas Reyes (47) Counsel of Pioneer since June 2007 and Assistant Secretary of all the None Pioneer Funds since June 2010; Vice President and Counsel at State Street Bank from October 2004 to June 2007 - -------------------------------------------------------------------------------------------------------------------------- Mark E. Bradley (50) Vice President -- Fund Accounting, Administration and Controllership None Services of Pioneer; and Treasurer of all of the Pioneer Funds since March 2008; Deputy Treasurer of Pioneer from March 2004 to February 2008; Assistant Treasurer of all of the Pioneer Funds from March 2004 to February 2008; and Treasurer and Senior Vice Presi- dent, CDC IXIS Asset Management Services from 2002 to 2003 - -------------------------------------------------------------------------------------------------------------------------- Luis I. Presutti (45) Assistant Vice President -- Fund Accounting, Administration and Con- None trollership Services of Pioneer; and Assistant Treasurer of all of the Pioneer Funds - -------------------------------------------------------------------------------------------------------------------------- Gary Sullivan (52) Fund Accounting Manager -- Fund Accounting, Administration and None Controllership Services of Pioneer; and Assistant Treasurer of all of the Pioneer Funds - -------------------------------------------------------------------------------------------------------------------------- Pioneer Short Term Income Fund | Annual Report | 8/31/10 67 Fund Officers (continued) - -------------------------------------------------------------------------------- Position Held Length of Service Name and Age with the Fund and Term of Office - -------------------------------------------------------------------------------- David F. Johnson (30) Assistant Treasurer Since 2009. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- Jean M. Bradley (57) Chief Compliance Officer Since 2010. Serves at the discretion of the Board. - -------------------------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------- Other Directorships Name and Age Principal Occupation(s) Held by Officer - ----------------------------------------------------------------------------------------------------------------------- David F. Johnson (30) Fund Administration Manager -- Fund Accounting, Administration and None Controllership Services since November 2008 and Assistant Treasurer of all of the Pioneer Funds since January 2009; Client Service Man- ager -- Institutional Investor Services at State Street Bank from March 2003 to March 2007 - ----------------------------------------------------------------------------------------------------------------------- Jean M. Bradley (57) Chief Compliance Officer of Pioneer and of all the Pioneer Funds None since March 2010; Director of Adviser and Portfolio Compliance at Pioneer since October 2005; Senior Compliance Officer for Columbia Management Advisers, Inc. from October 2003 to October 2005 - ----------------------------------------------------------------------------------------------------------------------- 68 Pioneer Short Term Income Fund | Annual Report | 8/31/10 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: - -------------------------------------------------------------------------------- PIMSS, Inc. 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: www.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 pioneerinvestments.com Securities offered through Pioneer Funds Distributor, Inc. 60 State Street, Boston, MA 02109 Underwriter of Pioneer Mutual Funds, Member SIPC (C) 2010 Pioneer Investments 19427-04-1010 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 10(a), 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; (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. $38,686 in 2010 and $37,000 in 2009. (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. $8,290 and $8,290 in 2010 and 2009, respectively. (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 accountant's 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 registrant's accountant for services rendered to the registrant, and rendered to the registrant's 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. $8,290 in 2010 and $8,290 in 2009. (h) Disclose whether the registrant's audit committee of the board of trustees has considered whether the provision of non-audit services that were rendered to the registrant's 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 registrants 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 I Investments in securities of unaffiliated issuers as of the close of the reporting period as set forth in 210.12- 12 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 registrants portfolio (Portfolio Manager). Also state each Portfolio Managers 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 registrants equity securities that is registered by the registrant pursuant to Section 12 of the Exchange Act (15 U.S.C. 781). Instruction to paragraph (a). Disclose all purchases covered by this Item, including purchases that do not satisfy the conditions of the safe harbor of Rule 10b-18 under the Exchange Act (17 CFR 240.10b-18), made in the period covered by the report. Provide disclosures covering repurchases made on a monthly basis. For example, if the reporting period began on January 16 and ended on July 15, the chart would show repurchases for the months from January 16 through February 15, February 16 through March 15, March 16 through April 15, April 16 through May 15, May 16 through June 15, and June 16 through July 15. 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 registrants board of directors, where those changes were implemented after the registrant last provided disclosure in response to the requirements of Item 7(d)(2)(ii)(G) 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 registrants board of directors since the registrant last provided disclosure in response to the requirements of Item 7(d)(2)(ii)(G) 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 officer or officers and principal financial officer or officers, or persons performing similar functions, about the effectiveness of the registrant's disclosure controls and procedures (as defined in Rule 30a-2(c) under the Act (17 CFR 270.30a-2(c))) based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of the report that includes the disclosure required by this paragraph. The registrant's principal executive officer and principal financial officer have concluded that the registrant's disclosure controls and procedures are effective based on their evaluation of these controls and procedures as of a date within 90 days of the filing date of this report. (b) Disclose whether or not there were significant changes in the registrant's internal controls or in other factors that could significantly affect these controls subsequent to the date of their evaluation, including any corrective actions with regard to significant deficiencies and material weaknesses. 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. File the exhibits listed below as part of this Form. Letter or number the exhibits in the sequence indicated. (a) 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. (b) A separate certification for each principal executive officer and principal financial officer of the registrant as required by Rule 30a-2 under the Act (17 CFR 270.30a-2). 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 Short Term Income Fund By (Signature and Title)* /s/ John F. Cogan, Jr. John F. Cogan, Jr, President Date October 29, 2010 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/ John F. Cogan, Jr. John F. Cogan, Jr., President Date October 29, 2010 By (Signature and Title)* /s/ Mark Bradley Mark Bradley, Treasurer Date October 29, 2010 * Print the name and title of each signing officer under his or her signature.