OMB APPROVAL OMB Number: 3235-0570 Expires: August 31, 2010 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 811-03564 Pioneer Mid Cap Growth Fund (Exact name of registrant as specified in charter) 60 State Street, Boston, MA 02109 (Address of principal executive offices) (ZIP code) Dorothy E. Bourassa, 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: September 30 Date of reporting period: October 1, 2006 through September 30, 2007 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 ------- MID CAP GROWTH FUND PITHX Ticker Symbol Annual Report 9/30/07 [LOGO]PIONEER Investments(R) Table of Contents - -------------------------------------------------------------------------------- Letter to Shareowners 2 Portfolio Management Discussion 4 Portfolio Summary 7 Prices and Distributions 8 Performance Update 9 Comparing Ongoing Fund Expenses 13 Schedule of Investments 15 Financial Statements 21 Notes to Financial Statements 29 Report of Independent Registered Public Accounting Firm 37 Trustees, Officers and Service Providers 38 President's Dear Shareowner, - -------------------------------------------------------------------------------- Staying diversified and keeping your portfolio invested in the markets are two general investment principles that have served investors well over time. They were particularly useful guides during the past year, when an otherwise healthy long-term bull market was buffeted by problems in the mortgage and banking industries. Since mid-year, issues tied to poor underwriting practices in the subprime sector of the mortgage industry and to problems with risk management by banks and hedge funds have resulted in increased market volatility and rising concern about risks to U.S. economic growth. Even against this backdrop, the long-term performance of major asset classes remained positive. In the 12 months ending September 30, 2007, equity investors were generally rewarded as, despite several interim corrections, the Standard & Poor's 500 Index returned 16%, the Dow Jones Industrial Average returned 22%, and the NASDAQ Composite Index returned 20%. International developed and emerging markets equities performed even better, reflecting both a weakening dollar (which boosts returns for U.S. dollar-based investors) and strong local currency returns, with the MSCI EAFE Developed Market Index returning 25% and the MSCI Emerging Markets Index returning 59% over the same 12-month period. The U.S. bond market, as measured by the Lehman Aggregate Bond Index, returned 5% in the 12 months ending September 30, 2007. The U.S. high-yield bond market, as measured by the Merrill Lynch High Yield Bond Master II Index, returned 8% for the same period, reflecting its higher coupon yield. U.S. economic growth has slowed in the past year, but this was due as much to the natural maturation of the cyclical expansion, as U.S. factories approached full utilization and the labor market approached full employment, as it was to rising commodity prices or short-term interest rates. This slowdown was, therefore, not entirely unwelcome, as it reduced the threat of higher inflation. More recently, however, there has been increasing concern that falling home prices, and/or disruptions in financial markets pose a larger threat to continuing economic growth. A weaker U.S. dollar has put upward pressure on some prices, but it has also benefited exporters and companies competing in the global marketplace. Although U.S. economic growth has slowed, growth in the rest of the world remains relatively strong. In Europe, robust GDP growth driven by a positive operating environment for European companies, especially exporters, has driven unemployment lower and supported growing consumption, although concerns about the impact of the strong Euro are a persistent source of worry. Japanese economic growth continues, albeit at a muted rate, and the country's deflationary problems are gradually receding. Economic growth in 2 Letter emerging market countries remains faster than in the developed world as they persist in "catching up," led by China, which continues its rise as a world economic power. The U.S. Federal Reserve and the world's other central banks have pursued policies aimed at producing low and stable inflation, believed to be the best backdrop for steady economic growth and low average unemployment over the long term. Keeping inflation low is also an important support for stock and bond valuations, and so central bank policies have also been "investor friendly." Looking forward, the economic outlook appears generally positive, although real estate prices, subprime mortgage defaults, and the possibility of a systemic liquidity/credit crunch all represent sources of risk. Central banks responded to this summer's liquidity squeeze in the inter-bank and commercial paper markets by acting as "lenders of last resort" and, in September 2007, the Fed cut rates to limit the risk of credit market problems spreading to the broader economy. While falling risk tolerances and reducing leverage may depress asset prices in the short term, valuations look reasonable if "Wall Street" problems do not spread to the broader "Main Street" economy. Sudden swings in the markets are always to be expected. Just as staying diversified and invested are important investment principles, it is also important to pay attention to asset allocation. As always, we encourage you to work closely with your financial advisor to find the mix of stocks, bonds and money market assets that is aligned to your particular risk tolerance and investment objective. Respectfully, /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. 3 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- PORTFOLIO MANAGEMENT DISCUSSION 9/30/07 - -------------------------------------------------------------------------------- Mid cap growth stocks scored solid gains over the Fund's recently completed fiscal year ended September 30, 2007 as equity markets overcame bouts of severe volatility. In the pages that follow, co-managers Andrew Acheson and Timothy Mulrenan describe the market background and the factors that affected performance during Pioneer Mid Cap Growth Fund's latest fiscal year. Q: Please describe market conditions over the past 12 months ended September 30, 2007. A: U.S. equity markets fought through significant headwinds this year to record respectable gains. Markets grew volatile early in 2007 amid the first signs of trouble in the subprime mortgage arena. Stocks then moved higher until more widespread credit concerns triggered a sharp mid-summer decline. The Federal Reserve Board's half-percentage point rate cut in September shored up investor confidence, allowing stocks to resume their climb, with major indices closing out the period at or near record levels. The strength of the market's rebound traces back to corporate earnings, which exceeded consensus expectations for each quarter of the 12-month period ended September 30, 2007. Q: How did the Fund perform in that environment? A: Pioneer Mid Cap Growth Fund's Class A shares had a total return of 20.54%, at net asset value, for the 12 months ended September 30, 2007. The Russell Mid Cap Growth Index, the Fund's benchmark, had a return of 21.22% for the same period. During the period the average return of the 617 funds in Lipper's Mid Cap Growth category was 25.56%. 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 represent 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. 4 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Q: Which of your investment strategies most affected the Fund's results during the 12-month period ended September 30, 2007? A: Our commitments to materials, energy and industrial companies were key drivers of the period's strong returns. The Fund and its benchmark had roughly equal weightings in these sectors. Within those sectors, the Fund's selections outperformed the benchmark's holdings. Nevertheless, Fund performance lagged the benchmark overall. Laggards included some financial and consumer stocks, although our consumer holdings did well overall. Our more conservative approach to growth investing may account for the Fund's underperformance within its Lipper peer group. Q: Which stocks contributed favorably over the 12-month period ended September 30, 2007? A: Freeport McMoRan, a major copper miner, continued to report good earnings thanks to surging demand from China and India. The Fund also benefited when Freeport acquired competitor Phelps Dodge on favorable terms to shareholders. We took profits in Terex, the world's third-largest heavy-equipment maker. High prices for minerals have intensified mining activity, producing brisk demand for earth-moving and related machinery at a time of short supply. In energy, Weatherford International, which provides advanced services to oil companies, benefited from increased drilling activity, especially outside the United States. Refiner Tesoro Petroleum moved higher as margins widened, although shares later slid back. New product introductions aided results at Juniper Networks, which makes routers and other network components for delivering enhanced media content over the Internet. We took some profits in Hansen Natural, whose fruit juices and energy drinks are well-positioned as consumers move away from carbonated beverages. Q: What were some of the disappointments during the 12-month period ended September 30, 2007? A: Results were unsatisfactory in the troubled financial services sector despite our underweight position compared to the benchmark. Concerns about its mortgage portfolio pressured shares of on-line broker, E-Trade, while difficulties stemming from a recent merger undercut Legg Mason's stock. In technology, we were premature in our commitment to Network Appliance, makers of network-linked 5 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- PORTFOLIO MANAGEMENT DISCUSSION 9/30/07 (continued) - -------------------------------------------------------------------------------- storage platforms. Although earnings slipped during this period, we anticipate a profit rebound and are maintaining the Fund's position. We sold Marvell Technology because of weak demand for hard drives that employ its controller chips. Marvell's results have failed to justify its high valuation. We also eliminated Constellation Brands, a wine distributor, which is feeling competitive pressure from lower-priced Australian wines. Q: What is your outlook for the economy and for mid-cap stocks in the months ahead? A: We believe economic growth will slow coming into the new year, in part because consumers are likely to rein in spending in the face of steep energy prices and higher mortgage payments as millions of adjustable rate mortgages are reset. For that reason, we are uncomfortable with most consumer stocks at this point. The broader U.S. economy has absorbed high oil prices without noticeable impact. Corporate cash flows are robust and equity valuations still appear reasonable despite the price gains of recent years. We are finding opportunities in selected areas such as technology, where the Fund is currently overweight compared to the benchmark. We are also overweight in health care and less so in materials stocks. In financials, we continue to emphasize capital markets and asset-management companies, while steering away from banks, thrifts and consumer finance firms, which are more vulnerable to possible disruptions in the credit markets. 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 these industries or sectors. Investing in mid-sized companies may offer the potential for higher returns, but is also subject to greater short-term price fluctuations than larger, more-established companies. 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. 6 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- PORTFOLIO SUMMARY 9/30/07 - -------------------------------------------------------------------------------- Portfolio Diversification - -------------------------------------------------------------------------------- (As a percentage of total investment portfolio) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] U.S. Common Stocks 81.3% Temporary Cash Investments 13.6% Depositary Receipts for International Stocks 5.1% Sector Distribution - -------------------------------------------------------------------------------- (As a percentage of equity holdings) [THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL] Information Technology 24.1% Health Care 15.5% Consumer Discretionary 13.5% Industrials 13.4% Energy 10.4% Financials 9.7% Consumer Staples 8.3% Materials 5.1% 10 Largest Holdings - -------------------------------------------------------------------------------- (As a percentage of equity holdings)* 1. TJX Companies, Inc. 3.15% 2. Loews Corp Carolina Group 3.12 3. Abercrombie & Fitch Co. 2.97 4. Teva Pharmaceutical Industries, Ltd. 2.90 5. F5 Networks, Inc. 2.61 6. Parker Hannifin Corp. 2.59 7. Juniper Networks, Inc. 2.57 8. Autodesk, Inc. 2.35 9. Freeport-McMoRan Copper & Gold, Inc. (Class B) 2.34 10. L-3 Communications Holdings, Inc. 2.31 * This list excludes temporary cash 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. 7 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- PRICES AND DISTRIBUTIONS - -------------------------------------------------------------------------------- Net Asset Value Per Share - -------------------------------------------------------------------------------- Class 9/30/07 9/30/06 ----- ------- ------- A $17.35 $15.38 B $14.35 $13.04 C $14.97 $13.54 Y $17.54 $15.48 Distributions Per Share - -------------------------------------------------------------------------------- 10/1/06 - 9/30/07 ----------------- Net Investment Short-Term Long-Term Class Income Capital Gains Capital Gains ----- ------ ------------- ------------- A $ - $0.6045 $0.4598 B $ - $0.6045 $0.4598 C $ - $0.6045 $0.4598 Y $ - $0.6045 $0.4598 8 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- PERFORMANCE UPDATE 9/30/07 CLASS A SHARES - -------------------------------------------------------------------------------- Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Pioneer Mid Cap Growth Fund at public offering price, compared to that of the Russell Midcap Growth Index. - ------------------------------------------------------------------- Average Annual Total Returns (As of September 30, 2007) Net Asset Public Offering Period Value (NAV) Price (POP) 10 Years 4.04% 3.43% 5 Years 14.79 13.44 1 Year 20.54 13.59 - ------------------------------------------------------------------- Expense Ratio (Per prospectus dated February 1, 2007) Gross Net 0.91% 0.91% - ------------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Mid Cap Russell Midcap Growth Fund Growth Index 9/97 $ 9,425 $10,000 $ 7,935 $ 9,063 9/99 $ 9,438 $12,434 $14,151 $19,940 9/01 $ 8,454 $ 9,618 $ 7,027 $ 8,127 9/03 $ 9,233 $11,288 $ 9,968 $12,831 9/05 $11,170 $15,843 $11,621 $16,958 9/07 $14,007 $20,557 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. NAV results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. POP returns reflect deduction of maximum 5.75% sales charge. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The 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 Russell Midcap Growth Index measures the performance of U.S. mid-cap growth stocks. 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. 9 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- PERFORMANCE UPDATE 9/30/07 CLASS B SHARES - -------------------------------------------------------------------------------- Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Pioneer Mid Cap Growth Fund, compared to that of the Russell Midcap Growth Index. - ------------------------------------------------------------- Average Annual Total Returns (As of September 30, 2007) If If Period Held Redeemed 10 Years 2.76% 2.76% 5 Years 13.36 13.36 1 Year 19.07 15.07 - ------------------------------------------------------------- Expense Ratio (Per prospectus dated February 1, 2007) Gross Net 2.26% 2.26% - ------------------------------------------------------------ [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Mid Cap Russell Midcap Growth Fund Growth Index 9/97 $10,000 $10,000 $ 8,325 $ 9,063 9/99 $ 9,791 $12,434 $14,540 $19,940 9/01 $ 8,567 $ 9,618 $ 7,013 $ 8,127 9/03 $ 9,102 $11,288 $ 9,709 $12,831 9/05 $10,737 $15,843 $11,023 $16,958 9/07 $13,125 $20,557 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. "If Held" results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. "If Redeemed" returns reflect the deduction of applicable contingent deferred sales charge (CDSC). Effective December 1, 2004, the period during which a CDSC is applied to withdrawals was shortened to 5 years. The maximum CDSC for Class B shares continues to be 4%. For more complete information, please see the prospectus for details. Note: Shares purchased prior to December 1, 2004 remain subject to the CDSC in effect at the time you purchased those shares. For performance information for shares purchased prior to December 1, 2004, please visit www.pioneerinvestments.com/bshares. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. The Russell Midcap Growth Index measures the performance of U.S. mid-cap growth stocks. 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 Mid Cap Growth Fund - -------------------------------------------------------------------------------- PERFORMANCE UPDATE 9/30/07 CLASS C SHARES - -------------------------------------------------------------------------------- Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Pioneer Mid Cap Growth Fund, compared to that of the Russell Midcap Growth Index. - ------------------------------------------------------------- Average Annual Total Returns (As of September 30, 2007) If If Period Held Redeemed 10 Years 2.83% 2.83% 5 Years 13.44 13.44 1 Year 19.26 19.26 - ------------------------------------------------------------- Expense Ratio (Per prospectus dated February 1, 2007) Gross Net 2.08% 2.08% - ------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Mid Cap Russell Midcap Growth Fund Growth Index 9/97 $10,000 $10,000 $ 8,333 $ 9,063 9/99 $ 9,831 $12,434 $14,610 $19,940 9/01 $ 8,610 $ 9,618 $ 7,039 $ 8,127 9/03 $ 9,113 $11,288 $ 9,733 $12,831 9/05 $10,778 $15,843 $11,087 $16,958 9/07 $13,222 $20,557 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). The performance of Class C shares does not reflect the 1% front-end sales charge in effect prior to February 1, 2004. If you paid a 1% sales charge, your returns would be lower than those shown above. "If Held" results represent the percent change in net asset value per share. Returns would have been lower had sales charges been reflected. All results are historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. The Russell Midcap Growth Index measures the performance of U.S. mid-cap growth stocks. 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. 11 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- PERFORMANCE UPDATE 9/30/07 CLASS Y SHARES - -------------------------------------------------------------------------------- Investment Returns - -------------------------------------------------------------------------------- The mountain chart on the right shows the change in value of a $10,000 investment made in Pioneer Mid Cap Growth Fund, compared to that of the Russell Midcap Growth Index. - ------------------------------------------------------------- Average Annual Total Returns (As of September 30, 2007) If If Period Held Redeemed 10 Years 4.15% 4.15% 5 Years 15.03 15.03 1 Year 21.01 21.01 - ------------------------------------------------------------- Expense Ratio (Per prospectus dated February 1, 2007) Gross Net 0.51% 0.51% - ------------------------------------------------------------- [THE FOLLOWING DATA WAS REPRESENTED AS A MOUNTAIN CHART IN THE PRINTED MATERIAL] Value of $10,000 Investment Pioneer Mid Cap Russell Midcap Growth Fund Growth Index 9/97 $10,000 $10,000 $ 8,420 $ 9,063 9/99 $10,015 $12,434 $15,016 $19,940 9/01 $ 8,971 $ 9,618 $ 7,456 $ 8,127 9/03 $ 9,797 $11,288 $10,578 $12,831 9/05 $11,876 $15,843 $12,410 $16,958 9/07 $15,017 $20,557 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. Performance for periods prior to the inception of Class Y shares reflects the NAV performance of the Fund's Class A share. The performance does not reflect differences in expenses, including the Rule 12b-1 fees applicable to Class A shares. Since the fees for Class A shares are generally higher than those of Class Y shares, the performances shown for Class Y Shares prior to their inception (2/1/05) would have been higher. Class Y shares are not subject to sales charges and are available for limited groups of eligible investors, including institutional investors, All result in historical and assume the reinvestment of dividends and capital gains. Other share classes are available for which performance and expenses will differ. Performance results reflect any applicable expense waivers in effect during the periods shown. Without such waivers Fund performance would be lower. Waivers may not be in effect for all funds. Certain fee waivers are contractual through a specified period. Otherwise, fee waivers can be rescinded at any time. See the prospectus and financial statements for more information. The performance table and graph do not reflect the deduction of fees and taxes that a shareowner would pay on Fund distributions or the redemption of Fund shares. The Russell Midcap Growth Index measures the performance of U.S. mid-cap growth stocks. 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 Mid Cap Growth Fund - -------------------------------------------------------------------------------- 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 Mid Cap Growth Fund Based on actual returns from April 1, 2007 through September 30, 2007. Share Class A B C Y - ---------------------------------------------------------------------------------------- Beginning Account Value $1,000.00 $1,000.00 $1,000.00 $1,000.00 On 4/1/07 Ending Account Value $1,097.41 $1,081.28 $1,091.92 $1,099.69 On 9/30/07 Expenses Paid During Period* $ 4.63 $ 11.11 $ 10.33 $ 2.58 * Expenses are equal to the Fund's annualized expense ratio of 0.88%, 2.12%, 1.97% and 0.49% for Class A, Class B, Class C and Class Y shares, respectively, multiplied by the average account value over the period, multiplied by 183/365 (to reflect the one-half year period). 13 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- COMPARING ONGOING FUND EXPENSES (continued) - -------------------------------------------------------------------------------- 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 Mid Cap Growth Fund Based on a hypothetical 5% return per year before expenses, reflect ing the period from April 1, 2007 through September 30, 2007. Share Class A B C Y - ---------------------------------------------------------------------------------------- Beginning Account Value $1,000.00 $1,000.00 $1,000.00 $1,000.00 On 4/1/07 Ending Account Value $1,020.66 $1,014.44 $1,015.19 $1,022.61 On 9/30/07 Expenses Paid During Period* $ 4.46 $ 10.71 $ 9.95 $ 2.48 * Expenses are equal to the Fund's annualized expense ratio of 0.88%, 2.12%, 1.97% and 0.49% for Class A, Class B, Class C and Class Y shares, respectively, multiplied by the average account value over the period, multiplied by 183/365 (to reflect the one-half year period). 14 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- SCHEDULE OF INVESTMENTS 9/30/07 - -------------------------------------------------------------------------------- Shares Value COMMON STOCKS - 99.1% Energy - 10.3% Oil & Gas Drilling - 1.4% 237,000 Helmerich & Payne, Inc. $ 7,780,710 ------------ Oil & Gas Equipment & Services - 2.2% 174,600 Weatherford International, Inc.* $ 11,729,628 ------------ Oil & Gas Exploration & Production - 5.6% 95,900 Devon Energy Corp. $ 7,978,880 167,800 Noble Affiliates, Inc. 11,752,712 203,200 Southwestern Energy Co.* 8,503,920 124,700 Veneco, Inc.* 2,138,605 ------------ $ 30,374,117 ------------ Oil & Gas Refining & Marketing - 1.1% 125,000 Tesoro Petroleum Corp. $ 5,752,500 ------------ Total Energy $ 55,636,955 ------------ Materials - 5.0% Diversified Metals & Mining - 3.7% 75,000 First Quantum Minerals, Ltd. $ 7,359,231 119,525 Freeport-McMoRan Copper & Gold, Inc. (Class B) 12,536,977 ------------ $ 19,896,208 ------------ Industrial Gases - 1.3% 73,000 Air Products & Chemicals, Inc. $ 7,136,480 ------------ Total Materials $ 27,032,688 ------------ Capital Goods - 12.2% Aerospace & Defense - 2.3% 121,200 L-3 Communications Holdings, Inc. $ 12,379,368 ------------ Construction & Farm Machinery & Heavy Trucks - 1.4% 340,000 Force Protection, Inc.*(b) $ 7,364,400 ------------ Electrical Component & Equipment - 1.2% 115,200 Thomas & Betts Corp.* $ 6,755,328 ------------ Industrial Conglomerates - 1.5% 130,700 Textron, Inc.* $ 8,130,847 ------------ The accompanying notes are an integral part of these financial statements. 15 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- SCHEDULE OF INVESTMENTS 9/30/07 (continued) - -------------------------------------------------------------------------------- Shares Value Industrial Machinery - 5.8% 126,900 Dover Corp. $ 6,465,555 158,200 ITT Corp. 10,746,526 124,100 Parker Hannifin Corp. 13,878,103 ------------ $ 31,090,184 ------------ Total Capital Goods $ 65,720,127 ------------ Commercial Services & Supplies - 1.1% Diversified Commercial Services - 1.1% 60,000 The Dun & Bradstreet Corp. $ 5,916,600 ------------ Total Commercial Services & Supplies $ 5,916,600 ------------ Consumer Services - 3.6% Casinos & Gaming - 1.8% 223,000 International Game Technology $ 9,611,300 ------------ Restaurants - 1.8% 284,400 Yum! Brands, Inc. $ 9,621,252 ------------ Total Consumer Services $ 19,232,552 ------------ Media - 3.8% Advertising - 0.8% 91,600 Omnicom Group $ 4,405,044 ------------ Broadcasting & Cable TV - 1.5% 66,500 Liberty Media Holding Corp.* $ 8,301,195 ------------ Publishing - 1.5% 138,100 Meredith Corp. $ 7,913,130 ------------ Total Media $ 20,619,369 ------------ Retailing - 6.1% Apparel Retail - 6.1% 197,000 Abercrombie & Fitch Co. $ 15,897,900 579,200 TJX Companies, Inc. 16,837,344 ------------ $ 32,735,244 ------------ Total Retailing $ 32,735,244 ------------ Food & Drug Retailing - 2.7% Food Retail - 0.9% 258,501 Winn-Dixie Stores, Inc.* $ 4,839,139 ------------ 16 The accompanying notes are an integral part of these financial statements. Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Shares Value Hypermarkets & Supercenters - 1.8% 297,600 BJ'S Wholesale Club, Inc.*(b) $ 9,868,416 ------------ Total Food & Drug Retailing $ 14,707,555 ------------ Food, Beverage & Tobacco - 5.5% Soft Drinks - 2.4% 170,100 Fomento Economico Mexicano SA de C.V. $ 6,361,740 116,200 Hansen Natural Corp.*(b) 6,586,216 ------------ $ 12,947,956 ------------ Tobacco - 3.1% 202,800 Loews Corp Carolina Group $ 16,676,244 ------------ Total Food, Beverage & Tobacco $ 29,624,200 ------------ Health Care Equipment & Services - 6.1% Health Care Equipment - 2.4% 107,200 Edwards Lifesciences Group* $ 5,286,032 380,000 Thoratec Corp.* 7,862,200 ------------ $ 13,148,232 ------------ Health Care Services - 1.3% 122,000 Quest Diagnostics, Inc. $ 7,047,940 ------------ Health Care Technology - 1.1% 202,700 IMS Health, Inc. $ 6,210,728 ------------ Managed Health Care - 1.3% 109,300 Coventry Health Care, Inc.* $ 6,799,553 ------------ Total Health Care Equipment & Services $ 33,206,453 ------------ Pharmaceuticals & Biotechnology - 9.2% Biotechnology - 3.2% 389,300 Cubist Pharmaceuticals, Inc.* $ 8,225,909 242,300 Vertex Pharmaceuticals, Inc.* 9,306,743 ------------ $ 17,532,652 ------------ Life Sciences Tools & Services - 3.1% 149,400 Charles River Laboratories International, Inc.* $ 8,388,810 140,000 Thermo Fisher Scientific, Inc.* 8,080,800 ------------ $ 16,469,610 ------------ The accompanying notes are an integral part of these financial statements. 17 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- SCHEDULE OF INVESTMENTS 9/30/07 (continued) - -------------------------------------------------------------------------------- Shares Value Pharmaceuticals - 2.9% 349,521 Teva Pharmaceutical Industries, Ltd. (b) $ 15,543,199 ------------ Total Pharmaceuticals & Biotechnology $ 49,545,461 ------------ Diversified Financials - 8.8% Asset Management & Custody Banks - 4.8% 50,600 Affiliated Managers Group, Inc.*(b) $ 6,452,006 197,400 Federated Investors, Inc. 7,836,780 134,000 Legg Mason, Inc. 11,294,860 ------------ $ 25,583,646 ------------ Investment Banking & Brokerage - 4.0% 436,100 E*TRADE Financial Corp.* $ 5,695,466 170,000 Investment Technology Group, Inc. 7,306,600 205,000 Lazard, Ltd. 8,692,000 ------------ $ 21,694,066 ------------ Total Diversified Financials $ 47,277,712 ------------ Insurance - 0.8% Reinsurance - 0.8% 127,400 Platinum Underwriter Holdings, Ltd. $ 4,581,304 ------------ Total Insurance $ 4,581,304 ------------ Software & Services - 6.5% Application Software - 6.5% 82,800 Amdocs, Ltd.* $ 3,079,332 251,900 Autodesk, Inc.* 12,587,443 804,600 BEA Systems, Inc.* 11,159,802 201,500 Citrix Systems, Inc.* 8,124,480 ------------ $ 34,951,057 ------------ Total Software & Services $ 34,951,057 ------------ Technology Hardware & Equipment - 7.3% Communications Equipment - 5.1% 375,300 F5 Networks, Inc.* $ 13,957,407 375,800 Juniper Networks, Inc.*(b) 13,758,038 ------------ $ 27,715,445 ------------ 18 The accompanying notes are an integral part of these financial statements. Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Shares Value Computer Storage & Peripherals - 2.2% 444,000 Network Appliance, Inc.* $ 11,948,040 ------------ Total Technology Hardware & Equipment $ 39,663,485 ------------ Semiconductors - 10.2% Semiconductor Equipment - 1.9% 171,300 MEMC Electronic Materials, Inc.* $ 10,082,718 ------------ Semiconductors - 8.3% 251,800 Analog Devices, Inc. $ 9,105,088 400,000 Infineon Technologies (A.D.R.)* 6,872,000 210,700 Intersil Holding Corp. 7,043,701 227,800 Linear Technology Corp. 7,970,722 263,200 National Semiconductor Corp. (b) 7,137,984 520,000 SGC Holding Corp.* 6,531,200 ------------ $ 44,660,695 ------------ Total Semiconductors $ 54,743,413 ------------ TOTAL COMMON STOCKS (Cost $435,136,917) $535,194,175 ------------ Principal Amount TEMPORARY CASH INVESTMENTS - 15.6% Repurchase Agreement - 6.6% $35,500,000 UBS Warburg, Inc., 3.85%, dated 9/28/07, repurchase price of $35,500,000 plus accrued interest on 10/1/07 collateralized by $35,850,000 U.S. Treasury Bill, 4.875%, 8/31/08 $ 35,500,000 ------------ The accompanying notes are an integral part of these financial statements. 19 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- SCHEDULE OF INVESTMENTS 9/30/07 (continued) - -------------------------------------------------------------------------------- Shares Value Security Lending Collateral - 9.0% 48,568,678 Securities Lending Investment Fund, 5.24% $ 48,568,678 ------------ TOTAL TEMPORARY CASH INVESTMENTS (Cost $84,068,678) $ 84,068,678 ------------ TOTAL INVESTMENT IN SECURITIES - 114.7% (Cost $519,205,595) (a) $619,262,853 ------------ OTHER ASSETS AND LIABILITIES - (14.7)% $(79,166,251) ------------ TOTAL NET ASSETS - 100.0% $540,096,602 ============ * Non-income producing security. (A.D.R.) American Depositary Receipt. (a) At September 30, 2007, the net unrealized gain on investments based on cost for federal income tax purposes of $519,903,081 was as follows Aggregate gross unrealized gain for all investments in which there is an excess of value over tax cost $109,406,850 Aggregate gross unrealized loss for all investments in which there is an excess of tax cost over value (10,047,078) ------------ Net unrealized gain $ 99,359,772 ============ (b) At September 30, 2007, the following securities were out on loan: Shares Security Value 50,094 Affiliated Managers Group, Inc.* $ 6,387,486 247,447 Force Protection, Inc.* 5,359,702 14,510 Hansen Natural Corp.* 822,427 40,881 National Semiconductor Corp. 1,108,693 346,026 Teva Pharmaceutical Industries, Ltd. 15,387,776 152,850 BJ'S Wholesale Club, Inc.* 5,068,506 369,000 Juniper Networks, Inc.* 13,509,090 ----------- $47,643,680 =========== Purchases and sales of securities (excluding temporary cash investments) for the year ended September 30, 2007 aggregated $253,350,330 and $332,067,567, respectively. 20 The accompanying notes are an integral part of these financial statements. Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- STATEMENT OF ASSETS AND LIABILITIES 9/30/07 - -------------------------------------------------------------------------------- ASSETS: Investment in securities (including securities loaned of ($47,643,680) (cost $519,205,595) $619,262,853 Cash 414,515 Receivables - Investment securities sold 5,826,974 Fund shares sold 261,226 Dividends, interest and foreign taxes withheld 120,103 Other 44,830 ------------ Total assets $625,930,501 ------------ LIABILITIES: Payables - Investment securities purchased $ 36,674,901 Fund shares repurchased 399,647 Upon return of securities loaned 48,568,678 Due to affiliates 109,627 Accrued expenses 81,046 ------------ Total liabilities $ 85,833,899 ------------ NET ASSETS: Paid-in capital $424,414,219 Accumulated net investment loss (37,374) Accumulated net realized gain on investments 15,662,499 Net unrealized gain on investments 100,057,258 ------------ Total net assets $540,096,602 ============ NET ASSET VALUE PER SHARE: (No par value, unlimited number of shares authorized) Class A (based on $474,138,214/27,325,266 shares) $ 17.35 ============ Class B (based on $19,404,307/1,352,507 shares) $ 14.35 ============ Class C (based on $11,527,006/770,163 shares) $ 14.97 ============ Class Y (based on $35,027,075/1,997,354 shares) $ 17.54 ============ MAXIMUM OFFERING PRICE: Class A ($17.35 [divided by] 94.25%) $ 18.41 ============ The accompanying notes are an integral part of these financial statements. 21 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- STATEMENT OF OPERATIONS - -------------------------------------------------------------------------------- For the Year Ended 9/30/07 INVESTMENT INCOME: Dividends (net of foreign taxes withheld of $19,131) $ 3,366,495 Interest 429,692 Income from securities loaned, net 26,707 ----------- Total investment income $ 3,822,894 ----------- EXPENSES: Management fees Basic Fee $ 3,362,153 Performance Adjustment (1,076,558) Transfer agent fees and expenses Class A 810,323 Class B 133,515 Class C 58,537 Class Y 205 Distribution fees Class A 1,066,266 Class B 198,199 Class C 118,048 Administrative reimbursements 118,354 Custodian fees 24,216 Registration fees 53,178 Professional fees 72,122 Printing expense 40,309 Fees and expenses of nonaffiliated trustees 9,480 Miscellaneous 31,402 ----------- Total expenses $ 5,019,749 Less fees paid indirectly (58,287) ----------- Net expenses $ 4,961,462 ----------- Net investment loss $(1,138,568) ----------- REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS: Net realized gain (loss) on: Investments $19,242,268 Other assets and liabilities denominated in foreign currencies (37,374) $19,204,894 ----------- ----------- Change in net unrealized gain (loss) on investments $80,607,722 ----------- Net gain on investments and foreign currency transactions $99,812,616 ----------- Net increase in net assets resulting from operations $98,674,048 =========== 22 The accompanying notes are an integral part of these financial statements. Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- STATEMENTS OF CHANGES IN NET ASSETS - -------------------------------------------------------------------------------- For the Years Ended 9/30/07 and 9/30/06 Year Ended Year Ended 9/30/07 9/30/06 FROM OPERATIONS: Net investment loss $ (1,138,568) $ (1,497,113) Net realized gain on investments and foreign currency transactions 19,204,894 43,892,975 Change in net unrealized gain (loss) on investments and foreign currency transactions 80,607,722 (21,390,674) -------------- -------------- Net increase in net assets resulting from operations $ 98,674,048 $ 21,005,188 -------------- -------------- DISTRIBUTIONS TO SHAREOWNERS: Net realized gain: Class A ($1.06 and $0.56 per share, respectively) $ (30,928,010) $ (17,966,208) Class B ($1.06 and $0.56 per share, respectively) (1,695,217) (1,043,154) Class C ($1.06 and $0.56 per share, respectively) (966,666) (457,496) Class Y ($1.06 and $0.56 per share, respectively) (2,046,524) (749,675) -------------- -------------- Total distributions to shareowners $ (35,636,417) $ (20,216,533) -------------- -------------- FROM FUND SHARE TRANSACTIONS: Net proceeds from sale of shares $ 47,883,377 $ 54,204,971 Reinvestment of distributions 33,763,337 18,952,554 Cost of shares repurchased (120,177,490) (106,086,621) -------------- -------------- Net decrease in net assets resulting from Fund share transactions $ (38,530,776) $ (32,929,096) -------------- -------------- Capital Contribution+ $ 1,240,204 $ - -------------- -------------- Net increase (decrease) in net assets $ 25,747,059 $ (11,923,908) NET ASSETS: Beginning of year 514,349,543 546,489,984 -------------- -------------- End of year $ 540,096,602 $ 514,349,543 ============== ============== Accumulated net investment loss $ (37,374) $ - ============== ============== + Represents amount contributed to the Fund by PIM. For more information see note 2 in the "notes to financial statements". The accompanying notes are an integral part of these financial statements. 23 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- STATEMENTS OF CHANGES IN NET ASSETS (continued) - -------------------------------------------------------------------------------- '07 Shares '07 Amount '06 Shares '06 Amount CLASS A Shares sold 1,218,752 $ 19,875,074 1,368,265 $ 21,028,238 Reinvestment of distributions 1,885,618 29,302,560 1,135,329 16,870,993 Less shares repurchased (5,295,060) (85,783,139) (5,822,884) (88,565,526) ---------- ------------ ---------- ------------ Net decrease (2,190,690) $(36,605,505) (3,319,290) $(50,666,295) ========== ============ ========== ============ CLASS B Shares sold 407,752 $ 5,608,826 339,301 $ 4,492,308 Reinvestment of distributions 124,761 1,619,434 76,498 974,589 Less shares repurchased (711,997) (9,531,808) (854,776) (11,101,900) ---------- ------------ ---------- ------------ Net decrease (179,484) $ (2,303,548) (438,977) $ (5,635,003) ========== ============ ========== ============ CLASS C Shares sold 276,930 $ 3,937,360 179,687 $ 2,445,402 Reinvestment of distributions 67,455 912,659 31,783 419,862 Less shares repurchased (376,270) (5,277,833) (249,688) (3,366,520) ---------- ------------ ---------- ------------ Net decrease (31,885) $ (427,814) (38,218) $ (501,256) ========== ============ ========== ============ CLASS Y Shares sold 1,167,500 $ 18,462,117 1,733,823 $ 26,239,023 Reinvestment of distributions 123,160 1,928,684 46,115 687,110 Less shares repurchased (1,203,641) (19,584,710) (204,167) (3,052,675) ---------- ------------ ---------- ------------ Net increase 87,019 $ 806,091 1,575,771 $ 23,873,458 ========== ============ ========== ============ 24 The accompanying notes are an integral part of these financial statements. Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- FINANCIAL HIGHLIGHTS - -------------------------------------------------------------------------------- Year Ended Year Ended Year Ended Year Ended Year Ended 9/30/07 9/30/06 9/30/05 9/30/04 9/30/03 CLASS A Net asset value, beginning of period $ 15.38 $ 15.34 $ 13.69 $ 12.68 $ 9.65 -------- -------- -------- -------- -------- Increase (decrease) from investment operations: Net investment loss $ (0.03) $ (0.03) $ (0.02) $ (0.06) $ (0.05) Net realized and unrealized gain on investments 3.02 0.63 1.67 1.07 3.08 -------- -------- -------- -------- -------- Net increase from investment operations $ 2.99 $ 0.60 $ 1.65 $ 1.01 $ 3.03 Distributions to shareowners: Net realized gain (1.06) (0.56) - - - -------- -------- -------- -------- -------- Capital contribution 0.04 - - - - -------- -------- -------- -------- -------- Net increase in net asset value $ 1.97 $ 0.04 $ 1.65 $ 1.01 $ 3.03 -------- -------- -------- -------- -------- Net asset value, end of period $ 17.35 $ 15.38 $ 15.34 $ 13.69 $ 12.68 ======== ======== ======== ======== ======== Total return* 20.54%# 4.03% 12.05% 7.97% 31.40% Ratio of net expenses to average net assets+ 0.89% 0.90% 0.90% 0.90% 0.97% Ratio of net investment loss to average net assets+ (0.18)% (0.21)% (0.14)% (0.44)% (0.46)% Portfolio turnover rate 48% 96% 115% 98% 52% Net assets, end of period (in thousands) $474,138 $453,950 $503,683 $516,935 $522,269 Ratios with reduction for fees paid indirectly: Net expenses 0.88% 0.90% 0.90% 0.90% 0.96% Net investment loss (0.17)% (0.21)% (0.14)% (0.44)% (0.45)% * 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 sale charges. Total return would be reduced if sales charges were taken into account. + Ratios with no reduction for fees paid indirectly. # Total return shown includes capital contribution by PIM. Without such contributions, the total return would have been reduced by 0.28%. The accompanying notes are an integral part of these financial statements. 25 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- FINANCIAL HIGHLIGHTS - -------------------------------------------------------------------------------- Year Ended Year Ended Year Ended Year Ended Year Ended 9/30/07 9/30/06 9/30/05 9/30/04 9/30/03 CLASS B Net asset value, beginning of period $ 13.04 $ 13.26 $ 11.99 $ 11.24 $ 8.66 ------- ------- ------- ------- ------- Increase (decrease) from investment operations: Net investment loss $ (0.21) $ (0.24) $ (0.20) $ (0.24) $ (0.16) Net realized and unrealized gain on investments 2.55 0.58 1.47 0.99 2.74 ------- ------- ------- ------- ------- Net increase from investment operations $ 2.34 $ 0.34 $ 1.27 $ 0.75 $ 2.58 Distributions to shareowners: Net realized gain (1.06) (0.56) - - - ------- ------- ------- ------- ------- Capital contribution 0.03 - - - - ------- ------- ------- ------- ------- Net increase (decrease) in net asset value $ 1.31 $ (0.22) $ 1.27 $ 0.75 $ 2.58 ------- ------- ------- ------- ------- Net asset value, end of period $ 14.35 $ 13.04 $ 13.26 $ 11.99 $ 11.24 ======= ======= ======= ======= ======= Total return* 19.07%# 2.66% 10.59% 6.67% 29.79% Ratio of net expenses to average net assets+ 2.16% 2.25% 2.16% 2.18% 2.30% Ratio of net investment loss to average net assets+ (1.46)% (1.57)% (1.41)% (1.72)% (1.79)% Portfolio turnover rate 48% 96% 115% 98% 52% Net assets, end of period (in thousands) $19,404 $19,972 $26,132 $29,247 $31,392 Ratios with reduction for fees paid indirectly: Net expenses 2.12% 2.25% 2.15% 2.17% 2.29% Net investment loss (1.42)% (1.57)% (1.40)% (1.71)% (1.78)% * 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. + Ratios with no reduction for fees paid indirectly. # Total return shown includes capital contribution by PIM. Without such contributions, the total return would have been reduced by 0.25%. The accompanying notes are an integral part of these financial statements. 26 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- FINANCIAL HIGHLIGHTS - -------------------------------------------------------------------------------- Year Ended Year Ended Year Ended Year Ended Year Ended 9/30/07 9/30/06 9/30/05 9/30/04 9/30/03 CLASS C Net asset value, beginning of period $ 13.54 $ 13.72 $ 12.39 $ 11.60 $ 8.96 ------- ------- ------- ------- ------- Increase (decrease) from investment operations: Net investment loss $ (0.19) $ (0.19) $ (0.18) $ (0.29) $ (0.10) Net realized and unrealized gain on investments 2.65 0.57 1.51 1.08 2.74 ------- ------- ------- ------- ------- Net increase from investment operations $ 2.46 $ 0.38 $ 1.33 $ 0.79 $ 2.64 Distributions to shareowners: Net realized gain (1.06) (0.56) - - - ------- ------- ------- ------- ------- Capital contribution 0.03 - - - - ------- ------- ------- ------- ------- Net increase (decrease) in net asset value $ 1.43 $ (0.18) $ 1.33 $ 0.79 $ 2.64 ------- ------- ------- ------- ------- Net asset value, end of period $ 14.97 $ 13.54 $ 13.72 $ 12.39 $ 11.60 ======= ======= ======= ======= ======= Total return* 19.26%# 2.87% 10.73% 6.81% 29.46% Ratio of net expenses to average net assets+ 1.99% 2.07% 2.05% 1.95% 2.26% Ratio of net investment loss to average net assets+ (1.28)% (1.38)% (1.29)% (1.48)% (1.75)% Portfolio turnover rate 48% 96% 115% 98% 52% Net assets, end of period (in thousands) $11,527 $10,858 $11,532 $12,405 $18,155 Ratios with reduction for fees paid indirectly: Net expenses 1.97% 2.07% 2.04% 1.95% 2.25% Net investment loss (1.26)% (1.38)% (1.28)% (1.48)% (1.74)% * Assumes initial investment at net asset value at the beginning of each period, reinvestment of 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. + Ratios with no reduction for fees paid indirectly. # Total return shown includes capital contribution by PIM. Without such contributions, the total return would have been reduced by 0.24%. The accompanying notes are an integral part of these financial statements. 27 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- FINANCIAL HIGHLIGHTS - -------------------------------------------------------------------------------- For the Period from 2/1/05 (Commencement Year Ended Year Ended of Operations) 9/30/07 9/30/06 to 9/30/05 CLASS Y Net asset value, beginning of period $ 15.48 $ 15.37 $14.72 ------- ------- ------ Increase from investment operations: Net investment income $ 0.04 $ 0.03 $ 0.01 Net realized and unrealized gain on investments 3.04 0.64 0.64 ------- ------- ------ Net increase from investment operations $ 3.08 $ 0.67 $ 0.65 Distributions to shareowners: Net realized gain (1.06) (0.56) - ------- ------- ------ Capital contribution 0.04 - - ------- ------- ------ Net increase in net asset value $ 2.06 $ 0.11 $ 0.65 ------- ------- ------ Net asset value, end of period $ 17.54 $ 15.48 $15.37 ======= ======= ====== Total return* 21.01%# 4.50% 4.42%++ Ratio of net expenses to average net assets+ 0.49% 0.48% 0.51%** Ratio of net investment income to average net assets+ 0.23% 0.23% 0.28%** Portfolio turnover rate 48% 96% 115%++ Net assets, end of period (in thousands) $35,027 $29,569 $5,143 Ratios with reduction for fees paid indirectly: Net expenses 0.49% 0.48% 0.51%** Net investment income 0.23% 0.23% 0.28%** * Assumes initial investment at net asset value at the beginning of each period, reinvestment of distributions, the complete redemption of the investment at net asset value at the end of each period and no sales charges. ** Annualized. + Ratios with no reduction for fees paid indirectly. ++ Not Annualized. # Total return shown includes capital contribution by PIM. Without such contributions, the total return would have been reduced by 0.28%. 28 The accompanying notes are an integral part of these financial statements. Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- NOTES TO FINANCIAL STATEMENTS 9/30/07 - -------------------------------------------------------------------------------- 1. Organization and Significant Accounting Policies Pioneer Mid Cap Growth 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 capital growth by investing in a diversified portfolio consisting primarily of common stocks. The Fund offers four classes of shares - Class A, Class B, Class C, and Class Y shares. Class Y shares were first publicly offered on February 1, 2005. Each class of shares represents an interest in the same portfolio of investments of the Fund and has equal rights to voting, redemptions, dividends and liquidation, except that each class of shares can bear different transfer agent and distributions fees and has exclusive voting rights with respect to the distribution plans that have been adopted by Class A, Class B, and Class C shareowners, respectively. There is no distribution plan for Class Y shares. 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 these industries or sectors. Information regarding the Fund's principal investment risks is contained in the Fund's prospectus(es). Please refer to those documents when considering the Fund's investment 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 reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of income, expenses and gains and losses on investments during the reporting period. Actual results could differ from those estimates. The 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 29 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- NOTES TO FINANCIAL STATEMENTS 9/30/07 (continued) - -------------------------------------------------------------------------------- York Stock Exchange (NYSE) is open, as of the close of regular trading on the NYSE. In computing the net asset value, securities are valued at the last sale price on the principal exchange where they are traded. Securities that have not traded on the date of valuation, or securities for which sale prices are not generally reported, are valued at the mean between the last bid and asked prices. Securities for which market quotations are not readily available are valued at their fair values as determined by, or under the direction of, the Board of Trustees. Trading in foreign securities is substantially completed each day at various times prior to the close of the NYSE. The values of such securities used in computing the net asset value of the Fund's shares are determined as of such times. The Fund also may use the fair value of a security including a non-U.S. security when the closing market price on the principal exchange where the security is traded no longer reflects the value of the security. At September 30, 2007 there were no securities fair valued. Temporary cash investments are valued at amortized cost which approximates market value. Dividend income is recorded on the ex-dividend date except that certain dividends from foreign securities where the ex-dividend date may have passed are recorded as soon as the Fund becomes aware of the ex-dividend data in the exercise of reasonable diligence. Interest income is recorded on the accrual basis. Dividend and interest income are reported 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. Futures Contracts The Fund may enter into futures transactions to hedge against changes in interest rates, securities prices, and currency rates or to seek to increase total return. Upon entering into a futures contract, the Fund is required to deposit with a broker an amount of cash or securities equal to the minimum "initial margin" requirements of the associated futures exchange. Subsequent payments for futures contracts ("variation margin") are received or paid by the Fund, depending on the daily fluctuation in the value of the contracts, and are recorded by the Fund as unrealized gains or 30 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- losses, respectively. When the contract is closed, the Fund realizes a gain or loss equal to the difference between the opening and closing value of the contract. The use of futures contracts involves, to varying degrees, elements of market and counterparty risks, which may exceed the amounts recognized by the Fund. Changes in value of the contracts may not directly correlate to the changes in value of the underlying securities. These risks may decrease the effectiveness of the Fund's hedging strategies and potentially result in a loss. At September 30, 2007, there were no open futures contracts. C. Federal Income Taxes It is the Fund's policy to comply with the requirements of the Internal Revenue Code applicable to regulated investment companies and to distribute all of its taxable income and net realized capital gains, if any, to its shareowners. Therefore, no federal income tax provision is required. The amounts and characterizations of distributions to shareowners for financial reporting purposes are determined in accordance with federal income tax rules. Therefore, the sources of the Fund's distributions may be shown in the accompanying financial statements as either from or in excess of net investment income or net realized gain on investment transactions, or from paid-in-capital, depending on the type of book/tax differences that may exist. The Fund has elected to defer approximately $37,374 of currency losses recognized between November 1, 2006 and September 30, 2007 to its fiscal year ending September 30, 2008. At September 30, 2007, the Fund has reclassified $1,101,194 to decrease accumulated net investment loss, $37,374 to increase accumulated net realized gain on investments and $1,138,568 to decrease paid-in capital to reflect permanent book/tax differences. The reclassification has no impact on the net assets of the Fund and is designed to present the Fund's capital accounts on a tax basis. 31 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- NOTES TO FINANCIAL STATEMENTS 9/30/07 (continued) - -------------------------------------------------------------------------------- The tax character of distributions paid during the years ended September 30, 2007 and 2006 were as follows: - -------------------------------------------------------------------------------- 2007 2006 - -------------------------------------------------------------------------------- Ordinary income $17,477,854 $ 3,483,864 Long-term capital gain 18,158,563 16,732,669 ----------- ----------- Total $35,636,417 $20,216,533 =========== =========== - -------------------------------------------------------------------------------- The following shows the components of distributable earnings on a federal income tax basis at September 30, 2007. - -------------------------------------------------------------------------------- 2007 - -------------------------------------------------------------------------------- Undistributed long-term gain $ 16,359,985 Current Year Post October Loss Deferred-Currency (37,374) Unrealized appreciation 99,359,772 ------------ Total $115,682,383 ============ - -------------------------------------------------------------------------------- The difference between book-basis and tax-basis unrealized appreciation is attributable to the tax deferral of losses on wash sales. D. Fund Shares The Fund records sales and repurchases of its shares as of trade date. Pioneer Funds Distributor, Inc. (PFD), the principal underwriter for the Fund and a wholly owned indirect subsidiary of UniCredito Italiano S.p.A., Inc. (UniCredito Italiano), earned $35,090 in underwriting commissions on the sale of Class A shares during the year ended September 30, 2007. E. Class Allocations 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. Class Y shares are not subject to a distribution plan (see Note 4). Shareowners of each class share all expenses and fees paid to the transfer agent, Pioneer Investment Management Shareholder Services, Inc. (PIMSS), for its services, which are allocated based on the number of accounts in each class and the ratable allocation of related out-of-pocket expenses 32 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- (see Note 3). 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 the respective percentage of adjusted net assets at the beginning of the day. 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, at the same time, and in the same amount, except that Class A, Class B and Class C shares can bear different transfer agent and distribution fees. F. Securities Lending The Fund lends securities in its portfolio to certain broker-dealers or other institutional investors, with the Fund's custodian acting as the lending agent. When entering into a loan, the Fund receives collateral, which is maintained by the custodian and earns income in the form of negotiated lenders' fees. The Fund also continues to receive interest or payments in lieu of dividends 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 loans are secured by collateral of at least 102% at all times, of the fair value of the securities loaned. The amount of collateral will be adjusted daily to reflect any price fluctuation in the value of loaned securities. The Fund has the right under the lending agreements to recover the securities on loan from the borrower on demand. The Fund invests cash collateral in the Securities Lending Investment Fund, which is sponsored by Brown Brothers Harriman & Co., the Fund's custodian. G. Repurchase Agreements With respect to repurchase agreements entered into by the Fund, the value of the underlying securities (collateral), including accrued interest received from counterparties, is required to be at least equal to or in excess of the value of the repurchase agreement at the time of purchase. The collateral for all repurchase agreements is held in safekeeping in the customer-only account of the Fund's custodian, or subcustodians. 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. 33 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- NOTES TO FINANCIAL STATEMENTS 9/30/07 (continued) - -------------------------------------------------------------------------------- 2. Management Agreement PIM, a wholly owned indirect subsidiary of UniCredito Italiano, manages the Fund's portfolio. PIM receives a basic fee that is calculated at the annual rate of 0.625% of the Fund's average daily net assets. The basic fee is subject to a performance adjustment (limited to a maximum of -0.20% applied to average assets during the measurement period) based on the Fund's Class A investment performance as compared with the Russell Midcap Growth Index over a rolling 36-month period. In addition, the fee is further limited on an annual basis to a maximum annualized rate adjustment of +0.20% of the average daily net assets during the current month. On June 28, 2007 PIM made a voluntary capital contribution of $1,240,204 to the Fund to reflect a current revision in the management contract. For the year ended September 30, 2007, the aggregate performance adjustment resulted in a reduction to the basic fee of $1,076,558. For the year ended September 30, 2007, the management fee was equivalent to 0.42% of average daily net assets. In addition, under the management and administrative agreements, certain other services and costs, including accounting, regulatory and insurance premiums, are paid by the Fund. At September 30, 2007, $15,479 was payable to PIM related to management fees, administrative costs and certain other services, and is included in due to affiliates. 3. Transfer Agent PIMSS, a wholly owned indirect subsidiary of UniCredito Italiano, provides substantially all transfer agent and shareowner services to the Fund at negotiated rates. Included in due to affiliates is $82,641 in transfer agent fees payable to PIMSS at September 20, 2007. 4. Distribution Plan The Fund adopted a Plan of Distribution with respect to Class A, Class B and Class C shares in accordance with Rule 12b-1 of the Investment Company Act of 1940. Pursuant to the Class A Plan, the Fund pays PFD a service fee of up to 0.25% of the Fund's average daily net assets attributable to Class A shares in reimbursement of its actual expenditures to finance activities primarily intended to result in the sale of Class A shares. Pursuant to the Class B Plan and the Class C Plan, the Fund pays PFD 1.00% of the average daily net assets attributable to each class of shares. The fee consists of a 0.25% 34 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- 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 is $11,507 in distribution fees payable to PFD at September 30, 2007. 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. Class B shares that are redeemed within five years of purchase are subject to a CDSC at declining rates beginning at 4.00%, 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%. Proceeds from the CDSCs are paid to PFD. For the year ended September 30, 2007, CDSCs in the amount of $39,422 were paid to PFD. 5. Commission Recapture and Expense Offset Arrangements The Fund has entered into commission recapture arrangements with brokers with whom PIM places trades on behalf of the Fund where they provide services to the Fund in addition to trade execution. These services included payments of certain expenses on behalf of the Fund. For the year ended September 30, 2007, expenses have not been reduced by this agreement. In addition, 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 September 30, 2007, the Fund's expenses were reduced by $58,287 under such arrangements. 6. Line of Credit The Fund, along with certain other funds in the Pioneer Family of Funds (the Funds), collectively participate in a $200 million committed, unsecured revolving line of credit facility. Borrowings are used solely for temporary or emergency purposes. The Fund may borrow up to the lesser of $200 million or the limits set by its prospectus for borrowings. Interest on collective borrowings is payable at the Federal Funds Rate plus 1/2% on an annualized basis. The Funds pay an annual commitment fee for this facility. The commitment fee is allocated among such Funds based on their respective borrowing 35 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- NOTES TO FINANCIAL STATEMENTS 9/30/07 (continued) - -------------------------------------------------------------------------------- limits. For the year ended September 30, 2007, the Fund had no borrowings under this agreement. 7. New Pronouncements On July 13, 2006, the Financial Accounting Standards Board (FASB) released FASB Interpretation No. 48 "Accounting for Uncertainty in Income Taxes" (FIN 48). FIN 48 provides guidance for how uncertain tax positions should be recognized, measured, presented and disclosed in the financial statements. FIN 48 requires the evaluation of tax positions taken or expected to be taken in the course of preparing the Fund's tax returns to determine whether the tax positions have "more-likely-than-not" probability of being sustained by the applicable tax authority. Tax positions not deemed to meet the more-likely-than-not threshold would be recorded as a tax benefit or expense in the reporting period. Adoption of FIN 48 is required for fiscal years beginning after December 15, 2006 and is to be applied to all open tax years as of no later than March 31, 2008. At this time, management is evaluating the implications of FIN 48 and any impact in the financial statements has not yet been determined. In September 2006, Statement of Financial Accounting Standards No. 157, Fair Value Measurements (SFAS 157), was issued and is effective for fiscal years beginning after November 15, 2007. SFAS 157 defines fair value, establishes a framework for measuring fair value and expands disclosures about fair value measurements. Management is currently evaluating the impact the adoption of SFAS 157 will have on the Fund's financial statement disclosures. 36 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM - -------------------------------------------------------------------------------- To the Board of Trustees and the Shareowners of Pioneer Mid Cap Growth Fund: We have audited the statement of assets and liabilities of Pioneer Mid Cap Growth Fund (the "Fund"), including the schedule of investments as of September 30, 2007, 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 periods indicated therein. 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 September 30, 2007, by correspondence with the custodian and brokers or by other appropriate auditing procedures where replies from brokers 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 Mid Cap Growth Fund at September 30, 2007, 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 periods indicated therein, in conformity with U.S. generally accepted accounting principles. /s/ Ernst & Young LLP Boston, Massachusetts November 16, 2007 37 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- 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 Board of Trustees provides broad supervision over the Fund's affairs. The officers of the Fund are responsible for the Fund's operations. The Fund's Trustees and officers are listed below, together with their principal occupations during 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 (except Mr. Kingsbury, Mr. West and Mr. Bock) serves as a Trustee of each of the 81 U.S. registered investment portfolios for which Pioneer serves as investment adviser (the "Pioneer Funds"). Mr. Kingsbury serves as Trustee of 33 of the 81 Pioneer Funds, Mr. West serves as Trustee of 32 of the 81 Pioneer Funds, and Mr. Bock serves as Trustee of 80 of the 81 Pioneer Funds. The address for all Interested Trustees and all officers of the fund is 60 State Street, Boston, Massachusetts 02109. Proxy Voting Policies and Procedures of the Fund are available without charge, upon request, by calling our toll free number (1-800-225-6292). Information regarding how the Fund voted proxies relating to portfolio securities during the most recent 12-month period ended June 30 is publicly available to shareowners at www.pioneerfunds.com and on the SEC's web site at http://www.sec.gov. 38 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- INTERESTED TRUSTEES - -------------------------------------------------------------------------------- Position Held Length of Service Principal Occupation Other Directorships Name and Age With the Fund and Term of Office During Past Five Years Held by this Trustee John F. Cogan, Jr. (81)* Chairman of the Trustee since 1982. Deputy Chairman and a None Board, Trustee and Serves until a succes- Director of Pioneer Global President sor trustee is elected Asset Management S.p.A. or earlier retirement or ("PGAM"); Non-Executive removal. Chairman and a Director of Pioneer Investment Management 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 Management Limited (Dublin); President and a Director of Pioneer Alternative Investment Management (Bermuda) Limited and affiliated funds; 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 (49)* Trustee and Executive Trustee since March Director, CEO and President None Vice President 2007. Serves until a of Pioneer Investment successor trustee is Management USA Inc.; Pioneer elected or earlier Investment Management, Inc. retirement or removal. and Pioneer Institutional Asset Management, Inc. (since March 2007); Executive Vice President of all of the Pioneer Funds (since March 2007); Director of Pioneer Global Asset Management S.p.A. (since March 2007); Head of New Markets Division, Pioneer Global Asset Management S.p.A. (2000 - 2007) - ------------------------------------------------------------------------------------------------------------------------------------ 39 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- INDEPENDENT TRUSTEES - -------------------------------------------------------------------------------- Position Held Length of Service Principal Occupation Other Directorships Name, Age and Address With the Fund and Term of Office During Past Five Years Held by this Trustee David R. Bock (63) Trustee Trustee since 2005. Executive Vice President and Director of The 3050 K Street NW, Serves until a succes- Chief Financial Officer, Enterprise Social Washington, DC 20007 sor trustee is elected I-trax, Inc. (publicly Investment Company or earlier retirement traded health care services (privately-held or removal. company) (2004 - present); affordable housing Partner, Federal City finance company); Capital Advisors (boutique and Director of New merchant bank) (1997 to York Mortgage Trust 2004); and Executive Vice (publicly traded President and Chief mortgage REIT) Financial Officer, Pedestal, Inc. (internet-based mortgage trading company) (2000 - 2002) - ------------------------------------------------------------------------------------------------------------------------------------ Mary K. Bush (59) Trustee Trustee since 1997. President, Bush Director of Brady 3509 Woodbine Street Serves until a succes- International, LLC Corporation Chevy Chase, MD 20815 sor trustee is elected (international financial (industrial or earlier retirement advisory firm) identification and or removal. specialty coated material products manufacturer); Director of Briggs & Stratton Co. (engine manufacturer); Director of UAL Corporation (airline holding company); Director of Mantech International Corporation (national security, defense, and intelligence technology firm): and Member, Board of Governors, Investment Company Institute - ------------------------------------------------------------------------------------------------------------------------------------ 40 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Position Held Length of Service Principal Occupation Other Directorships Name, Age and Address With the Fund and Term of Office During Past Five Years Held by this Trustee Margaret B.W. Graham (60) Trustee Trustee since 1990. Founding Director, None 1001 Sherbrooke Street West Serves until a succes- Vice-President and Corporate Montreal, Quebec, Canada sor trustee is elected Secretary, The Winthrop H3A 1G5 or earlier retirement Group, Inc. (consulting or removal. firm); and Desautels Faculty of Management, McGill University - ------------------------------------------------------------------------------------------------------------------------------------ Thomas J. Perna (57) Trustee Trustee since 2006. Private investor (2004 - Director of 89 Robbins Avenue, Serves until a succes- present); and Senior Quadriserv Berkeley Heights, NJ 07922 sor trustee is elected Executive Vice President, Inc. (technology or earlier retirement The Bank of New York products or removal. (financial and securities for securities services) (1986 - 2004) lending industry) - ------------------------------------------------------------------------------------------------------------------------------------ Marguerite A. Piret (59) Trustee Trustee since 1982. President and Chief Director of New 200 State Street, 12th Floor Serves until a succes- Executive Officer, Newbury, America High Income Boston, MA 02109 sor trustee is elected Piret & Company, Inc. Fund, Inc.(closed- or earlier retirement (investment banking firm) end investment or removal. company) - ------------------------------------------------------------------------------------------------------------------------------------ Stephen K. West (79) Trustee Trustee since 1993. Senior Counsel, Sullivan & Director, The Swiss 125 Broad Street, Serves until a succes- Cromwell (law firm) Helvetia Fund, Inc. New York, NY 10004 sor trustee is elected (closed-end or earlier retirement investment company) or removal. - ------------------------------------------------------------------------------------------------------------------------------------ John Winthrop (71) Trustee Trustee since 1985. President, John Winthrop & None One North Adgers Wharf, Serves until a succes- Co., Inc. (private Charleston, SC 29401 sor trustee is elected investment firm) or earlier retirement or removal. - ------------------------------------------------------------------------------------------------------------------------------------ 41 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- FUND OFFICERS - -------------------------------------------------------------------------------- Position Held Length of Service Principal Occupation Other Directorships Name and Age With the Fund and Term of Office During Past Five Years Held by this Officer Dorothy E. Bourassa (59) Secretary Since 2003. Serves Secretary of PIM-USA; Senior None at the discretion of Vice President - Legal of the Board Pioneer; Secretary/Clerk of most of PIM-USA's subsidiar- ies; and Secretary of all of the Pioneer Funds since September 2003 (Assistant Secretary from November 2000 to September 2003) - ------------------------------------------------------------------------------------------------------------------------------------ Christopher J. Kelley (42) Assistant Secretary Since 2003. Serves Vice President and Senior None at the discretion of Counsel of Pioneer since the Board July 2002 and Assistant Secretary of all of the Pioneer Funds since September 2003; Vice President and Senior Counsel of BISYS Fund Services, Inc. (April 2001 to June 2002); Senior Vice President and Deputy General Counsel of Funds Distributor, Inc. (July 2000 to April 2001) - ------------------------------------------------------------------------------------------------------------------------------------ Vincent Nave (62) Treasurer Since 2000. Serves Vice President - Fund None at the discretion of Accounting, Administration the Board and Controllership Services of Pioneer; and Treasurer of all of the Pioneer Funds - ------------------------------------------------------------------------------------------------------------------------------------ Mark E. Bradley (47) Assistant Treasurer Since 2004. Serves Deputy Treasurer of Pioneer None at the discretion of since 2004 and Assistant the Board Treasurer of all of the Pioneer Funds since November 2004; Treasurer and Senior Vice President, CDC IXIS Asset Management Services from 2002 to 2003 - ------------------------------------------------------------------------------------------------------------------------------------ Luis I. Presutti (42) Assistant Treasurer Since 2000. Serves Assistant Vice President - None at the discretion of Fund Accounting, the Board Administration and Controllership Services of Pioneer; and Assistant Treasurer of all of the Pioneer Funds - ------------------------------------------------------------------------------------------------------------------------------------ Gary Sullivan (49) Assistant Treasurer Since 2002. Serves Fund Accounting Manager - None at the discretion of Fund Accounting, Administra- the Board tion and Controllership Services of Pioneer; and Assistant Treasurer of all of the Pioneer Funds - ------------------------------------------------------------------------------------------------------------------------------------ 42 Pioneer Mid Cap Growth Fund - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- Position Held Length of Service Principal Occupation Other Directorships Name and Age With the Fund and Term of Office During Past Five Years Held by this Officer Katherine Kim Sullivan (33) Assistant Treasurer Since 2003. Serves at the Fund Administration Manager None discretion of the Board - Fund Accounting, Administration and Controllership Services since June 2003 and Assistant Treasurer of all of the Pioneer Funds since September 2003; Assistant Vice President - Mutual Fund Operations of State Street Corporation from June 2002 to June 2003 (formerly Deutsche Bank Asset Management) - ------------------------------------------------------------------------------------------------------------------------------------ Teri W. Anderholm (48) Chief Compliance Since January 2007. Chief Compliance Officer of None Officer Serves at the discre- Pioneer since December 2006 tion of the Board and of all the Pioneer Funds since January 2007; Vice President and Compliance Officer, MFS Investment Management (August 2005 to December 2006); Consultant, Fidelity Investments (February 2005 to July 2005); Independent Consultant (July 1997 to February 2005) - ------------------------------------------------------------------------------------------------------------------------------------ *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. - ------------------------------------------------------------------------------------------------------------------------------------ The outstanding capital stock of PFD, Pioneer and PIMSS is indirectly wholly owned by UniCredito Italiano S.p.A. ("UniCredito Italiano"), one of the largest banking groups in Italy. Pioneer, the fund's investment adviser, provides investment management and financial services to mutual funds, institutional and other clients 43 - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- This page for your notes. 44 - -------------------------------------------------------------------------------- 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 Telecommunications Device for the Deaf (TDD) 1-800-225-1997 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 Before investing consider the Fund's investment objectives, risks, charges and expenses. Contact your advisor or Pioneer Investments for a prospectus containing this information. Read it carefully. 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. 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. Audit Fees Fees for audit services provided to the Fund, including fees associated with the annual filing of its Form N-1A, totaled approximately $31,990 in 2007 and $30,760 in 2006. (b) Disclose, under the caption AUDIT-RELATED FEES, the aggregate fees billed in each of the last two fiscal years for assurance and related services by the principal accountant that are reasonably related to the performance of the audit of the registrant's financial statements and are not reported under paragraph (a) of this Item. Registrants shall describe the nature of the services comprising the fees disclosed under this category. Audit-Related Fees There were no fees for audit-related services provided to the Fund during the fiscal years ended September 30, 2007 and 2006. (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. Tax Fees Fees for tax compliance services, primarily for tax returns, totaled approximately $7,820 and $7,515 in 2007 and 2006, 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. Other Fees There were no fees for other services provided to the Fund during the fiscal years ended September 30, 2007 and 2006. (e) (1) Disclose the audit committee's pre-approval policies and procedures described in paragraph (c)(7) of Rule 2-01 of Regulation S-X. PIONEER FUNDS APPROVAL OF AUDIT, AUDIT-RELATED, TAX AND OTHER SERVICES PROVIDED BY THE INDEPENDENT AUDITOR SECTION I - POLICY PURPOSE AND APPLICABILITY The Pioneer Funds recognize the importance of maintaining the independence of their outside auditors. Maintaining independence is a shared responsibility involving Pioneer Investment Management, Inc ("PIM"), the audit committee and the independent auditors. The Funds recognize that a Fund's independent auditors: 1) possess knowledge of the Funds, 2) are able to incorporate certain services into the scope of the audit, thereby avoiding redundant work, cost and disruption of Fund personnel and processes, and 3) have expertise that has value to the Funds. As a result, there are situations where it is desirable to use the Fund's independent auditors for services in addition to the annual audit and where the potential for conflicts of interests are minimal. Consequently, this policy, which is intended to comply with Rule 210.2-01(C)(7), sets forth guidelines and procedures to be followed by the Funds when retaining the independent audit firm to perform audit, audit-related tax and other services under those circumstances, while also maintaining independence. Approval of a service in accordance with this policy for a Fund shall also constitute approval for any other Fund whose pre-approval is required pursuant to Rule 210.2-01(c)(7)(ii). In addition to the procedures set forth in this policy, any non-audit services that may be provided consistently with Rule 210.2-01 may be approved by the Audit Committee itself and any pre-approval that may be waived in accordance with Rule 210.2-01(c)(7)(i)(C) is hereby waived. Selection of a Fund's independent auditors and their compensation shall be determined by the Audit Committee and shall not be subject to this policy. SECTION II - POLICY - ---------------- -------------------------------- ------------------------------------------------- SERVICE SERVICE CATEGORY DESCRIPTION SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES CATEGORY - ---------------- -------------------------------- ------------------------------------------------- I. AUDIT Services that are directly o Accounting research assistance SERVICES related to performing the o SEC consultation, registration independent audit of the Funds statements, and reporting o Tax accrual related matters o Implementation of new accounting standards o Compliance letters (e.g. rating agency letters) o Regulatory reviews and assistance regarding financial matters o Semi-annual reviews (if requested) o Comfort letters for closed end offerings - ---------------- -------------------------------- ------------------------------------------------- II. Services which are not o AICPA attest and agreed-upon procedures AUDIT-RELATED prohibited under Rule o Technology control assessments SERVICES 210.2-01(C)(4) (the "Rule") o Financial reporting control assessments and are related extensions of o Enterprise security architecture the audit services support the assessment audit, or use the knowledge/expertise gained from the audit procedures as a foundation to complete the project. In most cases, if the Audit-Related Services are not performed by the Audit firm, the scope of the Audit Services would likely increase. The Services are typically well-defined and governed by accounting professional standards (AICPA, SEC, etc.) - ---------------- -------------------------------- ------------------------------------------------- ------------------------------------- ------------------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY ------------------------------------- ------------------------------------ o "One-time" pre-approval o A summary of all such for the audit period for all services and related fees pre-approved specific service reported at each regularly subcategories. Approval of the scheduled Audit Committee independent auditors as meeting. auditors for a Fund shall constitute pre approval for these services. ------------------------------------- ------------------------------------ o "One-time" pre-approval o A summary of all such for the fund fiscal year within services and related fees a specified dollar limit (including comparison to for all pre-approved specified dollar limits) specific service subcategories reported quarterly. o Specific approval is needed to exceed the pre-approved dollar limit for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for Audit-Related Services not denoted as "pre-approved", or to add a specific service subcategory as "pre-approved" ------------------------------------- ------------------------------------ SECTION III - POLICY DETAIL, CONTINUED - ----------------------- --------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES DESCRIPTION - ----------------------- --------------------------- ----------------------------------------------- III. TAX SERVICES Services which are not o Tax planning and support prohibited by the Rule, o Tax controversy assistance if an officer of the Fund o Tax compliance, tax returns, excise determines that using the tax returns and support Fund's auditor to provide o Tax opinions these services creates significant synergy in the form of efficiency, minimized disruption, or the ability to maintain a desired level of confidentiality. - ----------------------- --------------------------- ----------------------------------------------- - ------------------------------------- ------------------------- AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY - ------------------------------------- ------------------------- - ------------------------------------- ------------------------- o "One-time" pre-approval o A summary of for the fund fiscal year all such services and within a specified dollar limit related fees 				 (including comparison 			 to specified dollar 			 limits) reported 			 quarterly. o Specific approval is needed to exceed the pre-approved dollar limits for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for tax services not denoted as pre-approved, or to add a specific service subcategory as "pre-approved" - ------------------------------------- ------------------------- SECTION III - POLICY DETAIL, CONTINUED - ----------------------- --------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES DESCRIPTION - ----------------------- --------------------------- ----------------------------------------------- IV. OTHER SERVICES Services which are not o Business Risk Management support prohibited by the Rule, o Other control and regulatory A. SYNERGISTIC, if an officer of the Fund compliance projects UNIQUE QUALIFICATIONS determines that using the Fund's auditor to provide these services creates significant synergy in the form of efficiency, minimized disruption, the ability to maintain a desired level of confidentiality, or where the Fund's auditors posses unique or superior qualifications to provide these services, resulting in superior value and results for the Fund. - ----------------------- --------------------------- ----------------------------------------------- - --------------------------------------- ------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY - ------------------------------------- -------------------------- o "One-time" pre-approval o A summary of for the fund fiscal year within all such services and a specified dollar limit related fees 			 (including comparison 			 to specified dollar 				 limits) reported quarterly. o Specific approval is needed to exceed the pre-approved dollar limits for these services (see general Audit Committee approval policy below for details on obtaining specific approvals) o Specific approval is needed to use the Fund's auditors for "Synergistic" or "Unique Qualifications" Other Services not denoted as pre-approved to the left, or to add a specific service subcategory as "pre-approved" - ------------------------------------- -------------------------- SECTION III - POLICY DETAIL, CONTINUED - ----------------------- ------------------------- ----------------------------------------------- SERVICE CATEGORY SERVICE CATEGORY SPECIFIC PROHIBITED SERVICE SUBCATEGORIES DESCRIPTION - ----------------------- ------------------------- ----------------------------------------------- PROHIBITED SERVICES Services which result 1. Bookkeeping or other services in the auditors losing related to the accounting records or independence status financial statements of the audit under the Rule. client* 2. Financial information systems design and implementation* 3. Appraisal or valuation services, fairness* opinions, or contribution-in-kind reports 4. Actuarial services (i.e., setting actuarial reserves versus actuarial audit work)* 5. Internal audit outsourcing services* 6. Management functions or human resources 7. Broker or dealer, investment advisor, or investment banking services 8. Legal services and expert services unrelated to the audit 9. Any other service that the Public Company Accounting Oversight Board determines, by regulation, is impermissible - ----------------------- ------------------------- ----------------------------------------------- - ------------------------------------------- ------------------------------ AUDIT COMMITTEE APPROVAL POLICY AUDIT COMMITTEE REPORTING POLICY - ------------------------------------------- ------------------------------ o These services are not to be o A summary of all performed with the exception of the(*) services and related services that may be permitted fees reported at each if they would not be subject to audit regularly scheduled procedures at the audit client (as Audit Committee meeting defined in rule 2-01(f)(4)) level will serve as continual the firm providing the service. confirmation that has 				 not provided any restricted services. - ------------------------------------------- ------------------------------ - -------------------------------------------------------------------------------- GENERAL AUDIT COMMITTEE APPROVAL POLICY: o For all projects, the officers of the Funds and the Fund's auditors will each make an assessment to determine that any proposed projects will not impair independence. o Potential services will be classified into the four non-restricted service categories and the "Approval of Audit, Audit-Related, Tax and Other Services" Policy above will be applied. Any services outside the specific pre-approved service subcategories set forth above must be specifically approved by the Audit Committee. o At least quarterly, the Audit Committee shall review a report summarizing the services by service category, including fees, provided by the Audit firm as set forth in the above policy. - -------------------------------------------------------------------------------- (2) Disclose the percentage of services described in each of paragraphs (b) through (d) of this Item that were approved by the audit committee pursuant to paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X. Non-Audit Services Beginning with non-audit service contracts entered into on or after May 6, 2003, the effective date of the new SEC pre-approval rules, the Fund's audit committee is required to pre-approve services to affiliates defined by SEC rules to the extent that the services are determined to have a direct impact on the operations or financial reporting of the Fund. For the years ended September 30, 2007 and 2006, there were no services provided to an affiliate that required the Fund's audit committee pre-approval. (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. The aggregate non-audit fees for the Fund and affiliates, as previously defined, totaled approximately $7,820 in 2007 and $7,515 in 2006. (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 Mid Cap Growth Fund By (Signature and Title)* /s/ John F. Cogan, Jr. John F. Cogan, Jr, President Date November 29, 2007 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 November 29, 2007 By (Signature and Title)* /s/ Vincent Nave Vincent Nave, Treasurer Date November 29, 2007 * Print the name and title of each signing officer under his or her signature.