Pioneer Treasury Reserves Fund

Before you invest, you may want to review the fund’s prospectus, which contains more information about the fund and its risks. You can find the fund’s prospectus, statement of additional information and other information about the fund online at http://us.pioneerinvestments.com/misc/prospectus.jsp. You also can obtain this information at no cost by calling 1-800-225-6292 or by sending an email request to askpioneer@pioneerinvestments.com or by asking any financial intermediary that offers shares of the fund. The fund’s current prospectus and statement of additional information, dated December 1, 2010, and the independent registered public accounting firm’s report and financial statements in the fund’s annual report to shareholders dated July 31, 2010, are incorporated by reference into this summary prospectus.

Current income, preservation of capital and liquidity through investments in high-quality short-term securities.

This table describes the fees and expenses that you may pay if you buy and hold shares of the fund.

This example is intended to help you compare the cost of investing in the fund with the cost of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods shown and then, except as indicated, redeem all of your shares at the end of those periods. It also

assumes that (a) your investment has a 5% return each year and (b) the fund’s total annual operating expenses remain the same.

Although your actual costs may be higher or lower, based on these assumptions your costs would be:

The fund is a money market fund. The fund seeks to maintain a constant net asset value of $1.00 per share by investing in high-quality, U.S. dollar denominated money market securities. Normally, the fund invests at least 80% of its net assets (plus the amount of borrowings, if any, for investment purposes) in U.S. Treasury bills, notes and bonds, and repurchase agreements with respect to these securities. U.S. Treasury securities are direct obligations of the U.S. government. In addition, the fund may invest up to 20% of its net assets in obligations issued by agencies and instrumentalities of the U.S. government, repurchase agreements with respect to these securities and other eligible money market securities.

The fund invests in accordance with the credit quality, maturity, liquidity and diversification standards applicable to money market funds. Within these standards, the adviser’s assessment of broad economic factors that are expected to affect economic activity and interest rates influences securities selection. The adviser also employs fundamental research and an evaluation of the issuer based on its financial statements and operations to assess an issuer’s credit quality.

The fund invests in U.S. government obligations and money market securities that, at the time of purchase, are rated in one of the two highest rating categories for short-term debt by a nationally recognized statistical rating organization or, if unrated, determined to be of equivalent credit quality by the fund’s investment adviser. If rating organizations differ in the rating assigned to a security, the fund will only treat the security as having the higher rating if at least two rating organizations assigned that rating.

The fund invests exclusively in securities with a maximum remaining maturity of 397 days and maintains a dollar-weighted average portfolio maturity of 60 days or less. The fund’s investments may have fixed, floating or variable interest rates. If, after purchase, the credit rating on a security held by the fund is downgraded by one or more rating agencies or the credit quality deteriorates, or if the maturity on a security is extended, the adviser or the Board (where required by applicable regulations) will decide whether the security should be held or sold.

An investment in the fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Although the fund seeks to maintain a constant net asset value of $1.00 per share, there can be no assurance that this will be the case, and it is possible to lose money by investing in the fund. As with any mutual fund, there is no guarantee that the fund will achieve its objectives. You should be aware that money market funds have, in the past, “broken the buck,” which means that investors did not receive $1.00 per share for their investment in those funds, and this could happen again. You should also be aware that the fund’s investment adviser and its affiliates are under no obligation to provide financial support to the fund or take other measures to ensure that you receive $1.00 per share for your investment in the fund. You should not invest in the fund with the expectation that any such action will be taken. The recent adoption of more stringent regulations governing the management of money market funds could have a negative effect on the fund’s yield. From time to time, the adviser and its affiliates may reimburse or otherwise reduce the fund’s expenses or the adviser may waive a portion of its management fee in an effort to maintain a net asset value of $1.00 per share, for the purpose of avoiding a negative yield or increasing the fund’s yield during the period of the limitation. Any such expense reimbursements, reductions or waivers are voluntary and temporary and may be terminated by the adviser at any time without notice.

Interest rate and market risk. There may be changes in interest rates, lack of liquidity or other disruptions in the bond markets or other adverse market events. An increase in interest rates, decline in the market value of a fund investment, lack of liquidity in the bond markets or other market events, including the recent global financial crisis, could cause the value of your investment, or its yield, to decline. In response to the crisis, the U.S. government and the Federal Reserve have taken steps to support financial markets. The withdrawal of this support could also negatively affect the value and liquidity of certain securities. In addition, legislation recently enacted in the U.S. calls for changes in many aspects of financial regulation. The impact of the legislation on the markets, and the practical implications for market participants, may not be known for some time.

U.S. government agency obligations risk. The fund invests in obligations issued by agencies and instrumentalities of the U.S. government. Government sponsored entities such as Federal National Mortgage Association (Fannie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac) and the Federal Home Loan Banks (FHLBs), although chartered or sponsored by Congress, are not funded by congressional appropriations and the debt and mortgage-backed securities issued by them are neither guaranteed nor issued by the U.S. government. Although the U.S. government has provided financial support to

Fannie Mae and Freddie Mac in the past, there can be no assurance that it will support these or other government sponsored entities in the future. Such debt and mortgage-backed securities are subject to the risk of default in the payment of interest and/or principal, similar to debt of private issuers.

Credit risk. If an issuer or obligor of a security held by the fund or a counterparty to a financial contract with the fund defaults on its obligation to pay principal and/or interest, has its credit rating downgraded or is perceived to be less creditworthy, or the credit quality or value of any underlying assets declines, the value of your investment will decline. In addition, the default or downgrade of a single holding or issuer may cause significant deterioration in the fund’s share price. The credit quality of the fund’s holdings can change rapidly in certain markets.

Yield risk. The amount of income you receive from the fund will go up or down depending on day-to-day variations in short-term interest rates, and when interest rates are very low the fund’s expenses could absorb all or a significant portion of the fund’s income.

Risk of increase in expenses. Your actual costs of investing in the fund may be higher than the expenses shown in “Annual fund operating expenses” for a variety of reasons. For example, expense ratios may be higher than those shown if overall net assets decrease or if a voluntary fee waiver is changed or terminated.

Structured securities risk. The structured securities in which the fund invests are a type of derivative instrument. The value of these instruments depends on the value of the underlying assets and the terms of the particular security. Some of the instruments may have the effect of increasing the fund’s exposure to interest rate, market or credit risk, even if they are not primarily intended for these purposes. Investments in structured securities raise certain tax, legal, regulatory and accounting issues that may not be presented by direct investments in securities. These issues could be resolved in a manner that could hurt the performance of the fund.

Portfolio selection risk. The adviser’s judgment about the quality, relative yield, relative value or market trends affecting a particular sector or region, market segment, security, or about interest rates generally, may prove to be incorrect.

Redemption risk. The fund may experience periods of heavy redemptions that could cause the fund to liquidate its assets at inopportune times or at a loss or depressed value particularly during periods of declining or illiquid markets. Redemption risk is greater to the extent that the fund has investors with large shareholdings, short investment horizons, or unpredictable cash flow needs. The redemption by one or more large shareholders of their holdings in the fund could cause the remaining shareholders in the fund to lose money. In addition, the fund may suspend redemptions when permitted by applicable regulations.

Please note that there are many other factors that could adversely affect your investment and that could prevent the fund from achieving its goals.

The bar chart and table indicate the risks and volatility of an investment in the fund by showing how the fund has performed in the past. The bar chart shows changes in the performance of the fund’s Class A shares from calendar year to calendar year. The table shows the average annual total returns for each class of the fund over time. You can obtain updated performance information by visiting http://us.pioneerinvestments.com/performance or by calling 1-800-225-6292.

The fund acquired the assets and liabilities of AmSouth Treasury Reserve Money Market Fund (the predecessor fund) on September 23, 2005. The performance of Class A shares of the fund includes the net asset value performance of the predecessor fund’s Class A shares prior to the reorganization, which has been restated to reflect differences in any applicable sales charges (but not differences in expenses). The performance of Class Y shares of the fund includes the net asset value performance of the predecessor fund’s Class I shares prior to the reorganization, which has not been restated to reflect differences in expenses. Performance is not shown for Class C shares because Class C shares have not yet commenced operations.

The fund’s past performance (before and after taxes) does not necessarily indicate how it will perform in the future.

The bar chart does not reflect any sales charge you may pay when you buy fund shares. If this amount was reflected, returns would be less than those shown.

You may purchase, exchange or sell (redeem) shares each day the New York Stock Exchange is open through your financial intermediary or, for accounts held directly with the fund, by contacting the fund’s transfer agent in writing or by telephone (Pioneer Investment Management Shareholder Services, Inc., P.O. Box 55014, Boston, MA 02205-5014, tel. 1-800-225-6292).

Your initial investment for Class A or Class C shares must be at least $1,000. Additional investments must be at least $100 for Class A shares and $500 for Class C shares. The initial investment for Class Y shares must be at least

$5 million. This amount may be invested in one or more of the Pioneer mutual funds that currently offer Class Y shares. There is no minimum additional investment amount for Class Y shares.

You normally will have to pay income taxes on the dividends and capital gain distributions you receive from the fund, unless you are investing through a tax-deferred account, such as a 401(k) plan or individual retirement account.

If you purchase the fund through a broker-dealer or other financial intermediary (such as a bank), the fund and its related companies may pay the intermediary for the sale of fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your salesperson or investment professional to recommend the fund over another investment. Ask your salesperson or investment professional or visit your financial intermediary’s website for more information.


(expenses that you pay each year as a percentage of the value of your investment)	Class A		Class C		Class Y
Management Fees		0.40%		0.40%		0.40%
Distribution and Service (12b-1) Fees		0.15%		1.00%		0.00%
Other Expenses¹		0.12%		0.12%		0.09%
Total Annual Fund Operating Expenses		0.67%		1.52%		0.49%


	If you redeem your shares								If you do not redeem your shares
	Number of years you own your shares
	1		3		5		10		1		3		5		10
Class A	$	68	$	214	$	373	$	835	$	68	$	214	$	373	$	835
Class C		255		480		829		1,813		155		480		829		1,813
Class Y		50		157		274		616		50		157		274		616


	1 Year		5 Years		10 Years		Since Inception		Inception Date
Class A		0.02		2.45		2.30		3.17		3/29/94
Class Y		0.02		2.59		2.42		3.29		3/29/94


Investment adviser		Pioneer Investment Management, Inc.

Portfolio management		Seth Roman, Portfolio Manager (portfolio manager of the fund since 2006)


Class A Shares (ITAXX)		Class C Shares ( )*		Class Y Shares (ITMXX)


Summary Prospectus		December 1, 2010