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                                 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 811-05099

                          Pioneer Money Market Trust
               (Exact name of registrant as specified in charter)


                       60 State Street, Boston, MA 02109
              (Address of principal executive offices) (ZIP code)


            Terrence J. Cullen, Pioneer Investment Management, Inc.,
                       60 State Street, Boston, MA 02109
                    (Name and address of agent for service)


Registrant's telephone number, including area code:  (617) 742-7825


Date of fiscal year end:  December 31


Date of reporting period:  January 1, 2010 through December 31, 2010


Form N-CSR is to be used by management investment companies to file reports with
the Commission not later than 10 days after the transmission to stockholders of
any report that is required to be transmitted to stockholders under Rule 30e-1
under the Investment Company Act of 1940 (17 CFR 270.30e-1).  The Commission may
use the information provided on Form N-CSR in its regulatory, disclosure review,
inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-CSR,
and the Commission will make this information public. A registrant is not
required to respond to the collection of information contained in Form N-CSR
unless the Form displays a currently valid Office of Management and Budget
("OMB") control number. Please direct comments concerning the accuracy of the
information collection burden estimate and any suggestions for reducing the
burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW,
Washington, DC 20549-0609.  The OMB has reviewed this collection of information
under the clearance requirements of 44 U.S.C. ss. 3507.


ITEM 1. REPORTS TO SHAREOWNERS.



                       Pioneer Cash
                       Reserves Fund
--------------------------------------------------------------------------------
                       Annual Report | December 31, 2010
--------------------------------------------------------------------------------

                       Ticker Symbols:
                       Class A   PMTXX
                       Class B   PBTXX
                       Class C   PSVXX
                       Class R   PCHXX
                       Class Y   PRYXX





                       [LOGO] PIONEER
                              Investments(R)


<PAGE>



                        visit us: pioneerinvestments.com



<PAGE>

Table of Contents

<TABLE>
<S>                                                                        <C>
Letter to Shareowners                                                        2

Portfolio Management Discussion                                              4

Portfolio Summary                                                            7

Performance Update                                                           8

Comparing Ongoing Fund Expenses                                             10

Schedule of Investments                                                     12

Financial Statements                                                        18

Notes to Financial Statements                                               27

Report of Independent Registered Public Accounting Firm                     34

Approval of Investment Advisory Agreement                                   36

Trustees, Officers and Service Providers                                    40
</TABLE>


                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10     1
<PAGE>

President's Letter

Dear Shareowner,

Throughout 2010, the U.S. economy moved forward on a slow path to recovery. But
with the memory of a deep recession still lingering, businesses and consumers
remained cautious about both investing and spending. While business
fundamentals showed signs of improvement, there was still a reluctance to hire,
and high unemployment remains a problem. Wary investors, concerned about risk,
gravitated towards cash and bonds, until a rally late in the year lifted equity
returns. We remain generally optimistic about the prospects for economic
recovery, although it may occur more slowly than many would like.

At Pioneer, we have long advocated the benefits of staying diversified and
investing for the long term. This strategy has generally performed well for
many investors. Bond markets certainly rewarded investors in the first eleven
months of 2010. While the equity markets barely budged for those first eleven
months, valuations were inexpensive relative to bonds, compared with historic
levels, and represented potentially good value for long-term investors, many of
whom were rewarded in the subsequent late-year equity rally.

Pioneer has not changed the basic approach to investing that we have used for
more than 80 years. We remain focused on company fundamentals and risk
management. Our investment process is based on careful research into individual
companies, quantitative analysis, and active portfolio management. This
three-pillared process, which we apply to each of our portfolios, is supported
by an integrated team approach and is designed to carefully balance risk and
reward. Our experienced professionals devote themselves to the careful research
needed to identify investment opportunities in markets around the world.

Our advice, as always, is to work closely with a trusted financial advisor to
discuss your goals and work together to develop an investment strategy that
meets your individual needs. There is no single best strategy that works for
every investor.


2     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

We invite you to learn more about Pioneer and our time-tested approach to
investing by consulting with your financial advisor or visiting us online at
www.pioneerinvestments.com. We greatly appreciate your trust in us and we thank
you for investing with Pioneer.

Sincerely,

/s/ Daniel K. Kingsbury

Daniel K. Kingsbury
President and CEO
Pioneer Investment Management USA Inc.



Any information in this shareholder report regarding market or economic trends
or the factors influencing the Fund's historical or future performance are
statements of the opinion of Fund management as of the date of this report.
These statements should not be relied upon for any other purposes. Past
performance is no guarantee of future results, and there is no guarantee that
market forecasts discussed will be realized.


                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10     3
<PAGE>

Portfolio Management Discussion | 12/31/10

Yields of short-term securities remained at extraordinarily low levels
throughout 2010, as the U.S. Federal Reserve Board (the Fed) maintained a
highly accommodative monetary policy aimed at prodding an economic recovery.
While signs of improvement appeared in many parts of the economy, weak jobs
growth and persistent problems in the housing market caused continued concerns
about the pace and durability of the economic expansion. In the following
interview, Seth Roman reviews the investment environment and the factors that
affected Pioneer Cash Reserves Fund during the 12 months ended December 31,
2010. Mr. Roman is a member of Pioneer's Fixed Income Group, which is
responsible for the daily management of the Fund.

Q  How did the Fund perform during the 12 months ended December 31, 2010?

A  Pioneer Cash Reserves Class A shares returned 0.02% at net asset value over
   the 12 months ended December 31, 2010. During the same period, the average
   return of the 281 mutual funds in Lipper's Money Market Funds category was
   0.03%. The 30-day SEC yield on Class A shares as of December 31, 2010, was
   0.01%.

Q  What were the principal factors affecting the Fund's performance during the
   12 months ended December 31, 2010?

A  We kept our focus on capital preservation and liquidity throughout the year.
   When we say liquidity, we refer to maintaining investments in money market
   instruments that can easily be bought and sold at par (face) value in the
   market. Throughout 2010, the Fed kept the influential federal funds target
   rate at close to zero.

   While signs of improving economic conditions were increasingly evident, a
   relatively high unemployment rate continued to worry monetary authorities.
   Moreover, inflationary pressures appeared minimal and some authorities
   openly worried about the potential threat of deflation, in which prices
   spiral downward. (Deflation had crippled the Japanese economy.) In the late
   spring and early summer of 2010, authorities also worried about the
   potential contagion effects of widening credit problems in some European
   nations, including Greece, Ireland and Spain. The credit problems raised
   questions about the quality of some sovereign debt in Europe and the amount
   of exposure of the major European banking institutions that may have held
   the sovereign debt. While the European worries initially caused some
   volatility in some short-term benchmarks, the consequence of all the
   factors was to keep short-term interest rates low and trading in a
   relatively narrow band.


4     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

   Given all the factors in play during the 12-month period, we managed the
   Fund very conservatively, avoiding credit risk and focusing on very short
   maturities that were highly liquid. In the final six months of the Fund's
   fiscal year, for example, the average maturity of Fund holdings declined
   from 23 days to 16 days. By comparison, the average maturity of the Fund's
   holdings in 2009 was between 50 and 60 days. We increased the Fund's
   exposure to variable rate, short-term municipal securities issued by
   high-quality institutions and agencies, and sometimes secured with letters
   of credit from financially solid banking institutions. The municipal
   securities offered the Fund somewhat higher yields. We also increased the
   Fund's exposure to Treasury securities and to floating-rate U.S. government
   agency securities, while minimizing exposures to European banks.

Q  What is your investment outlook?

A  We do not anticipate that the Fed will start raising short-term rates in the
   near future. While there have been some pressures on fuel and food prices,
   core inflation remains very low. Assuming inflationary pressures stay muted,
   we would expect that the Fed will keep rates very low until there is evidence
   of solid gains in employment and some improvement in housing. Moreover, we do
   not anticipate any other pressures for market overnight lending rates to
   increase, barring some kind of disaster in the European credit markets. Given
   these views, we think it makes sense to keep the Fund's portfolio very
   conservatively positioned, with an emphasis on capital preservation and a
   continued focus on high-quality, highly liquid securities. The policy also
   gives us the flexibility to respond quickly should market conditions change
   and yields start moving higher.

Although the Fund seeks to preserve the value of your investment at $1.00 per
share, it is possible to lose money by investing in the Fund. Fund shares are
not federally insured by the Federal Deposit Insurance Corporation, the Federal
Reserve Board or any other government agency.

At times, the Fund's investments may represent industries or industry sectors
that are interrelated or have common risks, making it more susceptible to any
economic, political, or regulatory developments or other risks affecting those
industries and sectors. Investing in foreign and/or emerging markets securities
involves risks relating to interest rates, currency exchange rates, economic,
and political conditions.

Please refer to the Schedule of Investments on pages 12-17 for a full listing
of Fund securities.

Past performance is no guarantee of future results, and there is no guarantee
that market forecasts discussed will be realized.


                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10     5
<PAGE>

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 opinions should not be relied upon for any other purposes.


6     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

Portfolio Summary | 12/31/10

Portfolio Diversification
--------------------------------------------------------------------------------
(As a percentage of total investment portfolio)

[THE FOLLOWING DATA WAS REPRESENTED AS A PIE CHART IN THE PRINTED MATERIAL]

<TABLE>
<S>                                                    <C>
Repurchase Agreements                                  33.3%
U.S. Government Securities                             20.7%
Municipal Bonds                                        19.6%
Commercial Paper                                       18.6%
Tax Exempt Money Market Mutual Fund                     6.2%
U.S. Corporate Bonds                                    1.6%
</TABLE>

10 Largest Holdings
--------------------------------------------------------------------------------

<TABLE>
<S>    <C>                                                                 <C>
 1.    Federal Home Loan Mortgage Corp., 0.34969%, 4/1/11                  4.71%
--------------------------------------------------------------------------------
 2.    U.S. Treasury Bills, 0.3285%, 4/7/11                                4.62
--------------------------------------------------------------------------------
 3.    U.S. Treasury Bills, 0.0%, 4/14/11                                  4.39
--------------------------------------------------------------------------------
 4.    U.S. Treasury Bills, 0.18%, 3/3/11                                  4.03
--------------------------------------------------------------------------------
 5.    Federal Home Loan Mortgage Corp., Floating Rate Note, 2/14/11       3.27
--------------------------------------------------------------------------------
 6.    Metropolitan Washington Airport, Floating Rate Note, 10/1/39        3.20
--------------------------------------------------------------------------------
 7.    Jackson County Mississippi, Floating Rate Note, 6/1/23              3.06
--------------------------------------------------------------------------------
 8.    Harvard University, 0.25%, 1/4/11                                   2.70
--------------------------------------------------------------------------------
 9.    University of Minnesota, Floating Rate Note, 12/1/36                2.64
--------------------------------------------------------------------------------
10.    Bank of Nova Scotia/Houston, Floating Rate Note, 7/6/11             2.52
--------------------------------------------------------------------------------
</TABLE>

The Fund is actively managed, and current holdings may be different. The
holdings listed should not be considered recommendations to buy or sell any
security listed.


                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10     7
<PAGE>

Performance Update | 12/31/10

Net Asset Value per Share
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>
     Class                      12/31/10                   12/31/09
<S>                              <C>                        <C>
       A                         $1.00                      $1.00
--------------------------------------------------------------------------------
       B                         $1.00                      $1.00
--------------------------------------------------------------------------------
       C                         $1.00                      $1.00
--------------------------------------------------------------------------------
       R                         $1.00                      $1.00
--------------------------------------------------------------------------------
       Y                         $1.00                      $1.00
--------------------------------------------------------------------------------
</TABLE>

Distributions per Share: 1/1/10-12/31/10
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                   Net Investment        Short-Term        Long-Term
      Class           Income          Capital Gains     Capital Gains
<S>                     <C>                  <C>               <C>
       A                $0.0002              $--               $--
--------------------------------------------------------------------------------
       B                $0.0002              $--               $--
--------------------------------------------------------------------------------
       C                $0.0002              $--               $--
--------------------------------------------------------------------------------
       R                $0.0002              $--               $--
--------------------------------------------------------------------------------
       Y                $0.0002              $--               $--
--------------------------------------------------------------------------------
</TABLE>

Yields*
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>
      Class                7-Day Annualized         7-Day Effective**
<S>                              <C>                      <C>
       A                         0.01%                    0.01%
--------------------------------------------------------------------------------
       B                         0.01%                    0.01%
--------------------------------------------------------------------------------
       C                         0.01%                    0.01%
--------------------------------------------------------------------------------
       R                         0.01%                    0.01%
--------------------------------------------------------------------------------
       Y                         0.01%                    0.01%
--------------------------------------------------------------------------------
</TABLE>

*  The 7-day yields do not reflect the deduction of the contingent deferred
   sales charge (CDSC) for Class B shares (maximum 4%) and Class C shares
   (maximum 1%) shares. Please contact Pioneer to obtain the Fund's current
   7-day yields.

** Assumes daily compounding of dividends.

8     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

Expense Ratio (Per prospectus dated May 1, 2010)
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>
     Class                      Gross                      Net
<S>                              <C>                       <C>
       A                         0.76%                     0.70%
--------------------------------------------------------------------------------
       B                         1.85%                     1.85%
--------------------------------------------------------------------------------
       C                         1.74%                     1.74%
--------------------------------------------------------------------------------
       R                         1.40%                     1.40%
--------------------------------------------------------------------------------
       Y                         0.50%                     0.45%
--------------------------------------------------------------------------------
</TABLE>

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.

The net expense ratio reflects contractual expense limitations currently in
effect through June 1, 2012, for Class A and Class Y shares. There can be no
assurance that Pioneer will extend the expense limitations beyond such time.
Please see the prospectus for more information.

Pioneer has agreed to limit the Fund's expenses for any class of shares or
waive a portion of its management fee in an effort to maintain a net asset
value of $1.00 per share. Under certain circumstances, this limitation may
result in a 0.00% yield for one or more classes of shares. From time to time,
Pioneer and its affiliates may limit the expenses of one or more classes for
the purpose of avoiding a negative yield or increasing its yield during the
period of the limitation. These expense limitation policies are voluntary and
temporary and may be revised or terminated by Pioneer at any time without
notice.

Performance does not reflect the deduction of taxes that a shareowner would pay
on Fund distributions or the redemption of Fund shares.


                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10     9
<PAGE>

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 Cash Reserves Fund

Based on actual returns from July 1, 2010 through December 31, 2010.

<TABLE>
<CAPTION>
 Share Class                 A               B               C               R               Y
 <S>                     <C>             <C>             <C>             <C>             <C>
 Beginning Account       $1,000.00       $1,000.00       $1,000.00       $1,000.00       $1,000.00
 Value On 7/1/10
--------------------------------------------------------------------------------------------------
 Ending Account          $1,000.20       $1,000.20       $1,000.20       $1,000.20       $1,000.20
 Value On 12/31/10
--------------------------------------------------------------------------------------------------
 Expenses Paid               $1.16           $1.16           $1.16           $1.21           $1.11
 During Period*
--------------------------------------------------------------------------------------------------
</TABLE>

* Expenses are equal to the Fund's annualized expense ratio of 0.23%, 0.23%,
  0.23%, 0.24% and 0.22% for Class A, Class B, Class C, Class R and Class Y
  shares, respectively, multiplied by the average account value over the
  period, multiplied by 184/365 (to reflect the one-half year period).


10     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

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 Cash Reserves Fund

Based on a hypothetical 5% return per year before expenses, reflecting the
period from July 1, 2010 through December 31, 2010.

<TABLE>
<CAPTION>
 Share Class                 A               B               C               R               Y
 <S>                     <C>             <C>             <C>             <C>             <C>
 Beginning Account       $1,000.00       $1,000.00       $1,000.00       $1,000.00       $1,000.00
 Value On 7/1/10
--------------------------------------------------------------------------------------------------
 Ending Account          $1,024.05       $1,024.05       $1,024.05       $1,024.00       $1,024.10
 Value On 12/31/10
--------------------------------------------------------------------------------------------------
 Expenses Paid               $1.17           $1.17           $1.17           $1.22           $1.12
 During Period*
--------------------------------------------------------------------------------------------------
</TABLE>

* Expenses are equal to the Fund's annualized expense ratio of 0.23%, 0.23%,
  0.23%, 0.24% and 0.22% for Class A, Class B, Class C, Class R and Class Y
  shares, respectively, multiplied by the average account value over the
  period, multiplied by 184/365 (to reflect the one-half year period).


                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     11
<PAGE>

Schedule of Investments | 12/31/10

<TABLE>
<CAPTION>
             Floating       S&P/Moody's
Principal    Rate (b)       Ratings
Amount ($)   (unaudited)    (unaudited)                                                   Value
<S>          <C>            <C>            <C>                                            <C>
                                           CORPORATE BONDS -- 1.6%
                                           BANKS -- 1.6%
                                           Diversified Banks -- 1.6%
 4,750,000                        NR/Aaa   Rabobank Nederland NV, 0.51%, 8/16/14          $  4,749,940
 4,500,000   0.31                 AA/Aa1   Westpac Banking Corp., Floating Rate Note,
                                           3/2/11                                            4,499,964
                                                                                          ------------
                                                                                          $  9,249,904
                                                                                          ------------
                                           Total Banks                                    $  9,249,904
------------------------------------------------------------------------------------------------------
                                           TOTAL CORPORATE BONDS
                                           (Cost $9,249,904)                              $  9,249,904
------------------------------------------------------------------------------------------------------
                                           U.S. GOVERNMENT AGENCY OBLIGATIONS -- 20.4%
   500,000   0.75                AAA/Aaa   Federal Farm Credit Bank, Floating Rate Note,
                                           3/24/11                                        $    500,549
 2,870,000   0.75                AAA/Aaa   Federal Farm Credit Bank, Floating Rate Note,
                                           5/12/11                                           2,874,190
 4,730,000                       AAA/AAA   Federal Home Loan Bank, 0.2%, 5/6/11              4,729,206
 8,500,000                       AAA/Aaa   Federal Home Loan Bank, 0.24%, 5/6/11             8,498,946
 1,900,000                       AAA/Aaa   Federal Home Loan Bank, 0.33%, 2/28/12            1,900,665
 4,640,000   0.28                AAA/AAA   Federal Home Loan Bank, Floating Rate Note,
                                           5/27/11                                           4,640,184
16,338,000                       AAA/Aaa   Federal Home Loan Mortgage Corp.,
                                           0.34969%, 4/1/11                                 16,343,279
 3,895,000   0.33                AAA/Aaa   Federal Home Loan Mortgage Corp., Floating
                                           Rate Note, 11/7/11                                3,896,332
11,355,000   0.33                AAA/Aaa   Federal Home Loan Mortgage Corp., Floating
                                           Rate Note, 2/14/11                               11,356,433
 5,720,000                         NR/NR   U.S. Treasury Bills, 0.0%, 3/17/11                5,717,983
15,260,000                         NR/NR   U.S. Treasury Bills, 0.0%, 4/14/11               15,252,443
 4,000,000                         NR/NR   U.S. Treasury Bills, 0.0%, 7/28/11                3,994,560
 4,505,000                         NR/NR   U.S. Treasury Bills, 0.1195%, 1/20/11             4,504,844
 4,210,000                         NR/NR   U.S. Treasury Bills, 0.1545%, 2/3/11              4,209,447
13,995,000                       AAA/Aaa   U.S. Treasury Bills, 0.18%, 3/3/11               13,990,929
16,035,000                       AAA/Aaa   U.S. Treasury Bills, 0.3285%, 4/7/11             16,029,677
                                                                                          ------------
                                                                                          $118,439,667
------------------------------------------------------------------------------------------------------
                                           TOTAL U.S. GOVERNMENT
                                           AGENCY OBLIGATIONS
                                           (Cost $118,439,667)                            $118,439,667
------------------------------------------------------------------------------------------------------
                                           MUNICIPAL BONDS -- 19.4%
                                           Municipal Airport -- 1.9%
11,100,000   0.28                AAA/Aa1   Metropolitan Washington Airport, Floating
                                           Rate Note, 10/1/39                             $ 11,100,000
------------------------------------------------------------------------------------------------------
</TABLE>

The accompanying notes are an integral part of these financial statements.

12     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

<TABLE>
<CAPTION>
              Floating       S&P/Moody's
Principal     Rate (b)       Ratings
Amount ($)    (unaudited)    (unaudited)                                                       Value
<S>           <C>            <C>             <C>                                               <C>
                                             Municipal Development -- 2.2%
10,615,000    0.27                 AA/Aa1    Jackson County Mississippi, Floating Rate
                                             Note, 6/1/23                                      $ 10,615,000
 2,550,000    0.26                AAA/Aaa    Loudoun County Virginia Industrial
                                             Development Authority, Floating Rate Note,
                                             2/15/38                                              2,550,000
                                                                                               ------------
                                                                                               $ 13,165,000
-----------------------------------------------------------------------------------------------------------
                                             Municipal Education -- 0.2%
 1,100,000    0.49                 AA-/NR    Illinois Financial Authority Revenue, Floating
                                             Rate Note, 9/1/41                                 $  1,100,000
-----------------------------------------------------------------------------------------------------------
                                             Municipal Higher Education -- 6.3%
 3,930,000    0.23                AAA/Aaa    Connecticut State Health & Education,
                                             Floating Rate Note, 7/1/33                        $  3,930,000
 4,470,000    0.30                AAA/Aa1    District of Columbia, Floating Rate Note,
                                             4/1/41                                               4,470,000
 2,505,000    0.29                 AA/Aa2    Maryland State Health & Higher Education
                                             Facilities Authority Revenue, Floating Rate
                                             Note, 7/1/36                                         2,505,000
 5,950,000    0.24                AA+/Aaa    Massachusetts Health & Education, Floating
                                             Rate Note, 7/1/39                                    5,950,000
 5,785,000                        AAA/Aa1    Syracuse Industrial, 0.15%, 12/1/35                  5,785,000
 9,180,000    0.34                 AA/Aa2    University of Minnesota, Floating Rate Note,
                                             12/1/36                                              9,180,000
 1,150,000    0.28                AA+/Aa1    Virginia College Building Authority, Floating
                                             Rate Note, 2/1/26                                    1,150,000
 3,805,000    0.28                AAA/Aa1    Wisconsin State Health & Educational
                                             Facilities, Floating Rate Note, 12/1/33              3,805,000
                                                                                               ------------
                                                                                               $ 36,775,000
-----------------------------------------------------------------------------------------------------------
                                             Municipal Medical -- 4.6%
 1,250,000    0.28                 AA/Aaa    Harris County Texas Health, Floating Rate
                                             Note, 12/1/41                                     $  1,250,000
 8,145,000    0.33                 AA/Aa1    Illinois Finance Authority, Floating Rate
                                             Note, 7/1/32                                         8,145,000
   700,000    0.26                AAA/Aaa    Loudoun County Virginia Industrial
                                             Development Authority, Floating Rate Note,
                                             2/15/38                                                700,000
 7,600,000    0.29                AAA/Aaa    Loudoun County Virginia Industrial
                                             Development Authority, Floating Rate Note,
                                             2/15/38                                              7,600,000
 5,020,000    0.27                 NR/Aa2    North Carolina Medical Care Community,
                                             Floating Rate Note, 6/1/15                           5,020,000
 2,495,000    0.33                  AA/NR    Oregon State Facilities Authority, Floating Rate
                                             Note, 5/1/47                                         2,495,000
</TABLE>

The accompanying notes are an integral part of these financial statements.

                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     13
<PAGE>

Schedule of Investments | 12/31/10   (continued)

<TABLE>
<CAPTION>
             Floating       S&P/Moody's
Principal    Rate (b)       Ratings
Amount ($)   (unaudited)    (unaudited)                                                     Value
<S>          <C>            <C>             <C>                                             <C>
                                            Municipal Medical -- (continued)
 1,400,000   0.28                AA+/Aa2    University of Michigan, Floating Rate Note,
                                            12/1/37                                         $  1,400,000
                                                                                            ------------
                                                                                            $ 26,610,000
--------------------------------------------------------------------------------------------------------
                                            Municipal Pollution -- 1.1%
 6,330,000   0.23                AAA/Aaa    Lincoln County Wyoming Pollutant Control,
                                            Floating Rate Note, 11/1/14                     $  6,330,000
--------------------------------------------------------------------------------------------------------
                                            Municipal Utilities -- 1.0%
 5,635,000   0.33                 AA/Aa2    Gainsville Florida Utilities, Floating Rate
                                            Note, 10/1/38                                   $  5,635,000
--------------------------------------------------------------------------------------------------------
                                            Municipal Water -- 2.1%
 3,600,000   0.39                AA-/Aa2    Boston Massachusetts Water & Sewer
                                            Community Revenue, Floating Rate Note,
                                            11/1/24                                         $  3,600,000
 8,480,000   0.29                AAA/Aaa    Texas Water Development Board, Floating
                                            Rate Note, 7/15/19                                 8,480,000
                                                                                            ------------
                                                                                            $ 12,080,000
--------------------------------------------------------------------------------------------------------
                                            TOTAL MUNICIPAL BONDS
                                            (Cost $112,795,000)                             $112,795,000
--------------------------------------------------------------------------------------------------------
                                            TEMPORARY CASH INVESTMENTS -- 57.3%
                                            Commercial Paper -- 18.4%
 8,740,000   0.31                AA-/Aa1    Bank of Nova Scotia/Houston, Floating
                                            Rate Note, 7/6/11                               $  8,737,092
 9,362,000                      A-1+/P-1    Harvard University, 0.25%, 1/4/11                  9,361,640
 5,590,000                      A-1+/P-1    Johns Hopkins University, 0.29%, 2/4/11            5,590,000
 3,510,000                         NR/NR    Massachusetts Health & Educational Facilities
                                            Authority, 0.25%, 1/6/11                           3,510,000
 4,480,000                      A-1+/P-1    Massachusetts Health & Educational Facilities
                                            Authority, 0.25%, 2/4/11                           4,480,000
 4,000,000                      A-1+/P-1    Nordea Bank Finland Plc/New York, 0.26%,
                                            1/10/11                                            4,000,000
   800,000                       A-1+/NR    Private Colleges & Universities, 0.3%, 2/1/11        800,000
 1,870,000   0.38                AA-/Aaa    Royal Bank of Canada, Floating Rate Note,
                                            10/3/11                                            1,869,979
 4,800,000   0.85                AA-/Aaa    Royal Bank of Canada, Floating Rate Note,
                                            8/1/11                                             4,803,977
 1,900,000                       A-1/P-1    State Street Corp., 0.25%, 1/3/11                  1,900,000
 4,000,000                       AA-/Aa2    Svenska Handelsbanken/New York, 0.27%,
                                            2/4/11                                             4,000,035
 4,510,000                      A-1+/P-1    Texas A&M University, 0.28%, 1/3/11                4,510,000
 6,135,000                      A-1+/P-1    Texas Public Finance Authority, 0.27%,
                                            2/1/11                                             6,135,000
 6,085,000                      A-1+/P-1    Texas Public Finance Authority, 0.28%,
                                            3/4/11                                             6,085,000
 4,730,000                       AA-/Aaa    Toronto Dominion Bank, 0.0%, 2/4/11                4,729,551
</TABLE>

The accompanying notes are an integral part of these financial statements.

14     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

<TABLE>
<CAPTION>
             Floating       S&P/Moody's
Principal    Rate (b)       Ratings
Amount ($)   (unaudited)    (unaudited)                                                    Value
<S>          <C>            <C>             <C>                                            <C>
                                            Commercial Paper -- (continued)
 2,900,000                      A-1+/AAA    Toronto Dominion Bank, 0.23%, 3/10/11          $  2,899,983
 3,735,000   0.31                 NR/AAA    Toronto Dominion Bank/NY, Floating Rate
                                            Note, 5/19/11                                     3,735,093
 1,390,000                      A-1+/P-1    Toyota Motor Credit Corp., 0.26%, 1/3/11          1,390,000
 3,560,000                         NR/NR    University of Minnesota, 0.25%, 1/6/11            3,560,000
 4,350,000                      A-1+/P-1    University of Texas System, 0.25%, 2/3/11         4,350,000
 6,892,000                      A-1+/P-1    University of Texas, 0.24%, 1/6/11                6,892,000
 5,850,000                      A-1+/P-1    Vanderbilt University, 0.27%, 1/28/11             5,849,937
 7,470,000                      A-1+/P-1    Yale University, 0.25%, 1/5/11                    7,469,860
                                                                                           ------------
                                                                                           $106,659,147
-------------------------------------------------------------------------------------------------------
                                            Repurchase Agreements -- 32.8%
28,430,000                        NR/Aaa    Barclays Plc, 0.10%, dated 12/31/10,
                                            repurchase price of $28,430,000 plus
                                            accrued interest on 1/3/11 collateralized by
                                            $28,998,610 U.S. Treasury Strip,
                                            1.25%, 4/15/14                                 $ 28,430,000
31,020,000                        NR/Aaa    BNP Paribas SA, 0.18%, dated 12/31/10,
                                            repurchase price of $31,020,000 plus
                                            accrued interest on 1/3/11 collateralized by
                                            $31,640,400 Federal National Mortgage
                                            Association, 4.0% - 5.5%, 8/1/37 - 11/1/40       31,020,000
 8,650,000                        NR/Aaa    BNP Paribas SA, 0.15%, dated 12/31/10,
                                            repurchase price of $8,650,000 plus
                                            accrued interest on 1/3/11 collateralized
                                            by the following:
                                              $1,049,001 U.S. Treasury Strip, 0.0%,
                                               8/15/22 - 5/15/28
                                              $923,378 U.S. Treasury Bond,
                                               4.375%, 2/15/38
                                              $6,850,620 U.S. Treasury Notes,
                                               2.375%, 8/31/14                                8,650,000
 8,650,000                        NR/Aaa    Deutsche Bank, 0.18%, dated 12/31/10,
                                            repurchase price of $8,650,000 plus accrued
                                            interest on 1/3/11 collateralized by the
                                            following:
                                              $5,343,867 U.S. Treasury Strip,
                                               0.0%, 2/15/36
                                              $3,479,133 U.S. Treasury Inflation
                                                Protected Security, 0.0%, 8/15/22             8,650,000
26,020,000                        NR/Aaa    Deutsche Bank AG, 0.28%, dated 12/31/10,
                                            repurchase price of $26,020,000 plus
                                            accrued interest on 1/3/11 collateralized by
                                            $26,540,400 Federal National Mortgage
                                            Association, 7.0%, 8/1/38                        26,020,000
</TABLE>

The accompanying notes are an integral part of these financial statements.

                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     15
<PAGE>

Schedule of Investments | 12/31/10   (continued)

<TABLE>
<CAPTION>
              Floating       S&P/Moody's
Principal     Rate (b)       Ratings
Amount ($)    (unaudited)    (unaudited)                                                     Value
<S>           <C>            <C>             <C>                                             <C>
                                             Repurchase Agreements -- (continued)
10,290,000                         NR/Aaa    JPMorgan, Inc., 0.20%, dated 12/31/10,
                                             repurchase price of $10,290,000 plus
                                             accrued interest on 1/3/11 collateralized
                                             by the following:
                                               $10,495,903 Federal National
                                                 Mortgage Association, 4.0% - 5.0%,
                                                 2/1/20 - 3/1/40                             $ 10,290,000
36,910,000                         NR/Aaa    RBC Capital Markets, Inc., 0.20%, dated
                                             12/31/10, repurchase price of $36,910,000
                                             plus accrued interest on 1/3/11
                                             collateralized by the following:
                                               $6,324,482 Fannie Mae, 1.75%,
                                                 11/17/15
                                               $31,323,829 Federal Farm Credit Bank,
                                                 1.70% - 4.33%, 10/28/16 - 4/20/20             36,910,000
 8,650,000                         NR/Aaa    Societe Generale SA, 0.20%, dated
                                             12/31/10, repurchase price of $8,650,000
                                             plus accrued interest on 1/3/11
                                             collateralized by the following:
                                               $8,391,350 U.S. Treasury Note,
                                                 0.5%, 10/15/13
                                               $431,650 U.S. Treasury Bill,
                                                 0.0%, 12/15/11                                 8,650,000
32,020,000                         NR/Aaa    Societe Generale SA, 0.21%, dated
                                             12/31/10, repurchase price of $32,020,000
                                             plus accrued interest on 1/3/11
                                             collateralized by $32,660,400 Federal
                                             National Mortgage Association, 4.5% - 6.5%,
                                             6/1/33 - 1/1/40                                   32,020,000
                                                                                             ------------
                                                                                             $190,640,000
---------------------------------------------------------------------------------------------------------
Shares
                                             Tax Exempt Money Market Mutual Fund -- 6.1%
35,250,000                                   BlackRock Liquidity Funds TempCash Portfolio    $ 35,250,000
---------------------------------------------------------------------------------------------------------
                                             TOTAL TEMPORARY CASH INVESTMENTS
                                             (Cost $332,549,439)                             $332,549,147
---------------------------------------------------------------------------------------------------------
                                             TOTAL INVESTMENT IN SECURITIES -- 98.6%
                                             (Cost $573,033,718)(a)                          $573,033,718
---------------------------------------------------------------------------------------------------------
                                             OTHER ASSETS AND LIABILITIES -- 1.4%            $  7,976,844
---------------------------------------------------------------------------------------------------------
                                             TOTAL NET ASSETS -- 100.0%                      $581,010,562
=========================================================================================================
</TABLE>

NR   Not rated by either S&P or Moody's.

(a)  At December 31, 2010, cost for federal income tax purposes was
     $573,033,718.

(b)  Debt obligation with a variable interest rate. Rate shown is rate at end of
     period.

The accompanying notes are an integral part of these financial statements.

16     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

Purchases and sales of securities (excluding temporary cash investments) for
the year ended December 31, 2010 aggregated $194,853,651 and $228,507,336,
respectively.

Various inputs are used in determining the value of the Fund's investments.
These inputs are summarized in the three broad levels listed below.

Highest priority is given to Level 1 inputs and lowest priority is given to
Level 3.

     Level 1 -- quoted prices in active markets for identical securities
     Level 2 -- other significant observable inputs (including quoted prices for
                similar securities, interest rates, prepayment speeds, credit
                risk, etc.)
     Level 3 -- significant unobservable inputs (including the Fund's own
                assumptions in determining fair value of investments)

The following is a summary of the inputs used as of December 31, 2010, in
valuing the Fund's assets:

<TABLE>
<CAPTION>
                                        Level 1         Level 2            Level 3        Total
<S>                                     <C>             <C>                <C>            <C>
 Corporate Bonds                        $        --     $  9,249,904       $--        $  9,249,904
 U.S. Government Agency Obligations              --      118,439,667        --         118,439,667
 Municipal Bonds                                 --      112,795,000        --         112,795,000
 Commercial Paper                                --      106,659,147        --         106,659,147
 Repurchase Agreements                           --      190,640,000        --         190,640,000
 Money Market Mutual Fund                35,250,000               --        --          35,250,000
--------------------------------------------------------------------------------------------------
    Total                               $35,250,000     $537,783,718       $--        $573,033,718
==================================================================================================
</TABLE>

The accompanying notes are an integral part of these financial statements.

                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     17
<PAGE>

Statement of Assets and Liabilities | 12/31/10

<TABLE>
<S>                                                      <C>
ASSETS:
  Investment in securities (cost $382,393,718)            $382,393,718
  Repurchase agreements (cost $190,640,000)                190,640,000
----------------------------------------------------------------------
  Total investment in securities (cost $573,033,718)      $573,033,718
  Cash                                                       4,025,372
  Receivables --
   Investment securities sold                                5,764,887
   Fund shares sold                                          4,655,992
   Interest                                                    259,400
   Due from Pioneer Investment Management, Inc.                188,158
  Other                                                         50,111
----------------------------------------------------------------------
     Total assets                                         $587,977,638
----------------------------------------------------------------------
LIABILITIES:
  Payables --
   Investment securities purchased                        $  5,762,821
   Fund shares repurchased                                     927,855
   Dividends                                                     7,062
  Due to affiliates                                            131,081
  Accrued expenses                                             138,257
----------------------------------------------------------------------
     Total liabilities                                    $  6,967,076
----------------------------------------------------------------------
NET ASSETS:
  Paid-in capital                                         $581,220,760
  Distributions in excess of net investment income              (7,062)
  Accumulated net realized loss on investments                (203,136)
----------------------------------------------------------------------
     Total net assets                                     $581,010,562
======================================================================
NET ASSET VALUE PER SHARE:
(No par value, unlimited number of shares authorized)
  Class A (based on $454,784,109/454,876,445 shares)      $       1.00
  Class B (based on $21,190,234/21,166,414 shares)        $       1.00
  Class C (based on $39,197,682/39,196,774 shares)        $       1.00
  Class R (based on $6,268,313/6,268,619 shares)          $       1.00
  Class Y (based on $59,570,224/59,557,171 shares)        $       1.00
======================================================================
</TABLE>

The accompanying notes are an integral part of these financial statements.

18     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

Statement of Operations

For the Year Ended 12/31/10

<TABLE>
<S>                                                         <C>             <C>
INVESTMENT INCOME:
  Interest                                                  $1,823,222
---------------------------------------------------------------------------------------
     Total investment income                                                $1,823,222
---------------------------------------------------------------------------------------
EXPENSES:
  Management fees                                           $2,676,070
  Transfer agent fees and expenses
   Class A                                                     873,454
   Class B                                                     107,680
   Class C                                                      85,529
   Class R                                                       7,208
   Class Y                                                         539
  Distribution fees
   Class A                                                     779,475
   Class B                                                     305,813
   Class C                                                     585,188
   Class R                                                      30,475
  Shareholder communications expense                           261,574
  Administrative reimbursements                                209,163
  Custodian fees                                                31,125
  Registration fees                                            173,962
  Professional fees                                            102,293
  Printing expense                                              77,999
  Fees and expenses of nonaffiliated trustees                   19,800
  Miscellaneous                                                 25,296
---------------------------------------------------------------------------------------
     Total expenses                                                         $6,352,643
     Less fees waived and expenses reimbursed by Pioneer
       Investment Management, Inc.                                          (4,794,198)
---------------------------------------------------------------------------------------
     Net expenses                                                           $1,558,445
---------------------------------------------------------------------------------------
       Net investment income                                                $  264,777
---------------------------------------------------------------------------------------
REALIZED GAIN ON INVESTMENTS:
  Net realized gain on:
   Investments                                              $   44,401
   Class actions                                                    57      $   44,458
---------------------------------------------------------------------------------------
  Net realized gain on investments                                          $   44,458
---------------------------------------------------------------------------------------
  Net increase in net assets resulting from operations                      $  309,235
---------------------------------------------------------------------------------------
</TABLE>

The accompanying notes are an integral part of these financial statements.

                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     19
<PAGE>

Statements of Changes in Net Assets

For the Years Ended 12/31/10 and 12/31/09, respectively

<TABLE>
<CAPTION>
                                                              Year Ended            Year Ended
                                                             12/31/10              12/31/09
<S>                                                          <C>                   <C>
FROM OPERATIONS:
Net investment income                                        $      264,777        $    1,377,362
Net realized gain on investments and class action                    44,458               251,512
--------------------------------------------------------------------------------------------------
   Net increase in net assets resulting from operations      $      309,235        $    1,628,874
--------------------------------------------------------------------------------------------------
DISTRIBUTIONS TO SHAREOWNERS:
Net investment income:
   Class A ($0.0002 and $0.0016 per share, respectively)     $      (88,743)       $   (1,039,677)
   Class B ($0.0002 and $0.0002 per share, respectively)             (4,766)               (8,419)
   Class C ($0.0002 and $0.0002 per share, respectively)             (9,047)              (10,277)
   Class R ($0.0002 and $0.0004 per share, respectively)             (1,096)                 (706)
   Class Y ($0.0002 and $0.0030 per share, respectively)             (9,945)             (466,477)
--------------------------------------------------------------------------------------------------
     Total distributions to shareowners                      $     (113,597)       $   (1,525,556)
--------------------------------------------------------------------------------------------------
FROM FUND SHARE TRANSACTIONS:
Net proceeds from sale of shares                             $  842,011,151        $1,378,998,385
Shares issued in reorganization                                          --            65,917,709
Reinvestment of distributions                                       104,230             1,061,937
Cost of shares repurchased                                   (1,129,122,437)       (1,544,238,392)
--------------------------------------------------------------------------------------------------
   Net decrease in net assets resulting from
     Fund share transactions                                 $ (287,007,056)       $  (98,260,361)
--------------------------------------------------------------------------------------------------
   Net decrease in net assets                                $ (286,811,418)       $  (98,157,043)
NET ASSETS:
Beginning of year                                               867,821,980           965,979,023
--------------------------------------------------------------------------------------------------
End of year                                                  $  581,010,562        $  867,821,980
--------------------------------------------------------------------------------------------------
Distributions in excess of net investment income             $       (7,062)       $     (178,215)
--------------------------------------------------------------------------------------------------
</TABLE>

The accompanying notes are an integral part of these financial statements.

20     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

<TABLE>
<CAPTION>
                                     '10 Shares        '10 Amount        '09 Shares        '09 Amount
<S>                                  <C>               <C>               <C>               <C>
Class A
Shares sold                           552,128,179    $ 552,306,110       477,946,610    $ 477,773,358
Shares issued in reorganization                --               --        57,600,032       57,736,180
Reinvestment of distributions              88,743           88,743         1,039,677        1,039,677
Less shares repurchased              (631,151,257)    (631,151,258)     (670,546,568)    (670,546,570)
------------------------------------------------------------------------------------------------------
   Net decrease                       (78,934,335)   $ (78,756,405)     (133,960,249)   $(133,997,355)
======================================================================================================
Class B
Shares sold                            24,245,571    $  24,245,553        29,148,400    $  29,148,400
Reinvestment of distributions               4,766            4,766             8,419            8,419
Less shares repurchased               (40,587,874)     (40,587,878)      (51,028,376)     (51,028,380)
------------------------------------------------------------------------------------------------------
   Net decrease                       (16,337,537)   $ (16,337,559)      (21,871,557)   $ (21,871,561)
======================================================================================================
Class C
Shares sold                           130,578,372    $ 130,578,372        94,637,552    $  94,637,552
Reinvestment of distributions               9,047            9,047            10,277           10,277
Less shares repurchased              (140,796,477)    (140,796,478)     (107,556,972)    (107,556,973)
------------------------------------------------------------------------------------------------------
   Net decrease                       (10,209,058)   $ (10,209,059)      (12,909,143)   $ (12,909,144)
======================================================================================================
Class R
Shares sold                            40,597,723    $  40,597,722         9,788,236    $   9,788,236
Reinvestment of distributions               1,037            1,037               695              695
Less shares repurchased               (37,428,880)     (37,428,880)       (8,533,483)      (8,533,483)
------------------------------------------------------------------------------------------------------
   Net increase                         3,169,880    $   3,169,879         1,255,448    $   1,255,448
======================================================================================================
Class Y
Shares sold                            94,283,394    $  94,283,394       767,675,345    $ 767,650,839
Shares issued in reorganization                --               --         8,147,274        8,181,529
Reinvestment of distributions                 637              637             2,869            2,869
Less shares repurchased              (279,157,943)    (279,157,943)     (706,572,986)    (706,572,986)
------------------------------------------------------------------------------------------------------
   Net increase (decrease)           (184,873,912)   $(184,873,912)       69,252,502    $  69,262,251
======================================================================================================
</TABLE>

The accompanying notes are an integral part of these financial statements.

                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     21
<PAGE>

Financial Highlights

<TABLE>
<CAPTION>
                                                                            Year Ended    Year Ended
                                                                            12/31/10      12/31/09
<S>                                                                         <C>           <C>
Class A
Net asset value, beginning of period                                        $   1.00      $   1.00
----------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income                                                      $  0.000(a)   $  0.002
----------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                      $ (0.000)(a)  $ (0.002)
----------------------------------------------------------------------------------------------------
Net asset value, end of period                                              $   1.00      $   1.00
====================================================================================================
Total return*                                                                   0.02%         0.16%
Ratio of net expenses to average net assets+                                    0.23%         0.60%
Ratio of net investment income to average net assets+                           0.04%         0.15%
Net assets, end of period (in thousands)                                    $454,784      $533,382
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                   0.85%         0.79%
 Net investment income (loss)                                                  (0.58)%       (0.04)%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                   0.23%         0.60%
 Net investment income                                                          0.04%         0.15%
====================================================================================================

<CAPTION>
                                                                          Year Ended    Year Ended    Year Ended
                                                                          12/31/08      12/31/07      12/31/06
<S>                                                                       <C>           <C>           <C>
Class A
Net asset value, beginning of period                                      $   1.00      $   1.00      $   1.00
----------------------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income                                                    $  0.024      $  0.046      $  0.043
----------------------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $ (0.024)     $ (0.046)     $ (0.043)
----------------------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $   1.00      $   1.00      $   1.00
=================================================================================================================
Total return*                                                                 2.46%         4.72%         4.38%
Ratio of net expenses to average net assets+                                  0.73%         0.71%         0.75%
Ratio of net investment income to average net assets+                         2.46%         4.61%         4.33%
Net assets, end of period (in thousands)                                  $667,293      $739,517      $708,103
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                 0.73%         0.71%         0.75%
 Net investment income (loss)                                                 2.46%         4.61%         4.33%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                 0.73%         0.70%         0.75%
 Net investment income                                                        2.46%         4.61%         4.33%
================================================================================================================
</TABLE>

*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, the complete redemption of the
     investment at net asset value at the end of each period, and no sales
     charges. Total return would be reduced if sales charges were taken into
     account.
+    Ratio with no reduction for fees paid indirectly.
(a)  Amount rounds to less than $0.001 or $(0.001) per share.

The accompanying notes are an integral part of these financial statements.

22    Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

<TABLE>
<CAPTION>
                                                                             Year Ended     Year Ended
                                                                             12/31/10       12/31/09
<S>                                                                          <C>            <C>
Class B
Net asset value, beginning of period                                         $  1.00        $  1.00
-------------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income (loss)                                                $ 0.000(a)     $ 0.000(a)
-------------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                       $(0.000)(a)    $(0.000)(a)
-------------------------------------------------------------------------------------------------------
Net asset value, end of period                                               $  1.00        $  1.00
=======================================================================================================
Total return*                                                                   0.02%          0.02%
Ratio of net expenses to average net assets+                                    0.23%          0.80%
Ratio of net investment income (loss) to average net assets+                    0.04%         (0.01)%
Net assets, end of period (in thousands)                                     $21,190        $37,518
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                   1.92%          1.88%
 Net investment income (loss)                                                  (1.65)%        (1.09)%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                   0.23%          0.80%
 Net investment income (loss)                                                   0.04%         (0.01)%
=======================================================================================================

<CAPTION>
                                                                          Year Ended    Year Ended   Year Ended
                                                                          12/31/08      12/31/07     12/31/06
<S>                                                                       <C>           <C>          <C>
Class B
Net asset value, beginning of period                                      $  1.00       $  1.00      $  1.00
---------------------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income (loss)                                             $ 0.015       $ 0.035      $ 0.032
---------------------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $(0.015)      $(0.035)     $(0.032)
---------------------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $  1.00       $  1.00      $  1.00
===============================================================================================================
Total return*                                                                1.54%         3.55%        3.21%
Ratio of net expenses to average net assets+                                 1.74%         1.84%        1.87%
Ratio of net investment income (loss) to average net assets+                 1.37%         3.48%        3.22%
Net assets, end of period (in thousands)                                  $59,390       $41,539      $33,817
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                1.74%         1.84%        1.87%
 Net investment income (loss)                                                1.37%         3.48%        3.22%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                1.74%         1.82%        1.86%
 Net investment income (loss)                                                1.37%         3.50%        3.23%
===============================================================================================================
</TABLE>

*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, the complete redemption of the
     investment at net asset value at the end of each period, and no sales
     charges. Total return would be reduced if sales charges were taken into
     account.
+    Ratio with no reduction for fees paid indirectly.
(a)  Amount rounds to less than $0.001 or $(0.001) per share.

The accompanying notes are an integral part of these financial statements.

                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10    23
<PAGE>

Financial Highlights (continued)

<TABLE>
<CAPTION>
                                                                          Year Ended      Year Ended
                                                                          12/31/10        12/31/09
<S>                                                                       <C>             <C>
Class C
Net asset value, beginning of period                                      $  1.00         $  1.00
-----------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income (loss)                                             $ 0.001         $ 0.000(a)
-----------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $(0.000)(a)     $(0.000)(a)
-----------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $  1.00         $  1.00
=====================================================================================================
Total return*                                                                0.02%           0.02%
Ratio of net expenses to average net assets+                                 0.23%           0.80%
Ratio of net investment income (loss) to average net assets+                 0.04%          (0.02)%
Net assets, end of period (in thousands)                                  $39,198         $49,391
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                1.68%           1.77%
 Net investment income (loss)                                               (1.41)%         (0.99)%
Ratios with waiver of fees and assumption of expenses by the
 Adviser and reduction for fees paid indirectly:
 Net expenses                                                                0.23%           0.80%
 Net investment income (loss)                                                0.04%          (0.02)%
=====================================================================================================

<CAPTION>
                                                                          Year Ended   Year Ended    Year Ended
                                                                          12/31/08     12/31/07      12/31/06
<S>                                                                       <C>          <C>           <C>
Class C
Net asset value, beginning of period                                      $  1.00      $   1.00      $   1.00
---------------------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income (loss)                                             $ 0.016      $  0.036      $  0.033
---------------------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $(0.016)     $ (0.036)     $ (0.033)
---------------------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $  1.00      $   1.00      $   1.00
===============================================================================================================
Total return*                                                                1.57%         3.69%         3.33%
Ratio of net expenses to average net assets+                                 1.63%         1.68%         1.71%
Ratio of net investment income (loss) to average net assets+                 1.55%         3.64%         3.48%
Net assets, end of period (in thousands)                                  $62,303      $ 68,250      $ 54,906
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                1.63%         1.68%         1.71%
 Net investment income (loss)                                                1.55%         3.64%         3.45%
Ratios with waiver of fees and assumption of expenses by the
 Adviser and reduction for fees paid indirectly:
 Net expenses                                                                1.63%         1.67%         1.70%
 Net investment income (loss)                                                1.55%         3.65%         3.48%
===============================================================================================================
</TABLE>

*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, the complete redemption of the
     investment at net asset value at the end of each period, and no sales
     charges. Total return would be reduced if sales charges were taken into
     account.
+    Ratio with no reduction for fees paid indirectly.
(a)  Amount rounds to less than $0.001 or $(0.001) per share.

The accompanying notes are an integral part of these financial statements.

24    Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

<TABLE>
<CAPTION>
                                                                          Year Ended       Year Ended
                                                                          12/31/10         12/31/09
<S>                                                                       <C>              <C>
Class R
Net asset value, beginning of period                                      $  1.00          $ 1.00
-----------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income (loss)                                             $ 0.001          $0.000(a)
-----------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $(0.000)(a)      $0.000)(a)
-----------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $  1.00          $ 1.00
=====================================================================================================
Total return*                                                                0.02%           0.04%
Ratio of net expenses to average net assets+                                 0.24%           0.70%
Ratio of net investment income (loss) to average net assets+                 0.04%          (0.06)%
Net assets, end of period (in thousands)                                  $ 6,268          $3,097
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                1.37%           1.43%
 Net investment income (loss)                                               (1.09)%         (0.79)%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                0.24%           0.70%
 Net investment income (loss)                                                0.04%          (0.06)%
=====================================================================================================

<CAPTION>
                                                                         Year Ended      Year Ended     Year Ended
                                                                         12/31/08        12/31/07       12/31/06
<S>                                                                      <C>             <C>            <C>
Class R
Net asset value, beginning of period                                      $  1.00        $  1.00        $  1.00
------------------------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income (loss)                                             $ 0.020        $ 0.039        $ 0.038
------------------------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $(0.020)       $(0.039)       $(0.038)
------------------------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $  1.00        $  1.00        $  1.00
==================================================================================================================
Total return*                                                                2.04%          3.94%          3.90%
Ratio of net expenses to average net assets+                                 1.15%          1.42%          1.19%
Ratio of net investment income (loss) to average net assets+                 1.97%          3.90%          3.93%
Net assets, end of period (in thousands)                                  $ 1,843        $ 1,582        $   747
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                1.15%          1.42%          1.53%
 Net investment income (loss)                                                1.97%          3.90%          3.59%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                1.15%          1.41%          1.19%
 Net investment income (loss)                                                1.97%          3.90%          3.93%
==================================================================================================================
</TABLE>

*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, and the complete redemption of
     the investment at net asset value at the end of each period.
+    Ratio with no reduction for fees paid indirectly.
(a)  Amount rounds to less than $0.001 or $(0.001) per share.

The accompanying notes are an integral part of these financial statements.

                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10    25
<PAGE>

Financial Highlights (continued)

<TABLE>
<CAPTION>
                                                                          Year Ended        Year Ended
                                                                          12/31/10          12/31/09
<S>                                                                       <C>               <C>
Class Y
Net asset value, beginning of period                                      $   1.00          $   1.00
------------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income                                                    $ (0.000)(a)      $  0.003
------------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $ (0.000)(a)      $ (0.003)
------------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $   1.00          $   1.00
======================================================================================================
Total return*                                                                 0.02%             0.30%
Ratio of net expenses to average net assets+                                  0.22%             0.44%
Ratio of net investment income to average net assets+                         0.02%             0.29%
Net assets, end of period (in thousands)                                  $ 59,570          $244,435
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                 0.51%             0.53%
 Net investment income (loss)                                                (0.27)%            0.20%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                 0.22%             0.44%
 Net investment income                                                        0.02%             0.29%
======================================================================================================

<CAPTION>

                                                                          Year Ended    Year Ended   Year Ended
                                                                          12/31/08      12/31/07     12/31/06
<S>                                                                       <C>           <C>          <C>
Class Y
Net asset value, beginning of period                                      $   1.00      $  1.00      $  1.00
---------------------------------------------------------------------------------------------------------------
Increase from investment operations:
 Net investment income                                                    $  0.027      $ 0.048      $ 0.046
---------------------------------------------------------------------------------------------------------------
Distributions to shareowners:
 Net investment income                                                    $ (0.027)     $(0.048)     $(0.046)
---------------------------------------------------------------------------------------------------------------
Net asset value, end of period                                            $   1.00      $  1.00      $  1.00
===============================================================================================================
Total return*                                                                 2.70%        4.96%        4.67%
Ratio of net expenses to average net assets+                                  0.52%        0.47%        0.47%
Ratio of net investment income to average net assets+                         2.63%        4.85%        4.54%
Net assets, end of period (in thousands)                                  $175,151      $83,209      $76,726
Ratios with no waiver of fees and assumption of expenses by the Adviser
 and no reduction for fees paid indirectly:
 Net expenses                                                                 0.52%        0.47%        0.47%
 Net investment income (loss)                                                 2.63%        4.85%        4.54%
Ratios with waiver of fees and assumption of expenses by the Adviser
 and reduction for fees paid indirectly:
 Net expenses                                                                 0.52%        0.46%        0.47%
 Net investment income                                                        2.63%        4.86%        4.54%
===============================================================================================================
</TABLE>

(a)  Amount rounds to less than $0.001 or $(0.001) per share.
*    Assumes initial investment at net asset value at the beginning of each
     period, reinvestment of all distributions, and the complete redemption of
     the investment at net asset value at the end of each period.
+    Ratio with no reduction for fees paid indirectly.

The accompanying notes are an integral part of these financial statements.

26    Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

Notes to Financial Statements | 12/31/10

1. Organization and Significant Accounting Policies

Pioneer Cash Reserves Fund (the Fund) is a series of Pioneer Money Market
Trust, a Delaware statutory trust. The Fund is registered under the Investment
Company Act of 1940 as a diversified, open-end management investment company.
The investment objective of the Fund is to provide high current income,
preservation of capital, and liquidity through investments in high-quality
short-term securities.

The Fund offers five classes of shares designated as Class A, Class B, Class C,
Class R and Class Y shares. Class Y shares were first publicly offered on
September 23, 2005. Effective as of the close of business on December 31, 2009,
Class B shares are no longer offered to new or existing shareholders, except
that dividends and/or capital gain distributions may continue to be reinvested
in Class B shares, and shareholders may exchange their Class B shares for Class
B shares of other Pioneer funds, as permitted by existing exchange privileges.
Each class of shares represents an interest in the same portfolio of
investments of the Fund and has identical rights (based on relative net asset
values) to assets and liquidation proceeds. Share classes can bear different
rates of class-specific fees and expenses such as transfer agent and
distribution fees. Differences in class-specific fees and expenses will result
in differences in net investment income and, therefore, the payment of
different dividends from net investment income earned by each class. The
Amended and Restated Declaration of Trust of the Fund gives the Board the
flexibility to specify either per-share voting or dollar-weighted voting when
submitting matters for shareholder approval. Under per-share voting, each share
of a class of the Fund is entitled to one vote. Under dollar-weighted voting, a
shareholder's voting power is determined not by the number of shares owned, but
by the dollar value of the shares on the record date. Each share class has
exclusive voting rights with respect to matters affecting only that class,
including with respect to the distribution plan for that class. There is no
distribution plan for Class Y shares. Class B shares convert to Class A shares
approximately eight years after the date of purchase.

At times, the Fund's investments may represent industries or industry sectors
that are interrelated or have common risks, making the Fund more susceptible to
any economic, political, or regulatory developments or other risks affecting
those industries and industry sectors. The Fund's prospectus contains unaudited
information regarding the Fund's principal risks. Please refer to that document
when considering the Fund's principal risks.


                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     27
<PAGE>

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 consistently
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. Securities are valued at
   amortized cost, which approximates fair market value. Money market mutual
   funds are valued at net asset value. Investments purchased at a discount or
   premium are valued by amortizing the difference between the original purchase
   price and maturity value of the issue over the period to maturity. Interest
   income, including interest on income bearing cash accounts, is recorded on
   the accrual basis.

B. Federal Income Taxes

   It is the Fund's policy to comply with the requirements of the Internal
   Revenue Code applicable to regulated investment companies and to distribute
   all of its taxable income and net realized capital gains, if any, to its
   shareowners. Therefore, no federal income tax provision is required. Tax
   years for the three prior fiscal years remain subject to examination by tax
   authorities.

   The amounts and characterizations of distributions to shareowners for
   financial reporting purposes are determined in accordance with federal income
   tax rules. Therefore, the sources of the Fund's distributions may be shown in
   the accompanying financial statements as from or in excess of net investment
   income or as from net realized gain on investment transactions, or as from
   paid-in capital, depending on the type of book/tax differences that may
   exist.

   At December 31, 2010, the Fund had a net capital loss carryforward of
   $203,136 of which the following amounts will expire in 2015 and 2016 if not
   utilized: $190,618 in 2015 and $12,518 in 2016.

   At December 31, 2010, the Fund reclassified $19,973 to decrease paid-in
   capital and $19,973 to decrease distributions in excess of net investment
   income to reflect permanent book/tax differences. The reclassification has no
   impact on the net assets of the Fund and presents the Fund's capital accounts
   on a tax basis.


28     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

   The tax character of distributions paid during the years ended December 31,
   2010 and December 31, 2009 was as follows:

<TABLE>
<CAPTION>
                                                    2010                2009
<S>                                             <C>               <C>
   Distributions paid from:
   Ordinary income                              $113,597          $1,525,556
   --------------------------------------------------------------------------
     Total                                      $113,597          $1,525,556
   ==========================================================================
</TABLE>

   The following shows the components of distributable earnings on a federal
   income tax basis at December 31, 2010:

<TABLE>
<CAPTION>
                                                                        2010
<S>                                                                <C>
   Distributable earnings:
   Capital loss carryforward                                       $(203,136)
   Dividends payable                                                  (7,062)
   --------------------------------------------------------------------------
     Total                                                         $(210,198)
   ==========================================================================
</TABLE>

C. Fund Shares

   The Fund records sales and repurchases of its shares as of trade date. The
   Fund declares as daily dividends substantially all of its net investment
   income. All dividends are paid on a monthly basis. Short-term capital gain
   distributions, if any, may be declared with the daily dividends.

D. Class Allocations

   Income, common expenses and realized and unrealized gains and losses are
   calculated at the Fund level and allocated daily to each class of shares
   based on its respective percentage of adjusted net assets at the beginning of
   the day. During the year ended December 31, 2010, the Fund recognized gains
   of $57 in the settlement of class action lawsuits from several different
   companies, as reflected on the Statement of Operations.

   Distribution fees are calculated based on the average daily net asset value
   attributable to Class A, Class B, Class C and Class R shares of the Fund,
   respectively (see Note 4). Class Y shares do not pay distribution fees. All
   expenses and fees paid to the transfer agent, Pioneer Investment Management
   Shareholder Services, Inc. (PIMSS), for its services are allocated among the
   classes of shares based on the number of accounts in each class and the
   ratable allocation of related out-of-pocket expenses (see Note 3).

   Distributions to shareowners are recorded as of the ex-dividend date.
   Distributions paid by the Fund with respect to each class of shares are
   calculated in the same manner and at the same time, except that net
   investment income dividends to Class A, Class B, Class C, Class R and Class Y
   shares can reflect different transfer agent and distribution expense rates.


                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     29
<PAGE>

E. Repurchase Agreements

   With respect to repurchase agreements entered into by the Fund, the value of
   the underlying securities (collateral), including accrued interest, is
   required to be equal to or in excess of the repurchase price. The collateral
   for all repurchase agreements is held in safekeeping in the customer-only
   account of the Fund's custodian or a subcustodian of the Fund. The Fund's
   investment adviser, Pioneer Investment Management, Inc. (PIM), is responsible
   for determining that the value of the collateral remains at least equal to
   the repurchase price.

2. Management Agreement

PIM, a wholly owned indirect subsidiary of UniCredit S.p.A. (UniCredit),
manages the Fund's portfolio. Management fees are calculated daily at the
annual rate of 0.40% of the Fund's average net daily net assets up to $1
billion and 0.35% on assets over $1 billion. For the year ended December 31,
2010, the net management fee (excluding waivers and/or reimbursement of
expenses) was equivalent to 0.40%.

PIM has agreed to limit the Fund's expenses for any class of shares or waive a
portion of its management fee in an effort to maintain a net asset value of
$1.00 per share. From time to time, PIM and its affiliates may limit the
expenses of one or more classes for the purpose of avoiding a negative yield or
increasing its yield during the period of the limitation. These expense
limitation policies are voluntary and temporary and may be revised or
terminated by PIM at any time without notice.

PIM has contractually agreed to limit ordinary operating expenses to the extent
required to reduce Fund expenses to 0.70% and 0.45% of the average daily net
assets attributable to Class A and Class Y shares, respectively. Class B, Class
C and Class R shares do not have an expense limitation. Expenses waived during
the year ended December 31, 2010 are reflected on the Statement of Operations.
These expense limitations are in effect through June 1, 2012. There can be no
assurance that PIM will extend the expense limitation agreement for a class of
shares beyond the date referred to above.

In addition, under the management and administration agreements, certain other
services and costs, including accounting, regulatory reporting and insurance
premiums, are paid by the Fund as administrative reimbursements. Included in
"Due to affiliates" reflected on the Statement of Assets and Liabilities is
$2,643 in management fees, administrative costs and certain other
reimbursements payable to PIM at December 31, 2010.


30     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

3. Transfer Agent

PIMSS, a wholly owned indirect subsidiary of UniCredit, provides substantially
all transfer agent and shareowner services to the Fund at negotiated rates.

In addition, the Fund reimburses PIMSS for out-of-pocket expenses incurred by
PIMSS related to shareholder communications activities such as proxy and
statement mailings, outgoing phone calls and omnibus relationship contracts.
For the year ended December 31, 2010, such out-of-pocket expenses by class of
shares were as follows:

<TABLE>
<CAPTION>
Shareholder Communications:
<S>                                                                  <C>
Class A                                                              $186,508
Class B                                                                21,031
Class C                                                                24,338
Class R                                                                15,240
Class Y                                                                14,457
-----------------------------------------------------------------------------
  Total                                                              $261,574
=============================================================================
</TABLE>

Included in "Due to affiliates" reflected on the Statement of Assets and
Liabilities is $124,839 in transfer agent fees and out-of-pocket reimbursements
payable to PIMSS at December 31, 2010.

4. Distribution and Service Plans

The Fund has adopted a Distribution Plan pursuant to Rule 12b-1 of the
Investment Company Act of 1940 with respect to its Class A, Class B, Class C
and Class R shares. Pursuant to the Plan, the Fund pays PFD 0.15% of the
average daily net assets attributable to Class A shares as compensation for
personal services and/or account maintenance services or distribution services
with regard to Class A shares. Pursuant to the Plan, the Fund also pays PFD
1.00% of the average daily net assets attributable to Class B and Class C
shares. The fee for Class B and Class C shares consists of a 0.25% service fee
and a 0.75% distribution fee paid as compensation for personal services and/or
account maintenance services or distribution services with regard to Class B
and Class C shares. Pursuant to the Plan, the Fund further pays PFD 0.50% of
the average daily net assets attributable to Class R shares for distribution
services. Included in "Due to affiliates" reflected on the Statement of Assets
and Liabilities is $3,599 in distribution fees payable to PFD at December 31,
2010.

The Fund also has adopted a separate service plan for Class R shares (Service
Plan). The Service Plan authorizes the Fund to pay securities dealers, plan
administrators or other service organizations that agree to provide certain
services to retirement plans or plan participants holding shares of the Fund a
service fee of up to 0.25% of the Fund's average daily net assets attributable
to Class R shares held by such plans.


                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     31
<PAGE>

In addition, redemptions of Class B and Class C shares may be subject to a
contingent deferred sales charge (CDSC). 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%, based on the lower of cost or market value of shares being
redeemed. Shares purchased as part of an exchange remain subject to any CDSC
that applied to the original purchase of those shares. There is no CDSC for
Class A, Class R or Class Y shares. Proceeds from the CDSCs are paid to PFD.
For the year ended December 31, 2010, CDSCs in the amount of $106,437 were paid
to PFD.

5. Expense Offset Arrangements

The Fund has entered into certain expense offset arrangements with PIMSS
resulting in a reduction in the Fund's total expenses, due to interest earned
on cash held by PIMSS. For the year ended December 31, 2010, the Fund's
expenses were not reduced under such arrangements.

6. Reorganization Information

On May 8, 2009, beneficial owners of Regions Morgan Keegan Select Money Market
Fund approved a proposed Agreement and Plan of Reorganization that provided for
the reorganization listed below. The purpose of this transaction was to combine
two funds with similar investment objectives and strategies. This tax-free
reorganization was accomplished on May 15, 2009 ("Closing Date"), by exchanging
the assets and stated liabilities of Regions Morgan Keegan Select Money Market
Fund for shares of Pioneer Cash Reserves Fund. Shareowners holding Class A and
Class I shares of Regions Morgan Keegan Select Money Market Fund received Class
A and Class Y shares, respectively, of Pioneer Cash Reserves Fund in the
reorganization. The investment portfolio of Regions Morgan Keegan Select Money
Market Fund, with a fair value of $57,874,151 and an identified cost of
$57,874,151 at May 15, 2009, was the principal asset acquired by Pioneer Cash
Reserves Fund. For financial reporting purposes, assets received and shares
issued by Pioneer Cash Reserves Fund were recorded at net asset value; however,
the cost basis of the investments received from Regions Morgan Keegan Select
Money Market Fund was carried forward to align ongoing reporting of Pioneer
Cash Reserves Fund's realized and unrealized gains and losses with amounts
distributable to shareowners for tax purposes. The following charts show the
details of the reorganization as of that Closing Date:


32     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

<TABLE>
<CAPTION>
                      Pioneer                 RMK Select            Pioneer
                      Cash Reserves           Money Market Fund     Cash Reserves
                      (Pre-Reorganization)    (Pre-Reorganization)  (Post-Reorganization)
<S>                   <C>                     <C>                   <C>
 Net Assets
 Class A              $617,403,807            $57,736,180           $675,139,987
 Class B              $ 52,740,518            $        --           $ 52,740,518
 Class C              $ 62,440,580            $        --           $ 62,440,580
 Class R              $  2,020,036            $        --           $  2,020,036
 Class Y/I            $124,005,796            $ 8,181,529           $132,187,325
-----------------------------------------------------------------------------------------
 Total Net Assets     $858,610,737            $65,917,709           $924,528,446
-----------------------------------------------------------------------------------------
 Shares Outstanding
 Class A               617,750,245             57,600,032            675,350,277
 Class B                52,716,354                     --             52,716,354
 Class C                62,441,480                     --             62,441,480
 Class R                 2,020,398                     --              2,020,398
 Class Y/I             123,998,824              8,147,274            132,146,098
 Shares Issued in
  Reorganization
 Class A                                                              57,600,032
 Class Y                                                               8,147,274
</TABLE>


<TABLE>
<CAPTION>
                                Unrealized                Accumulated
                                Appreciation on           Gain on
                                Closing Date              Closing Date
<S>                             <C>                       <C>
 Regions Morgan Keegan
 Select Money Market Fund       $--                       $3,002
</TABLE>

Assuming the reorganization had been completed on January 1, 2009, the
beginning of the annual reporting period for Pioneer Cash Reserves Fund,
Pioneer Cash Reserves Fund's pro forma results of operations for the year ended
December 31, 2009, are as follows:

<TABLE>
--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
<S>                                                                   <C>
 Net investment income                                                $1,418,142
 Net gain on investments                                              $  251,883
 Net increase in net assets resulting from operations                 $1,670,025
</TABLE>

Since the combined investment portfolios have been managed as a single
integrated portfolio since the reorganization was completed, it is not
practical to separate the amounts of revenue and earnings of Regions Morgan
Keegan Select Money Market Fund that have been included in Pioneer Cash
Reserves Fund's statement of operations since May 15, 2009.

7. Subsequent Events

In preparing these financial statements, PIM has evaluated the impact of all
events and transactions for potential recognition or disclosure and has
determined that there were no subsequent events requiring recognition or
disclosure in the financial statements.


                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     33
<PAGE>

Report of Independent Registered Public Accounting Firm

To the Board of Trustees of Pioneer Money Market Trust
and Shareowners of Pioneer Cash Reserves Fund:
--------------------------------------------------------------------------------
We have audited the accompanying statement of assets and liabilities of Pioneer
Cash Reserves Fund, a series of the Pioneer Money Market Trust (the "Trust"),
including the schedule of investments, as of December 31, 2010, and the related
statement of operations for the year then ended, the statements of changes in
net assets for each of the two years in the period then ended, and the
financial highlights for each of the five years in the period then ended. These
financial statements and financial highlights are the responsibility of the
Trust'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 Trust'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 Trust'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 December 31, 2010, 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 Cash Reserves Fund of the Pioneer Money Market Trust at December 31,
2010, the results of its operations for the year then ended, the changes in its
net assets for each of the two years in the period then ended, and financial
highlights for each of the five years in the period then ended, in conformity
with U.S. generally accepted accounting principles.

                                                         Ernst & Young LLP

Boston, Massachusetts
February 25, 2011

34     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

ADDITIONAL INFORMATION (unaudited)

The percentages of the Fund's ordinary income distributions that are exempt
from nonresident alien (NRA) tax withholding resulting from qualified interest
income and qualified short term gains were 76.55% and 0.0%, respectively.







                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     35
<PAGE>

Approval of Investment Advisory Agreement

Pioneer Investment Management, Inc. (PIM) serves as the investment adviser to
Pioneer Cash Reserves Fund (the Fund) pursuant to an investment advisory
agreement between PIM and the Fund. In order for PIM to remain the investment
adviser of the Fund, the Trustees of the Fund must determine annually whether
to renew the investment advisory agreement for the Fund.

The contract review process began in March 2010 as the Trustees of the Fund
agreed on, among other things, an overall approach and timeline for the
process. In July 2010, the Trustees approved the format of the contract review
materials and submitted their formal request to PIM to furnish information
necessary to evaluate the terms of the investment advisory agreement. The
contract review materials were provided to the Trustees in September 2010.
After reviewing and discussing the materials, the Trustees submitted a request
for additional information to PIM, and materials were provided in response to
this request. Meetings of the independent Trustees of the Fund were held in
July, September, October, and November, 2010 to review and discuss the contract
review materials. In addition, the Trustees took into account the information
related to the Fund provided to the Trustees at each regularly scheduled
meeting.

At a meeting held on November 16, 2010, based on their evaluation of the
information provided by PIM and third parties, the Trustees of the Fund,
including the Independent Trustees voting separately, unanimously approved the
renewal of the investment advisory agreement for another year. In considering
the renewal of the investment advisory agreement, the Trustees considered
various factors that they determined were relevant, including the factors
described below. The Trustees did not identify any single factor as the
controlling factor in determining to approve the renewal of the agreement.

Nature, Extent and Quality of Services
The Trustees considered the nature, extent and quality of the services that had
been provided by PIM to the Fund, taking into account the investment objective
and strategy of the Fund. The Trustees reviewed the terms of the investment
advisory agreement. The Trustees also reviewed PIM's investment approach for
the Fund, its research process and its process for trade execution. The
Trustees considered the resources of PIM and the personnel of PIM who provide
investment management services to the Fund. The Trustees considered the
non-investment resources and personnel of PIM involved in PIM's services to the
Fund, including PIM's compliance and legal resources and personnel. In
addition, the Trustees considered the arrangements put in place to retain key
investment and other personnel. The Trustees also considered the substantial


36     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

attention and high priority given by PIM's senior management to the Pioneer
fund complex.

The Trustees considered that PIM supervises and monitors the performance of the
Fund's service providers and provides the Fund with personnel (including Fund
officers) and other resources that are necessary for the Fund's business
management and operations. The Trustees also considered that, as administrator,
PIM is responsible for the administration of the Fund's business and other
affairs. The Trustees considered the fees paid to PIM for the provision of
administration services.

Based on these considerations, the Trustees concluded that the nature, extent
and quality of services that had been provided by PIM to the Fund were
satisfactory and consistent with the terms of the investment advisory
agreement.

Performance of the Fund
The Trustees considered the performance results of the Fund over various time
periods. They reviewed information comparing the Fund's performance with the
performance of its peer group of funds as classified by Lipper, Inc. (Lipper),
an independent provider of investment company data, and with the performance of
the Fund's benchmark index. The Trustees considered that the Fund's annualized
total return was in the third quintile of its Lipper category for the one year
period ended June 30, 2010, in the second quintile of its Lipper category for
the three and five year periods ended June 30, 2010, and in the fourth quintile
of its Lipper category for the ten year period ended June 30, 2010. (In all
quintile rankings referred to throughout this disclosure, first quintile is
most favorable to the Fund's shareowners. Thus, highest relative performance
would be first quintile and lowest relative expenses would also be first
quintile.) The Trustees concluded that the investment performance of the Fund
was satisfactory.

Management Fee and Expenses
The Trustees considered information showing the fees and expenses of the Fund
in comparison to the management fees of its peer group of funds as classified
by Lipper and the expense ratios of a peer group of funds selected on the basis
of criteria determined by the independent Trustees for this purpose using data
provided by Strategic Insight Mutual Trust Research and Consulting, LLC
(Strategic Insight), an independent third party.

The Trustees considered that the Fund's management fee for the twelve months
ended June 30, 2010 was in the fourth quintile relative to the management fees
paid by other funds in its Lipper peer group for the comparable period. The
Trustees also considered the breakpoint in the management fee schedule and the
reduced fee rate on assets over $1 billion. The Trustees considered that the
Fund's asset-weighted management fee was only three basis points higher than
the median management fee of the Fund's peer group and only one basis point
higher than the last fund in the third quintile of the Fund's peer group. The


                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     37
<PAGE>

Trustees considered that the Fund's expense ratio for the twelve months ended
June 30, 2010 was in the third quintile relative to its Strategic Insight peer
group for the comparable period. The Trustees noted that PIM currently was
waiving fees and/or reimbursing expenses of the Fund in order to maintain a
positive yield.

The Trustees also reviewed management fees charged by PIM to its institutional
and other clients. In evaluating the fees associated with PIM's client
accounts, the Trustees took into account the respective demands, resources and
complexity associated with the Fund and client accounts. The Trustees noted
that in some instances the fee rates for those clients were lower than the
management fee for the Fund and considered that, under the investment advisory
agreement with the Fund, PIM performs additional services for the Fund that it
does not provide to those other clients or services that are broader in scope,
including oversight of the Fund's other service providers and activities
related to compliance and the extensive regulatory and tax regimes to which the
Fund is subject.

The Trustees concluded that the management fee payable by the Fund to PIM was
reasonable in relation to the nature and quality of the services provided by
PIM. The Trustees also concluded that the Fund's expense ratio was reasonable
taking into account the nature and quality of services provided by PIM.

Profitability
The Trustees considered information provided by PIM regarding the profitability
of PIM with respect to the advisory services provided by PIM to the Fund,
including the methodology used by PIM in allocating certain of its costs to the
management of the Fund. The Trustees also considered PIM's profit margin in
connection with the overall operation of the Fund. They further reviewed the
financial results realized by PIM and its affiliates from non-fund businesses.
The Trustees considered PIM's profit margins with respect to the Fund in
comparison to the limited industry data available and noted that the
profitability of any adviser was affected by numerous factors, including its
organizational structure and method for allocating expenses. The Trustees
concluded that PIM's profitability with respect to the management of the Fund
was not unreasonable.

Economies of Scale
The Trustees considered PIM's views relating to economies of scale in
connection with the Pioneer Funds as fund assets grow and the extent to which
any such economies of scale are shared with funds and fund shareholders. The
Trustees recognize that economies of scale are difficult to identify and
quantify and that, among other factors that may be relevant, are the following:
fee levels, expense subsidization, investment by PIM in research and analytical
capabilities and PIM's commitment and resource allocation to the Funds. The
Trustees noted that profitability also may be an indicator of the availability
of any


38     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

economies of scale, although profitability may vary for other reasons
particularly, for example during the recent difficult periods for financial
markets, as the level of services was maintained notwithstanding a significant
decline in PIM's fee revenues from the Funds. Accordingly, the Trustees
concluded that economies of scale, if any, were being appropriately shared with
the Fund.

Other Benefits
The Trustees considered the other benefits to PIM from its relationship with
the Fund. The Trustees considered the character and amount of fees paid by the
Fund, other than under the investment advisory agreement, for services provided
by PIM and its affiliates. The Trustees further considered the revenues and
profitability of PIM's businesses other than the fund business. The Trustees
considered the intangible benefits to PIM by virtue of its relationship with
the Fund and the other Pioneer funds. The Trustees concluded that the receipt
of these benefits was reasonable in the context of the overall relationship
between PIM and the Fund.

Conclusion
After consideration of the factors described above as well as other factors,
the Trustees, including all of the independent Trustees, concluded that the
investment advisory agreement between PIM and the Fund, including the fees
payable thereunder, was fair and reasonable and voted to approve the proposed
renewal of the investment advisory agreement for the Fund.


                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     39
<PAGE>

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.

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.pioneerinvestments.com. This information is also available
on the Securities and Exchange Commission's web site at http://www.sec.gov.

Trustees and Officers

The Fund's Trustees and officers are listed below, together with their
principal occupations during at least the past five years. Trustees who are
interested persons of the Fund within the meaning of the 1940 Act are referred
to as Interested Trustees. Trustees who are not interested persons of the Fund
are referred to as Independent Trustees. Each of the Trustees serves as a
trustee of each of the 56 U.S. registered investment portfolios for which
Pioneer serves as investment adviser (the "Pioneer Funds"). The address for all
Trustees and all officers of the Fund is 60 State Street, Boston, Massachusetts
02109.

The Statement of Additional Information of the Fund includes additional
information about the Trustees and is available, without charge, upon request,
by calling 1-800-225-6292.


40     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>


Interested Trustees
<TABLE>
<CAPTION>
                            Position Held            Length of Service
Name and Age                with the Fund            and Term of Office
<S>                         <C>                      <C>
John F. Cogan, Jr. (84)*    Chairman of the Board,   Trustee since 1987.
                            Trustee and President    Serves until a successor
                                                     trustee is elected or
                                                     earlier retirement or
                                                     removal.
--------------------------------------------------------------------------------
Daniel K. Kingsbury (52)*   Trustee and Executive    Trustee since 2007.
                            Vice President           Serves until a successor
                                                     trustee is elected or
                                                     earlier retirement or
                                                     removal.
--------------------------------------------------------------------------------

<CAPTION>
                                                                                               Other Directorships
Name and Age                Principal Occupation                                               Held by this Trustee
<S>                         <C>                                                                <C>
John F. Cogan, Jr. (84)*    Non-Executive Chairman and a director of Pioneer Investment        None
                            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 (Ber-
                            muda) Limited and affiliated funds; Deputy Chairman and a
                            director of Pioneer Global Asset Management S.p.A. ("PGAM")
                            (until April 2010); Director of PIOGLOBAL Real Estate Invest-
                            ment 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); Presi-
                            dent of all of the Pioneer Funds; and Of Counsel, Wilmer Cutler
                            Pickering Hale and Dorr LLP
--------------------------------------------------------------------------------------------------------------------
Daniel K. Kingsbury (52)*   Director, CEO and President of PIM-USA (since February             None
                            2007); Director and President of Pioneer and Pioneer Institu-
                            tional Asset Management, Inc. (since February 2007); Execu-
                            tive Vice President of all of the Pioneer Funds (since March
                            2007); Director of PGAM (2007 - 2010); Head of New Europe
                            Division, PGAM (2000 - 2005); and Head of New Markets
                            Division, PGAM (2005 - 2007)
--------------------------------------------------------------------------------------------------------------------
* Mr. Cogan and Mr. Kingsbury are Interested Trustees because they are officers or directors of the Fund's investment
  adviser and certain of its affiliates.
</TABLE>

                     Pioneer Cash Reserves Fund | Annual Report | 12/31/10    41
<PAGE>

Independent Trustees

<TABLE>
<CAPTION>
                     Position Held    Length of Service
Name and Age         with the Fund    and Term of Office
<S>                  <C>              <C>
David R. Bock (67)   Trustee          Trustee since 2005.
                                      Serves until a successor
                                      trustee is elected or
                                      earlier retirement or
                                      removal.
--------------------------------------------------------------------------------
Mary K. Bush (62)    Trustee          Trustee since 1997.
                                      Serves until a successor
                                      trustee is elected or
                                      earlier retirement or
                                      removal.
--------------------------------------------------------------------------------

<CAPTION>
                                                                                          Other Directorships
Name and Age         Principal Occupation                                                 Held by this Trustee
<S>                  <C>                                                                  <C>
David R. Bock (67)   Managing Partner, Federal City Capital Advisors (corporate           Director of Enterprise Community
                     advisory services company) (1997 - 2004 and 2008 -                   Investment, Inc. (privately held
                     present); Interim Chief Executive Officer, Oxford Analytica, Inc.    affordable housing finance com-
                     (privately held research and consulting company) (2010);             pany) (1985 - 2010); Director
                     Executive Vice President and Chief Financial Officer, I-trax, Inc.   of Oxford Analytica, Inc.
                     (publicly traded health care services company) (2004 - 2007);        (2008 - present); Director of The
                     and Executive Vice President and Chief Financial Officer,            Swiss Helvetia Fund, Inc. (closed-
                     Pedestal Inc. (internet-based mortgage trading company)              end fund) (2010 - present); and
                     (2000 - 2002)                                                        Director of New York Mortgage Trust
                                                                                          (publicly traded mortgage REIT)
                                                                                          (2004 - 2009)
--------------------------------------------------------------------------------------------------------------------------------
Mary K. Bush (62)    Chairman, Bush International, LLC (international financial           Director of Marriott International,
                     advisory firm) (1991 - present); Senior Managing Director,           Inc. (2008 - present); Director
                     Brock Capital Group, LLC (strategic business advisors) (2010 -       of Discover Financial Services
                     present); Managing Director, Federal Housing Finance Board           (credit card issuer and electronic
                     (oversight of Federal Home Loan Bank system) (1989 - 1991);          payment services) (2007 - present);
                     Vice President and Head of International Finance, Federal            Former Director of Briggs & Stratton
                     National Mortgage Association (1988 - 1989); U.S. Alternate          Co. (engine manufacturer) (2004 -
                     Executive Director, International Monetary Fund (1984 -              2009); Former Director of UAL Cor-
                     1988); Executive Assistant to Deputy Secretary of the U.S.           poration (airline holding company)
                     Treasury, U.S. Treasury Department (1982 - 1984); and Vice           (2006 - 2010); Director of ManTech
                     President and Team Leader in Corporate Banking, Bankers              International Corporation (national
                     Trust Co. (1976 - 1982)                                              security, defense, and intelligence
                                                                                          technology firm) (2006 - present);
--------------------------------------------------------------------------------------------------------------------------------
</TABLE>

42    Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

<TABLE>
<CAPTION>
                            Position Held   Length of Service
Name and Age                with the Fund   and Term of Office
<S>                         <C>             <C>
Mary K. Bush (62) (continued)
--------------------------------------------------------------------------------
Benjamin M. Friedman (66)   Trustee         Trustee since 2008.
                                            Serves until a successor
                                            trustee is elected or
                                            earlier retirement or
                                            removal.
--------------------------------------------------------------------------------
Margaret B.W. Graham (63)   Trustee         Trustee since 1990.
                                            Serves until a successor
                                            trustee is elected or
                                            earlier retirement or
                                            removal.
--------------------------------------------------------------------------------

<CAPTION>
                                                                                           Other Directorships
Name and Age                Principal Occupation                                           Held by this Trustee
<S>                         <C>                                                            <C>
Mary K. Bush (62) (continued)                                                              Member, Board of Governors, Invest-
                                                                                           ment Company Institute (2007 -
                                                                                           present); Member, Board of Gover-
                                                                                           nors, Independent Directors Council
                                                                                           (2007 - present); Former Director of
                                                                                           Brady Corporation (2000 - 2007);
                                                                                           Former Director of Mortgage Guar-
                                                                                           anty Insurance Corporation (1991 -
                                                                                           2006); Former Director of Millen-
                                                                                           nium Chemicals, Inc. (commodity
                                                                                           chemicals) (2002 - 2005); Former
                                                                                           Director, R.J. Reynolds Tobacco
                                                                                           Holdings, Inc. (tobacco) (1999 -
                                                                                           2005); and Former Director of
                                                                                           Texaco, Inc. (1997 - 2001)
--------------------------------------------------------------------------------------------------------------------------------
Benjamin M. Friedman (66)   William Joseph Maier Professor of Political Economy, Harvard   Trustee, Mellon Institutional Funds
                            University (1972 - present)                                    Investment Trust and Mellon Institu-
                                                                                           tional Funds Master Portfolio (over-
                                                                                           saw 17 portfolios in fund complex)
                                                                                           (1989 - 2008)
--------------------------------------------------------------------------------------------------------------------------------
Margaret B.W. Graham (63)   Founding Director, Vice President and Corporate Secretary,     None
                            The Winthrop Group, Inc. (consulting firm) (1982 - present);
                            Desautels Faculty of Management, McGill University (1999 -
                            present); and Manager of Research Operations and Organiza-
                            tional Learning, Xerox PARC, Xerox's Advance Research Center
                            (1990 - 1994)
--------------------------------------------------------------------------------------------------------------------------------
</TABLE>

                      Pioneer Cash Reserves Fund | Annual Report | 12/31/10
43
<PAGE>

Independent Trustees (continued)

<TABLE>
<CAPTION>
                            Position Held   Length of Service
 Name and Age              with the Fund   and Term of Office
<S>                        <C>             <C>
Thomas J. Perna (60)       Trustee         Trustee since 2006.
                                           Serves until a successor
                                           trustee is elected or
                                           earlier retirement or
                                           removal.
--------------------------------------------------------------------------------
Marguerite A. Piret (62)   Trustee         Trustee since 1987.
                                           Serves until a successor
                                           trustee is elected or
                                           earlier retirement or
                                           removal.
--------------------------------------------------------------------------------

<CAPTION>
                                                                                            Other Directorships
Name and Age               Principal Occupation                                             Held by this Trustee
<S>                        <C>                                                              <C>
Thomas J. Perna (60)       Chief Executive Officer, Quadriserv, Inc. (technology products   Director, Broadridge Financial Solu-
                           for securities lending industry) (2008 - present); private       tions, Inc. (investor communications
                           investor (2004 - 2008); and Senior Executive Vice President,     and securities processing provider
                           The Bank of New York (financial and securities services)         for financial services industry)
                           (1986 - 2004)                                                    (2009 - present); and Director,
                                                                                            Quadriserv, Inc. (2005 - present)
--------------------------------------------------------------------------------------------------------------------------------
Marguerite A. Piret (62)   President and Chief Executive Officer, Newbury, Piret & Com-     Director of New America High
                           pany, Inc. (investment banking firm) (1981 - present)            Income Fund, Inc. (closed-end
                                                                                            investment company) (2004 -
                                                                                            present); and member, Board of
                                                                                            Governors, Investment Company
                                                                                            Institute (2000 - 2006)
--------------------------------------------------------------------------------------------------------------------------------
</TABLE>

44    Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

Fund Officers

<TABLE>
<CAPTION>
                              Position Held         Length of Service
 Name and Age                with the Fund         and Term of Office
<S>                          <C>                   <C>
Christopher J. Kelley (46)   Secretary             Since 2010. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------
Carol B. Hannigan (49)       Assistant Secretary   Since 2010. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------
Thomas Reyes (48)            Assistant Secretary   Since 2010. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------
Mark E. Bradley (51)         Treasurer             Since 2008. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------
Luis I. Presutti (45)        Assistant Treasurer   Since 2000. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------

<CAPTION>
                                                                                              Other Directorships
Name and Age                 Principal Occupation                                             Held by this Officer
<S>                          <C>                                                              <C>
Christopher J. Kelley (46)   Vice President and Associate General Counsel of Pioneer since    None
                             January 2008 and Secretary of all of the Pioneer Funds since
                             June 2010; Assistant Secretary of all of the Pioneer Funds from
                             September 2003 to May 2010; and Vice President and Senior
                             Counsel of Pioneer from July 2002 to December 2007
---------------------------------------------------------------------------------------------------------------------
Carol B. Hannigan (49)       Fund Governance Director of Pioneer since December 2006          None
                             and Assistant Secretary of all the Pioneer Funds since June
                             2010; Manager - Fund Governance of Pioneer from December
                             2003 to November 2006; and Senior Paralegal of Pioneer from
                             January 2000 to November 2003
---------------------------------------------------------------------------------------------------------------------
Thomas Reyes (48)            Counsel of Pioneer since June 2007 and Assistant Secretary of    None
                             all the Pioneer Funds since June 2010; and Vice President and
                             Counsel at State Street Bank from October 2004 to June 2007
---------------------------------------------------------------------------------------------------------------------
Mark E. Bradley (51)         Vice President - Fund Accounting, Administration and Control-    None
                             lership Services of Pioneer; Treasurer of all of the Pioneer
                             Funds since March 2008; Deputy Treasurer of Pioneer from
                             March 2004 to February 2008; Assistant Treasurer of all of the
                             Pioneer Funds from March 2004 to February 2008; and Trea-
                             surer and Senior Vice President, CDC IXIS Asset Management
                             Services, from 2002 to 2003
---------------------------------------------------------------------------------------------------------------------
Luis I. Presutti (45)        Assistant Vice President - Fund Accounting, Administration and   None
                             Controllership Services of Pioneer; and Assistant Treasurer of
                             all of the Pioneer Funds
---------------------------------------------------------------------------------------------------------------------
</TABLE>

                      Pioneer Cash Reserves Fund | Annual Report | 12/31/10
45
<PAGE>

Fund Officers (continued)

<TABLE>
<CAPTION>
                        Position Held              Length of Service
Name and Age            with the Fund              and Term of Office
<S>                     <C>                        <C>
Gary Sullivan (52)      Assistant Treasurer        Since 2002. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------
David F. Johnson (31)   Assistant Treasurer        Since 2009. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------
Jean M. Bradley (58)    Chief Compliance Officer   Since 2010. Serves at
                                                   the discretion of the
                                                   Board.
--------------------------------------------------------------------------------

<CAPTION>
                                                                                         Other Directorships
Name and Age            Principal Occupation                                             Held by this Officer
<S>                     <C>                                                              <C>
Gary Sullivan (52)      Fund Accounting Manager - Fund Accounting, Administration        None
                        and Controllership Services of Pioneer; and Assistant Treasurer
                        of all of the Pioneer Funds
---------------------------------------------------------------------------------------------------------------
David F. Johnson (31)   Fund Administration Manager - Fund Accounting, Administra-       None
                        tion and Controllership Services since November 2008; Assis-
                        tant Treasurer of all of the Pioneer Funds since January 2009;
                        and Client Service Manager - Institutional Investor Services at
                        State Street Bank from March 2003 to March 2007
---------------------------------------------------------------------------------------------------------------
Jean M. Bradley (58)    Chief Compliance Officer of Pioneer and of all the Pioneer       None
                        Funds since March 2010; Director of Adviser and Portfolio
                        Compliance at Pioneer since October 2005; and Senior
                        Compliance Officer for Columbia Management Advisers, Inc.
                        from October 2003 to October 2005
---------------------------------------------------------------------------------------------------------------
</TABLE>


46    Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>



                           This page for your notes.




                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     47
<PAGE>



                           This page for your notes.




48     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>



                           This page for your notes.




                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     49
<PAGE>



                           This page for your notes.




50     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>



                           This page for your notes.




                    Pioneer Cash Reserves Fund | Annual Report | 12/31/10     51
<PAGE>



                           This page for your notes.




52     Pioneer Cash Reserves Fund | Annual Report | 12/31/10
<PAGE>

How to Contact Pioneer

We are pleased to offer a variety of convenient ways for you to contact us for
assistance or information.

Call us for:
--------------------------------------------------------------------------------
Account Information, including existing accounts,
new accounts, prospectuses, applications
and service forms                                               1-800-225-6292

FactFone(SM) for automated fund yields, prices,
account information and transactions                            1-800-225-4321

Retirement plans information                                    1-800-622-0176


Write to us:
--------------------------------------------------------------------------------
PIMSS, Inc.
P.O. Box 55014
Boston, Massachusetts 02205-5014

Our toll-free fax                                               1-800-225-4240

Our internet e-mail address                 ask.pioneer@pioneerinvestments.com
(for general questions about Pioneer only)


Visit our web site: pioneerinvestments.com



This report must be preceded or accompanied by a prospectus.

The Fund files a complete schedule of investments with the Securities and
Exchange Commission for the first and third quarters for each fiscal year on
Form N-Q. Shareholders may view the filed Form N-Q by visiting the Commission's
web site at http://www.sec.gov. The filed form may also be viewed and copied at
the Commission's Public Reference Room in Washington, DC. Information regarding
the operations of the Public Reference Room may be obtained by calling
1-800-SEC-0330.
<PAGE>


[LOGO] PIONEER
       Investments(R)

Pioneer Investment Management, Inc.
60 State Street
Boston, MA 02109
pioneerinvestments.com






Securities offered through Pioneer Funds Distributor, Inc.
60 State Street, Boston, MA 02109
Underwriter of Pioneer Mutual Funds, Member SIPC
(C) 2011 Pioneer Investments 18624-05-0211





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 routine filing of its Form N-1A, totaled
approximately $32,986 in 2010 and $32,500 in 2009.

(b) Disclose, under the caption AUDIT-RELATED FEES, the aggregate fees billed in
each of the last two fiscal years for assurance and related services by the
principal accountant that are reasonably related to the performance of the audit
of the registrant's financial statements and are not reported under
paragraph (a) of this Item. Registrants shall describe the nature of the
services comprising the fees disclosed under this category.

Audit-Related Fees
There were no audit-related services provided to
the Fund during the fiscal years ended December 31, 2010
and 2009.


(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 $8,290 in 2010 and $8,290 in 2009.


(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 other services provided to
the Fund during the fiscal years ended December 31, 2010
and 2009.

(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.
<PAGE>
<TABLE>
<CAPTION>
                               SECTION II - POLICY

---------------- -------------------------------- -------------------------------------------------
SERVICE           SERVICE CATEGORY DESCRIPTION      SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
CATEGORY
---------------- -------------------------------- -------------------------------------------------
<S>              <C>                              <C>
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.)
---------------- -------------------------------- -------------------------------------------------
<CAPTION>
 ------------------------------------- ------------------------------------
<S>                                    <C>
   AUDIT COMMITTEE APPROVAL POLICY               AUDIT COMMITTEE
                                                REPORTING POLICY
 ------------------------------------- ------------------------------------
<S>                                    <C>
 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"
 ------------------------------------- ------------------------------------
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- --------------------------- -----------------------------------------------
   SERVICE CATEGORY          SERVICE CATEGORY        SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
                               DESCRIPTION
----------------------- --------------------------- -----------------------------------------------
<S>                     <C>                         <C>
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"
------------------------------------- -------------------------
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- --------------------------- -----------------------------------------------
   SERVICE CATEGORY          SERVICE CATEGORY        SPECIFIC PRE-APPROVED SERVICE SUBCATEGORIES
                               DESCRIPTION
----------------------- --------------------------- -----------------------------------------------
<S>                     <C>                         <C>
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.
----------------------- --------------------------- -----------------------------------------------
<CAPTION>
--------------------------------------- ------------------------
    AUDIT COMMITTEE APPROVAL POLICY         AUDIT COMMITTEE
                                            REPORTING POLICY
------------------------------------- --------------------------
<S>                                   <C>
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"
------------------------------------- --------------------------
</TABLE>
<PAGE>
<TABLE>
<CAPTION>
                     SECTION III - POLICY DETAIL, CONTINUED

----------------------- ------------------------- -----------------------------------------------
   SERVICE CATEGORY         SERVICE CATEGORY        SPECIFIC PROHIBITED SERVICE SUBCATEGORIES
                              DESCRIPTION
----------------------- ------------------------- -----------------------------------------------
<S>                     <C>                       <C>
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
----------------------- ------------------------- -----------------------------------------------
<CAPTION>
------------------------------------------- ------------------------------
     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.
------------------------------------------- ------------------------------
</TABLE>
--------------------------------------------------------------------------------
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 December 31, 2010 and 2009, 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 $8,290 in 2010 and $8,290 in
2009.


(h) Disclose whether the registrant's audit committee of the board of trustees
has considered whether the provision of non-audit services that were rendered to
the registrant's investment adviser (not including any subadviser whose role is
primarily portfolio management and is subcontracted with or overseen by another
investment adviser), and any entity controlling, controlled by, or under common
control with the investment adviser that provides ongoing services to the
registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of
Rule 2-01 of Regulation S-X is compatible with maintaining the principal
accountant's independence.

The Fund's audit committee of the Board of Trustees has
considered whether the provision of non-audit services that
were rendered to the Affiliates (as defined) that were not pre-
approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of
Regulation S-X is compatible with maintaining the principal
accountant's independence.

Item 5. Audit Committee of Listed Registrants

(a) If the registrant is a listed issuer as defined in Rule 10A-3
under the Exchange Act (17 CFR 240.10A-3), state whether
or not the registrant has a separately-designated standing
 audit committee established in accordance with Section
3(a)(58)(A) of the Exchange Act (15 U.S.C. 78c(a)(58)(A)).
If the registrant has such a committee, however designated,
identify each committee member. If the entire board of directors
is acting as the registrants audit committee as specified in
Section 3(a)(58)(B) of the Exchange Act (15 U.S.C. 78c(a)(58)(B)),
so state.

N/A

(b) If applicable, provide the disclosure required by Rule 10A-3(d)
under the Exchange Act (17 CFR 240.10A-3(d)) regarding an exemption
from the listing standards for audit committees.

N/A

Item 6. Schedule of Investments.

File Schedule I Investments in securities of unaffiliated issuers
as of the close of the reporting period as set forth in 210.12-
12 of Regulation S-X [17 CFR 210.12-12], unless the schedule is
included as part of the report to shareholders filed under Item
1 of this Form.

Included in Item 1


ITEM 7. DISCLOSURE OF PROXY VOTING POLICIES AND PROCEDURES FOR
CLOSED-END MANAGEMENT INVESTMENT COMPANIES.

A closed-end management investment company that is filing an annual report on
this Form N-CSR must, unless it invests exclusively in non-voting securities,
describe the policies and procedures that it uses to determine how to vote
proxies relating to portfolio securities, including the procedures that the
company uses when a vote presents a conflict between the interests of its
shareholders, on the one hand, and those of the company's investment adviser;
principal underwriter; or any affiliated person (as defined in Section 2(a)(3)
of the Investment Company Act of 1940 (15 U.S.C. 80a-2(a)(3)) and the rules
thereunder) of the company, its investment adviser, or its principal
underwriter, on the other. Include any policies and procedures of the company's
investment adviser, or any other third party, that the company uses, or that are
used on the company's behalf, to determine how to vote proxies relating to
portfolio securities.

Not applicable to open-end management investment companies.



Item 8. Portfolio Managers of Closed-End Management Investment
        Companies.

(a) If the registrant is a closed-end management investment company that
is filing an annual report on this Form N-CSR,provide the following
information:
(1) State the name, title, and length of service of the person or persons
employed by or associated with the registrant or an investment adviser
of the registrant who are primarily responsible for the day-to-day management
of the registrants portfolio (Portfolio Manager). Also state each Portfolio
Managers business experience during the past 5 years.


Not applicable to open-end management investment companies.


Item 9. Purchases of Equity Securities by Closed-End Management
Investment Company and Affiliated Purchasers.

(a) If the registrant is a closed-end management investment company,
in the following tabular format, provide the information specified in
paragraph (b) of this Item with respect to any purchase made by or on
behalf of the registrant or any affiliated purchaser, as defined in
Rule 10b-18(a)(3) under the Exchange Act (17 CFR 240.10b-18(a)(3)), of
shares or other units of any class of the registrants equity securities
that is registered by the registrant pursuant to Section 12 of the
Exchange Act (15 U.S.C. 781). Instruction to paragraph (a). Disclose
all purchases covered by this Item, including purchases that do not
satisfy the conditions of the safe harbor of Rule 10b-18 under the
Exchange Act (17 CFR 240.10b-18), made in the period covered by the
report. Provide disclosures covering repurchases made on a monthly basis.
For example, if the reporting period began on January 16 and ended on
July 15, the chart would show repurchases for the months from January 16
through February 15, February 16 through March 15, March 16 through
April 15, April 16 through May 15, May 16 through June 15, and June 16
through July 15.

Not applicable to open-end management investment companies.


Item 10. Submission of Matters to a Vote of Security Holders.

Describe any material changes to the procedures by which shareholders
may recommend nominees to the registrants board of directors, where
those changes were implemented after the registrant last provided
disclosure in response to the requirements of Item 7(d)(2)(ii)(G)
of Schedule 14A (17 CFR 240.14a-101), or this Item.


There have been no material changes to the procedures by which the
shareholders may recommend nominees to the registrants board of
directors since the registrant last provided disclosure in response
to the requirements of Item 7(d)(2)(ii)(G) of Schedule 14(A) in
its definitive proxy statement, or this Item.


ITEM 11. CONTROLS AND PROCEDURES.

(a) Disclose the conclusions of the registrant's principal executive officer or
officers and principal financial officer or officers, or persons performing
similar functions, about the effectiveness of the registrant's disclosure
controls and procedures (as defined in Rule 30a-2(c) under the Act (17 CFR
270.30a-2(c))) based on their evaluation of these controls and procedures as of
a date within 90 days of the filing date of the report that includes the
disclosure required by this paragraph.

The registrant's principal executive officer
and principal financial officer have
concluded that the registrant's disclosure
controls and procedures are effective based
on their evaluation of these controls and
procedures as of a date within 90 days of the
filing date of this report.


(b) Disclose whether or not there were significant changes in the registrant's
internal controls or in other factors that could significantly affect these
controls subsequent to the date of their evaluation, including any corrective
actions with regard to significant deficiencies and material weaknesses.

There were no significant changes in the
registrant's internal control over financial
reporting that occurred during the second
fiscal quarter of the period covered by this
report that have materially affected, or are
reasonably likely to materially affect, the
registrant's internal control over financial
reporting.

The registrant's principal executive officer and principal financial
officer, however, voluntarily are reporting the following information:

In August of 2006 the registrant's investment adviser
enhanced its internal procedures for reporting performance
information required to be included in prospectuses.
Those enhancements involved additional internal controls
over the appropriateness of performance data
generated for this purpose.  Such enhancements were made
following an internal review which identified
prospectuses relating to certain classes of shares of
a limited number of registrants where, inadvertently,
performance information not reflecting the deduction of
applicable sales charges was included. Those prospectuses
were revised, and the revised prospectuses were distributed to
shareholders.


ITEM 12. EXHIBITS.

File the exhibits listed below as part of this Form. Letter or number the
exhibits in the sequence indicated.

(a) Any code of ethics, or amendment thereto, that is the subject of the
disclosure required by Item 2, to the extent that the registrant intends to
satisfy the Item 2 requirements through filing of an exhibit.



(b) A separate certification for each principal executive officer and principal
financial officer of the registrant as required by Rule 30a-2 under the Act
(17 CFR 270.30a-2).

Filed herewith.


<PAGE>


                                   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 Money Market Trust


By (Signature and Title)* /s/ John F. Cogan, Jr.
John F. Cogan, Jr, President

Date February 28, 2011


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 February 28, 2011


By (Signature and Title)* /s/ Mark Bradley
Mark Bradley, Treasurer

Date February 28, 2011

* Print the name and title of each signing officer under his or her signature.