<PAGE>


      [PIONEER LOGO]

       PIONEER
       FUND

      -------------------------
      SEMIANNUAL REPORT 6/30/00
      -------------------------
<PAGE>

    TABLE OF CONTENTS
   -----------------------------------------------------------------------------

<TABLE>
      <S>                                                      <C>
      Letter from the Chairman                                  1
      Portfolio Summary                                         2
      Performance Update                                        3
      Portfolio Management Discussion                           7
      Schedule of Investments                                  10
      Financial Statements                                     19
      Notes to Financial Statements                            27
      Retirement Plans from Pioneer                            32
      Programs and Services for Pioneer Shareowners            34
      Trustees, Officers and Service Providers                 36
</TABLE>
<PAGE>

     PIONEER FUND

     --------------------------------
     LETTER FROM THE CHAIRMAN 6/30/00
     --------------------------------

     DEAR SHAREOWNER,
     ---------------------------------------------------------------------------
     For over a year, the Federal Reserve has been trying to suppress
     inflationary pressures and restrain economic growth in the U.S. by
     raising short-term interest rates. Because they represent increased
     costs, higher interest rates cut into corporate profits.

     With the possibility of a slowing economy and an uncertain profit
     outlook overhanging the stock market, investors shifted from sector
     to sector in the first half of 2000 looking for attractive
     opportunities. Heightened stock market volatility was the result.
     Bonds also lost luster, because existing, lower-paying issues could
     not compete with the higher rates that now prevail. By summer, we
     began to see evidence that the Fed's tactics were having some impact,
     as key statistics hinted at a contraction of the economy's growth
     rate.

     Volatile markets should not sidetrack your plans for dealing with
     your essential financial goals. Whatever your long-range needs may
     be - money for a child's education, funding a comfortable retirement,
     or some other cherished objective - those needs remain in place no
     matter what the market may do this week or next month. For that
     reason, it makes sense to focus your investment strategy beyond
     interim ups and downs.

     Mid-year is a good time to talk to your financial representative to
     review what has been happening and to make sure your strategy is
     intact. Part of that discussion should be devoted to your portfolio's
     diversification. Do you have a blend of stocks and bonds that you are
     comfortable with and that can help you meet your goals? Or is it time
     to make adjustments? Be sure to include your IRAs and other
     retirement vehicles when you evaluate your overall portfolio.

     I hope you will take time to read the following discussion with John
     Carey, the portfolio manager of Pioneer Fund. It's an excellent way
     to understand the Fund's performance during the past six months and
     to learn what the manager's expectations are for the months ahead. If
     you have questions or would like more information about your Fund,
     visit our web site at www.pioneerfunds.com.

     Respectfully,

     /s/ John F. Cogan, Jr.

     John F. Cogan, Jr.
     Chairman and President

                                                                               1
<PAGE>

     PIONEER FUND

     --------------------------------------------
     PORTFOLIO SUMMARY 6/30/00
     --------------------------------------------

     PORTFOLIO DIVERSIFICATION
     ---------------------------------------------------------------------------
     (As a percentage of total investment portfolio)

                                     [PIE CHART]

     Short-Term Cash Equivalents 1%
     International Common Stocks 2%
     Depositary Receipts for International Stocks 4%
     U.S. Common Stocks 93%

     SECTOR DISTRIBUTION
     ---------------------------------------------------------------------------
     (As a percentage of equity holdings)

                                    [PIE CHART]

     Other 3%
     Basic Materials 3%
     Capital Goods 3%
     Energy 6%
     Communications Services 11%
     Healthcare 12%
     Consumer Staples 12%
     Consumer Cyclicals 12%
     Financial 15%
     Technology 23%

     10 LARGEST HOLDINGS
     ---------------------------------------------------------------------------
     (As a percentage of equity holdings)

<TABLE>
      <C>  <S>                             <C>    <C>  <C>                             <C>
       1.  Schering-Plough Corp.           3.33%   6.  U.S. West Communications        1.97%
                                                       Group, Inc.
       2.  Intel Corp.                     2.54    7.  Hewlett-Packard Co.             1.84
       3.  SBC Communications, Inc.        2.52    8.  BellSouth Corp.                 1.58
       4.  Texas Instruments, Inc.         2.46    9.  Motorola Inc.                   1.54
       5.  IBM Corp.                       2.38   10.  Exxon Mobil Corp.               1.53
</TABLE>

     Fund holdings will vary for other periods.

  2
<PAGE>

     PIONEER FUND

     -----------------------------------------------------------------------
     PERFORMANCE UPDATE 6/30/00                               CLASS A SHARES
     -----------------------------------------------------------------------

    SHARE PRICES AND DISTRIBUTIONS
   -----------------------------------------------------------------------------

<TABLE>
<CAPTION>
     NET ASSET VALUE
        PER SHARE           06/30/00    12/31/99
<S>                         <C>       <C>            <C>
                            $49.34      $47.60
<CAPTION>
 DISTRIBUTIONS PER SHARE     INCOME     SHORT-TERM      LONG-TERM
   (12/31/99 - 6/30/00)     DIVIDENDS  CAPITAL GAINS  CAPITAL GAINS
<S>                         <C>        <C>            <C>
                            $0.080     -              -
</TABLE>

    INVESTMENT RETURNS
   -----------------------------------------------------------------------------
    The mountain chart on the right shows the growth of a $10,000
    investment made in Pioneer Fund at public offering price, compared to
    the growth of the Standard & Poor's 500 Index and the Lipper Growth &
    Income Funds Index.

Growth of $10,000
[mountain chart]
<TABLE>
<CAPTION>
                                                                              STANDARD & POOR'S 500      LIPPER GROWTH & INCOME
                                                      PIONEER FUND*                   INDEX                    FUNDS INDEX
                                                      -------------           ---------------------      ----------------------
<S>                                             <C>                         <C>                         <C>
6/90                                                     9425                       10000                    10000
6/91                                                     9780                       10738                    10589
                                                        11120                       12174                    12009
                                                        12808                       13825                    13973
6/94                                                    13323                       14025                    14521
                                                        15631                       17673                    17350
                                                        18649                       22253                    21148
6/97                                                    24968                       29960                    27281
                                                        32929                       38980                    33320
                                                        40664                       47826                    37836
6/00                                                    44197                       51279                    37599
</TABLE>
[end mountain chart]

AVERAGE ANNUAL TOTAL RETURNS
(As of June 30, 2000)

<TABLE>
        PERIOD        NET ASSET VALUE   PUBLIC OFFERING PRICE*
         <S>               <C>                  <C>
       10 Years           16.71%               16.02%
        5 Years           23.11                21.66
        1 Year             8.69                 2.45
</TABLE>
* Reflects deduction of the maximum 5.75% sales charge at the beginning of the
  period and assumes reinvestment of distributions at net asset value.

    The Standard & Poor's (S&P) 500 Index is an unmanaged measure of 500
    widely held common stocks listed on the New York Stock Exchange,
    American Stock Exchange and the over-the-counter market. The Lipper
    Growth and Income Funds Index reflects the performance (excluding sales
    charges) of mutual funds with similar portfolio characteristics and
    capitalization. Index returns assume reinvestment of dividends and,
    unlike Fund returns, do not reflect any fees, expenses or sales
    charges. You cannot invest directly in either Index.

    Past performance does not guarantee future results. Return and share
    price fluctuate, and your shares, when redeemed, may be worth more or
    less than their original cost.

                                                                               3
<PAGE>

     PIONEER FUND

     -----------------------------------------------------------------------
     PERFORMANCE UPDATE 6/30/00                               CLASS B SHARES
     -----------------------------------------------------------------------

    SHARE PRICES AND DISTRIBUTIONS
   -----------------------------------------------------------------------------

<TABLE>
<CAPTION>
     NET ASSET VALUE
        PER SHARE           6/30/00       12/31/99
<S>                         <C>           <C>
                            $48.84        $47.24
</TABLE>

<TABLE>
<CAPTION>
 DISTRIBUTIONS PER SHARE     INCOME       SHORT-TERM        LONG-TERM
   (12/31/99 - 6/30/00)     DIVIDENDS    CAPITAL GAINS    CAPITAL GAINS
<S>                         <C>          <C>              <C>
                            -            -                -
</TABLE>

    INVESTMENT RETURNS
   -----------------------------------------------------------------------------
    The mountain chart on the right shows the growth of a $10,000
    investment made in Pioneer Fund, compared to the growth of the Standard
    & Poor's 500 Index and the Lipper Growth & Income Funds Index.

Growth of $10,000
[mountain chart]
<TABLE>
<CAPTION>
                                                                              STANDARD & POOR'S 500      LIPPER GROWTH & INCOME
                                                      PIONEER FUND*                   INDEX                    FUNDS INDEX
                                                      -------------           ---------------------      ----------------------
<S>                                             <C>                         <C>                         <C>
7/1/96                                                  10000                        10000                      10000
                                                        10212                        10247                      10322
                                                        10991                        11100                      11125
                                                        11235                        11399                      11313
6/30/97                                                 13253                        13385                      12900
                                                        14473                        14387                      13979
                                                        15079                        14799                      14116
                                                        17056                        16859                      15725
6/30/98                                                 17319                        17415                      15755
                                                        15803                        15686                      13791
                                                        19275                        19020                      16033
                                                        19543                        19965                      16372
6/30/99                                                 21194                        21367                      17891
                                                        19891                        20035                      16460
                                                        22094                        23013                      17934
                                                        22599                        23536                      18236
6/30/00                                                 22543                        22910                      17778
</TABLE>
[end mountain chart]

AVERAGE ANNUAL TOTAL RETURNS
(As of June 30, 2000)

<TABLE>
<CAPTION>
PERIOD                             IF HELD             IF REDEEMED*
<S>                                <C>                 <C>
Life of Fund (7/1/96)              22.94%                 22.53
Year                                7.78                   3.78
</TABLE>

* Reflects deduction of the maximum applicable contingent deferred sales charge
  (CDSC)( at the end of the period and assumes reinvestment of distributions.
  The maximum CDSC of 4% declines over six years.

    The Standard & Poor's (S&P) 500 Index is an unmanaged measure of 500
    widely held common stocks listed on the New York Stock Exchange,
    American Stock Exchange and the over-the-counter market. The Lipper
    Growth and Income Funds Index reflects the performance (excluding sales
    charges) of mutual funds with similar portfolio characteristics and
    capitalization. Index returns assume reinvestment of dividends and,
    unlike Fund returns, do not reflect any fees, expenses or sales charges.
    You cannot invest directly in either Index.

    Past performance does not guarantee future results. Return and share
    price fluctuate, and your shares, when redeemed, may be worth more or
    less than their original cost.

  4
<PAGE>

     PIONEER FUND

     -----------------------------------------------------------------------
     PERFORMANCE UPDATE 6/30/00                               CLASS C SHARES
     -----------------------------------------------------------------------

    SHARE PRICES AND DISTRIBUTIONS
   -----------------------------------------------------------------------------

<TABLE>
<CAPTION>
     NET ASSET VALUE
        PER SHARE           6/30/00       12/31/99
<S>                         <C>           <C>
                            $48.34        $46.76
</TABLE>

<TABLE>
<CAPTION>
 DISTRIBUTIONS PER SHARE     INCOME       SHORT-TERM        LONG-TERM
   (12/31/99 - 6/30/00)     DIVIDENDS    CAPITAL GAINS    CAPITAL GAINS
<S>                         <C>          <C>              <C>
                            -            -                -
</TABLE>

    INVESTMENT RETURNS
   -----------------------------------------------------------------------------
    The mountain chart on the right shows the growth of a $10,000
    investment made in Pioneer Fund, compared to the growth of the Standard
    & Poor's 500 Index and the Lipper Growth & Income Funds Index.

Growth of $10,000
[mountain chart]
<TABLE>
<CAPTION>
                                                                              STANDARD & POOR'S 500      LIPPER GROWTH & INCOME
                                                      PIONEER FUND*                   INDEX                    FUNDS INDEX
                                                      -------------           ---------------------      ----------------------
<S>                                             <C>                         <C>                         <C>
7/1/96                                                  10000                        10000                      10000
                                                        10117                        10247                      10322
                                                        10874                        11100                      11125
                                                        11117                        11399                      11313
6/30/97                                                 13114                        13385                      12900
                                                        14326                        14387                      13979
                                                        14925                        14799                      14116
                                                        16880                        16859                      15725
6/30/98                                                 17139                        17415                      15755
                                                        15644                        15686                      13791
                                                        19081                        19020                      16033
                                                        19349                        19965                      16372
6/30/99                                                 20987                        21367                      17891
                                                        19701                        20035                      16460
                                                        21883                        23013                      17934
                                                        22384                        23536                      18236
6/30/00                                                 22622                        22910                      17778
</TABLE>
[end mountain chart]

AVERAGE ANNUAL TOTAL RETURNS
(As of June 30, 2000)

<TABLE>
<CAPTION>
PERIOD                             IF HELD             IF REDEEMED*
<S>                                <C>                 <C>
Life of Fund (7/1/96)              22.64%                 22.64%
Year                                7.79                   7.79
</TABLE>

* Assumes reinvestment of distributions. The 1% contingent deferred sales charge
  (CDSC) applies to redemptions made within one year of purchase.

    The Standard & Poor's (S&P) 500 Index is an unmanaged measure of 500
    widely held common stocks listed on the New York Stock Exchange,
    American Stock Exchange and the over-the-counter market. The Lipper
    Growth and Income Funds Index reflects the performance (excluding sales
    charges) of mutual funds with similar portfolio characteristics and
    capitalization. Index returns assume reinvestment of dividends and,
    unlike Fund returns, do not reflect any fees, expenses or sales
    charges. You cannot invest directly in either Index.

    Past performance does not guarantee future results. Return and share
    price fluctuate, and your shares, when redeemed, may be worth more or
    less than their original cost.

                                                                               5

 <PAGE>
     PIONEER FUND

     -----------------------------------------------------------------------
     PERFORMANCE UPDATE 6/30/00                               CLASS Y SHARES
     -----------------------------------------------------------------------

    SHARE PRICES AND DISTRIBUTIONS
   -----------------------------------------------------------------------------

<TABLE>
<CAPTION>
     NET ASSET VALUE
        PER SHARE           6/30/00       12/31/99
<S>                         <C>           <C>
                            $49.37        $47.62
</TABLE>

<TABLE>
<CAPTION>
 DISTRIBUTIONS PER SHARE     INCOME       SHORT-TERM        LONG-TERM
   (12/31/99 - 6/30/00)     DIVIDENDS    CAPITAL GAINS    CAPITAL GAINS
<S>                         <C>          <C>              <C>
                            $0.160       -                -
</TABLE>

    INVESTMENT RETURNS
   -----------------------------------------------------------------------------
    The mountain chart on the right shows the growth of a $10,000
    investment made in Pioneer Fund, compared to the growth of the Standard
    & Poor's 500 Index and the Lipper Growth & Income Funds Index.

Growth of $10,000
[mountain chart]
<TABLE>
<CAPTION>
                                                                              STANDARD & POOR'S 500      LIPPER GROWTH & INCOME
                                                      PIONEER FUND*                   INDEX                    FUNDS INDEX
                                                      -------------           ---------------------      ----------------------
<S>                                             <C>                         <C>                         <C>
5/31/99                                                 10000                         10000                       10000
                                                         9811                          9773                        9854
                                                        10293                         10337                       10262
                                                         9972                         10005                        9968
8/31/99                                                  9877                          9943                        9747
                                                         9692                          9692                        9441
                                                        10273                         10299                        9845
                                                        10402                         10495                        9931
                                                        10800                         11133                       10287
1/31/00                                                 10372                         10566                        9883
                                                        10168                         10353                        9562
                                                        11079                         11386                       10460
                                                        10984                         11035                       10274
                                                        11116                         10793                       10236
6/30/00                                                 11234                         11083                       10197
</TABLE>
[end mountain chart]

AVERAGE ANNUAL TOTAL RETURNS*
(As of June 30, 2000)

<TABLE>
<CAPTION>
PERIOD                             IF HELD             IF REDEEMED*
<S>                                <C>                 <C>
Life of Fund (5/6/99)              10.55%                 10.55%
Year                                9.13                   9.13
</TABLE>

* Assumes reinvestment of distributions.

    The Standard & Poor's (S&P) 500 Index is an unmanaged measure of 500
    widely held common stocks listed on the New York Stock Exchange,
    American Stock Exchange and the over-the-counter market. The Lipper
    Growth and Income Funds Index comparison begins on 4/30/99 and reflects
    the performance (excluding sales charges) of mutual funds with similar
    portfolio characteristics and capitalization. Index returns assume
    reinvestment of dividends and, unlike Fund returns, do not reflect any
    fees, expenses or sales charges. You cannot invest directly in either
    Index.

    Past performance does not guarantee future results. Return and share
    price fluctuate, and your shares, when redeemed, may be worth more or
    less than their original cost.

  6

 <PAGE>
     PIONEER FUND

--------------------------------------------------------------------------------
     PORTFOLIO MANAGEMENT DISCUSSION 6/30/00
--------------------------------------------------------------------------------

In the following discussion John Carey, the portfolio manager for Pioneer Fund,
discusses the events and factors that influenced your Fund's performance over
the last six months.

Q:  HOW WOULD YOU CHARACTERIZE THE MARKET ENVIRONMENT OVER THE LAST SIX MONTHS?

A:  The stock market in the United States has been extremely volatile. From the
    beginning of the year through the end of the first week of March, it seemed
    investors were only interested in technology; but the tables turned, and a
    deep correction in that sector ensued. In the last week of May, the tables
    turned yet again, and technology began to recover. This continued through
    the end of our six-month period.

    In the meantime, the rest of the market varied greatly. Several sectors that
    had lagged during most of 1999 performed relatively well, such as
    pharmaceuticals, electric utilities, and some of the financial and food
    stocks. Other stocks that should have done better in a period of higher
    inflation, such as the basic materials and the large oil stocks, performed
    poorly. On the whole, a diversified approach to the market, with an emphasis
    on more conservatively valued names, proved a worthwhile strategy.

Q:  HOW DID THE FUND PERFORM DURING THE PERIOD?

A:  The Fund managed to hold its own in a quite difficult period, producing a
    total return on Class A shares of 3.82% (3.39% for Class B and 3.38% for
    Class C), all at net asset value for the six months ended June 30, 2000.
    That exceeded the returns for the S&P 500 and the Lipper large-cap value
    category, which both showed losses. The S&P 500 returned -0.45%, and the
    Lipper category in which our fund is included returned -1.64%. We stayed
    almost fully invested and maintained a diversified portfolio that included
    many stocks that did fairly well. BestFoods, which received a take-over
    offer from Unilever, rose by about 40%, and, prior to our liquidations of
    both positions during the first quarter, Sun Microsystems and Oracle had
    both risen sharply from the beginning of the year. Our largest position,
    Schering-Plough, gained about 25% during the six months.

Q:  HOW DO YOU DETERMINE IF A STOCK IS APPROPRIATE FOR PIONEER FUND?

A:  There are three steps. First, we establish the general suitability of a
    company for the portfolio; we look for financial strength, prominent
    industry position, a dynamic of sales and earnings growth and a skilled
    management committed to shareholders. Second, within that universe of
    suitable stocks

                                                                               7
<PAGE>
     PIONEER FUND

--------------------------------------------------------------------------------
     PORTFOLIO MANAGEMENT DISCUSSION 6/30/00                      (CONTINUED)
--------------------------------------------------------------------------------

    we focus our research on identifying investment opportunities: companies
    with the potential to earn more money over the next three to five years than
    the stock market is anticipating. We especially look for companies that can
    enhance earnings by turning around a troubled division, successfully
    executing a change in strategy, introducing new products, entering new
    markets or improving productivity through better management or new
    technology. Third, we apportion new investments among different industries
    and sectors to keep the portfolio diversified and to moderate the risk of
    exposures to the various economic and business cycles.

    Although there is no guarantee, we also aim to pay an income dividend on the
    Class A shares of the Fund (which we have done every year since 1928) and we
    do pay attention to the effect of new investments on the aggregate "yield"
    of the portfolio. Finally, we avoid stocks of companies whose primary
    business is tobacco or alcohol.

    Here are four examples of companies we have recently found attractive, and
    why. Motorola is a leader in three areas: cellular phones,
    telecommunications equipment and semiconductors. During the correction in
    the technology sector the share price fell by more than half. We thought
    that Wall Street analysts were too closely focused on short-term
    disappointments instead of the long-term strengths of the company in some
    very rapidly expanding industries, so we added to our position. Likewise we
    have maintained our positions in such companies as BellSouth, Colgate-
    Palmolive and Bristol-Myers Squibb, despite their rather cool reception by
    the stock market so far this year. In each case we can see value in the
    stock beyond what the market perceives because we are taking, we think, a
    more long-term perspective.

Q:  WHY IS PATIENCE SO IMPORTANT WHEN MANAGING PIONEER FUND?

A:  We think that everyone will be familiar with the fable of the hare and the
    tortoise. It was our founder, Philip L. Carret, who set us on "the tortoise
    road to wealth." "Slow and steady" may win the race, but along the way one
    does sometimes wish that the scenery would change just a bit more quickly.
    That is where patience - discipline and an outlook and interest in the
    subtle changes in detail formed by many decades of investment
    experience - comes in.

  8
<PAGE>
     PIONEER FUND

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------


Q:  WHAT IS YOUR OUTLOOK FOR ATTRACTIVELY VALUED STOCKS?

A:  The most striking thing about the stock market over the last few years has
    been its infatuation with technology, and not just the Internet but also
    everything having to do with computers, telecommunications equipment,
    software and semiconductors. At a certain point it seems to us that prices
    are no longer being driven by the "fundamentals" of sales, earnings and
    shareholder equity but by frenzied demand. Pioneer Fund has benefited from
    the strength of the tech sector, as we have owned a number of the popular
    names that we purchased when they were out of favor. But every trend in the
    market reaches a limit. Eventually prices, earnings, book value and
    dividends do matter. We think that the rockiness of the market over the past
    few months should indicate that we are in a time of change and that a more
    diversified and value-oriented approach will work better in the future.

                                                                               9
<PAGE>

     PIONEER FUND

--------------------------------------------------------------------------------
     SCHEDULE OF INVESTMENTS 6/30/00 (unaudited)
--------------------------------------------------------------------------------

<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               COMMON STOCKS - 99.5%
               BASIC MATERIALS - 2.7%
               ALUMINUM - 0.5%
  1,476,000    Alcoa, Inc.                                                 $   42,804,000
                                                                           --------------
               CHEMICALS - 0.6%
    916,896    E.I. du Pont de Nemours & Co.                               $   40,114,200
    200,000    Rohm & Haas Co.                                                  6,900,000
                                                                           --------------
                                                                           $   47,014,200
                                                                           --------------
               CONTAINERS & PACKAGING (PAPER) - 0.3%
    896,600    Greif Brothers Corp. (Non-voting)                           $   27,570,450
                                                                           --------------
               GOLD & PRECIOUS METALS MINING - 0.4%
  1,313,500    Newmont Mining Corp.                                        $   28,404,437
                                                                           --------------
               IRON & STEEL - 0.1%
    177,700    Nucor Corp.                                                 $    5,897,419
                                                                           --------------
               METALS MINING - 0.7%
    947,900    Phelps Dodge Corp.                                          $   35,250,032
  1,000,000    Rio Tinto Plc                                                   16,339,869
                                                                           --------------
                                                                           $   51,589,901
                                                                           --------------
               PAPER & FOREST PRODUCTS - 0.1%
    200,000    Weyerhaeuser Co.                                            $    8,600,000
                                                                           --------------
               TOTAL BASIC MATERIALS                                       $  211,880,407
                                                                           --------------
               CAPITAL GOODS - 3.1%
               AEROSPACE/DEFENSE - 1.0%
    500,000    Boeing Co.                                                  $   20,906,250
    312,300    General Dynamics Corp.                                          16,317,675
  1,525,000    Lockheed Martin Corp.                                           37,839,063
                                                                           --------------
                                                                           $   75,062,988
                                                                           --------------
               ELECTRICAL EQUIPMENT - 0.6%
    445,800    Emerson Electric Co.                                        $   26,915,175
    336,000    General Electric Co.                                            17,808,000
                                                                           --------------
                                                                           $   44,723,175
                                                                           --------------
               MACHINERY (DIVERSIFIED) - 0.5%
    720,600    Deere & Co.                                                 $   26,662,200
    404,450    Ingersoll-Rand Co.                                              16,279,113
                                                                           --------------
                                                                           $   42,941,313
                                                                           --------------
</TABLE>

 10   The accompanying notes are an integral part of these financial statements.
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------


<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               MANUFACTURING (DIVERSIFIED) - 0.6%
    266,100    Diebold Inc.                                                $    7,417,538
          1    Energizer Holdings, Inc.*                                                6
    355,800    Illinois Tool Works, Inc.                                       20,280,600
    343,300    Johnson Controls, Inc.                                          17,615,581
                                                                           --------------
                                                                           $   45,313,725
                                                                           --------------
               OFFICE EQUIPMENT & SUPPLIES - 0.4%
    693,900    Canon Inc. (A.D.R.)                                         $   34,955,211
                                                                           --------------
               TOTAL CAPITAL GOODS                                         $  242,996,412
                                                                           --------------
               COMMUNICATION SERVICES - 11.3%
               CELLULAR/WIRELESS TELECOMMUNICATIONS - 1.3%
    169,000    AT&T Wireless Group*                                        $    4,710,875
  1,600,000    Sprint Corp. (PCS Group)*                                       95,200,000
                                                                           --------------
                                                                           $   99,910,875
                                                                           --------------
               TELECOMMUNICATIONS (LONG-DISTANCE) - 1.4%
  2,068,000    Sprint Corp.                                                $  105,468,000
                                                                           --------------
               TELEPHONE - 8.6%
    505,448    Alltel Corp.                                                $   31,306,186
  1,666,708    Bell Atlantic Corp.                                             84,689,600
  2,859,600    BellSouth Corp.                                                121,890,450
  1,360,900    GTE Corp.                                                       84,716,025
  4,495,637    SBC Communications, Inc.                                       194,436,300
  1,774,351    U.S. West Communications Group, Inc.                           152,150,598
                                                                           --------------
                                                                           $  669,189,159
                                                                           --------------
               TOTAL COMMUNICATION SERVICES                                $  874,568,034
                                                                           --------------
               CONSUMER CYCLICALS - 12.2%
               AUTOMOBILES - 1.2%
  2,263,600    Ford Motor Co.                                              $   97,334,800
                                                                           --------------
               AUTO PARTS & EQUIPMENT - 0.1%
    296,380    Visteon Corp.*                                              $    3,593,607
                                                                           --------------
               HOUSEHOLD FURNISHINGS & APPLIANCES - 0.9%
    729,600    Sony Corp. (A.D.R.)                                         $   68,810,400
                                                                           --------------
               LEISURE TIME (PRODUCTS) - 0.1%
    300,000    Hasbro, Inc.                                                $    4,518,750
                                                                           --------------
</TABLE>
 <PAGE>
   The accompanying notes are an integral part of these financial statements. 11

     PIONEER FUND

-------------------------------------------------------------------------------
     SCHEDULE OF INVESTMENTS 6/30/00 (unaudited)  (continued)
-------------------------------------------------------------------------------


<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               PUBLISHING - 2.1%
  3,494,400    John Wiley & Sons, Inc.+                                    $   78,624,000
  1,606,000    McGraw-Hill Co., Inc.                                           86,724,000
                                                                           --------------
                                                                           $  165,348,000
                                                                           --------------
               PUBLISHING (NEWSPAPER) - 1.4%
    636,100    Central Newspapers, Inc.                                    $   40,233,325
    443,000    Dow Jones & Co., Inc.                                           32,449,750
    600,000    Gannett Co., Inc.                                               35,887,500
                                                                           --------------
                                                                           $  108,570,575
                                                                           --------------
               RETAIL (COMPUTERS & ELECTRONICS) - 0.2%
    250,000    Best Buy Co., Inc.*                                         $   15,812,500
    100,000    Circuit City Stores - Circuit City Group                         3,318,750
                                                                           --------------
                                                                           $   19,131,250
                                                                           --------------
               RETAIL (DEPARTMENT STORES) - 1.6%
    474,500    Harcourt General, Inc.                                      $   25,800,938
  1,192,800    Kohl's Corp.*                                                   66,349,500
  1,234,800    May Department Stores Co.                                       29,635,200
                                                                           --------------
                                                                           $  121,785,638
                                                                           --------------
               RETAIL (DISCOUNTERS) - 0.6%
  2,304,843    Dollar General Corp.                                        $   44,944,439
                                                                           --------------
               RETAIL (GENERAL MERCHANDISE) - 1.8%
  1,380,000    Target Corp.                                                $   80,040,000
  1,052,000    Wal-Mart Stores, Inc.                                           60,621,500
                                                                           --------------
                                                                           $  140,661,500
                                                                           --------------
               RETAIL (SPECIALTY) - 0.1%
    505,700    Barnes & Noble, Inc.*                                       $   11,251,825
                                                                           --------------
               RETAIL (SPECIALTY/APPAREL) - 0.5%
  1,197,900    Gap Inc.                                                    $   37,434,373
                                                                           --------------
               SERVICES (ADVERTISING/MARKETING) - 1.6%
  1,000,000    The Interpublic Group of Companies, Inc.                    $   43,000,000
    890,200    Omnicom Group                                                   79,283,438
                                                                           --------------
                                                                           $  122,283,438
                                                                           --------------
               TOTAL CONSUMER CYCLICALS                                    $  945,668,595
                                                                           --------------
</TABLE>

 12   The accompanying notes are an integral part of these financial statements.
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               CONSUMER STAPLES - 11.4%
               BEVERAGES (NON-ALCOHOLIC) - 0.8%
  1,357,900    PepsiCo, Inc.                                               $   60,341,681
                                                                           --------------
               BROADCASTING (TELEVISION/RADIO/CABLE) - 0.6%
    202,000    Cox Communication, Inc. *                                   $    9,203,625
    565,700    MediaOne Group, Inc.*                                           37,516,375
                                                                           --------------
                                                                           $   46,720,000
                                                                           --------------
               DISTRIBUTORS (FOOD & HEALTH) - 0.5%
    866,200    Sysco Corp.                                                 $   36,488,675
                                                                           --------------
               ENTERTAINMENT - 1.4%
  1,640,411    Viacom, Inc. (Class B) (Non-voting)*                        $  111,855,526
                                                                           --------------
               FOODS - 3.9%
  1,611,800    BestFoods                                                   $  111,617,150
  1,116,000    Campbell Soup Co.                                               32,503,500
    960,600    General Mills, Inc.                                             36,742,950
  1,055,150    H.J. Heinz Co.                                                  46,162,813
    750,000    Hershey Foods Corp.                                             36,375,000
    589,100    Ralston-Ralston Purina Group                                    11,745,181
  1,330,000    Sara Lee Corp.                                                  25,685,625
                                                                           --------------
                                                                           $  300,832,219
                                                                           --------------
               HOUSEHOLD PRODUCTS (NON-DURABLE) - 1.5%
  1,358,600    Colgate-Palmolive Co.                                       $   81,346,175
    600,000    Procter & Gamble Co.                                            34,350,000
                                                                           --------------
                                                                           $  115,696,175
                                                                           --------------
               RESTAURANTS - 0.3%
    640,000    McDonald's Corp.                                            $   21,080,000
                                                                           --------------
               RETAIL STORES (FOOD CHAINS) - 0.1%
    300,000    Safeway Inc.*                                               $   13,537,500
                                                                           --------------
               RETAIL (DRUG STORES) - 1.5%
    709,800    CVS Corp.                                                   $   28,392,000
  2,851,200    Walgreen Co.                                                    91,773,000
                                                                           --------------
                                                                           $  120,165,000
                                                                           --------------
               SERVICES (EMPLOYMENT) - 0.8%
  2,133,800    Robert Half International, Inc.*                            $   60,813,300
                                                                           --------------
               TOTAL CONSUMER STAPLES                                      $  887,530,076
                                                                           --------------
</TABLE>

   The accompanying notes are an integral part of these financial statements. 13
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     SCHEDULE OF INVESTMENTS 6/30/00 (unaudited)  (continued)
-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               ENERGY - 6.1%
               OIL (DOMESTIC INTEGRATED) - 0.4%
    700,000    Conoco Inc. (Class A)                                       $   15,400,000
    711,256    Conoco Inc. (Class B)                                           17,470,226
                                                                           --------------
                                                                           $   32,870,226
                                                                           --------------
               OIL (INTERNATIONAL INTEGRATED) - 4.6%
  1,884,852    BP Amoco Plc (A.D.R.)                                       $  106,611,941
  1,115,500    Chevron Corp.                                                   94,608,344
  1,503,493    Exxon Mobil Corp.                                              118,024,201
    800,000    Texaco, Inc.                                                    42,600,000
                                                                           --------------
                                                                           $  361,844,486
                                                                           --------------
               OIL & GAS (DRILLING & EQUIPMENT) - 1.1%
    523,000    Schlumberger Ltd.                                           $   39,028,875
    370,100    Smith International, Inc.*                                      26,947,906
    301,252    Transocean Sedco Forex Inc.                                     16,098,154
                                                                           --------------
                                                                           $   82,074,935
                                                                           --------------
               TOTAL ENERGY                                                $  476,789,647
                                                                           --------------
               FINANCIAL - 15.3%
               BANKS (MAJOR REGIONAL) - 5.2%
  2,446,800    The Bank of New York Co., Inc.                              $  113,776,200
    773,700    Comerica, Inc.                                                  34,719,787
    532,980    Fleet Boston Financial Corp.                                    18,121,320
    738,100    Huntington Bancshares, Inc.                                     11,671,206
  1,886,600    Mellon Bank Corp.                                               68,742,988
  2,864,648    National City Corp.                                             48,878,057
    806,800    State Street Corp.                                              85,571,225
    500,000    Wells Fargo Co.                                                 19,375,000
                                                                           --------------
                                                                           $  400,855,783
                                                                           --------------
               BANKS (REGIONAL) - 0.5%
    925,700    First Tennessee National Corp.                              $   15,331,906
    539,200    Zions Bancorporation                                            24,744,225
                                                                           --------------
                                                                           $   40,076,131
                                                                           --------------
               FINANCIAL (DIVERSIFIED) - 1.7%
  2,136,400    Axa Financial, Inc.                                         $   72,637,600
    693,500    Morgan Stanley, Dean Witter, Discover & Co.                     57,733,875
                                                                           --------------
                                                                           $  130,371,475
                                                                           --------------
</TABLE>

 14   The accompanying notes are an integral part of these financial statements.
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               INSURANCE (MULTI-LINE) - 1.2%
    574,812    American International Group, Inc.                          $   67,540,410
    536,200    ReliaStar Financial Corp.                                       28,116,988
                                                                           --------------
                                                                           $   95,657,398
                                                                           --------------
               INSURANCE (PROPERTY/CASUALTY) - 2.0%
  1,174,200    Chubb Corp.                                                 $   72,213,300
    607,300    Exel Ltd.                                                       32,870,113
    331,300    Partnerre Ltd.                                                  11,740,443
    830,400    Safeco Corp.                                                    16,504,200
    647,600    St. Paul Companies, Inc.                                        22,099,350
                                                                           --------------
                                                                           $  155,427,406
                                                                           --------------
               INSURANCE BROKERS - 1.0%
    729,000    Marsh & McLennan Co., Inc.                                  $   76,134,937
                                                                           --------------
               INVESTMENT MANAGEMENT - 3.4%
    677,000    Federated Investors Inc. (Class B)                          $   23,737,313
    621,000    Merrill Lynch & Co., Inc.                                       71,415,000
  1,820,500    Paine Webber Group Inc.                                         82,832,750
  2,100,000    T. Rowe Price Associates, Inc.                                  89,250,000
                                                                           --------------
                                                                           $  267,235,063
                                                                           --------------
               SAVINGS & LOAN COMPANIES - 0.3%
    693,840    Washington Mutual, Inc.                                     $   20,034,630
                                                                           --------------
               TOTAL FINANCIAL                                             $1,185,792,823
                                                                           --------------
               HEALTHCARE - 11.5%
               HEALTHCARE (DIVERSIFIED) - 3.3%
  1,333,300    Abbott Laboratories                                         $   59,415,181
  1,728,000    Bristol-Myers Squibb Co.                                       100,656,000
    950,000    Johnson & Johnson                                               96,781,250
                                                                           --------------
                                                                           $  256,852,431
                                                                           --------------
               HEALTHCARE (DRUGS & MAJOR PHARMACEUTICALS) - 7.6%
    749,000    Eli Lilly & Co.                                             $   74,806,375
  1,100,600    Merck & Co., Inc.                                               84,333,475
  1,100,000    Pfizer, Inc.                                                    52,800,000
      3,898    Roche Holdings AG                                               37,944,181
  5,092,800    Schering-Plough Corp.                                          257,186,400
  1,243,000    Smithkline Beecham Plc (A.D.R.)                                 81,028,063
                                                                           --------------
                                                                           $  588,098,494
                                                                           --------------
</TABLE>

   The accompanying notes are an integral part of these financial statements. 15
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     SCHEDULE OF INVESTMENTS 6/30/00 (unaudited)  (continued)
-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               HEALTHCARE (MEDICAL PRODUCTS & SUPPLIES) - 0.6%
  1,532,800    Becton, Dickinson & Co.                                     $   43,972,200
                                                                           --------------
               TOTAL HEALTHCARE                                            $  888,923,125
                                                                           --------------
               TECHNOLOGY - 23.0%
               COMMUNICATIONS EQUIPMENT - 3.3%
    500,000    ADC Telecommunications, Inc.*                               $   41,937,500
  1,216,968    Lucent Technologies, Inc.*                                      72,105,354
  4,082,061    Motorola Inc.                                                  118,634,898
    300,000    Tellabs, Inc.*                                                  20,531,250
                                                                           --------------
                                                                           $  253,209,002
                                                                           --------------
               COMPUTERS (HARDWARE) - 5.3%
  3,290,000    Compaq Computer Corp.                                       $   84,100,625
  1,140,000    Hewlett-Packard Co.                                            142,357,500
  1,674,000    IBM Corp.                                                      183,407,625
                                                                           --------------
                                                                           $  409,865,750
                                                                           --------------
               COMPUTERS (NETWORKING) - 1.0%
    930,000    3COM Corp.*                                                 $   53,591,250
    394,400    Lycos, Inc.*                                                    21,297,600
                                                                           --------------
                                                                           $   74,888,850
                                                                           --------------
               COMPUTERS (SOFTWARE & SERVICES) - 2.9%
    408,000    Adobe Systems, Inc.                                         $   53,040,000
    480,000    BMC Software, Inc.*                                             17,512,500
  1,290,000    Microsoft Corp.*                                               103,200,000
    498,500    Peoplesoft Inc.*                                                 8,349,875
  1,300,000    Synopsys, Inc.*                                                 44,931,250
                                                                           --------------
                                                                           $  227,033,625
                                                                           --------------
               ELECTRONICS (COMPONENT DISTRIBUTORS) - 0.5%
    800,000    Koninklijke Philips Electronics NV                          $   38,000,000
                                                                           --------------
               ELECTRONICS (INSTRUMENTATION) - 6.4%
    434,796    Agilent Technologies Inc.*                                  $   32,066,205
    800,000    Altera Corp.*                                                   81,550,000
  1,470,000    Intel Corp.                                                    196,520,625
  2,768,000    Texas Instruments, Inc.                                        190,127,000
                                                                           --------------
                                                                           $  500,263,830
                                                                           --------------
</TABLE>

 16   The accompanying notes are an integral part of these financial statements.
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               EQUIPMENT (SEMICONDUCTORS) - 0.9%
    590,000    Applied Materials, Inc.*                                    $   53,468,750
    330,000    Novellus Systems, Inc.*                                         18,665,625
                                                                           --------------
                                                                           $   72,134,375
                                                                           --------------
               PHOTOGRAPHY/IMAGING - 0.6%
    729,100    Eastman Kodak Co.                                           $   43,381,450
                                                                           --------------
               SERVICES (COMPUTER SYSTEMS) - 0.8%
    823,100    Computer Sciences Corp.*                                    $   61,475,281
                                                                           --------------
               SERVICES (DATA PROCESSING) - 1.3%
    914,200    Automatic Data Processing, Inc.                             $   48,966,838
    276,400    DST Systems, Inc.*                                              21,040,950
    454,000    Electronic Data Systems Corp.                                   18,727,500
    367,500    Fiserv, Inc.*                                                   15,894,375
                                                                           --------------
                                                                           $  104,629,663
                                                                           --------------
               TOTAL TECHNOLOGY                                            $1,784,881,826
                                                                           --------------
               TRANSPORTATION - 1.8%
               AIRLINES - 0.7%
    422,908    Delta Air Lines, Inc.                                       $   21,383,286
  1,892,400    Southwest Airlines Co.                                          35,837,325
                                                                           --------------
                                                                           $   57,220,611
                                                                           --------------
               RAILROADS - 1.1%
  1,154,200    Burlington Northern, Inc.                                   $   26,474,463
  2,730,100    Norfolk Southern Corp.                                          40,610,235
    470,800    Union Pacific Corp.                                             17,507,875
                                                                           --------------
                                                                           $   84,592,573
                                                                           --------------
               TOTAL TRANSPORTATION                                        $  141,813,184
                                                                           --------------
               UTILITIES - 1.1%
               ELECTRIC COMPANIES - 0.7%
  1,125,100    Allegheny Energy, Inc.                                      $   30,799,613
  1,068,900    DPL, Inc.                                                       23,448,993
                                                                           --------------
                                                                           $   54,248,606
                                                                           --------------
               NATURAL GAS - 0.2%
    767,533    Vectren Corp.                                               $   13,239,945
                                                                           --------------
</TABLE>

   The accompanying notes are an integral part of these financial statements. 17
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     SCHEDULE OF INVESTMENTS 6/30/00 (unaudited)  (continued)
-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
  SHARES                                                                       VALUE
<C>            <S>                                                         <C>
               WATER UTILITIES - 0.2%
    552,600    American Water Works Co., Inc.                              $   13,815,000
                                                                           --------------
               TOTAL UTILITIES                                             $   81,303,551
                                                                           --------------
               TOTAL COMMON STOCKS
               (Cost $4,352,130,867)                                       $7,722,147,680
                                                                           --------------
<CAPTION>
 PRINCIPAL
  AMOUNT
<C>            <S>                                                         <C>
               TEMPORARY CASH INVESTMENT - 0.5%
               COMMERCIAL PAPER - 0.5%
$36,912,000    Citigroup Inc., 6.88%, 7/3/00                               $   36,912,000
                                                                           --------------
               TOTAL TEMPORARY CASH INVESTMENT
               (Cost $36,912,000)                                          $   36,912,000
                                                                           --------------
               TOTAL INVESTMENT IN SECURITIES - 100.0%
               (Cost $4,389,042,867)(a)                                    $7,759,059,680
                                                                           ==============
</TABLE>

    * Non-income producing security.

    + Investment held by the Fund representing 5% or more of the
      outstanding voting stock of such company.

    (a) At June 30, 2000, the net unrealized gain on investments based on
        cost for federal income tax purposes of $4,389,672,502 was as
        follows:

<TABLE>
<S>                                                           <C>
          Aggregate gross unrealized gain for all
          investments in which there is an excess of value
          over tax cost                                       $3,593,146,392
          Aggregate gross unrealized loss for all
          investments in which there is an excess of tax
          cost over value                                     $ (223,759,214)
                                                              --------------
          Net unrealized gain                                 $3,369,387,178
                                                              ==============
</TABLE>

    Purchases and sales of securities (excluding temporary cash
    investments) for the six months ended June 30, 2000 aggregated
    $861,733,899 and $753,035,010, respectively.

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

 <PAGE>
     PIONEER FUND

--------------------------------------------------------------------------------
     BALANCE SHEET 6/30/00 (unaudited)
-------------------------------------------------------------------------------

<TABLE>
  <S>                                                           <C>
  ASSETS:
     Investment in securities, at value (including temporary
       cash investment of $36,912,000) (cost $4,389,042,867)    $7,759,059,680
     Cash                                                                  293
     Receivables -
        Fund shares sold                                            27,340,160
        Dividends, interest and foreign taxes withheld               6,247,526
     Other                                                             423,066
                                                                --------------
           Total assets                                         $7,793,070,725
                                                                --------------
  LIABILITIES:
     Payables -
        Investment securities purchased                         $   14,208,693
        Fund shares repurchased                                      8,100,858
     Due to affiliates                                               7,980,084
     Accrued expenses                                                  418,114
                                                                --------------
           Total liabilities                                    $   30,707,749
                                                                --------------
  NET ASSETS:
     Paid-in capital                                            $3,908,149,776
     Accumulated undistributed net investment income                   295,518
     Accumulated undistributed net realized gain on
       investments and foreign currency transactions               483,902,103
     Net unrealized gain on investments                          3,370,016,813
     Net unrealized loss on assets and liabilities denominated
       in foreign currencies                                            (1,234)
                                                                --------------
           Total net assets                                     $7,762,362,976
                                                                ==============
  NET ASSET VALUE PER SHARE:
  (Unlimited number of shares authorized)
     Class A (based on $6,894,249,997/139,719,111 shares)       $        49.34
                                                                ==============
     Class B (based on $659,548,210/13,505,073 shares)          $        48.84
                                                                ==============
     Class C (based on $198,103,877/4,097,753 shares)           $        48.34
                                                                ==============
     Class Y (based on $10,460,892/211,874 shares)              $        49.37
                                                                ==============
  MAXIMUM OFFERING PRICE:
     Class A                                                    $        52.35
                                                                ==============
</TABLE>

   The accompanying notes are an integral part of these financial statements. 19

 <PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     STATEMENT OPERATIONS (unaudited)
-------------------------------------------------------------------------------

     FOR THE SIX MONTHS ENDED 6/30/00

<TABLE>
 <S>                                                     <C>                 <C>
 INVESTMENT INCOME:
    Dividends (net of foreign taxes withheld of
      $332,473)                                          $  53,655,313
    Interest                                                 1,598,384
                                                         -------------
          Total investment income                                            $  55,253,697
                                                                             -------------
 EXPENSES:
    Management fees
       Basic fee                                         $  22,161,244
       Performance adjustment                                2,644,299
    Transfer agent fees
       Class A                                               6,838,544
       Class B                                                 904,372
       Class C                                                 219,942
       Class Y                                                     201
    Distribution fees
       Class A                                               6,904,179
       Class B                                               3,028,731
       Class C                                                 861,622
    Administrative fees                                        400,164
    Custodian fees                                             132,066
    Registration fees                                          196,244
    Professional fees                                           75,772
    Printing                                                   233,704
    Fees and expenses of nonaffiliated trustees                 50,764
    Miscellaneous                                               49,144
                                                         -------------
          Total expenses                                                     $  44,700,992
          Less fees paid indirectly                                               (628,733)
                                                                             -------------
          Net expenses                                                       $  44,072,259
                                                                             -------------
             Net investment income                                           $  11,181,438
                                                                             -------------
 REALIZED AND UNREALIZED GAIN (LOSS) ON INVESTMENTS AND FOREIGN CURRENCY TRANSACTIONS:
    Net realized gain (loss) from:
       Investments                                       $ 484,532,747
       Other assets and liabilities denominated in
         foreign currencies                                     (1,009)      $ 484,531,738
                                                         -------------       -------------
    Change in net unrealized gain or loss from:
       Investments                                       $(215,081,735)
       Other assets and liabilities denominated in
         foreign currencies                                      1,177       $(215,080,558)
                                                         -------------       -------------
             Net gain on investments                                         $ 269,451,180
                                                                             -------------
             Net increase in net assets resulting
               from operations                                               $ 280,632,618
                                                                             =============
</TABLE>

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

 <PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
    STATEMENTS OF CHANGES IN NET ASSETS
-------------------------------------------------------------------------------

     FOR THE SIX MONTHS ENDED 6/30/00 AND THE YEAR ENDED 12/31/99

<TABLE>
<CAPTION>
                                                                SIX MONTHS
                                                                  ENDED
                                                                 6/30/00         YEAR ENDED
FROM OPERATIONS:                                               (UNAUDITED)        12/31/99
 <S>                                                          <C>              <C>
 Net investment income                                        $   11,181,438   $   21,585,530
 Net realized gain on investments                                484,531,738      325,811,540
 Change in net unrealized gain or loss on investments and
  foreign currency transactions                                 (215,080,558)     609,475,052
                                                              --------------   --------------
       Net increase in net assets resulting
          from operations                                     $  280,632,618   $  956,872,122
                                                              --------------   --------------
 DISTRIBUTIONS TO SHAREHOLDERS FROM:
 Net investment income
       Class A ($0.08 and $0.17 per share, respectively)      $  (10,849,179)  $  (22,551,949)
       Class Y ($0.16 and $0.24 per share, respectively)             (36,741)         (58,721)
 Net realized gain:
       Class A ($0.00 and $2.22 per share, respectively)                  --     (296,872,046)
       Class B ($0.00 and $2.22 per share, respectively)                  --      (25,951,539)
       Class C ($0.00 and $2.22 per share, respectively)                  --       (6,757,201)
       Class Y ($0.00 and $2.22 per share, respectively)                  --         (546,104)
                                                              --------------   --------------
             Total distributions to shareholders              $  (10,885,920)  $ (352,737,560)
                                                              --------------   --------------
 FROM FUND SHARE TRANSACTIONS:
 Net proceeds from sale of shares                             $  819,826,023   $1,652,707,636
 Reinvestment of distributions                                     9,923,426      317,373,755
 Cost of shares repurchased                                     (737,495,255)    (881,798,971)
                                                              --------------   --------------
    Net increase in net assets resulting from fund share
      transactions                                            $   92,254,194   $1,088,282,420
                                                              --------------   --------------
    Net increase in net assets                                $  362,000,892   $1,692,416,982
 NET ASSETS:
 Beginning of period                                           7,400,362,084    5,707,945,102
                                                              --------------   --------------
 End of period (including accumulated undistributed net
  investment income of $295,518 and $0, respectively)         $7,762,362,976   $7,400,362,084
                                                              ==============   ==============
</TABLE>

   The accompanying notes are an integral part of these financial statements. 21
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     STATEMENTS OF CHANGES IN NET ASSETS                          (continued)
-------------------------------------------------------------------------------

     FOR THE SIX MONTHS ENDED 6/30/00 AND THE YEAR ENDED 12/31/99

<TABLE>
<CAPTION>
                                   '00 SHARES      '00 AMOUNT
 CLASS A                           (UNAUDITED)     (UNAUDITED)    '99 SHARES      '99 AMOUNT
<S>                                <C>           <C>              <C>           <C>
 Shares sold                       12,661,604    $  599,461,028   25,703,151    $ 1,175,889,963
 Reinvestment of distributions        200,773         9,887,328    6,247,722        289,977,993
 Less shares repurchased          (12,609,738)     (595,418,343) (16,931,541)      (775,592,354)
                                  ------------   --------------  ------------   ---------------
    Net increase                      252,639    $   13,930,013   15,019,332    $   690,275,602
                                  ============   ==============  ============   ===============
 CLASS B
 Shares sold                        3,252,463    $  152,612,785    7,621,706    $   346,726,886
 Reinvestment of distributions             --                --      485,474         22,383,744
 Less shares repurchased           (2,303,132)     (107,119,978)  (1,842,368)       (84,273,185)
                                  ------------   --------------  ------------   ---------------
    Net increase                      949,331    $   45,492,807    6,264,812    $   284,837,445
                                  ============   ==============  ============   ===============
 CLASS C
 Shares sold                        1,429,194    $   66,400,933    2,613,225    $   117,740,196
 Reinvestment of distributions             --                --       96,697          4,413,373
 Less shares repurchased             (683,744)      (31,320,343)    (465,754)       (21,021,787)
                                  ------------   --------------  ------------   ---------------
    Net increase                      745,450    $   35,080,590    2,244,168    $   101,131,782
                                  ============   ==============  ============   ===============
 CLASS Y*
 Shares sold                           28,600    $    1,351,277      265,515    $    12,350,591
 Reinvestment of distributions            733            36,098       12,888            598,645
 Less shares repurchased              (76,772)       (3,636,591)     (19,090)          (911,645)
                                  ------------   --------------  ------------   ---------------
    Net increase (decrease)           (47,439)   $   (2,249,216)     259,313    $    12,037,591
                                  ============   ==============  ============   ===============
</TABLE>

* Class Y shares were first publicly offered on May 6, 1999.

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

<PAGE>
PIONEER FUND

-------------------------------------------------------------------------------
FINANCIAL HIGHLIGHTS 6/30/00
-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                                  SIX
                                                MONTHS
                                                 ENDED
                                                6/30/00      YEAR ENDED    YEAR ENDED    YEAR ENDED    YEAR ENDED    YEAR ENDED
CLASS A                                       (UNAUDITED)     12/31/99      12/31/98      12/31/97      12/31/96      12/31/95
<S>                                           <C>            <C>           <C>           <C>           <C>           <C>
Net asset value, beginning of period          $    47.60     $   43.30     $   34.95     $   26.89     $   24.36     $    21.32
                                              ----------     ----------    ----------    ----------    ----------    ----------
Increase from investment operations:
   Net investment income                      $     0.10     $    0.18     $    0.21     $    0.30     $    0.37     $     0.49
   Net realized and unrealized gain on
     investments and foreign currency
     transactions                                   1.72          6.51          9.84          9.97          4.35           5.13
                                              ----------     ----------    ----------    ----------    ----------    ----------
      Net increase from investment
        operations                            $     1.82     $    6.69     $   10.05     $   10.27     $    4.72     $     5.62
Distributions to shareholders:
   Net investment income                           (0.08)        (0.17)        (0.21)        (0.31)        (0.37)         (0.49)
   Net realized gain                                  --         (2.22)        (1.49)        (1.90)        (1.82)         (2.09)
                                              ----------     ----------    ----------    ----------    ----------    ----------
Net increase in net asset value               $     1.74     $    4.30     $    8.35     $    8.06     $    2.53     $     3.04
                                              ----------     ----------    ----------    ----------    ----------    ----------
Net asset value, end of period                $    49.34     $   47.60     $   43.30     $   34.95     $   26.89     $    24.36
                                              ==========     ==========    ==========    ==========    ==========    ==========
Total return*                                       3.82%        15.63%        29.00%        38.47%        19.70%         26.64%
Ratio of net expenses to average net assets+        1.12%**       1.10%         1.09%         1.03%         1.01%          0.95%
Ratio of net investment income to average
  net assets+                                       0.38%**       0.39%         0.52%         0.93%         1.40%          2.01%
Portfolio turnover rate                               21%**         10%            9%           17%           25%            31%
Net assets, end of period (in thousands)      $6,894,250     $6,638,130    $5,388,761    $3,991,726    $2,896,670    $2,466,098
Ratios assuming reduction for fees paid
  indirectly:
   Net expenses                                     1.10%**       1.09%         1.08%         1.02%         0.99%          0.94%
   Net investment income                            0.40%**       0.40%         0.53%         0.94%         1.42%          2.02%
</TABLE>

<TABLE>
<S>  <C>
*    Assumes initial investment at net asset value at the
     beginning of each period, reinvestment of all distributions,
     the complete redemption of the investment at net asset value
     at the end of each period, and no sales charges. Total
     return would be reduced if sales charges were taken into
     account.
**   Annualized.
+    Ratios assuming no reduction for fees paid indirectly.
</TABLE>

  The accompanying notes are an integral part of these financial statements.  23

 <PAGE>
PIONEER FUND

-------------------------------------------------------------------------------
FINANCIAL HIGHLIGHTS 6/30/00
-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                                   SIX MONTHS ENDED
                                                       6/30/00         YEAR ENDED    YEAR ENDED    YEAR ENDED      7/1/96 TO
CLASS B                                              (UNAUDITED)        12/31/99      12/31/98     12/31/97(a)    12/31/96(a)
<S>                                                <C>                 <C>           <C>           <C>            <C>
Net asset value, beginning of period                   $  47.24         $  43.20      $  35.01       $ 27.02      $    26.40
                                                       --------         --------      --------       -------      ----------
Increase (decrease) from investment operations:
   Net investment income (loss)                        $  (0.10)        $  (0.12)     $  (0.04)      $  0.01      $     0.07
   Net realized and unrealized gain on
     investments and foreign currency
     transactions                                          1.70             6.38          9.72          9.99            2.50
                                                       --------         --------      --------       -------      ----------
         Net increase from investment
           operations                                  $   1.60         $   6.26      $   9.68       $ 10.00      $     2.57
Distributions to shareholders:
   Net investment income                                     --               --            --         (0.11)          (0.07)
   In excess of net investment income                        --               --            --            --           (0.06)
   Net realized gain                                         --            (2.22)        (1.49)        (1.90)          (1.82)
                                                       --------         --------      --------       -------      ----------
Net increase in net asset value                        $   1.60         $   4.04      $   8.19       $  7.99      $     0.62
                                                       --------         --------      --------       -------      ----------
Net asset value, end of period                         $  48.84         $  47.24      $  43.20       $ 35.01      $    27.02
                                                       ========         ========      ========       =======      ==========
Total return*                                              3.39%           14.63%        27.82%        37.19%           9.92%
Ratio of net expenses to average net assets+               2.00%**          1.98%         1.99%         1.92%           1.82%**
Ratio of net investment income (loss) to
  average net assets+                                     (0.51)%**        (0.50)%       (0.41)%       (0.02)%          0.46%**
Portfolio turnover rate                                      21%**            10%            9%           17%             25%
Net assets, end of period (in thousands)               $659,548         $593,145      $271,796       $53,010      $    8,940
Ratios assuming reduction for fees paid
  indirectly:
   Net expenses                                            1.98%**          1.96%         1.96%         1.88%           1.80%**
   Net investment income (loss)                           (0.49)%**        (0.48)%       (0.38)%        0.02%           0.48%**
</TABLE>

<TABLE>
<S>  <C>
(a)  The per share data presented above is based upon the average
     shares outstanding for the period presented.
*    Assumes initial investment at net asset value at the
     beginning of each period, reinvestment of all distributions,
     the complete redemption of the investment at net asset value
     at the end of each period, and no sales charges. Total
     return would be reduced if sales charges were taken into
     account.
**   Annualized.
+    Ratios assuming no reduction for fees paid indirectly.
</TABLE>

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

<PAGE>

PIONEER FUND

-------------------------------------------------------------------------------
FINANCIAL HIGHLIGHTS 6/30/00
-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                                         SIX MONTHS
                                                            ENDED
                                                           6/30/00      YEAR ENDED    YEAR ENDED    YEAR ENDED      7/1/96 TO
CLASS C                                                  (UNAUDITED)     12/31/99      12/31/98     12/31/97(a)    12/31/96(a)
<S>                                                      <C>            <C>           <C>           <C>            <C>
Net asset value, beginning of period                      $  46.76       $  42.76      $  34.66       $ 26.74        $26.40
                                                          --------       --------      --------       -------        ------
Increase (decrease) from investment operations:
   Net investment income (loss)                           $  (0.07)      $  (0.09)     $  (0.04)      $  0.02        $ 0.03
   Net realized and unrealized gain on investments and
     foreign currency transactions                            1.65           6.31          9.63          9.89          2.23
                                                          --------       --------      --------       -------        ------
      Net increase from investment operations             $   1.58       $   6.22      $   9.59       $  9.91        $ 2.26
Distributions to shareholders:
   Net investment income                                        --             --            --         (0.09)        (0.03)
   In excess of net investment income                           --             --            --            --         (0.07)
   Net realized gain                                            --          (2.22)        (1.49)        (1.90)        (1.82)
                                                          --------       --------      --------       -------        ------
Net increase in net asset value                           $   1.58       $   4.00      $   8.10       $  7.92        $ 0.34
                                                          --------       --------      --------       -------        ------
Net asset value, end of period                            $  48.34       $  46.76      $  42.76       $ 34.66        $26.74
                                                          ========       ========      ========       =======        ======
Total return*                                                 3.38%         14.68%        27.85%        37.25%         8.74%
Ratio of net expenses to average net assets+                  1.95%**        1.96%         1.97%         1.87%         2.11%**
Ratio of net investment income (loss) to average net
  assets+                                                    (0.47)%**      (0.49)%       (0.39)%        0.02%         0.20%**
Portfolio turnover rate                                         21%**          10%            9%           17%           25%
Net assets, end of period (in thousands)                  $198,104       $156,739      $ 47,389       $ 8,261        $1,831
Ratios assuming reduction for fees paid indirectly:
   Net expenses                                               1.93%**        1.93%         1.93%         1.83%         2.08%**
   Net investment income (loss)                              (0.45)%**      (0.46)%       (0.35)%        0.06%         0.23%**
</TABLE>

<TABLE>
<S>  <C>
(a)  The per share data presented above is based upon the average
     shares outstanding for the period presented.
*    Assumes initial investment at net asset value at the
     beginning of each period, reinvestment of all distributions,
     the complete redemption of the investment at net asset value
     at the end of each period, and no sales charges. Total
     return would be reduced if sales charges were taken into
     account.
**   Annualized.
+    Ratios assuming no reduction for fees paid indirectly.
</TABLE>

  The accompanying notes are an integral part of these financial statements.  25

<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     FINANCIAL HIGHLIGHTS 6/30/00
-------------------------------------------------------------------------------

<TABLE>
<CAPTION>
                                             SIX MONTHS ENDED
                                                 6/30/00         5/6/99 TO
 CLASS Y                                       (UNAUDITED)        12/31/99
 <S>                                         <C>                 <C>
 Net asset value, beginning of period            $ 47.62          $ 46.44
                                                 -------          -------
 Increase from investment operations:
    Net investment income                        $  0.18          $  0.23
    Net realized and unrealized gain on
      investments and foreign currency
      transactions                                  1.73             3.41
                                                 -------          -------
          Net increase from investment
             operations                          $  1.91          $  3.64
 Distributions to shareholders:
    Net investment income                          (0.16)           (0.24)
    Net realized gain                                 --            (2.22)
                                                 -------          -------
 Net increase in net asset value                 $  1.75          $  1.18
                                                 -------          -------
 Net asset value, end of period                  $ 49.37          $ 47.62
                                                 =======          =======
 Total return*                                      4.02%            8.00%
 Ratio of net expenses to average net
    assets+                                         0.71%**          0.72%**
 Ratio of net investment income to average
    net assets+                                     0.79%**          0.73%**
 Portfolio turnover rate                              21%**            10%
 Net assets, end of period (in thousands)        $10,461          $12,348
 Ratios assuming reduction for fees paid
    indirectly:
    Net expenses                                    0.70%**          0.71%**
    Net investment income                           0.80%**          0.74%**
</TABLE>

<TABLE>
 <S>  <C>
 *    Assumes initial investment at net asset value at the
      beginning of each period, reinvestment of all distributions,
      and the complete redemption of the investment at net asset
      value at the end of each period.
 **   Annualized.
 +    Ratios assuming no reduction for fees paid indirectly.
</TABLE>

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

 <PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     NOTES TO FINANCIAL STATEMENTS 6/30/00 (unaudited)
-------------------------------------------------------------------------------

     1.  ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES

     Pioneer Fund (the Fund) is a Delaware business trust registered under
     the Investment Company Act of 1940 as a diversified, open-end
     management investment company. The investment objective of the Fund is
     reasonable income and growth of capital.

     The Fund offers four classes of shares -- Class A, Class B, Class C
     and Class Y shares. Each class of shares represents an interest in the
     same portfolio of investments of the Fund and has equal rights to
     voting, redemptions, dividends and liquidation, except that the level
     of transfer agent and distribution fees may differ among classes.
     Class A, Class B and Class C shareholders have exclusive voting rights
     with respect to the distribution plan for each class. There is no
     distribution plan for Class Y shares.

     The Fund's financial statements have been prepared in conformity with
     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 revenues and
     expenses during the reporting periods. Actual results could differ
     from those estimates. The following is a summary of significant
     accounting policies consistently followed by the Fund, which are in
     conformity with those generally accepted in the investment company
     industry:

     A.  SECURITY VALUATION

         Security transactions are recorded as of trade date. The net asset
         value is computed once daily, on each day the New York Stock
         Exchange is open, as of the close of regular trading on the
         Exchange. In computing the net asset value, securities are valued
         at the last sale price on the principal exchange where they are
         traded. Securities that have not traded on the date of valuation,
         or securities for which sale prices are not generally reported,
         are valued at the mean between the last bid and asked prices.
         Securities for which market quotations are not readily available
         are valued at their fair values as determined by, or under the
         direction of, the Board of Trustees. Dividend income is recorded
         on the ex-dividend date and interest income, including interest on
         income bearing cash accounts, is recorded

                                                                              27
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     NOTES TO FINANCIAL STATEMENTS 6/30/00 (unaudited)            (continued)
-------------------------------------------------------------------------------

         on the accrual basis. Temporary cash investments are valued at
         amortized cost.

         Gains and losses on sales of investments are calculated on the
         identified cost method for both financial reporting and federal
         income tax purposes. It is the Fund's practice to first select for
         sale those securities that have the highest cost and also qualify
         for long-term capital gain or loss treatment for tax purposes.

     B. FOREIGN CURRENCY TRANSLATION

        The books and records of the Fund are maintained in U.S. dollars.
        Amounts denominated in foreign currencies are translated into U.S.
        dollars using current exchange rates.

        Net realized gains and losses on foreign currency transactions
        represent, among other things, the net realized gains and losses on
        foreign currency contracts, disposition of foreign currencies and
        the difference between the amount of income accrued and the U.S.
        dollar actually received. Further, the effects of changes in
        foreign currency exchange rates on investments are not segregated
        in the statement of operations from the effects of changes in
        market price of those securities but are included with the net
        realized and unrealized gain or loss on investments.

     C. 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 shareholders. Therefore, no federal
        income tax provision is required.

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

     D. FUND SHARES

        The Fund records sales and repurchases of its shares as of trade
        date. Pioneer Funds Distributor, Inc. (PFD), the principal

  28
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

        underwriter for the Fund and an indirect subsidiary of The Pioneer
        Group, Inc. (PGI), earned $651,276 in underwriting commissions on
        the sale of Fund shares during the six months ended June 30, 2000.

     E. CLASS ALLOCATIONS

        Distribution fees are calculated based on the average daily net
        asset values attributable to Class A, Class B and Class C shares of
        the Fund, respectively. Class Y shares are not subject to a
        distribution plan. Shareholders of each class share all expenses
        and fees paid to the transfer agent, Pioneering Services
        Corporation (PSC), for their services, which are allocated based on
        the number of accounts in each class and the ratable allocation of
        related out-of-pocket expense (see Note 3). Income, common expenses
        and realized and unrealized gains and losses are calculated at the
        Fund level and allocated daily to each class of shares based on the
        respective percentage of adjusted net assets at the beginning of
        the day.

        Distributions to shareholders are recorded as of the ex-dividend
        date. Distributions paid by the Fund with respect to each class of
        shares are calculated in the same manner, at the same time, and in
        the same amount, except that Class A, Class B, Class C and Class Y
        shares can bear different transfer agent and distribution fees.

     2. MANAGEMENT AGREEMENT

     Pioneer Investment Management, Inc. (PIM), the Fund's investment
     adviser, manages the Fund's portfolio and is a wholly owned subsidiary
     of PGI. PIM receives a basic fee that is calculated at the annual rate
     of 0.60% of the Fund's average daily net assets. The basic fee is
     subject to a performance adjustment to a maximum of +/-0.10% based on
     the Fund's investment performance as compared with the Lipper Growth &
     Income Funds Index. For the six months ended June 30, 2000, the
     aggregate performance adjustment resulted in an increase to management
     fees of $2,644,299, resulting in a management fee equivalent to 0.67%
     of the Fund's average daily net assets.

     In addition, under the management and administration agreements,
     certain other services and costs, including accounting, regulatory

                                                                              29
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------
     NOTES TO FINANCIAL STATEMENTS 6/30/00 (unaudited)            (continued)
-------------------------------------------------------------------------------

     reporting and insurance premiums, are paid by the Fund. At June 30,
     2000, $4,428,995 was payable to PIM related to management fees,
     administrative fees and certain other services.

     3. TRANSFER AGENT

     PSC, a wholly owned subsidiary of PGI, provides substantially all
     transfer agent and shareholder services to the Fund at negotiated
     rates. Included in due to affiliates is $1,636,736 in transfer agent
     fees payable to PSC at June 30, 2000.

     4. DISTRIBUTION PLANS

     The Fund adopted a Plan of Distribution with respect to Class A, Class
     B and Class C shares (Class A Plan, Class B Plan, and Class C Plan) in
     accordance with Rule 12b-1 of the Investment Company Act of 1940.
     Pursuant to the Class A Plan, the Fund pays PFD a service fee of up to
     0.25% of the average daily net assets attributable to Class A shares
     in reimbursement of its actual expenditures to finance activities
     primarily intended to result in the sale of Class A shares. On
     qualifying investments made prior to August 19, 1991, the Class A Plan
     provides for reimbursement of such expenditures in an amount not to
     exceed 0.15%. Pursuant to the Class B Plan and the Class C Plan, the
     Fund pays PFD 1.00% of the average daily net assets attributable to
     each class of shares. The fee consists of a 0.25% service fee and a
     0.75% distribution fee paid as compensation for personal services
     and/or account maintenance services or distribution services with
     regard to Class B and Class C shares. Included in due to affiliates is
     $1,914,353 in distribution fees payable to PFD at June 30, 2000.

     In addition, redemptions of each class of shares (except Class Y
     shares) may be subject to a contingent deferred sales charge (CDSC). A
     CDSC of 1.00% may be imposed on redemptions of certain net asset value
     purchases of Class A shares within one year of purchase. Class B
     shares that are redeemed within six years of purchase are subject to a
     CDSC at declining rates beginning at 4.00%, based on the lower of cost
     or market value of shares being redeemed. Redemptions of Class C
     shares within one year of purchase are subject to a CDSC of 1.00%.
     Proceeds from the CDSCs are paid to PFD. For the six months ended June
     30, 2000, CDSCs in the amount of $1,392,892 were paid to PFD.

  30
<PAGE>
     PIONEER FUND

-------------------------------------------------------------------------------

-------------------------------------------------------------------------------

     5. EXPENSE OFFSETS

     The Fund has entered into certain directed brokerage and expense
     offset arrangements resulting in a reduction in the Fund's total
     expenses. For the six months ended June 30, 2000, the Fund's expenses
     were reduced by $628,733 under such arrangements.

     6. LINE OF CREDIT FACILITY

     The Fund, along with certain other funds in the Pioneer Family of
     Funds (the Funds), collectively participate in a $50 million
     committed, unsecured revolving line of credit facility. Borrowings are
     used solely for temporary or emergency purposes. The Fund may borrow
     up to the lesser of $50 million or the limits set by its prospectus
     for borrowings. Interest on collective borrowings of up to $25 million
     is payable at the Federal Funds Rate plus 3/8% on an annualized basis,
     or at the Federal Funds Rate plus 1/2% if the borrowing exceeds $25
     million at any one time. The Funds pay an annual commitment fee for
     this facility. The commitment fee is allocated among such Funds based
     on their respective borrowing limits. For the six months ended June
     30, 2000, the Fund had no borrowings under this agreement.

     7. AFFILIATED COMPANIES

     The Fund's investments in certain companies exceed 5% of the
     outstanding voting stock. Such companies are deemed affiliates of the
     Fund for financial reporting purposes. The following summarizes
     transactions with affiliates of the Fund as of June 30, 2000:

-------------------------------------------------------------------------------
                                                   DIVIDEND
AFFILIATES                   PURCHASES    SALES     INCOME     VALUE

John Wiley & Sons, Inc.          -          -      $124,505   $78,624,000

-------------------------------------------------------------------------------

                                                                              31

 <PAGE>
--------------------------------------------------------------------------------
     RETIREMENT PLANS FROM PIONEER
-------------------------------------------------------------------------------

    Pioneer has a long history of helping people work toward their
    retirement goals, offering plans suited to the individual investor and
    businesses of all sizes. For more information on Pioneer retirement
    plans, contact your investment professional, or call Pioneer at
    1-800-622-0176

    INDIVIDUAL RETIREMENT ACCOUNT (IRA)
    An IRA is a tax-favored account that allows anyone under age 70 with
    earned income to contribute up to $2,000 annually. Spouses may
    contribute up to $2,000 annually into a separate IRA, for a total of
    $4,000 per year for a married couple. Earnings are tax-deferred, and
    contributions may be tax-deductible.

    ROTH IRA
    The Roth IRA came about as part of the Taxpayer Relief Act of 1997 and
    became available to investors in 1998. Contributions, up to $2,000 a
    year, are not tax-deductible, but earnings are tax-free for qualified
    withdrawals.

    401(K) PLAN
    The traditional 401(k) plan allows employees to make pre-tax
    contributions through payroll deduction, up to $10,500 per year or 25%
    of pay, whichever is less. Employers may contribute.

    SIMPLE (SAVINGS INCENTIVE MATCH PLAN FOR EMPLOYEES)
    IRA PLAN
    Businesses with 100 or fewer eligible employees can establish either
    plan; it resembles the traditional 401(k), but has no administration
    costs. Employees can make pre-tax contributions of up to $6,000 per
    year, and an employer contribution is required.

    Most retirement plan withdrawals must meet specific conditions to avoid
                                   penalties.
  32
<PAGE>
-------------------------------------------------------------------------------

--------------------------------------------------------------------------------

    403(B) PLAN
    Also known as a Tax-Sheltered Account (TSA), a 403(b) plan is
    available only to employees of public schools, not-for-profit
    hospitals and certain other tax-exempt organizations. A 403(b) plan
    lets employees set aside a portion of their salary, before taxes,
    through payroll deduction.

    SIMPLIFIED EMPLOYEE PENSION PLAN (SEP)
    SEPs let self-employed people and small-business owners make tax-
    deductible contributions of up to 15% of their income. Generally,
    employers must contribute the same percentage of pay for themselves
    and any eligible employees; contributions are made directly to
    employees' IRAs. SEPs are easy to administer and can be an especially
    good choice for firms with few or no employees.

    PROFIT SHARING PLAN
    Profit sharing plans offer companies considerable flexibility,
    allowing them to decide each year whether a contribution will be made
    and how much, up to 15% of each participant's pay. These plans can
    include provisions for loans and vesting schedules.

    AGE-WEIGHTED PROFIT SHARING PLAN
    Like traditional profit sharing plans, employer contributions are
    flexible, but age-weighted plans allocate contributions based on both
    age and salary. Age-weighted plans are designed for employers who want
    to maximize their own contributions while keeping contributions to
    employees affordable.

    MONEY PURCHASE PENSION PLAN (MPP)
    Money purchase plans are similar to profit-sharing plans, but allow
    for higher annual contributions - up to 25% of pay. MPPs aren't as
    flexible as profit sharing plans; a fixed percentage of pay must be
    contributed each year, determined when the plan is established.
    Businesses often set up both MPPs and profit sharing plans.

    Most retirement plan withdrawals must meet specific conditions to avoid
                                   penalties.
                                                                              33

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     PROGRAMS AND SERVICES FOR PIONEER SHAREOWNERS
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     Your investment professional can give you additional information on
     Pioneer's programs and services. If you want to order literature on
     any of the following items directly, simply call Pioneer at
     1-800-225-6292.

     FACTFONE(SM)
     Our automated account information service, available to you 24 hours
     a day, seven days a week. FactFone gives you a quick and easy way to
     check fund share prices, yields, dividends and distributions, as well
     as information about your own account. Simply call 1-800-225-4321.
     For specific account information, have your 13-digit account number
     and four-digit personal identification number at hand.

     90-DAY REINSTATEMENT PRIVILEGE (FOR CLASS A SHARES)
     Enables you to reinvest all or a portion of the money you redeem from
     your Pioneer account - without paying a sales charge - within 90 days
     of your redemption. You have the choice of investing in any Pioneer
     fund, as long as you meet its minimum investment requirement.

     INVESTOMATIC PLAN
     An easy and convenient way for you to invest on a regular basis. All
     you need to do is authorize a set amount of money to be moved out of
     your bank account into the Pioneer fund of your choice. Investomatic
     also allows you to change the dollar amount, frequency and investment
     date right over the phone. By putting aside affordable amounts of
     money regularly, you can build a long-term investment - without
     sacrificing your current standard of living.

     PAYROLL INVESTMENT PROGRAM (PIP)
     Lets you invest in a Pioneer fund directly through your paycheck. All
     that's involved is for your employer to fill out an authorization
     form allowing Pioneer to deduct from participating employees'
     paychecks. You specify the dollar amount you want to invest into the
     Pioneer fund(s) of your choice.

  34
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     AUTOMATIC EXCHANGE PROGRAM
     A simple way to move money from one Pioneer fund to another over a
     period of time. Just invest a lump sum in one fund, and select the
     other Pioneer funds you wish to invest in. You choose the amounts and
     dates for Pioneer to sell shares of your original fund and use the
     proceeds to buy shares of the other funds you have chosen. Over time,
     your investment will be shifted out of the original fund. (Automatic
     Exchange is available for originating accounts with a balance of
     $5,000 or more.)

     DIRECTED DIVIDENDS
     Lets you invest cash dividends from one Pioneer fund to an account in
     another Pioneer fund with no sales charge or fee. Simply fill out the
     applicable information on a Pioneer Account Options Form. (This
     program is available for dividend payments only; capital gains
     distributions are not eligible at this time.)

     DIRECT DEPOSIT
     Lets you move money into your bank account using electronic funds
     transfer (EFT). EFT moves your money faster than you would receive a
     check, eliminates unnecessary paper and mail, and avoids lost checks.
     Simply fill out a Pioneer Direct Deposit Form, giving your
     instructions.

     SYSTEMATIC WITHDRAWAL PLAN (SWP)
     Lets you establish automatic withdrawals from your account at set
     intervals. You decide the frequency and the day of the month you
     want. Pioneer will send the proceeds by check to the address you
     designate, or electronically to your bank account. You also can
     authorize Pioneer to make the redemptions payable to someone else.
     (SWPs are available for accounts with a value of $10,000 or more.)

                                                                              35

<PAGE>
     PIONEER FUND

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     TRUSTEES, OFFICERS AND SERVICE PROVIDERS
--------------------------------------------------------------------------------

<TABLE>
      <S>                                <C>
      TRUSTEES                           OFFICERS
      John F. Cogan, Jr.                 John F. Cogan, Jr., Chairman and
      Mary K. Bush                       President
      Richard H. Egdahl, M.D.            David D. Tripple, Executive Vice
      Margaret B.W. Graham               President
      Marguerite A. Piret                John A. Carey, Vice President
      David D. Tripple                   Eric W. Reckard, Treasurer
      Stephen K. West                    Joseph P. Barri, Secretary
      John Winthrop
</TABLE>

     INVESTMENT ADVISER
     Pioneer Investment Management, Inc.

     CUSTODIAN
     Brown Brothers Harriman & Co.

     PRINCIPAL UNDERWRITER
     Pioneer Funds Distributor, Inc.

     LEGAL COUNSEL
     Hale and Dorr LLP

     SHAREOWNER SERVICES AND TRANSFER AGENT
     Pioneering Services Corporation

  36
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                            THIS PAGE FOR YOUR NOTES

                                                                              37

<PAGE>
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    HOW TO CONTACT PIONEER
-------------------------------------------------------------------------------

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

   CALL US FOR:

   ACCOUNT INFORMATION, including existing accounts,
   new accounts, prospectuses, applications
   and service forms                                       1-800-225-6292

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

   RETIREMENT PLANS INFORMATION                            1-800-622-0176

   TELECOMMUNICATIONS DEVICE FOR THE DEAF (TDD)            1-800-225-1997

   WRITE TO US:

   Pioneering Services Corporation
   60 State Street
   Boston, Massachusetts 02109

   OUR TOLL-FREE FAX                                       1-800-225-4240

   OUR INTERNET E-MAIL ADDRESS                       ask.pioneer@piog.com

   (for general questions about Pioneer only)

   VISIT OUR WEBSITE:                                www.pioneerfunds.com

   THIS REPORT MUST BE PRECEDED OR ACCOMPANIED BY A CURRENT
   FUND PROSPECTUS.

<TABLE>
    <S>                   <C>                                   <C>
   [Pioneer Logo]         PIONEER INVESTMENT MANAGEMENT, INC.   8639-00-0800
                          60 STATE STREET                       (c) PIONEER FUNDS DISTRIBUTOR, INC.
                          BOSTON, MASSACHUSETTS 02109           RECYCLE LOGO PRINTED ON
                          www.pioneerfunds.com                  RECYCLED PAPER
</TABLE>