<PAGE>

                                 UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            WASHINGTON, D.C. 20549

                                  FORM 10-Q/A

               QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(D)
                    OF THE SECURITIES EXCHANGE ACT OF 1934

                   FOR THE THREE MONTHS ENDED March 31, 2001
                          COMMISSION FILE NO. 0-30889

                          HARBOR GLOBAL COMPANY LTD.
            (exact name of registrant as specified in its charter)

                     BERMUDA                             52-2256071
         (STATE OR OTHER JURISDICTION OF              (I.R.S. EMPLOYER
         INCORPORATION OR ORGANIZATION)             IDENTIFICATION NO.)

                          ONE FANEUIL HALL MARKETPLACE
                   4TH FLOOR                             02109-1820
             BOSTON, MASSACHUSETTS                       (ZIP CODE)
                    (ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)

                                (617) 878-1600
             (REGISTRANT'S TELEPHONE NUMBER, INCLUDING AREA CODE)

                                  NO CHANGES
  (Former name, former address and former fiscal year, if changes since last
                                    report)

Indicate by check mark whether the Registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding twelve months (or for such shorter period that the Registrant was
required to file such reports), and (2) has been subject to such filing
requirements for the past 90 days. Yes [X] No []

As of May 25, 2001, the Registrant had 5,643,311 common shares, par value $.0025
per share, issued and outstanding.
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PART II -- OTHER INFORMATION

ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K

(a) Exhibits: The Exhibit Index immediately precedes the Exhibits filed herein
    and is incorporated by reference.

(b) Reports on Form 8-K:

On April 11, 2001, the Company filed a Current Report on Form 8-K in connection
with the execution by Harbor Far East Exploration of a definitive agreement to
sell its Russian gold exploration business and the execution by PREA of
definitive agreements to purchase all outstanding shares of the Pioneer Polish
Real Estate Fund.
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                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.

Dated: May 25, 2001

                           HARBOR GLOBAL COMPANY LTD.

                                    /s/ Donald H. Hunter
                                    --------------------
                                       Donald H. Hunter
                                    Chief Operating Officer
                                    Chief Financial Officer

                           (Duly authorized officer and principal financial
                                      and accounting officer)
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                               INDEX TO EXHIBITS

Exhibit
Number  Description
------  -----------

2.1*     Form of Distribution Agreement by and among The Pioneer Group, Inc.,
          Harbor Global Company Ltd. and Harbor Global II Ltd.
3.1+     Memorandum of Association of Harbor Global Company Ltd.
3.2+     Bye-Laws of Harbor Global Company Ltd.
4.1**    Specimen Common Share Certificate
10.1++   Share Purchase Agreement dated as of March 30, 2001 by and between
          Harbor Far East Exploration L.L.C., Closed Joint-Stock Company "Artel
          Staratelei Amur" and Closed Joint-Stock Company "Tas-Yurjah" Mining
          Company.
10.2++   Share Purchase Agreement dated April 06, 2001 between Cadim
          Servotech B.V., Vienna Leas International S. A., Towarzystwo Obrotu
          Nieruchomosciami Agro S. A., Fundacja Na Rzecz Nauki Polskiej, Pioneer
          Real Estate Advisors Poland Spolka z o.o. i Spolka Spolka Komandytowa,
          PREA, L.L.C. and Pioneer Polski Fundusz Nieruchomosci S. A.
10.3++   Share Purchase Agreement dated April 06, 2001 between European Bank for
          Reconstruction and Development, PREA, L.L.C. and Pioneer Polski
          Fundusz Nieruchomosci S. A.
10.4++   Termination Agreement dated as of April 06, 2001 by and between
          European Bank for Reconstruction and Development, Cadim Servotech
          B.V., Vienna Leas International S. A., Towarzystwo Obrotu
          Nieruchomosciami Agro S. A., Fundacja Na Rzecz Nauki Polskiej, Pioneer
          Real Estate Advisors Poland Spolka z o.o. i Spolka Spolka Komandytowa,
          PREA, L.L.C. and Pioneer Polski Fundusz Nieruchomosci S. A.
10.5***# Guaranty, dated as of March 12, 2001, issued by Harbor Global Company
          Ltd. in favor of Rayonier Inc.
10.6***# Addendum No. 1, dated as of March 12, 2001, to Log Sales Contract No.
          11-21-01 dated November 27, 2000 by and between Closed Joint-Stock
          Company "Forest-Starma" and Rayonier Inc.
10.7***# Agreement on Pledge of Goods in Circulation dated as of March 12, 2001
          by and between Closed Joint-Stock Company Forest-Starma and
          Rayonier Inc.

***      Filed herewith.
**       Incorporated by reference to Harbor Global Company Ltd.'s Quarterly
         Report on Form 10-Q (file number 0-30889) filed on November 13, 2000.
++       Incorporated by reference to Harbor Global's Report on Form 8-K (file
         number 000-30889) filed on April 11, 2001.
*        Incorporated by reference to Amendment No. 1 to Harbor Global Company
         Ltd.'s Registration Statement on Form 10/A (file number 0-30889) filed
         on August 8, 2000.
+        Incorporated by reference to Harbor Global Company Ltd.'s Registration
         Statement on Form 10 (file number 0-30889) filed on June 26, 2000.
#        Confidential treatment has been requested with respect to certain
         portions of this exhibit. Such portions have been omitted from this
         exhibit and filed separately with the Securities and Exchange
         Commission. Asterisks (*) denote such omissions.