<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549



                                  FORM 10-Q/A

[X] Quarterly Report Pursuant to Section 13 or 15(d) of the Securities
    Exchange Act of 1934


                 FOR THE QUARTERLY PERIOD ENDED MARCH 31, 1998


                                       or


[ ] Transition Report Pursuant to Section 13 or 15(d) of the Securities
    Exchange Act of 1934

               For the transition period from _______ to ________

                         Commission file number 0-19066

                         INSIGNIA FINANCIAL GROUP, INC.
             (Exact name of registrant as specified in its charter)


          Delaware                                               13-3591193
(State or other jurisdiction of                               (I.R.S. Employer
 incorporation or organization)                              Identification No.)

One Insignia Financial Plaza, P.O. Box 1089                         29602
      Greenville, South Carolina                                  (Zip Code)
(Address of principal executive offices)


       Registrant's telephone number, including area code (864) 239-1000


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

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 12 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 March 31, 1998, there were outstanding 31,270,025 shares of Class A
Common Stock.




                                              
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                           PART II. OTHER INFORMATION

Item 6. Exhibits and Reports on Form 8-K.

     a)   Exhibits
     
          10. Amended and Restated Agreement and Plan of Merger By and Among
              Apartment Investment and Management Company and AIMCO Properties,
              L.P. and Insignia Financial Group, Inc. and Insignia/ESG
              Holdings, Inc., dated as of May 26, 1998.
 
          27. Financial Data Schedule for March 31, 1998.*

     b)   Reports on Form 8-K

          The following reports on Form 8-K were filed during the quarter ended
          March 31, 1998:

          1.  Form 8-K dated December 4, 1997 and filed January 14, 1998
              disclosing Registrants' announcement of acquisition of Fresh
              Meadows with The Witkoff Group.

          2.  Form 8-K dated January 7, 1998 and filed January 22, 1998
              disclosing Registrants' agreement with Cohen Financial to assume
              rights to perform property management, leasing, and construction
              supervision services for approximately 4.1 million square feet of
              commercial real estate located primarily in the Chicago area.

          3.  Form 8-K dated February 25, 1998 and filed March 29, 1998
              disclosing Registrants' announcement of the completed
              acquisition of 100% of the stock of RE Group Limited.

          4.  Form 8-K/A dated February 25, 1998 and filed April 1, 1998
              disclosing Registrants' sales of equity securities pursuant to
              Regulation S in connection with the RE acquisition. 

-----------------------------
* Previously filed.   

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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 there unto duly authorized.


Date: July 8, 1998                 INSIGNIA FINANCIAL GROUP, INC.


                                   by:  /s/ Andrew L. Farkas
                                        ----------------------------------------
                                        Andrew L. Farkas
                                        Chairman and Chief Executive Officer



                                   by:  /s/ James A. Aston
                                        ----------------------------------------
                                        James A. Aston
                                        Chief Financial Officer






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                               INDEX TO EXHIBITS

<TABLE>
<CAPTION>
Exhibit
Number                           Description
-------                          -----------
  <S>                 <C>
  10                  Amended and Restated Agreement and Plan of Merger By and
                      Among Apartment Investment and Management Company and
                      AIMCO Properties, L.P. and Insignia Financial Group, Inc.
                      and Insignia/ESG Holdings, Inc., dated as of May 26, 1998.

  27                  Financial Data Schedule for March 31, 1998.*
</TABLE>

----------------
* Previously filed.