<PAGE>

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

                                    FORM 13F

       INFORMATION REQUIRED OF INSTITUTIONAL INVESTMENT MANAGERS PURSUANT
  TO SECTION 13(f) OF THE SECURITIES EXCHANGE ACT OF 1934 AND RULES THEREUNDER

         Report for the Calendar Year or Quarter Ended June 30, 1999.
                                                       -------------

                (PLEASE READ INSTRUCTIONS BEFORE PREPARING FORM.)

If amended report, check here:  / /

White Mountains Insurance Group, Inc. 
          (Formerly known as Fund American Enterprises Holdings, Inc.)
--------------------------------------------------------------------------------

Name of Institutional Investment Manager

80 South Main Street                 Hanover         NH               03755-2053
--------------------------------------------------------------------------------
Business Address        (Street)     (City)        (State)               (Zip)

Michael S. Paquette     (603) 640-2205     Senior Vice President and Controller
--------------------------------------------------------------------------------
Name, Phone No., and Title of Person Duly Authorized to Submit This Report.

                                    ATTENTION
INTENTIONAL MISSTATEMENTS OR OMISSIONS OF FACTS CONSTITUTE FEDERAL CRIMINAL
                                  VIOLATIONS.
                    SEE 18 U.S.C. 1001 AND 15 U.S.C. 78ff(a).

     The institutional investment manager submitting this Form and its
attachments are the person by whom it is signed represent hereby that all
information contained therein is true, correct and complete. It is understood
that all required items, statements and schedules are considered integral parts
of this Form and that the submission of any amendment represents that all
unamended items, statements and schedules remain true, correct and complete as
previously submitted.

     Pursuant to the requirements of Securities Exchange Act of 1934, the
undersigned institutional investment manager has caused

this report to be signed on its behalf in the City of        Hanover      and
                                                      -------------------    

State of     New Hampshire      on the    12th     
         ----------------------        ----------- 

day of         August,             1999.  
       ----------------------    ---------   

                                     White Mountains Insurance Group, Inc.
                                   -------------------------------------------
                                   (Name of Institutional Investment Manager)


                                   -------------------------------------------
                                   (Manual Signature of Person Duly Authorized
                                                    to Submit This Report)

Name and 13F file numbers of ALL Institutional Investment Managers with respect
to which this schedule is filled (other than the one filing this report): (LIST
IN ALPHABETICAL ORDER).

13F File Numbers will be assigned to Institutional Investment Managers after
they file their first report.



<TABLE>
<CAPTION>
Name:                                    13F File No.:   Name:                                            13F File No.:

<S>                                                      <C>                                            <C>

1. Folksamerica Holding Company, Inc.                    5. (see attached report for security listings)

2. White Mountains Holdings, Inc.                        6.

3. White Mountains Properties, Inc.                      7.

4. White Mountains Services Corp.                        8.

</TABLE>




<PAGE>

                    FUND AMERICAN ENTERPRISES HOLDINGS, INC.

                           FORM 13F FOR JUNE 30, 1999


<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                   Investment Discretion 
                                                Title          CUSIP       Fair Market  Number of  ---------------------
                    Name of Issuer            of class         Number         Value       Shares   Sole  Shared Other    Managers *
------------------------------------------------------------------------------------------------------------------------------------

<S>                                          <C>              <C>             <C>          <C>       <C>    <C>   <C>    <C>
ACE Limited                                       ORD         G0070K103     5,394,874    190,969          x               4  
AGL Resources, Inc.                               COM         001204106       829,688     45,000          x               3   
ABB AB Sponsored ADR                         SPONSORED ADR    00256Q103       313,375     23,000          x **            1   
AlliedSignal, Inc.                                COM         019512102       655,200     10,400          x **            1   
Allmerica Financial Corp.                         COM         019754100       101,922      1,676          x               3   
AMBAC Financial Group, Inc.                       COM         023139108       297,050      5,200          x               3   
AMBAC Financial Group, Inc.                       COM         023139108       145,669      2,550          x **            2   
America Online, Inc.                              COM         02364J104     8,800,000     80,000          x **            1   
America Online, Inc.                              COM         02364J104       770,000      7,000          x               3   
American Express Co.                              COM         025816109       728,700      5,600          x **            1   
American International Group, Inc.                COM         026874107     1,758,750     15,000          x **            1   
Apple Computer, Inc.                              COM         037833100       287,138      6,200          x **            1   
Archstone Communities                        PFD SER A CV     039581202        30,750      1,000          x               3   
Astrazeneca PLC                              SPONSORED ADR    046353108       246,881      6,300          x **            1   
Avery Dennison Corp.                              COM         053611109        83,559      1,384          x               3   
BISYS Group, Inc.                                 COM         055472104       813,150     13,900          x               3   
BISYS Group, Inc.                                 COM         055472104       351,000      6,000          x **            2   
BRE Properties, Inc.                             CL A         05564E106       624,000     24,000          x               3   
Bank of Tokyo-Mitsubishi Ltd.                SPONSORED ADR    065379109       218,438     15,000          x **            1   
Bank UTD Corp.                                   CL A         065412108        25,599        637          x               3   
Berkshire Hathaway Inc.                          CL A         084670108     6,890,000        100          x               3   
Berkshire Hathaway Inc.                          CL B         084670207       786,240        351          x               3   
Berkshire Hathaway Inc.                          CL B         084670207        94,080         42          x **            2   
(H & R) Block, Inc.                               COM         093671105       785,000     15,700          x               3   
(H & R) Block, Inc.                               COM         093671105       295,000      5,900          x **            2   
Boeing Company                                    COM         097023105       343,200      7,800          x **            1   
Bristol Meyers Squibb Co.                         COM         110122108     6,339,375     90,000          x **            1   
Cellular Communications of Puerto Rico, Inc.      COM         15116N108       464,550     16,300          x               3   
Chase Manhattan Corp.                             COM         16161A108       674,700      7,800          x **            1   
Citigroup, Inc.                                   COM         172967101     4,898,438    103,125          x **            1   
Coca Cola Co.                                     COM         191216100       558,000      9,000          x               3   
Computer Associates International, Inc.           COM         204912109       525,600      9,600          x **            1   
Dell Computer                                     COM         247025109    10,360,000    280,000          x **            1   
Walt Disney Co.                                   COM         254687106     6,193,313    201,000          x **            1   
Walt Disney Co.                                   COM         254687106       218,769      7,100          x               3   
Donaldson Lufkin & Jenrette                       COM         257661108     3,615,000     60,000          x **            1   
EMC Corporation                                   COM         268648102     3,300,000     60,000          x **            1   
Equity Residential Properties                 SH BEN INT      29476L107       776,202     17,225          x               3   
Federal Home Loan Mortgage Corp.                  COM         313400301     1,554,400     26,800          x               3   
Federal National Mortgage Association             COM         313586109     5,801,250     85,000          x **            1   
Federal National Mortgage Association             COM         313586109     2,654,925     38,900          x               3   
Financial Security Assurance Holdings Ltd.        COM         31769P100   214,597,084  4,126,867          x               4   
First Data Corporation                            COM         319963104       592,144     12,100          x               3   
First Data Corporation                            COM         319963104        66,066      1,350          x **            2   
First Industrial Realty Trust                     COM         32054K103       617,344     22,500          x               3   
Fleet Financial Group, Inc.                       COM         338915101       470,375     10,600          x **            1   
General Electric Co.                              COM         369604103    12,204,000    108,000          x **            1   
General Electric Co.                              COM         369604103       904,000      8,000          x               3   
General Nutrition Companies, Inc.                 COM         37047F103       186,500      8,000          x **            1   
Gilette Company                                   COM         375766102     4,305,000    105,000          x **            1   
Gulf Canada Resources Ltd.                        ORD         40218L305       102,326     24,436          x               3   
HCC Insurance Holdings, Inc.                      COM         404132102         2,269        100          x **            1   
</TABLE>



<TABLE>
<CAPTION>
                                            ----------------------------  
                                               Voting Authority (Shares)  
                                             ---------------------------  
                                             Sole   Shared      None      
                                            ----------------------------  
                                                                  
<S>                                         <C>     <C>      <C>     
ACE Limited                                         190,969       
AGL Resources, Inc.                                  45,000       
ABB AB Sponsored ADR                                 23,000       
AlliedSignal, Inc.                                   10,400       
Allmerica Financial Corp.                             1,676       
AMBAC Financial Group, Inc.                           5,200       
AMBAC Financial Group, Inc.                           2,550       
America Online, Inc.                                 80,000       
America Online, Inc.                                  7,000       
American Express Co.                                  5,600       
American International Group, Inc.                   15,000       
Apple Computer, Inc.                                  6,200       
Archstone Communities                                 1,000       
Astrazeneca PLC                                       6,300       
Avery Dennison Corp.                                  1,384       
BISYS Group, Inc.                                    13,900       
BISYS Group, Inc.                                     6,000       
BRE Properties, Inc.                                 24,000       
Bank of Tokyo-Mitsubishi Ltd.                        15,000       
Bank UTD Corp.                                          637       
Berkshire Hathaway Inc.                                 100       
Berkshire Hathaway Inc.                                 351       
Berkshire Hathaway Inc.                                  42       
(H & R) Block, Inc.                                  15,700       
(H & R) Block, Inc.                                   5,900       
Boeing Company                                        7,800       
Bristol Meyers Squibb Co.                            90,000       
Cellular Communications of Puerto Rico, Inc.         16,300       
Chase Manhattan Corp.                                 7,800       
Citigroup, Inc.                                     103,125       
Coca Cola Co.                                         9,000       
Computer Associates International, Inc.               9,600       
Dell Computer                                       280,000       
Walt Disney Co.                                     201,000       
Walt Disney Co.                                       7,100       
Donaldson Lufkin & Jenrette                          60,000       
EMC Corporation                                      60,000       
Equity Residential Properties                        17,225       
Federal Home Loan Mortgage Corp.                     26,800       
Federal National Mortgage Association                85,000       
Federal National Mortgage Association                38,900       
Financial Security Assurance Holdings Ltd.        4,126,867       
First Data Corporation                               12,100       
First Data Corporation                                1,350       
First Industrial Realty Trust                        22,500       
Fleet Financial Group, Inc.                          10,600       
General Electric Co.                                108,000       
General Electric Co.                                  8,000       
General Nutrition Companies, Inc.                     8,000       
Gilette Company                                     105,000       
Gulf Canada Resources Ltd.                           24,436       
HCC Insurance Holdings, Inc.                            100       
</TABLE>




                                     Page 1

<PAGE>

                    FUND AMERICAN ENTERPRISES HOLDINGS, INC.

                           FORM 13F FOR JUNE 30, 1999



<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                   Investment Discretion 
                                                Title          CUSIP       Fair Market  Number of  ---------------------
                    Name of Issuer            of class         Number         Value       Shares   Sole  Shared Other    Managers *
------------------------------------------------------------------------------------------------------------------------------------

<S>                                          <C>              <C>             <C>          <C>       <C>    <C>   <C>    <C>
Healthsouth Corp.                                 COM         421924101          75,238      5,058          x               3    
Hershey Foods Corp.                               COM         427866108         486,875      8,200          x **            1    
Highwoods Properties, Inc.                        COM         431284108         521,313     19,000          x               3    
Home Depot, Inc.                                  COM         437076102       1,963,411     30,470          x               3    
Honda Motor Ltd.                               AMERN SHS      438128308         511,825      5,900          x **            1    
INMC Mortgage Holdings, Inc.                      COM         44977L100         305,600     19,100          x               3    
Intel Corp.                                       COM         458140100       8,806,000    148,000          x **            1    
Intel Corp.                                       COM         458140100         130,900      2,200          x               3    
Intergraph Corp.                                  COM         458683109          14,438      1,863          x               3    
Interstate Bakeries Corp.                         COM         46072H108       2,243,750    100,000          x **            1    
Intuit, Inc.                                      COM         461202103       1,108,538     12,300          x               3    
Johnson & Johnson, Inc.                           COM         478160104         833,000      8,500          x               3    
KeyCorp                                           COM         493267108         289,125      9,000          x **            1    
Laclede Gas Co.                                   COM         505588103         197,625      8,500          x               3    
LaSalle Re Holdings Ltd.                          ORD         G5383Q101         309,400     18,200          x               3    
Eli Lilly & Co.                                   COM         532457108       4,727,250     66,000          x **            1    
Loral Space & Communication                       COM         G56462107       2,070,000    115,000          x **            1    
MCN Energy Group, Inc.                            COM         55267J100         249,000     12,000          x               3    
Marsh & McLennan Cos., Inc.                       COM         571748102         544,950      7,200          x               3    
Marsh & McLennan Cos., Inc.                       COM         571748102          75,688      1,000          x **            2    
Meditrust Corp.                             PAIRED CTF NEW    58501T306         320,240     24,516          x               3    
Merry Land & Investment Company, Inc.             COM         590438107           8,023      1,625          x               3    
Microsoft Corp.                                   COM         594918104       8,116,875     90,000          x **            1    
Midway Airlines Corp.                             COM         598126100          97,375      9,500          x **            1    
Monsanto Co.                                      COM         611662107         280,894      7,100          x **            1    
News Corp. Ltd.                                 ADR NEW       652487703         522,625     14,800          x **            1    
Nordstrom, Inc.                                   COM         655664100       3,350,000    100,000          x **            1    
PartnerRe Limited                                 COM         G6852T105       1,162,363     31,100          x               3    
PartnerRe Limited                                 COM         G6852T105          48,588      1,300          x **            2    
Pfizer, Inc.                                      COM         717081103       2,180,000     20,000          x **            1    
Philip Morris Companies                           COM         718154107       3,243,132     80,100          x **            1    
Philip Morris Companies                           COM         718154107         401,875     10,600          x               3    
Provident Cos., Inc.                              COM         743862104         260,000      6,500          x               3    
Provident Cos., Inc.                              COM         743862104          48,000      1,200          x **            2    
Reuters Group PLC                            SPONSORED ADR    76132M102         632,206      7,799          x **            1    
Ross Stores                                       COM         778296103       2,518,750     50,000          x **            1    
Safeskin Corp.                                    COM         786454108         756,000     63,000          x **            1    
Safeskin Corp.                                    COM         786454108         309,600     25,800          x               3    
San Juan Basin Royalty Trust                 UNIT BEN INT     798241105      30,150,868  3,710,876          x               3    
Sara Lee Corp.                                    COM         803111103         326,700     14,400          x               3    
Schering Plough Corp.                             COM         806605101       7,103,250    135,300          x **            1    
Schering Plough Corp.                             COM         806605101         771,750     14,700          x               3    
Sears Roebuck & Co.                               COM         812387108         133,688      3,000          x **            1    
Security Capital Group B, Inc.                   CL B         81413P204          33,960      2,332          x               3    
Shaw Communications, Inc. Cl B Conv.           CL B CONV      82028K200         180,266      4,535          x               3    
Shurgard Storage Centers, Inc.                    COM         82567D104         669,988     24,700          x               3    
J.M. Smucker Co. Class A                         CL A         832696108          59,764      2,686          x               3    
J.M. Smucker Co. Class B                         CL B         832696207          68,153      3,587          x               3    
Superior National Insurance Group, Inc.           COM         868224106         953,750     35,000          x               3    
Superior National Insurance Group, Inc.           COM         868224106         103,550      3,800          x **            2    
Telefonos de Mexico                         SPNS ADR ORD L    879403780         210,113      2,600          x **            1    
Terra Nova (Bermuda) Holdings Ltd.             ORD CL A       G87615103         381,166     14,150          x               3    
</TABLE>



<TABLE>
<CAPTION>
                                            ----------------------------  
                                               Voting Authority (Shares)  
                                             ---------------------------  
                                             Sole   Shared      None      
                                            ----------------------------  
                                                                  
<S>                                         <C>     <C>      <C>     
Healthsouth Corp.                                     5,058       
Hershey Foods Corp.                                   8,200       
Highwoods Properties, Inc.                           19,000       
Home Depot, Inc.                                     30,470       
Honda Motor Ltd.                                      5,900       
INMC Mortgage Holdings, Inc.                         19,100       
Intel Corp.                                         148,000       
Intel Corp.                                           2,200       
Intergraph Corp.                                      1,863       
Interstate Bakeries Corp.                           100,000       
Intuit, Inc.                                         12,300       
Johnson & Johnson, Inc.                               8,500       
KeyCorp                                               9,000       
Laclede Gas Co.                                       8,500       
LaSalle Re Holdings Ltd.                             18,200       
Eli Lilly & Co.                                      66,000       
Loral Space & Communication                         115,000       
MCN Energy Group, Inc.                               12,000       
Marsh & McLennan Cos., Inc.                           7,200       
Marsh & McLennan Cos., Inc.                           1,000       
Meditrust Corp.                                      24,516       
Merry Land & Investment Company, Inc.                 1,625       
Microsoft Corp.                                      90,000       
Midway Airlines Corp.                                 9,500       
Monsanto Co.                                          7,100       
News Corp. Ltd.                                      14,800       
Nordstrom, Inc.                                     100,000       
PartnerRe Limited                                    31,100       
PartnerRe Limited                                     1,300       
Pfizer, Inc.                                         20,000       
Philip Morris Companies                              80,100       
Philip Morris Companies                              10,600       
Provident Cos., Inc.                                  6,500       
Provident Cos., Inc.                                  1,200       
Reuters Group PLC                                     7,799       
Ross Stores                                          50,000       
Safeskin Corp.                                       63,000       
Safeskin Corp.                                       25,800       
San Juan Basin Royalty Trust                      3,710,876       
Sara Lee Corp.                                       14,400       
Schering Plough Corp.                               135,300       
Schering Plough Corp.                                14,700       
Sears Roebuck & Co.                                   3,000       
Security Capital Group B, Inc.                        2,332       
Shaw Communications, Inc. Cl B Conv.                  4,535       
Shurgard Storage Centers, Inc.                       24,700       
J.M. Smucker Co. Class A                              2,686       
J.M. Smucker Co. Class B                              3,587       
Superior National Insurance Group, Inc.              35,000       
Superior National Insurance Group, Inc.               3,800       
Telefonos de Mexico                                   2,600       
Terra Nova (Bermuda) Holdings Ltd.                   14,150       
</TABLE>



                                     Page 2


<PAGE>

                    FUND AMERICAN ENTERPRISES HOLDINGS, INC.

                           FORM 13F FOR JUNE 30, 1999



<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------------
                                                                                                   Investment Discretion 
                                                Title          CUSIP       Fair Market  Number of  ---------------------
                    Name of Issuer            of class         Number         Value       Shares   Sole  Shared Other    Managers *
------------------------------------------------------------------------------------------------------------------------------------

<S>                                          <C>              <C>             <C>          <C>       <C>    <C>   <C>    <C>
Terra Nova (Bermuda) Holdings Ltd.             ORD CL A       G87615103         105,595      3,920          x **            2  
UCAR International, Inc.                          COM         90262K109         246,642      9,768          x               3  
Waddell & Reed Financial, Inc.                   CL A         930059100         794,379     28,821          x               3  
Waddell & Reed Financial, Inc.                   CL A         930059100          82,688      3,000          x **            2  
Wal Mart Stores, Inc.                             COM         931142103       5,645,250    117,000          x **            1  
Wal Mart Stores, Inc.                             COM         931142103         135,100      2,800          x               3  
Wells Fargo & Co.                                 COM         949746101       2,992,500     70,000          x **            1  
XL Capital Ltd.                                  CL A         G98255105         848,348     15,015          x               3  

                                                                         ---------------
GRAND TOTAL                                                               $ 415,368,833
                                                                         ---------------
                                                                         ---------------
</TABLE>



<TABLE>
<CAPTION>
                                            ----------------------------  
                                               Voting Authority (Shares)  
                                             ---------------------------  
                                             Sole   Shared      None      
                                            ----------------------------  
                                                                  
<S>                                         <C>     <C>      <C>     
Terra Nova (Bermuda) Holdings Ltd.                    3,920       
UCAR International, Inc.                              9,768       
Waddell & Reed Financial, Inc.                       28,821       
Waddell & Reed Financial, Inc.                        3,000       
Wal Mart Stores, Inc.                               117,000       
Wal Mart Stores, Inc.                                 2,800       
Wells Fargo & Co.                                    70,000       
XL Capital Ltd.                                      15,015       
</TABLE>





*  Managers
-----------

1  =   Folksamerica Holding Company, Inc.          (FORM 13F filed separately)
2  =   White Mountains Holdings, Inc.              (FORM 13F filed separately)
3  =   White Mountains Properties, Inc.            (FORM 13F filed separately)
4  =   White Mountains Services Corporation        (FORM 13F filed separately)

** Investment discretion shared with indirect wholly owned insurance
   subsidiaries


                                     Page 3