<TABLE> <S> <C>

<PAGE>
<ARTICLE> BD
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE 
COMPANY'S REPORT ON FORM 10-Q FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 1998 
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
       
<S>                             <C>                     <C>                     <C>                     <C>
<PERIOD-TYPE>                   3-MOS                   3-MOS                   9-MOS                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1997             DEC-31-1998             DEC-31-1997             DEC-31-1998
<PERIOD-START>                             JUL-01-1997             JUL-01-1998             JAN-01-1997             JAN-01-1998
<PERIOD-END>                               SEP-30-1997             SEP-30-1998             SEP-30-1997             SEP-30-1998
<CASH>                                           13797                  140505                   13797                  140505
<RECEIVABLES>                                    30152                   65639                   30152                   65639
<SECURITIES-RESALE>                                  0                       0                       0                       0
<SECURITIES-BORROWED>                                0                       0                       0                       0
<INSTRUMENTS-OWNED>                              61726                   55005                   61726                   55005
<PP&E>                                            7353                   11477                    7353                   11477
<TOTAL-ASSETS>                                  127872                  290474                  127872                  290474
<SHORT-TERM>                                       500                   25000                     500                   25000
<PAYABLES>                                       24854                   38110                   24854                   38110
<REPOS-SOLD>                                         0                       0                       0                       0
<SECURITIES-LOANED>                                  0                       0                       0                       0
<INSTRUMENTS-SOLD>                               21061                   44780                   21061                   44780
<LONG-TERM>                                          0                       0                       0                       0
<PREFERRED-MANDATORY>                            27484                       0                   27484                       0
<PREFERRED>                                          0                       0                       0                       0
<COMMON>                                          7345                     530                    7345                     530
<OTHER-SE>                                       46628                  182054                   46628                  182054
<TOTAL-LIABILITY-AND-EQUITY>                    127872                  290474                  127872                  290474
<TRADING-REVENUE>                                57835                   89962                  157666                  233023
<INTEREST-DIVIDENDS>                               511                    1062                    1442                    1885
<COMMISSIONS>                                      226                    1351                     535                    1546
<INVESTMENT-BANKING-REVENUES>                        0                       0                       0                       0
<FEE-REVENUE>                                        0                       0                       0                       0
<INTEREST-EXPENSE>                                   0                       0                       0                       0
<COMPENSATION>                                   15034                   28322                   39539                   67814
<INCOME-PRETAX>                                  13627                   23083                   32940                   58323
<INCOME-PRE-EXTRAORDINARY>                           0                       0                       0                       0
<EXTRAORDINARY>                                      0                       0                       0                       0
<CHANGES>                                            0                       0                       0                       0
<NET-INCOME>                                      7768                   13157                   18776                   33244
<EPS-PRIMARY>                                     0.15                    0.25                    0.36                    0.63
<EPS-DILUTED>                                     0.15                    0.25                    0.36                    0.63
        

</TABLE>