<TABLE> <S> <C>
<PAGE>
<ARTICLE> BD
<LEGEND>
THE SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE CONSOLIDATED STATEMENT OF
FINANCIAL CONDITION AND THE CONSOLIDATED STATEMENT OF OPERATIONS AS OF SEPTEMBER
30, 2000 AND FOR THE NINE MONTHS THEN ENDED AND THE NOTES THERETO AND IS
QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS FILED IN THE
1999 INVESTMENT TECHNOLOGY GROUP, INC. ANNUAL 10-K FILING.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-31-2000
<PERIOD-START> JAN-01-2000
<PERIOD-END> SEP-30-2000
<CASH> 116,939
<RECEIVABLES> 23,654
<SECURITIES-RESALE> 0
<SECURITIES-BORROWED> 0
<INSTRUMENTS-OWNED> 70,664
<PP&E> 22,775
<TOTAL-ASSETS> 266,902
<SHORT-TERM> 0
<PAYABLES> 64,517
<REPOS-SOLD> 0
<SECURITIES-LOANED> 0
<INSTRUMENTS-SOLD> 7,090
<LONG-TERM> 0
0
0
<COMMON> 337
<OTHER-SE> 187,959
<TOTAL-LIABILITY-AND-EQUITY> 266,902
<TRADING-REVENUE> (68)
<INTEREST-DIVIDENDS> 5,493
<COMMISSIONS> 244,497
<INVESTMENT-BANKING-REVENUES> 0
<FEE-REVENUE> 4,331
<INTEREST-EXPENSE> 86
<COMPENSATION> 58,147
<INCOME-PRETAX> 87,447
<INCOME-PRE-EXTRAORDINARY> 87,447
<EXTRAORDINARY> 0
<CHANGES> 0
<NET-INCOME> 49,028
<EPS-BASIC> 1.59
<EPS-DILUTED> 1.56
</TABLE>