POWER OF ATTORNEY

The undersigned, Kevin JP O'Hara, does hereby make,
constitute and appoint Howard C. Naphtali, P. Mats Goebels,
Angelo Bulone, Laurie Bennett, Benjamin Reynolds,
and Derek Lively, and each of them, true and lawful
attomeys-in-fact and agents with full power of substitution
 and resubstitution, in any and all capacities, to execute
for and on behalf of the undersigned the reports and
filings required under Section 16 of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"),
and the rules promulgated thereunder
(the "Section 16 Reports"), in connection with
transactions by and beneficial ownership of the
undersigned in securities issued by Investment
Technology Group, Inc. (the "Company"), and the
Form 144 required under Rule 144 of the Securities
Act of 1933, as amended (the "Securities Act"), in
connection with any sales by the undersigned of
securities issued by the Company, and any other
documents and instruments incidental to any of the
foregoing, granting unto said attomeys-in-fact and agents,
and each of them, full power and authority to do and
perform each and every act and thing that said attorneys-in-fact
nd agents, and each of them, deem advisable or necessary,
including filing the Section 16 Reports, the Forms 144, and
amendments thereto with the Securities and Exchange Commission,
and the undersigned does hereby fully ratify and confirm all that
said attorneys-in-fact and agents, or any of them, or their or
his or her substitute or substitutes, shall do or cause to be done
by virtue hereof.

The undersigned acknowledges that the foregoing
attorneys-in-fact, in serving in such capacity at the request of
the undersigned, are not assuming, nor is the Company assuming,
any of the undersigned's responsibilities to comply with Section
16 of the Exchange Act or Rule 144 of the Securities Act.

This Power of Attorney shall remain in full force and effect until
the undersigned is no longer required to file the Forms 144 or the
Section 16 Reports with respect to the undersigned's holdings of
and transactions in securities issued by the Company, unless
earlier revoked by the undersigned in a signed writing delivered
to the foregoing attorneys-in-fact.

IN WITNESS WHEREOF, the undersigned has subscribed his
name, this 18th day of January, 2007.



___/s/ Kevin JP O'Hara____
Kevin JP O'Hara