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


                                  SCHEDULE 13G


                    Under the Securities Exchange Act of 1934

                               (Amendment No. 1)*




                        Investment Technology Group, Inc.
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                                (Name of Issuer)

                     Common Stock, par value $.01 per share
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                         (Title of Class of Securities)

                                    46145F105
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                                 (CUSIP Number)

                                December 31, 2003
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             (Date of Event Which Requires Filing of this Statement)

Check the  appropriate box to designate the rule pursuant to which this Schedule
13G is filed:

         [ ]  Rule 13d-1(b)
         [X]  Rule 13d-1(c)
         [ ]  Rule 13d-1(d)

*The  remainder of this cover page shall be filled out for a reporting  person's
initial filing on this form with respect to the subject class of securities, and
for any  subsequent  amendment  containing  information  which  would  alter the
disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the  Securities  Exchange  Act of
1934 ("Act") or otherwise  subject to the liabilities of that section of the Act
but  shall be  subject  to all other  provisions  of the Act  (however,  see the
Notes).





                               CUSIP NO. 46145F105
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(1)  Names of  Reporting Persons.   I.R.S. Identification Nos. of Above  Persons
     (entities only):
                           Ronald Juvonen
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(2)   Check the Appropriate Box if a Member of a Group (See Instructions)
              (a)                      (b)
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(3) SEC Use Only
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(4) Citizenship or Place of Organization:  United States
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Number of Shares Beneficially Owned by
    Each Reporting Person                    (5)  Sole Voting Power:         *
                                                  ------------------------------
                                             (6)  Shared Voting Power:       *
                                                  ------------------------------
                                             (7)  Sole Dispositive Power:    *
                                                  ------------------------------
                                             (8)  Shared Dispositive Power:  *
                                                  ------------------------------
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(9)  Aggregate Amount Beneficially Owned by Each Reporting Person:   2,447,799*
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(10) Check  if the Aggregate  Amount in  Row (9) Excludes  Certain  Shares  (See
     Instructions)
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(11) Percent of Class Represented by Amount in Row (9):  5.2%
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(12) Type of Reporting Person (See Instructions):  IA
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* The shares of the common stock, par value $.01 per share (the "Common Stock"),
are held by Downtown  Associates I, L.P., Downtown Associates II, L.P., Downtown
Associates III, L.P.,  Downtown Associates IV, L.P., Downtown Associates V, L.P.
(collectively  referred to as the "Downtown Funds").  The general partner of the
Downtown Funds is Downtown  Associates,  L.L.C. (the "General Partner").  Ronald
Juvonen,  as the Managing Member of the General Partner,  has sole power to vote
and  direct  the  disposition  of all  shares of the  Common  Stock  held by the
Downtown Funds.  For the purposes of Reg. Section  240.13d-3,  Ronald Juvonen is
deemed to beneficially own 2,447,799 shares, or 5.2% of the Common Stock.




Item 1(a).  Name Of Issuer:  Investment Technology Group, Inc.

Item 1(b).  Address of Issuer's Principal Executive Offices: 380 Madison Avenue,
            New York, NY  10017


Item 2(a).  Name of Person Filing:  Ronald Juvonen

Item 2(b).  Address  of  Principal  Business  Office  or,  if  None,  Residence:
            c/o Downtown  Associates,  L.L.C., 674  Unionville  Road, Suite 105,
            Kennett Square, PA 19348

Item 2(c).  Citizenship:  United States

Item 2(d).  Title of Class of Securities: Common Stock, par value $.01 per share

Item 2(e).  CUSIP No.:  46145F105


Item 3.     If  This  Statement  Is Filed  Pursuant to  Sections 240.13d-1(b) or
            240.13d-2(b) or (c), check whether the Person Filing is a

            Not Applicable.


Item 4.     Ownership

         (a)  Amount Beneficially Owned (as of December 31, 2003)   2,447,799*

         (b)  Percent of Class (as of December 31, 2003):                5.2%*

         (c) Number of Shares as to which such person has:

                  (i)  sole power to vote or to direct the vote   *

                 (ii)  shared power to vote or to direct the vote   *

                 (iii) sole power to dispose or to direct the disposition of *

                  (iv) shared power to dispose or to direct the disposition of *

----------------
* The shares of the common stock, par value $.01 per share (the "Common Stock"),
are held by Downtown  Associates I, L.P., Downtown Associates II, L.P., Downtown
Associates III, L.P.,  Downtown Associates IV, L.P., Downtown Associates V, L.P.





(collectively  referred to as the "Downtown Funds").  The general partner of the
Downtown Funds is Downtown  Associates,  L.L.C. (the "General Partner").  Ronald
Juvonen,  as the Managing Member of the General Partner,  has sole power to vote
and  direct the  disposition  of all of the  Common  Stock held by the  Downtown
Funds.  For the purposes of Reg. Section  240.13d-3, Ronald Juvonen is deemed to
beneficially own 2,447,799 shares, or 5.2% of the Common Stock.


Item 5.     Ownership of Five Percent or Less of a Class

            Not Applicable.


Item 6.     Ownership of More Than Five Percent on Behalf of Another Person.

            Not Applicable.


Item 7.     Identification  and Classification of the Subsidiary  Which Acquired
            the Security Being Reported on by the Parent Holding Company.

            Not Applicable.


Item 8.     Identification and Classification of Members of the Group.

            Not Applicable.


Item 9.     Notice of Dissolution of Group.

            Not Applicable.


Item 10.    Certification

            By  signing below I certify that, to  the best of my  knowledge  and
belief, the securities referred to  above were not acquired and are not held for
the purpose of or  with the effect of changing or influencing the control of the
issuer of such securities and  were not acquired and are not held in  connection
with or as a participant in any transaction having that purpose or effect.






                                    SIGNATURE


       After reasonable  inquiry and to the best of my  knowledge  and belief, I
certify that the information  set forth in this statement is true,  complete and
correct.


                                                February 13, 2004


                                                /s/ Ronald Juvonen
                                                --------------------------------
                                                Ronald  Juvonen, in his capacity
                                                as   the   Managing   Member  of
                                                Downtown Associates, L.L.C.


      Attention: Intentional misstatements or omissions of fact constitute
                Federal criminal violations (See 18 U.S.C. 1001)