EXHIBIT 10.5.4
                                          
                            FIRST SUPPLEMENTAL AGREEMENT
                                          
          
          FIRST SUPPLEMENTAL AGREEMENT (hereinafter called the "Agreement"),
dated the  29th day of January, 1997, between SPARTAN MADISON CORP., a Delaware
corporation, having an address c/o HRO International Ltd., Tower 56, 126 East
56th Street, New York, New York 10022, Attention:  Tenant Services (hereinafter
referred to as "Landlord"), and INVESTMENT TECHNOLOGY GROUP, INC., a Delaware
corporation, having an address at 380 Madison Avenue, New York, New York 10017
(hereinafter referred to as "Tenant").

                                 W I T N E S S E T H:

          WHEREAS:

          A.   Landlord and Tenant heretofore entered into a certain lease dated
October 4, 1996 (such lease, as same has hereinbefore, and may be hereinafter,
amended, is hereinafter called the "Lease") with respect to the entire fourth
(4th) floor (hereinafter called the "Demised Premises") in the building known as
380 Madison Avenue, New York, New York (hereinafter called the "Building"), for
a term commencing and ending as set forth in the Lease.

          B.   The parties hereto desire to modify the Lease upon such terms,
provisions and conditions as are more particularly hereinafter set forth.  

          NOW, THEREFORE, in consideration of the premises and mutual covenants
hereinafter contained, the parties hereto agree as follows:

          1.   All terms contained in this Agreement and not otherwise defined
herein shall, for the purposes hereof, have the same meaning ascribed to them in
the Lease.

          2.   The first sentence of Section 44.01 of the Lease is hereby
deleted and the following provisions shall apply with respect to the Lease:

               Subject to the terms, provisions and conditions of this
          Lease, Tenant shall have the right at Tenant's sole cost and
          expense but without additional charge by way of increased
          rent to tie into the Building tenant emergency 


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          generator (hereinafter called the "Generator") to supply 
          emergency electricity to the demised premises not to exceed 
          three hundred fifty (350) kilovolt amperes (KVA) of the
          Generator's capacity.  All work to be performed to connect
          to the Generator shall be done at Tenant's sole cost and
          expense and solely in accordance with plans and
          specifications first approved in writing by Landlord as
          provided herein, provided, however, that it shall not be
          unreasonable for Landlord to withhold its consent in the
          event that Tenant's proposed method of connection to the
          Generator could potentially, in Landlord's good faith
          judgment, prevent or impair the ability of Landlord or other
          occupants or tenants of the Building to connect to the
          Generator in the future.

          3.   In consideration of Landlord modifying the Lease as set forth in
Section 2 hereof, Tenant is simultaneously herewith paying the sum of TWO
HUNDRED THOUSAND ($200,000.00) DOLLARS, and Landlord hereby acknowledges receipt
of same.

          4.   Tenant covenants, represents and warrants that Tenant has had no
dealings or negotiations with any broker or agent in connection with the
consummation of this Agreement.  Landlord and Tenant covenant and agree to pay,
hold harmless and indemnify each other from and against any and all cost,
expense (including, without limitation, reasonable attorneys' fees and
disbursements), loss and liability for any compensation, commissions or charges
claimed by any broker or agent with respect to this Lease or the negotiation
thereof if such claim or claims by any such broker or agent are based in whole
or in part on dealing with the indemnifying party or its representatives.  

          5.   Except as modified by this Agreement, the Lease and all
covenants, agreements, terms and conditions thereof shall remain in full force
and effect and are hereby in all respects ratified and confirmed.

          6.   In the event of any conflict between the provisions of this
Agreement and the original provisions of the Lease, the provisions of this
Agreement shall govern.

          7.   The covenants, agreements, terms and conditions contained in this
Agreement shall bind and inure to the benefit of the parties hereto and except
as otherwise provided in the Lease as hereby supplemented, their respective
legal successors and assigns.

          8.   This Agreement may not be changed or terminated orally but only
by a writing signed by the party against whom enforcement thereof is sought.    

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          IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year first above written.

Witness:                 SPARTAN MADISON CORP., Landlord


Brenda Sullivan          By:    C.R. Klotz/ President                 
- -----------------               ----------------------------------------


Witness:                 INVESTMENT TECHNOLOGY GROUP, INC., Tenant


Teresa Pang              By:    Scott P. Mason                             
- -----------------               ----------------------------------------


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COMMON WEALTH OF MASSACHUSETTS     )
                                      :  ss.:
COUNTY OF SUFFOLK                  )


          On this 29th day of January, 1997, before me personally came C. R.
Klotz, to be known, who, being duly sworn by me, did depose and say that he
resides in Wellesley; that he is the President of SPARTAN MADISON CORP., the
corporation described in and which executed the above instrument; and that he
signed his name thereto by order of the board of directors of said corporation.


                              C. Paula Barretto
                              -------------------------------
                              Notary Public

                              C. Paula Barretto
                              Notary Public
                              My Commission Expires Oct. 20, 2000


STATE OF NEW YORK   )
                    :  ss.:
COUNTY OF NEW YORK  )


          On this 29th day of January, 1997, before me personally came Scott
Mason, to be known, who, being duly sworn by me, did depose and say that he
resides in 46 Glen Rd, Wellesley, MA 02121; that he is the President of
INVESTMENT TECHNOLOGY GROUP, INC., the corporation described in and which
executed the above instrument; and that he signed his name thereto by order of
the board of directors of said corporation.


                              Teresa Pang
                              -------------------------------
                              Notary Public

Teresa Pang
Notary Public, State of New York
No. 01PA5035228
Qualified in Queens County
Commission Expires October 31, 1998


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