EX-24

                                                                      Exhibit 24

                               POWER OF ATTORNEY


     The undersigned hereby constitutes and appoints each of Scott A. Arenare,
Timothy J. Curt and Steven G. Schneider, acting together or individually,
his/her true and lawful attorneyin-fact to:


(1)  execute for and on behalf of the undersigned Forms 3, 4 and 5, together
     with any amendments thereto, in accordance with the Securities Exchange Act
     of 1934, as amended, and the rules thereunder;

(2)  do and perform any and all acts for and on behalf of the undersigned which
     may be necessary or desirable to complete the execution of any such Forms
     and the filing thereof with the United States Securities and Exchange
     Commission and any other person as may be required by law; and

(3)  take any other action of any type whatsoever in connection with the
     foregoing which, in the opinion of such attorney-in-fact, may be of benefit
     to, in the best interest of, or legally required by, the undersigned, it
     being understood that the documents executed by such attorney-in-fact on
     behalf of the undersigned pursuant to this power of attorney shall be in
     such form and shall contain such terms and conditions as such
     attorney-in-fact may approve in his discretion.

     The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform all and every act and thing whatsoever requisite,
necessary and proper to be done in the exercise of any of the rights and powers
herein granted, with full power of substitution or revocation, hereby ratifying
and confirming all that such attorney-in-fact, or his substitute or substitutes,
shall lawfully do or cause to be done by virtue of this power of attorney and
the rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneysin-fact, in serving in such capacity at the request of the
undersigned, are not assuming any of the undersigned's responsibilities to
comply with the Securities Exchange Act of 1934, as amended.

     This power of attorney shall continue in full force and effect until
revoked in writing by the undersigned or his/her attorney-in-fact.

     IN WITNESS WHEREOF, the undersigned has executed this Power of Attorney
this 28th day of February, 2006.



                                                /s/ William H. Janeway
                                                --------------------------------
                                                Print Name: William H. Janeway

EX-99

                                                                    EXHIBIT 99.1

                            EXPLANATION OF RESPONSES

(1) The common stock, par value $0.001 per share ("Common Stock") of NYFIX, Inc.
(the "Issuer") was issued in payment of a dividend on the Series B Voting
Convertible Preferred Stock {the "Preferred Stock") pursuant to the Certificate
of Designation, a copy of which was attached as Exhibit 3.2 to the Issuer's
current report on Form 8-K filed with the Securities and Exchange Commission on
October 18, 2006. The number of shares of Common Stock issued in payment of such
dividend was determined by dividing (i) the amount of the dividend that would
have been payable with respect to such share of Preferred Stock had such
dividend been paid in cash by (ii) the applicable conversion price ($5.00) now
in effect.

(2) Following the dividend discussed in Note 1, Warburg Pincus Private Equity
IX, L.P., a Delaware limited partnership ("WP IX"), is the direct record owner
of 227,500 shares of Common Stock and 1,500,000 shares of Preferred Stock, which
is convertible into 15,000,000 shares of Common Stock. The sole general partner
of WP IX is Warburg Pincus IX, LLC, a New York limited liability company ("WP IX
LLC"); Warburg Pincus Partners, LLC, a New York limited liability company ("WPP
LLC"), is the sole member of WP IX LLC; Warburg Pincus & Co., a New York general
partnership ("WP"), is the managing member of WPP LLC; Warburg Pincus LLC, a New
York limited liability company ("WP LLC"), manages WP IX; and Charles R. Kaye
and Joseph P. Landy are each Managing General Partners of WP and Co-Presidents
and Managing Members of WP LLC. By reason of the provisions of Rule 16a-1 of the
Securities Exchange Act of 1934, as amended (the "Act"), WP, WP LLC, WPP LLC, WP
IX LLC, Mr. Kaye and Mr. Landy may be deemed to be the beneficial owners of any
securities that may be deemed to be beneficially owned by WP IX. Each of WP, WP
LLC, WPP LLC, WP IX LLC, Mr. Kaye and Mr. Landy disclaim beneficial ownership of
all shares of the Common Stock and Preferred Stock beneficially owned by WP IX,
except to the extent of any indirect pecuniary interest therein.

Mr. Janeway, who became a director of the Issuer on October 12, 2006, is a
partner of WP, and a member and Managing Director of WP LLC. As such, Mr.
Janeway may be deemed to have an indirect pecuniary interest (within the meaning
of Rule 16a-1 of the Act) in an indeterminate portion of the securities reported
as beneficially owned by WP IX. Mr. Janeway disclaims beneficial ownership of
such securities, except to the extent of any indirect pecuniary interest
therein. Mr. Janeway does not directly own any shares of Common Stock or
Preferred Stock.

(3) Each share of Preferred Stock is initially convertible into 10 shares of
Common Stock at an initial conversion price of $5.00 per share, subject to
certain adjustments in accordance with the terms of the Preferred Stock.

(4) The Preferred Stock is convertible, in whole or in part, at any time and
from time to time at the holder's election. At any time after April 12, 2008,
the Preferred Stock is






convertible at the option of the Issuer, in whole or in part, if the price per
share of the Common Stock reaches certain levels. The conversion rights do not
expire.

(5) The exercise price of the Warrant to Purchase Common Stock (the "Warrant")
is initially equal to $7.75 per share of Common Stock, subject to certain
adjustments in accordance with the terms of the Warrant.

(6) The Warrant is convertible at any time, in whole or in part, at the holder's
option until 5:00 p.m. Eastern Time on October 12, 2016, at which point the
Warrant expires.

(7) WP IX is the direct record owner of the Warrant, which is convertible into
2,250,000 shares of Common Stock. The sole general partner of WP IX is WP IX
LLC; WPP LLC is the sole member of WP IX LLC; WP is the managing member of WPP
LLC; WP LLC manages WP IX; and Charles R. Kaye and Joseph P. Landy are each
Managing General Partners of WP and Co-Presidents and Managing Members of WP
LLC. By reason of the provisions of Rule 16a-1 of the Act, WP, WP LLC, WPP LLC,
WP IX LLC, Mr. Kaye and Mr. Landy may be deemed to be the beneficial owners of
any securities that may be deemed to be beneficially owned by WP IX. Each of WP,
WP LLC, WPP LLC, WP IX LLC, Mr. Kaye and Mr. Landy disclaim beneficial ownership
of the Warrant beneficially owned by WP IX, except to the extent of any indirect
pecuniary interest therein.

Mr. Janeway, who became a director of the Issuer on October 12, 2006, is a
partner of WP, and a member and Managing Director of WP LLC. As such, Mr.
Janeway may be deemed to have an indirect pecuniary interest (within the meaning
of Rule 16a-1 of the Act) in the Warrant reported as beneficially owned by WP
IX. Mr. Janeway disclaims beneficial ownership of the Warrant, except to the
extent of any indirect pecuniary interest therein. Mr. Janeway does not directly
own the Warrant.