EX-99 4 w4355620c.txt EXHIBIT 99.3 JOINT FILERS' SIGNATURES Designated Filer: Warburg Pincus Private Equity IX, L.P. Issuer & Ticker Symbol: NYFIX, Inc. (NYFX) Date of Event Requiring Statement: June 30, 2008 Exhibit 99.3 JOINT FILERS' SIGNATURES WARBURG PINCUS IX, LLC By: Warburg Pincus Partners, LLC, its Sole Member, By: Warburg Pincus & Co., its Managing Member By: /s/ Scott A. Arenare --------------------------- Date: 07/02/2008 Name: Scott A. Arenare Title: Partner WARBURG PINCUS PARTNERS, LLC By: Warburg Pincus & Co., its Managing Member By: /s/ Scott A. Arenare --------------------------- Date: 07/02/2008 Name: Scott A. Arenare Title: Partner WARBURG PINCUS LLC By: /s/ Scott A. Arenare --------------------------- Date: 07/02/2008 Name: Scott A. Arenare Title: Managing Director WARBURG PINCUS & CO. By: /s/ Scott A. Arenare --------------------------- Date: 07/02/2008 Name: Scott A. Arenare Title: Partner By: /s/ Scott A. Arenare --------------------------- Date: 07/02/2008 Name: Charles R. Kaye By: Scott A. Arenare, Attorney-in-Fact* By: /s/ Scott A. Arenare --------------------------- Date: 07/02/2008 Name: Joseph P. Landy By: Scott A. Arenare, Attorney-in-Fact** * Power of Attorney given by Mr. Kaye was previously filed with the SEC on March 2, 2006 as an exhibit to a Schedule 13D filed by Building Products, LLC with respect to Builders FirstSource, Inc. ** Power of Attorney given by Mr. Landy was previously filed with the SEC on March 2, 2006 as an exhibit to a Schedule 13D filed by Building Products, LLC with respect to Builders FirstSource, Inc.