X0202 3/A 2004-06-21 2004-06-21 0 0001235010 MOMENTA PHARMACEUTICALS INC MNTA 0001114126 POLARIS VENTURE MANAGEMENT CO III LLC 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 0001104639 POLARIS VENTURE PARTNERS III LP 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 0001114889 POLARIS VENTURE PARTNERS ENTREPRENEURS FUND III LP 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 0001114437 POLARIS VENTURE PARTNERS FOUNDERS FUND III LP 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 0001295787 Arnold Stephen D 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 0001295676 Flint Jonathan A 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 0001117003 MCGUIRE TERRANCE 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 0001018394 SPOON ALAN G 1000 WINTER STREET SUITE 3350 WALTHAM MA 02451-1215 0 0 1 0 Series A Convertible Preferred Stock Common Stock 282607 I See Footnote Series A Convertible Preferred Stock Common Stock 7338 I See Footnote Series A Convertible Preferred Stock Common Stock 4454 I See Footnote Series A Prime Convertible Preferred Stock Common Stock 719943 I See Footnote Series A Prime Convertible Preferred Stock Common Stock 18693 I See Footnote Series A Prime Convertible Preferred Stock Common Stock 11348 I See Footnote Series A Double Prime Convertible Preferred Stock Common Stock 1391416 I See Footnote Series A Double Prime Convertible Preferred Stock Common Stock 36128 I See Footnote Series A Double Prime Convertible Preferred Stock Common Stock 21932 I See Footnote Series B Convertible Preferred Stock Common Stock 1561944 I See Footnote Series B Convertible Preferred Stock Common Stock 40555 I See Footnote Series B Convertible Preferred Stock Common Stock 24618 I See Footnote Series C Convertible Preferred Stock Common Stock 753515 I See Footnote Series C Convertible Preferred Stock Common Stock 19564 I See Footnote Series C Convertible Preferred Stock Common Stock 11875 I See Footnote Automatically converts into common stock upon the closing of the Issuer's initial public offering of common stock. N/A Reflects a 1.28-for-1 forward stock split, which became effective on May 10, 2004, pursuant to which each share of Series A Convertible Preferred Stock, Series A Prime Convertible Preferred Stock, Series A Double Prime Convertible Preferred Stock, Series B Convertible Preferred Stock and Series C Convertible Preferred Stock will automatically convert into approximately 1.28 shares of common stock upon the closing of the Issuer's initial public offering of common stock. These shares are owned directly by Polaris Venture Partners III, L.P. ("PVP III") Polaris Venture Management Co. III, L.L.C. ("PVM III"), the general partner of PVP III, and Stephen D. Arnold, Jonathan A. Flint, Terrance G. McGuire and Alan G. Spoon, the managing members of PVM III, may be deemed to share voting and dispositive power over the shares held by PVP III. Such persons and entities disclaim beneficial ownership of shares held by PVP III except to the extent of any pecuniary interest therein. These shares are owned directly by Polaris Venture Partners Entrepreneurs' Fund III, L.P. ("PVPEF III") PVM III, the general partner of PVPEF III, and Stephen D. Arnold, Jonathan A. Flint, Terrance G. McGuire and Alan G. Spoon, the managing members of PVM III, may be deemed to share voting and dispositive power over the shares held by PVPEF III. Such persons and entities disclaim beneficial ownership of shares held by PVPEF III except to the extent of any pecuniary interest therein. These shares are owned directly by Polaris Venture Partners Founders' Fund III, L.P. ("PVPFF III") PVM III, the general partner of PVPFF III, and Stephen D. Arnold, Jonathan A. Flint, Terrance G. McGuire and Alan G. Spoon, the managing members of PVM III, may be deemed to share voting and dispositive power over the shares held by PVPFF III. Such persons and entities disclaim beneficial ownership of shares held by PVPFF III except to the extent of any pecuniary interest therein. This amendment is being filed to incorporate the EDGAR codes of the joint filers previously disclosed on Exhibit 99 hereto, and the Power of Attorney attached as Exhibit 24. /s/ Kevin Littlejohn Attorney-in-Fact 2004-10-26