X0202 4 2006-02-08 0 0001292470 NightHawk Radiology Holdings Inc NHWK 0000830588 SUMMIT PARTNERS L P 222 BERKELEY STREET 18TH FLOOR BOSTON MA 02116 0 0 0 1 Manager of GP of 10% Owner 0001258825 SUMMIT PARTNERS VI GP LLC 222 BERKELEY STREET 18TH FLOOR BOSTON MA 02116 0 0 0 1 Indirect GP of 10% Owner 0001258826 SUMMIT PARTNERS VI GP LP 222 BERKELEY STREET 18TH FLOOR BOSTON MA 02116 0 0 0 1 GP of 10% Owner 0001032090 SUMMIT PARTNERS SD II LLC C/O SUMMIT PARTNERS 222 BERKELEY STREET, 18TH FLOOR BOSTON MA 02116 0 0 0 1 GP of Owner Common Stock 2006-02-08 4 C 0 6500003 A 6500003 I See Footnotes Common Stock 2006-02-08 4 S 0 500000 16.00 D 6000003 I See Footnotes 6% Series A Convertible Preferred Stock 2006-02-08 4 C 0 6500003 D Common Stock 6500003 6500003 I See Footnotes These securities are preferred stock of NightHawk Radiology Holdings, Inc. and do not have an expiration date. These securities will automatically convert into shares of common stock upon the consummation of NightHawk Radiology Holdings, Inc. initial public offering. Each share of 6% Series A Convertible Preferred Stock is convertible into one share of common stock. Represents 4,249,940 shares beneficially held by Summit Ventures VI-A, L.P., 1,772,394 shares beneficially held by Summit Ventures VI-B, L.P., 88,388 shares beneficially held by Summit VI Advisors Fund, L.P., 135,704 shares beneficially held by Summit VI Entrepreneurs Fund, L.P., 203,125 shares beneficially held by Summit Subordinated Debt Fund II, L.P., and 50,452 shares beneficially held by Summit Investors VI, L.P. Each share of 6% Series A Convertible Preferred Stock is convertible into one share of common stock. Summit Partners, L.P. is the managing member of Summit Partners VI (GP), LLC, which is the general partner of Summit Partners VI (GP), L.P., which is the general partner of each of Summit Ventures VI-A, L.P., Summit Ventures VI-B, L.P., Summit VI Advisors Fund, L.P., Summit VI Entrepreneurs Fund, L.P. and Summit Investors VI, L.P. Summit Partners, L.P. is the managing member of Stamps, Woodsum & Co., IV, which is the general partner of Summit Partners SD II, LLC, which is the general part of Summit Subordinated Debt Fund II, L.P. Represents 326,918 shares beneficially held by Summit Ventures VI-A, L.P., 136,338 shares beneficially held by Summit Ventures VI-B, L.P., 6,799 shares beneficially held by Summit VI Advisors Fund, L.P., 10,439 shares beneficially held by Summit VI Entrepreneurs Fund, L.P., 15,625 shares beneficially held by Summit Subordinated Debt Fund II, L.P., and 3,881 shares beneficially held by Summit Investors VI, L.P. Represents 3,923,022 shares beneficially held by Summit Ventures VI-A, L.P., 1,636,056 shares beneficially held by Summit Ventures VI-B, L.P., 81,589 shares beneficially held by Summit VI Advisors Fund, L.P., 125,265 shares beneficially held by Summit VI Entrepreneurs Fund, L.P., 187,500 shares beneficially held by Summit Subordinated Debt Fund II, L.P., and 46,571 shares beneficially held by Summit Investors VI, L.P. Summit Partners, L.P. is the managing member of Summit Partners VI (GP), LLC, which is the general partner of Summit Partners VI (GP), L.P., which is the general partner of each of Summit Ventures VI-A, L.P., Summit Ventures VI-B, L.P., Summit VI Advisors Fund, L.P., Summit VI Entrepreneurs Fund, L.P. and Summit Investors VI, L.P. Summit Partners, L.P. is the managing member of Stamps, Woodsum & Co, IV, which is the general partner of Summit Partners SD II, LLC, which is the general partner of Summit Subordinated Debt Fund, L.P. Summit Partners, L.P. has voting and dispositive authority over the shares held by each of these entities and, therefore, may beneficially own such shares. Each of Summit Partners, L.P., Summit Partners VI (GP), LLC, Summit Partners VI (GP), L.P., Summit Partners SD II, LLC, and Summit Master Company, LLC, which is the general partner of Summit Partners, L.P., disclaims beneficial ownership of such shares, except to the extent of its pecuniary interest. Summit Partners, L.P., by Summit Master Company, LLC, Its General Partner, by Robin W. Devereux, Power of Attorney for Peter Y. Chung, Member 2006-02-08 Summit Partners VI (GP), LLC, by Summit Partners, L.P., its General Partner, by Summit Master Company, LLC, its General Partner, by Robin W. Devereux, Power of Attorney for Peter Y. Chung, Member 2006-02-08 Summit Partners VI (GP), L.P., by Summit Partners VI (GP), LLC, its General Partner, by Summit Partners L.P., its General Partner, by Summit Master Company, LLC, its General Partner, by Robin W. Devereux, Power of Attorney for Peter Y. Chung, Member 2006-02-08 Summit Partners SD II, LLC, by Stamps, Woodsum & Co., IV, Its General Partner, by Summit Partners, L.P., Its General Partner, by Summit Master Company, LLC, Irs General Partner, by Robin W. Devereux, Power of Attorney for Peter Y. Chung, Member 2006-02-08