X0306 4 2017-05-09 0 0001521036 Lantheus Holdings, Inc. LNTH 0001374781 Avista Capital Partners GP, LLC AVISTA CAPITAL HOLDINGS, L.P. 65 E. 55TH STREET, 18TH FLOOR NEW YORK NY 10022 0 0 1 0 0001374541 Avista Capital Partners, L.P. 65 EAST 55TH STREET 18TH FLOOR NEW YORK NY 10022 0 0 1 0 0001374540 Avista Capital Partners (Offshore), L.P. 65 EAST 55TH STREET 18TH FLOOR NEW YORK NY 10022 0 0 1 0 0001613694 ACP-Lantern Co-Invest, LLC 65 EAST 55TH STREET 18TH FLOOR NEW YORK NY 10022 0 0 1 0 Common Stock 2017-05-09 4 S 0 1709278 13.40 D 5295117 I See footnote Common Stock 2017-05-09 4 S 0 450722 13.40 D 1396274 I See footnote Common Stock 2017-05-09 4 S 0 840000 13.40 D 2602208 I See footnote Represents shares of the Issuer held by Avista Capital Partners, L.P. ("ACP"). Avista Capital Partners GP, LLC ("ACP GP") is the general partner of ACP. By virtue of this relationship, ACP GP may be deemed to share voting and dispositive power with respect to the shares of common stock held by ACP. Each of ACP GP and ACP expressly disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. Represents shares of the Issuer held by Avista Capital Partners (Offshore), L.P. ("ACP Offshore"). ACP GP is the general partner of ACP Offshore. By virtue of this relationship, ACP GP may be deemed to share voting and dispositive power with respect to the shares of common stock held by ACP Offshore. Each of ACP GP and ACP Offshore expressly disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. Represents shares of the Issuer held by ACP-Lantern Co-Invest, LLC ("ACP Co-Invest"). ACP GP is the manager of ACP Co-Invest. By virtue of this relationship, ACP GP may be deemed to share voting and dispositive power with respect to the shares of common stock held by ACP Co-Invest. Each of ACP GP and ACP Co-Invest expressly disclaims beneficial ownership of any such securities, except to the extent of its pecuniary interest therein. Avista Capital Partners GP, LLC, By: /s/ Ben Silbert, 2017-05-09 Avista Capital Partners, L.P., By: Avista Capital Partners GP, LLC, its General Partner, By: /s/ Ben Silbert 2017-05-09 Avista Capital Partners (Offshore), L.P., By: Avista Capital Partners GP, LLC, its General Partner, By: /s/ Ben Silbert 2017-05-09 ACP-Lantern Co-Invest, LLC, By: Avista Capital Partners GP, LLC, its Manager, By: /s/ Ben Silbert 2017-05-09