X0306 4 2013-09-24 0 0001280600 ACCELERON PHARMA INC XLRN 0000816284 CELGENE CORP /DE/ 86 MORRIS AVENUE SUMMIT NJ 07901 0 0 1 0 Common Stock 2013-09-24 4 C 0 457875 A 457875 D Common Stock 2013-09-24 4 J 0 57899 A 515774 D Common Stock 2013-09-24 4 C 0 1990446 A 2506220 D Common Stock 2013-09-24 4 P 0 666667 15.00 A 3172887 D Series C-1 Convertible Preferred Stock 2013-09-24 4 C 0 457875 0.00 D Common Stock 457875 0 D Series E Convertible Preferred Stock 2013-09-24 4 J 0 36496 0.00 D Common Stock 57899 0 D Series F Convertible Preferred Stock 2013-09-24 4 C 0 1990446 0.00 D Common Stock 1990446 0 D Upon closing of the Issuer's initial public offering, each share of Series C-1 Convertible Preferred Stock automatically converted into one share of Common Stock without payment of further consideration. The shares had no expiration date. Upon closing of the Issuer's initial public offering, each share of Series E Preferred Stock automatically converted at a ratio of 1-for-1.58645 into the number of shares of Common Stock shown in column 7 without payment of further consideration. The shares had no expiration date. Upon closing of the Issuer's initial public offering, each share of Series F Preferred Stock automatically converted into one share of Common Stock without payment of further consideration. The shares had no expiration date. Chairman of the Board of Directors, Chief Executive Officer and President /s/Robert J Hugin_______________________ Robert J Hugin, Attorney-in-Fact 2013-09-26