X0306 4 2016-07-19 0 0001178670 ALNYLAM PHARMACEUTICALS, INC. ALNY 0001180432 MARAGANORE JOHN 300 THIRD STREET CAMBRIDGE MA 02142 1 1 0 0 CEO Common Stock 2016-07-19 4 M 0 15076 22.75 A 148465 D Common Stock 2016-07-19 4 S 0 13571 63.727 D 134894 D Common Stock 2016-07-19 4 S 0 1505 64.5576 D 133389 D Common Stock 2016-07-20 4 M 0 15075 22.75 A 148464 D Common Stock 2016-07-20 4 S 0 600 64.2917 D 147864 D Common Stock 2016-07-20 4 S 0 12057 65.5578 D 135807 D Common Stock 2016-07-20 4 S 0 2418 65.9993 D 133389 D Common Stock 2801 I by Managed Account Stock Option (right to buy) 22.75 2016-07-19 4 M 0 15076 0 D 2016-12-14 Common Stock 15076 45226 D Stock Option (right to buy) 22.75 2016-07-20 4 M 0 15075 0 D 2016-12-14 Common Stock 15075 30151 D All sales reported on this Form 4 were made pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on November 16, 2015. The 30,151 options exercised and sold by the reporting person were due to expire on December 14, 2016. Sale prices ranged from $63.28 to $64.27. Sale prices ranged from $64.29 to $65.04. Sale prices ranged from $63.82 to $64.76. Sale prices ranged from $64.89 to $65.87. Sale prices ranged from $65.89 to $66.20. The reporting person owns 2,801 shares of ALNY common stock under the ALNY 401(k) plan as a result of the ALNY 401(k) matching contribution program. The stock option vests as to 25% of the shares on the 1st anniversary of the date of the stock option grant and as to an additional 6.25% of the shares each successive three month period thereafter. /s/ Michael P. Mason, Attorney-in-Fact for John M. Maraganore 2016-07-21