X0303 4 2011-01-12 0 0001104506 INSMED INC INSM 0001218860 ENGELSEN STEINAR J C/O INSMED INCORPORATED 8720 STONY POINT PKWY, SUITE 200 RICHMOND VA 23235 1 0 0 0 Restricted Stock Units 2011-01-12 4 A 0 54687.50 0.00 A Common Stock 54687.50 142187.50 D The RSU's have a one year cliff vesting period, provided that the director attends at least 75% of the meetings of the Board. The RSU's will be settled in a lump sum cash payment upon vesting; provided, however, that if the Company's shareholders approve an amendment to the Company's Amended & Restated 2000 Stock Incentive Plan to increase the number of shares of common stock that may be issued under the plan or additional shares become available to the plan through stock option expirations and/or employee terminations, the Company may settle the RSU's in shares of common stock in lieu of cash. /s/ Steinar Engelsen 2011-01-14