X0306 4 2016-03-18 0 0001093691 PLUG POWER INC PLUG 0001431827 Marsh Andrew C/O PLUG POWER INC., 968 ALBANY-SHAKER ROAD LATHAM NY 12110 1 1 0 0 President and CEO Common Stock 2016-03-18 4 X 0 21505 0.93 A 473927 D Common Stock 61843 I By 401(k) Plan Warrant (right to buy) 0.93 2016-03-18 4 X 0 21505 0 D 2016-05-31 Common Stock 21505 0 D The Reporting Person holds 61,843 shares of Issuer Common Stock under a 401(k) plan. The information in this report is based on a plan statement as of December 31, 2015. This Warrant was previously reported as relating to 15,000 shares with an exercise price of $3.00 per share. As a result of the Warrant's adjustment provisions, the Warrant was adjusted to relate to 48,387 shares and an exercise price of $0.93 per share. This Warrant has been exercised in exchange for a cash payment by the reporting owner. This Warrant was acquired in 2011 in connection with the purchase of Issuer Common Stock, and it is being exercised prior to its expiration date of May 31, 2016. The Reporting Person intends to hold the shares of common stock. Warrant became exercisable upon issuance. As previously reported on August 27, 2015, the Reporting Person partially exercised the Warrant. The total beneficially owned derivative securities following the transaction inadvertently included securities of a separate class, and, accordingly, such previously reported shares are now properly excluded. /s/ Gerard L. Conway Jr., Attorney-in-fact 2016-03-22