X0306 4 2012-12-14 0 0001126294 GenOn Energy, Inc. GEN 0001047738 LIVENGOOD THOMAS C 1000 MAIN STREET 12TH FLOOR HOUSTON TX 77002 0 1 0 0 SVP & Controller Common Stock 2012-12-14 4 F 0 9903 2.87 D 199049 D Common Stock 2012-12-14 4 D 0 199049 D 0 D Stock Options 3.505 2012-12-14 4 D 0 33500 D 2013-03-10 Common Stock 33500 0 D Stock Options 8.135 2012-12-14 4 D 0 108800 D 2014-02-12 Common Stock 108800 0 D Stock Options 16.26 2012-12-14 4 D 0 9106 D 2017-02-19 Common Stock 9106 0 D Stock Options 23.375 2012-12-14 4 D 0 6588 D 2018-02-18 Common Stock 6588 0 D Stock Options 4.28 2012-12-14 4 D 0 34920 D 2016-03-02 Common Stock 34920 0 D Stock Options 3.81 2012-12-14 4 D 0 46617 D 2021-02-22 Common Stock 46617 0 D Stock Options 2.44 2012-12-14 4 D 0 76699 D 2022-02-26 Common Stock 76699 0 D The reporting person disposed of these shares to satisfy tax withholding obligations related to the vesting of restricted stock units. The reporting person disposed of these shares in connection with the merger (the "Merger") involving GenOn Energy, Inc. and NRG Energy, Inc.("NRG") in exchange for shares of NRG common stock, based on the exchange ratio of 0.1216 and having a market value of $23.00 per share on the effective date of the Merger, plus cash consideration for fractional shares. Upon completion of the Merger involving GenOn Energy, Inc. and NRG Energy, Inc., this fully-vested option was converted into an option to purchase 4,073 shares of NRG Energy, Inc. common stock at $28.83 per share. Upon completion of the Merger involving GenOn Energy, Inc. and NRG Energy, Inc., this fully-vested option was converted into an option to purchase 13,230 shares of NRG Energy, Inc. common stock at $66.90 per share. Upon completion of the Merger involving GenOn Energy, Inc. and NRG Energy, Inc., this fully-vested option was converted into an option to purchase 1,107 shares of NRG Energy, Inc. common stock at $133.72 per share. Upon completion of the Merger involving GenOn Energy, Inc. and NRG Energy, Inc., this fully-vested option was converted into an option to purchase 801 shares of NRG Energy, Inc. common stock at $192.23 per share. Upon completion of the Merger involving GenOn Energy, Inc. and NRG Energy, Inc., this fully-vested option was converted into an option to purchase 4,246 shares of NRG Energy, Inc. common stock at $35.20 per share. Upon completion of the Merger involving GenOn Energy, Inc. and NRG Energy, Inc., this fully-vested option was converted into an option to purchase 5,668 shares of NRG Energy, Inc. common stock at $31.34 per share. Upon completion of the Merger involving GenOn Energy, Inc. and NRG Energy, Inc., this option, which vests in three equal annual installments beginning February 27, 2013, was converted into an option to purchase 9,326 shares of NRG Energy, Inc. common stock at $20.07 per share. /s/ Thomas C. Livengood 2012-12-18