X0304 4 2012-02-27 0 0001126294 GenOn Energy, Inc. GEN 0001464572 Cleary Anne M 1000 MAIN STREET HOUSTON TX 77002 0 1 0 0 SVP, Asset Mgmt Common Stock 2012-02-27 4 A 0 120781 0.00 A 256858 D Common Stock 2012-02-27 4 F 0 5904 2.44 D 250954 D Common Stock 5 I By Spouse Employee Stock Option - Right to Buy 2.44 2012-02-27 4 A 0 133164 0.00 A 2022-02-26 Common Stock 133164 133164 D Comprised of (i) 20,795 shares of common stock resulting from the vesting on February 27, 2012, upon the satisfaction of performance-based conditions, of one-third of the performance-based restricted stock units granted on February 23, 2011, (ii) 41,590 restricted stock units that, upon the satisfaction of the performance-based conditions on February 27, 2012, will vest ratably over the next two years on an annual basis and that may only be settled in common stock and (iii) 58,396 restricted stock units granted on February 27, 2012 that will vest ratably on an annual basis over the next three years and that may only be settled in common stock. The reporting person disposed of these shares to satisfy tax withholding obligations related to the vesting of performance-based restricted stock units. These stock options vest in three equal annual installments beginning February 27, 2013. /s/ Anne M. Cleary 2012-02-29