X0306 4 2015-12-31 0 0000916457 CALPINE CORP CPN 0001442784 MILLER W. THADDEUS CALPINE CORPORATION 717 TEXAS AVENUE, SUITE 1000 HOUSTON TX 77002 0 1 0 0 EVP, Chief Legal Officer & Sec Common Stock, par value $0.001 per share 2015-12-31 4 F 0 33968 14.47 D 322249 D Common Stock, par value $0.001 per share 2636 I By grantor retained annuity trust Common Stock, par value $0.001 per share 17097 I By grantor retained annuity trust Common Stock, par value $0.001 per share 40462 I As trustee for Son Common Stock, par value $0.001 per share 40462 I As trustee for Son Common Stock, par value $0.001 per share 26967 I As trustee for Son Common Stock, par value $0.001 per share 5808 I By grantor retained annuity trust Common Stock, par value $0.001 per share 17345 I By grantor retatined annuity trust Represents shares withheld by Calpine Corporation (the "Company") at the Reporting Person's request, as permitted under the Company's Amended and Restated 2008 Equity Incentive Plan to satisfy the Reporting Person's tax withholding obligation in connection with the vesting on Thursday, December 31, 2015 of certain shares of restricted stock previously awarded to the Reporting Person. There was no open market sale of shares by the Reporting Person. Closing market price per share of the Company common stock on the transaction date. On November 13, 2015, 9,217 shares of Company common stock were automatically transferred to the Reporting Person's direct ownership account in satisfaction of the annuity payment obligations pursuant to the terms of the November 2014 GRAT. The Reporting Person is the sole recipient of the annuity payments made by the November 2014 GRAT and serves as the trustee of the GRAT. See Footnote (5). On November 13, 2015, 7,880 shares of Company common stock were automatically transferred to the Reporting Person's direct ownership account in satisfaction of the annuity payment obligations pursuant to the terms of the November 2013 grantor retained annuity trust ("GRAT"). On November 13, 2015, the GRAT terminated pursuant to its terms. The Reporting Person was the sole recipient of the annuity payments made by the November 2013 GRAT and served as the trustee of the GRAT. See Footnote (5). On November 13, 2015, the Reporting Person contributed 7,880 and 9,217 shares of Company common stock from his direct ownership account to fund a new GRAT (November 2015 GRAT). The Reporting Person is the sole recipient of the annuity payments made by the November 2015 GRAT and serves as the trustee of this GRAT. The Reporting Person's children are respective beneficiaries of the trusts, and the Reporting Person and his spouse serve as trustees. The Reporting Person may be deemed to be an indirect beneficial owner of the shares held by each trust and these shares continue to be reported on this Form 4 as indirectly owned. The Reporting Person funded the GRAT in May 2014, is the sole recipient of the annuity payments made by this GRAT and serves as the trustee of this GRAT. The Reporting Person funded the GRAT in June 2015, is the sole recipient of the annuity payments made by this GRAT and serves as the trustee of this GRAT. /s/ W. Thaddeus Miller 2016-01-04