Sec Form 4 Filing - MILLER W. THADDEUS @ CALPINE CORP - 2017-12-13

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person MILLER W. THADDEUS 2. Issuer Name and Ticker or Trading Symbol CALPINE CORP [ CPN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) EVP, CLO and Secretary (Last) (First) (Middle) CALPINE CORPORATION, 717 TEXAS AVENUE, SUITE 1000 3. Date of Earliest Transaction (MM/DD/YY) 12/13/2017 (Street) HOUSTON, TX77002 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock, par value $0.001 per share 12/13/2017 S 177,627 D $ 15.12 ( 1 ) 157,381 I By December 2016 GRAT ( 2 ) Common Stock, par value $0.001 per share 61,150 ( 2 ) ( 3 ) ( 4 ) ( 5 ) D Common Stock, par value $0.001 per share 11,676 I By August 2016 GRAT ( 3 ) ( 5 ) Common Stock, par value $0.001 per share 26,967 I By Trust Common Stock, par value $0.001 per share 40,462 I By Trust Common Stock, par value $0.001 per share 40,462 I By Trust

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other MILLER W. THADDEUS CALPINE CORPORATION 717 TEXAS AVENUE, SUITE 1000 HOUSTON, TX77002 EVP, CLO and Secretary Signatures W. Thaddeus Miller 12/15/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents open-market sale of shares of common stock of Calpine Corporation (the "Company") in connection with year-end tax-planning activities. The price reported in column 4 is a weighted average price. These shares were sold in multiple open-market transactions at prices ranging from $15.08 per share to $15.135 per share, inclusive. The Reporting Person undertakes to provide to the Company, any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased sold at each separate price within the ranges set forth herein. ( 2 )On December 15, 2016, 2,636 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 and 10,123 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 2015 GRAT; the November 2014 GRAT terminated pursuant to its terms. The Reporting Person was the sole recipient of the annuity payments made by the November 2014 GRAT and served as the trustee of the GRAT. On December 29, 2016, the Reporting Person contributed 335,008 shares from his direct ownership account to fund a new GRAT (December 2016 GRAT). ( 3 )On August 22, 2016, 5,808 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 May 2014 GRAT and 12,969 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 June 2015 GRAT; the May 2014 GRAT terminated pursuant to its terms. The Reporting Person was the sole recipient of the annuity payments made by the November 2014 GRAT and served as the trustee of the GRAT. On August 22, 2016, the Reporting Person contributed 18,777 shares from his direct ownership account to fund a new GRAT (August 2016 GRAT). ( 4 )On June 30, 2017, 4,376 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 June 2015 GRAT; the June 2015 GRAT terminated pursuant to its terms. Reporting Person was the sole recipient of the annuity payments made by the June 2015 GRAT and served as the trustee ofthe GRAT. ( 5 )On November 21, 2017, 7,101 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 August 2016 GRAT. The Reporting Person is the sole recipient of the annuity payments made by the August 2016 GRAT and serves as the trustee; 6,974 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 2015 GRAT and the GRAT terminated pursuant to its terms. The Reporting Person was the sole recipient of the annuity payments made by the November 2015 GRAT and served as the trustee of the GRAT.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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