SEC Form 4

FORM 4		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 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* MILLER W. THADDEUS (Last) (First) (Middle) CALPINE CORPORATION 717 TEXAS AVENUE, SUITE 1000 (Street) HOUSTON TX 77002 (City) (State) (Zip)	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, Chief Legal Officer & Sec
	3. Date of Earliest Transaction (Month/Day/Year) 07/23/2015
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) X Form filed by One Reporting Person Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	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	07/23/2015		M		3,350(1)	A	$12.64	357,091	D
Common Stock, par value $0.001 per share	07/23/2015		F		2,863(1)	D	$16.87(2)	354,228	D
Common Stock, par value $0.001 per share	07/24/2015		M		12,445(3)	A	$12.64	366,673	D
Common Stock, par value $0.001 per share	07/24/2015		F		10,719(3)	D	$16.61(2)	355,954	D
Common Stock, par value $0.001 per share	07/27/2015		M		1,914(4)	A	$12.64	357,868	D
Common Stock, par value $0.001 per share	07/27/2015		F		1,651(4)	D	$16.57(2)	356,217	D
Common Stock, par value $0.001 per share								40,462	I	As trustee for Son(5)
Common Stock, par value $0.001 per share								40,462	I	As trustee for Son(5)
Common Stock, par value $0.001 per share								26,967	I	As trustee for Son(5)
Common Stock, par value $0.001 per share								7,880	I	By grantor retained annuity trust(6)
Common Stock, par value $0.001 per share								5,808	I	By grantor retained annuity trust(7)
Common Stock, par value $0.001 per share								11,853	I	By grantor retatined annuity trust(8)
Common Stock, par value $0.001 per share								17,345	I	By grantor retained annuity trust(9)

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 (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	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 (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (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: 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
Employee Stock Option (right to buy)	$12.64	07/23/2015		M			3,350	08/11/2013	08/11/2015	Common Stock, par value $0.001 per share	3,350	$0	51,214	D
Employee Stock Option (right to buy)	$12.64	07/24/2015		M			12,445	08/11/2013	08/11/2015	Common Stock, par value $0.001 per share	12,445	$0	38,769	D
Employee Stock Option (right to buy)	$12.64	07/27/2015		M			1,914	08/11/2013	08/11/2015	Common Stock, par value $0.001 per share	1,914	$0	36,855	D

Explanation of Responses:

1. Represents a "net exercise" of vested stock options. There was no open market sale of shares by the reporting person. A total of 2,863 shares were withheld by Calpine Corporation (the "Company") for payment of the exercise price and applicable taxes, and the net exercise resulted in 487 shares being issued by the Company to the reporting person.

2. Closing market price of the Company common stock on the transaction date.

3. Represents a "net exercise" of vested stock options. There was no open market sale of shares by the reporting person. A total of 10,719 shares were withheld by the Company for payment of the exercise price and applicable taxes, and the net exercise resulted in 1,726 shares being issued by the Company to the reporting person.

4. Represents a "net exercise" of vested stock options. There was no open market sale of shares by the reporting person. A total of 1,651 shares were withheld by the Company for payment of the exercise price and applicable taxes, and the net exercise resulted in 263 shares being issued by the Company to the reporting person.

5. 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.

6. The Reporting Person funded the GRAT in November 2013, is the sole recipient of the annuity payments made by this GRAT and serves as the trustee of this GRAT.

7. 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.

8. The Reporting Person funded the GRAT in November 2014, is the sole recipient of the annuity payments made by this GRAT and serves as the trustee of this GRAT.

9. 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.

Remarks:

	/s/ W. Thaddeus Miller	07/27/2015
	** Signature of Reporting Person	Date
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).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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