8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of
the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 28, 2005

CALPINE CORPORATION

(Exact name of registrant as specified in its charter)

Delaware
(State of Other Jurisdiction of Incorporation)

Commission file number: 001-12079

I.R.S. Employer Identification No. 77-0212977

50 West San Fernando Street
San Jose, California 95113
Telephone: (408) 995-5115
(Address of principal executive offices and telephone number)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

TABLE OF CONTENTS

	ITEM 2.05 — COSTS ASSOCIATED WITH EXIT OR DISPOSAL ACTIVITIES
	ITEM 8.01 — OTHER EVENTS
	ITEM 9.01 — FINANCIAL STATEMENTS AND EXHIBITS
SIGNATURES
EXHIBIT INDEX
EXHIBIT 99.1

ITEM 2.05 — COSTS ASSOCIATED WITH EXIT OR DISPOSAL ACTIVITIES

On June 28, 2005, we agreed to sell all of our domestic oil and gas exploration and production assets for $1.05 billion, less transaction fees and expenses. We incorporate by reference in this Item 2.05 our disclosure in the press release filed herewith as Exhibit 99.1. In connection with the sale we estimate that we will incur approximately $58 million of various transaction fees and expenses including investment banking, lending, legal, tax consulting and accounting costs. All of the transaction fees and expenses will be paid in cash. The transaction fees will be paid from the proceeds of the sale.

The expected closing date of the sale is July 7, 2005, subject to satisfaction of certain conditions, including the execution of definitive documentation.

ITEM 8.01 — OTHER EVENTS

On June 29, 2005, the Registrant issued the press release attached hereto as Exhibit 99.1.

ITEM 9.01 — FINANCIAL STATEMENTS AND EXHIBITS

(a) Financial Statements of Businesses Acquired.

Not Applicable

(b) Pro Forma Financial Information.

Not Applicable

(c) Exhibits.

99.1 Press Release dated June 29, 2005.

SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

CALPINE CORPORATION
By:	/s/ Charles B. Clark, Jr.
	Charles B. Clark, Jr.
	Senior Vice President, Controller and Chief Accounting Officer

Date: July 5, 2005

EXHIBIT INDEX

Exhibit
Number	Exhibit
99.1	Press Release dated June 29, 2005.

EX-99.1

EXHIBIT 99.1

NEWS RELEASE

CONTACTS: 408-995-5115
Media Relations: Katherine Potter, Ext. 1168
Investor Relations: Karen Bunton, Ext. 1121

Calpine Agrees to Sell Its Oil and Gas Properties For $1.05 Billion

     (SAN JOSE, Calif.) /PR Newswire-First Call/June 29, 2005 — Calpine Corporation [NYSE: CPN] announced today that it has agreed to sell all of its domestic oil and gas exploration and production assets for $1.05 billion, less transaction fees and expenses. The sale is scheduled to close on July 7, 2005.

     Rosetta Resources, Inc. (Rosetta), a newly formed indirect, wholly owned subsidiary of Calpine, has agreed to issue 45,312,500 of its common shares for $725 million. At closing, Rosetta will use the net proceeds from that transaction, together with $325 million of proceeds from a new credit facility, to purchase all of Calpine’s domestic oil and gas exploration and production assets. As of May 1, 2005, Calpine’s proved oil and gas reserves totaled approximately 383 billion cubic feet equivalent. Following this transaction, which is subject to customary closing conditions, Calpine will no longer own any interest in Rosetta.

     The Rosetta common shares have been offered in a private placement under Rule 144A, have not been registered under the Securities Act of 1933, and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements. This news release is issued pursuant to Rule 135c under the Securities Act and shall not constitute an offer to sell or the solicitation of an offer to buy. Securities laws applicable to private placements under Rule 144A limit the extent of information that can be provided at this time.

     A major power company, Calpine Corporation supplies customers and communities with electricity from clean, efficient, natural gas-fired and geothermal power plants. Calpine owns, leases and operates integrated systems of plants in 21 U.S. states, three Canadian provinces and the United Kingdom. Calpine was founded in 1984. It is included in the S&P 500 Index and is publicly traded on the New York Stock Exchange under the symbol CPN. For more information, visit www.calpine.com.