Filed by 3TEC Energy Corporation Pursuant to Rule 425 of the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 of the Securities Exchange Act of 1934

Subject Company:     3TEC Energy Corporation

Commission File No.:    001- 14745

This presentation includes “forward-looking statements” as defined by the Securities and Exchange Commission. Such statements are those concerning the companies’ merger and strategic plans, expectations and objectives for future operations. All statements included in this presentation that address activities, events or developments that the companies expect, believe or anticipate will or may occur in the future are forward-looking statements. This includes completion of the proposed merger, completion of reserve estimates, production, cash flow and EBITDA estimates, future financial performance, future equity issuance and other matters. These statements are based on certain assumptions made by the companies based on their experience and perception of historical trends, current conditions, expected future developments and other factors they believe are appropriate in the circumstances. Such statements are subject to a number of assumptions, risks and uncertainties, many of which are beyond the control of the companies. Statements regarding future production are subject to all of the risks and uncertainties normally incident to the exploration for and development and production of oil and gas. These risks include, but are not limited to, inflation or lack of availability of goods and services, environmental risks, drilling risks and regulatory changes. Investors are cautioned that any such statements are not guarantees of future performance and that actual results or developments may differ materially from those projected in the forward-looking statements.

INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE PROXY STATEMENT/PROSPECTUS THAT WILL BE INCLUDED IN THE REGISTRATION STATEMENT ON FORM S-4 TO BE FILED WITH THE SEC IN CONNECTION WITH THE PROPOSED MERGER. Plains Exploration & Production Company (“PXP”) and 3TEC Energy Corporation (“3TEC”) will file the proxy statement/prospectus with the SEC. Investors and security holders may obtain a free copy of the proxy statement/prospectus (when available) and other documents filed by PXP and 3TEC with the SEC at the SEC’s web site at www.sec.gov. The proxy statement/prospectus and such other documents (relating to PXP) may also be obtained for free from PXP by directing such request to: Plains Exploration & Production Company, 500 Dallas, Suite 700 Houston, Texas 77002, Attention: Joanna Pankey; telephone: (713) 739-6700; e-mail: jpankey@plainsxp.com. The proxy statement/prospectus and such other documents (relating to 3TEC) may also be obtained for free from 3TEC by directing such request to: 3TEC Energy Corporation, 700 Milam, Suite 1100, Houston, Texas 77002, Attention: Investor Relations; telephone: (713) 821-7100.

PXP, its directors, executive officers and certain members of management and employees may be considered “participants in the solicitation” of proxies from PXP’s stockholders in connection with the merger. Information regarding such persons and a description of their interests in the merger will be contained in the Registration Statement on Form S-4 when it is filed.

3TEC, its directors, executive officers and certain members of management and employees may be considered “participants in the solicitation” in connection with the merger. Information regarding such persons and a description of their interests in the merger will be contained in the Registration Statement on Form S-4 when it is filed.