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) March 21, 2003 -------------------------------- UNOCAL CORPORATION -------------------------------------------------------------------------------- (Exact name of registrant as specified in its charter) Delaware -------------------------------------------------------------------------------- (State or Other Jurisdiction of Incorporation) 1-8483 95-3825062 -------------------------------------------------------------------------------- (Commission File Number) (I.R.S. Employer Identification No.) 2141 Rosecrans Avenue, Suite 4000, El Segundo, California 90245 -------------------------------------------------------------------------------- (Address of Principal Executive Offices) (Zip Code) (310) 726-7600 -------------------------------------------------------------------------------- (Registrant's Telephone Number, Including Area Code) Item 5. Other Events. On the cover page of Unocal Corporation's Annual Report on Form 10-K for the fiscal year ended December 31, 2002, filed on March 21, 2003, it was stated that the aggregate market value of the common stock of the Company held by non-affiliates of the Company as of February 28, 2003, was approximately $6.8 billion. Pursuant to a recent release of the Securities and Exchange Commission, the Company is required to disclose that as of June 28, 2002, such aggregate market value, calculated in the same manner, was approximately $9.0 billion. -1- 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, thereunto duly authorized. UNOCAL CORPORATION (Registrant) Date: March 21, 2003 By: /s/ JOE D. CECIL --------------------- --------------------------------- Joe D. Cecil Vice President and Comptroller -2-