EXHIBIT 4 UNOCAL CORPORATION AND CONSOLIDATED SUBSIDIARIES INSTRUMENTS DEFINING THE RIGHTS OF SECURITY HOLDERS, INCLUDING INDENTURES Documents incorporated by reference: Common Stock, par value Certificate of Incorporation and Bylaws, $1.00 per share see Exhibit 3 on the Exhibit Index. Stock Purchase Rights Filed in Unocal's current report on Form 8-K dated January 29, 1990. Shelf registration statement Filed in Union Oil Company of California and Unocal Corporation Form S-3, #33-1924 and #33-1924-01, Exhibit 4.1, dated December 11, 1985. 9-3/4% Notes due 1994 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated March 3, 1986. 8-1/2% Notes due 1994 Filed in Union Oil Company of California and 8-3/4% Notes due 1997 Unocal Corporation Prospectus Supplement to above Form S-3, dated March 23, 1987. 9.00% Notes due 1993 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated April 25, 1988. Shelf registration statement Filed in Union Oil Company of California and Unocal Corporation Form S-3, #33-21825 and #33-21825-01, dated May 13, 1988. Also, constitutes Post-effective Amendment no. 2 with respect to above Form S-3, #33-1924 and #33-1924-01. Medium-Term Notes, Filed in Union Oil Company of California and Series A Unocal Corporation Prospectus Supplement to above Form S-3, dated September 19, 1988. 9.625% Notes due 1995 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated May 7, 1990. 9.75% Notes due 2000 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated November 15, 1990. UNOCAL CORPORATION AND CONSOLIDATED SUBSIDIARIES INSTRUMENTS DEFINING THE RIGHTS OF SECURITY HOLDERS, INCLUDING INDENTURES (CONTINUED) Documents incorporated by reference: Shelf registration statement Filed in Union Oil Company of California and Unocal Corporation Form S-3, #33-38505 and #33-38505-01, dated January 2, 1991. Also, constitutes Post-effective Amendment no. 1 with respect to above Form S-3, #33- 21825 and #33-21825-01. Medium-Term Notes, Filed in Union Oil Company of California and Series B Unocal Corporation Prospectus Supplements to above Form S-3, dated January 30, 1991 and February 18, 1994. 9.25% Debentures due 2003 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated January 31, 1991. 9.125% Debentures due 2006 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated February 12, 1991. 8.75% Notes due 2001 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated August 14, 1991. 6.375% Notes due 2004 Filed in Union Oil Company of California and Unocal Corporation Prospectus Supplement to above Form S-3, dated February 1, 1994. Any instrument defining the rights of security holders with respect to nonregistered long-term debt not being filed on the basis that the amount of securities authorized does not exceed 10 percent of the total assets of the company and subsidiaries on a consolidated basis will be furnished to the Commission upon request.