THE CORPORATE LIBRARY

Related Party Transactions and Outside Related Director Information

Western Gas Resources, Inc. (WGR)

3/28/2006 Proxy Information

Mr. Robinson is a shareholder of the law firm of Robinson and Diss P.C., which has represented us in various legal matters. For the year ended December 31, 2005, the total amount of legal fees paid to Robinson & Diss P.C. was $51,467.

4/5/2005 Proxy Information

Mr. Robinson is a stockholder of the law firm of Robinson and Diss P.C., which has represented us in various legal matters. For the year ended December 31, 2004, the total amount of legal fees paid to Robinson & Diss P.C. was approximately $16,074.

Mr. Sanderson was President of Western Gas Resources, Inc. from December 1986 through March 1996, Chief Operating Officer from May 1986 through March 1996 and Senior Vice President from 1981 through 1986.

Mr. Stonehocker was Senior Vice President of WGR from January 1985 to July 1992 and a Vice President from 1971 to 1985.

Mr. Wise served as Chairman of Western Gas Resources, Inc. from July 1987 until May 2003. He also served as Chief Executive Officer from December 1986 through October 1999 and as President from 1971 through 1986.

4/7/2004 Proxy Information

Richard B. Robinson has represented Western Gas Resources, Inc. since 1977 with respect to tax, corporate and partnership law matters.

Bill M. Sanderson was President of Western Gas Resources, Inc. from December 1986 through March 1996, Chief Operating Officer from May 1986 through March 1996 and Senior Vice President from 1981 through 1986.

Walter L. Stonehocker was Senior Vice President from January 1985 to July 1992 and a Vice President from 1971 to 1985.

Brion G. Wise served as Chief Executive Officer from December 1986 through October 1999 and as President from 1971 through 1986.

In June 2001, as an incentive to Mr. Outlaw to extend his retirement date to October 31, 2001 and to provide transitional support to Mr. Dea, his successor, the Compensation and Nominating Committee recommended, and the Board approved, a consulting agreement with Mr. Outlaw. The consulting agreement had a term from November 1, 2001 through May 31, 2003. This agreement required Mr. Outlaw to provide consulting services related to our business strategy, the budget and planning process and customer and business relations. As compensation for these services, Mr. Outlaw received lump sum payments of $167,000 on May 31, 2002 and $175,000 on May 31, 2003. The agreement also provided that the loans outstanding under the Agreement to Provide Loan(s) to Exercise Key Employees' Stock Options would be forgiven in equal parts on May 31, 2002 and 2003.

Mr. Robinson is a stockholder of the law firm of Robinson and Diss P.C. (formerly Lentz, Evans and King P.C.), which has represented us in various legal matters. For the year ended December 31, 2003, the total amount of legal fees paid to Lentz, Evans and King P.C. was approximately $43,286

4/15/2003 Proxy Information

Consulting Agreement

In June 2001, as an incentive to Mr. Outlaw to extend his retirement date to October 31, 2001 and to provide transitional support to Mr. Dea, his successor, the Compensation and Nominating Committee recommended, and the Board approved, a consulting agreement with Mr. Outlaw. The consulting agreement has a term from November 1, 2001 through May 31, 2003. This agreement requires Mr. Outlaw to provide consulting services related to our business strategy, the budget and planning process and customer and business relations. As compensation for these services, Mr. Outlaw received a lump sum payment of $167,000 on May 31, 2002 and will receive a lump sum payment of $175,000 on or about May 31, 2003. The agreement also provides that the loans outstanding under the Agreement to Provide Loan(s) to Exercise Key Employees' Stock Options will be forgiven in equal parts on May 31, 2002 and 2003. See further "—Loan Agreements" below.

Loan Agreements

In 1989, we entered into agreements with two officers, which committed us to loan amounts sufficient to exercise some of their respective stock options. We agreed to forgive the loans and accrued interest if the officers were continuously employed by us for periods specified by the Board. During the 2002 fiscal year, the following amounts, including accrued interest, were forgiven: Lanny F. Outlaw, $216,012 related to the exercise of 25,000 options, with $216,012 remaining outstanding as at December 31, 2002, and John C. Walter, $425,171 related to the exercise of 25,000 options. We have agreed to forgive, effective May 2003, the remaining $216,012 of the loan provided to Mr. Outlaw.

Fees Paid for Legal Services

Mr. Robinson is a stockholder of the law firm of Lentz, Evans and King P.C., which has represented us in various legal matters. For the year ended December 31, 2002, the total amount of legal fees paid to Lentz, Evans and King P.C. was approximately $16,636.

Transactions with The Prudential Insurance Company of America

At December 31, 2002, we had loans outstanding in the amount of $108.3 million with The Prudential Insurance Company of America, a wholly-owned subsidiary of Prudential Financial, Inc., and paid interest of approximately $9.2 million related to these loans.