================================================================================ 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) April 25, 1999 SOUTHWEST GAS CORPORATION (Exact name of registrant as specified in its charter) California 1-7850 88-0085720 (State or other jurisdiction of (Commission (I.R.S. Employer incorporation or organization) File Number) Identification No.) 5241 Spring Mountain Road Post Office Box 98510 Las Vegas, Nevada 89193-8510 (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code: (702) 876-7237 ================================================================================ Item 5. Other Events On April 25, 1999, the Board of Directors of Southwest Gas Corporation (Southwest) unanimously approved a revised offer from ONEOK, Inc. to acquire Southwest for $30 per share in cash. The revised agreement amends the $28.50-a-share accord reached on December 14, 1998. Amendment No. 1 to the agreement and plan of merger is included herein. Item 7. Exhibits 2 Amendment No. 1, dated as of April 25, 1999, to the Agreement and Plan of Merger, dated as of December 14, 1998, by and among ONEOK, Inc., Oasis Acquisition Corporation, and Southwest Gas Corporation. 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. SOUTHWEST GAS CORPORATION Date: April 28, 1999 /s/ EDWARD A. JANOV ---------------------------------------------- Edward A. Janov Vice President/Controller and Chief Accounting Officer