EXHIBIT 99A NEWS RELEASE ------------------------------ FOR IMMEDIATE RELEASE CONTACT: December 21, 1999 Barbara B. Forbes Director of Investor Relations 713-374-4870 - ------------------------------------------------------------------------------- NUEVO ENERGY COMPANY ANNOUNCES EXPIRATION OF ITS $257,310,000 EXCHANGE OFFER HOUSTON, December 21 Nuevo Energy Company (NYSE: NEV) announced today the expiration of its offer to exchange its 9 1/2% Senior Subordinated Notes due 2008, Series B, that have been registered under the Securities Act of 1933 for any and all outstanding 9 1/2% Senior Subordinated Notes due 2008, Series A. The exchange offer expired at 5:00 p.m., New York City time, on December 20, 1999. Nuevo Energy Company is a Houston, Texas-based company primarily engaged in the exploration for, and the acquisition, exploitation, development and production of crude oil and natural gas. Nuevo's principal domestic properties are located onshore and offshore California. Nuevo is the largest independent producer of oil and gas in California. The Company's international properties are located offshore the Republics of Congo and Ghana in West Africa and onshore the Republic of Tunisia in North Africa. To learn more about Nuevo, please refer to the Company's internet site at http://www.nuevoenergy.com.