Mesa sold 12.35 million common shares of Unocal.

David Batchelder, president of Mesa Petroleum, said the stock sale--the second-largest transaction in New York Stock Exchange history--was for $22.75 per share, or a total of $278 million. The sale makes Mesa’s net book value $249 million, or $3.79 a share. A Mesa spokesman said the company retained 367,045 Unocal shares, which will be sold later in the year.