P.M. BRIEFING : Compute Associates to Buy Cullinet

Computer Associates International Inc. said today it will buy Cullinet Software Inc. for about $320 million in stock, a move that will strengthen its standing as the world’s biggest independent software company.

Computer Associates had $1.03 billion in revenue last year, becoming the first software company to reach the billion-dollar mark. Cullinet had revenue of $203 million.

Both companies get most of their revenue from software that runs on big mainframe computers made by International Business Machines Corp., although Computer Associates’ appetite for acquisitions has carried it into other fields.

Computer Associates is headed by Charles B. Wang, who has vowed to increase revenue by 30% a year. Its growth strategy has vaulted it ahead of such better-known companies as Microsoft Corp. and Lotus Development Corp.