Prime Computer, the target of a hostile...

Prime Computer, the target of a hostile takeover bid from MAI Basic Four of Tustin, has filed a motion in U.S. District Court in Boston claiming that MAI’s proposed financing for its $970-million offer violates Federal Reserve Board margin requirements . . . Centaur Partners said its $765-million cash offer for chemical manufacturer Pennwalt Corp. was being extended to midnight on Jan. 25 . . . May Department Stores Co. said it will strengthen the presence of its Lord & Taylor division in New Jersey by turning four Hahne’s department stores into Lord & Taylor stores and adding one more . . . The Treasury reported that the average yield on seven-year Treasury notes at the latest auction rose to 9.30%, up from 8.73% at the last comparable auction Oct. 12 . . . Standard & Poor’s has lowered Santa Clara, Calif.-based National Semiconductor Corp.’s rating on $125 million of convertible exchangeable preferred stock to B-plus from double B . . . Norfolk Southern Corp. said its two rail subsidiaries, Norfolk & Western Railway and Southern Railway, plan to spend $695 million on capital improvements in 1989, up 12% from 1988.