A summary of Southern California-related business litigation developments during the past week.

Shearson Lehman Sues Former Employee: Shearson Lehman Hutton Inc. sued Mazen Ali-Ahmad, a former securities broker for the firm, in U.S. District Court in Los Angeles after he allegedly violated company rules about paying cash up front on all trades. The suit said that when a margin call was issued to Ali-Ahmad, his personal account was liquidated, leaving an unpaid balance of $377,000--of which at least $371,742 allegedly remains unpaid. Ali-Ahmad could not be reached for comment on the suit, which seeks the unpaid sum plus interest and costs. (Filed April 4, 1990. Case No. 90-1778)