Colorado became the 34th state to file a lawsuit against seven of the largest U.S. tobacco companies, seeking damages for tobacco-related medical costs. . . . San Francisco-Based BankAmerica Corp. may have agreed to buy investment bank Robertson, Stephens & Co. for about $500 million, in the latest merger between a bank and a securities firm, according to news reports by CNBC and the San Francisco Chronicle. . . . New York's American International Group Inc. said it appealed a California judge's decision approving the sale of San Diego-based Golden Eagle Insurance Co. to Boston-based Liberty Mutual Group. . . . Cincinnati-based Procter & Gamble Co. said it won antitrust clearance from the Justice Department to complete its $2-billion acquisition of Tambrands Inc., based in White Plains, N.Y. . . . Switzerland's Novartis faces an antitrust investigation tied to the firm's $36-million investment in Heska Corp., a Colorado firm that is using biotechnology to develop vaccines for pets. . . . Herzog, Heine, Geduld Inc., a large wholesale dealer based in New York, agreed to pay $30.6 million to settle a class-action lawsuit that accuses brokerages of price-fixing on Nasdaq. Herzog President Emanuel "Buzzy" Geduld said the company had done nothing wrong and settled to avoid the costs of litigation.