American Savings & Loan said it sold $725 million in troubled assets in 1986, 21% more than its target of $600 million . . . Canada's major banks cut their prime lending rates to 9% . . . Guinness PLC, embroiled in the worst British financial scandal in years, said it had turned down a merger bid from the Argyll supermarket chain, which it defeated in a bitter takeover battle for Distillers Co. last year . . . Marsh & McClennan Cos. of New York and two former employees settled charges with the Securities and Exchange Commission stemming from allegations that the employees, Dorothy Conway and Chester Gan, falsified financial records of the insurance broker's investment management group . . . Assets of the nation's 378 money-market mutual funds rose $168.9 million to $234.43 billion in the latest week, according to the Investment Company Institute, a Washington mutual fund trade group . . . MCI will lower interstate long-distance rates by an average of 13.5% for business customers and 8.5% for residential customers . . . Lloyd's of London, the world's largest insurance underwriting exchange, accepted a government panel's recommendation to restructure, shifting power to independent directors and investors.