The poison drip never stops. Last week, regulators in the United States fined Goldman Sachs US$22 million for failing to prevent research analysts from feloniously advising favored clients of changes to stock recommendations. And federal prosecutors reportedly will offer immunity against a back-office manager of the busted commodities firm MF Global in return for testimony against its former chief, Jon Corzine, who ran Goldman Sachs before becoming senator and governor in New Jersey. Corzine allegedly signed off on the improper transfer (that is, theft) of customer funds to meet margin calls for the firm's own account.