Citigroup ( C) is cashing in on its stake in asset manager Legg Mason ( LM). The world's biggest financial services firm intends to sell 8 million shares of Legg Mason stock in an upcoming offering. A week ago, Legg Mason registered the stock for sale in a regulatory filing. The shares Citigroup is selling stem from a deal last year in which Citigroup swapped its asset management business for Legg Mason's brokerage business. In Monday trading, shares of Legg Mason closed at $132.43, down $2.37, or 1.8%. Shares were halted in postclose action ahead of the announcement.