London stocks off on Moody’s warning By: MarketWatch September 04, 2012 at 06:23 AM EDT The main U.K. index trades lower, tracking losses across Europe after that region is warned by Moody’s Investors Services that it might lose its Aaa rating. Read More >> Related Stocks: BP Plc ADR Barclays Plc ADR Bhp Billiton Ltd ADR Gsk Plc ADR HSBC Holdings Plc ADR Rio Tinto Plc ADR Royal Bank Scotland Group Plc Royal Dutch Shell Cl B ADR