Big banks from the UK, France and Japan helped investors treble or quadruple their bets on Bernard Madoff by lending billions of dollars to “feeder” funds, which placed their money with the alleged fraudster. HSBC, RBS, Nomura and BNP Paribas lent the money without spotting a fraud, in at least one case without due diligence teams visiting Madoff’s brokerage, which actually held the assets.