Wall Street’s biggest banks are beginning to build their defences against downturns, signalling an end to the steady thinning of reserves that has helped boost profits in the past five years. Tapping into reserves set aside for bad loans has become a reliable source of income for the banks in the post-crisis environment, allowing them to offset the effects of weak demand and ultra-low interest rates. Regulators let lenders dip into reserves in this way if they can argue that an improving outlook makes losses less likely. CONTINUE