Related Link: Wells Fargo Blasted On Social Media Following Fraud Settlement Several years ago, Bank of America Corp BAC disclosed a $4 billion accounting error that resulted in the Federal Reserve retroactively rejecting the bank's dividend and capital return plan. The JPMorgan Chase & Co JPM London whale trading loss resulting from an ineffective CDS hedging strategy cost the bank about $6 billion. M&T Bank Corporation MTB 's acquisition of Hudson City Bancorp was delayed three years after a regulator found "significant weakness" in M&T's risk management.