In late 2011, mounting fines and liabilities over Bank of America Corp (NYSE: BAC ).'s role in the housing collapse pushed its stock price below $5. Still, the bank was able to add more than $80 billion in assets the following year. Ratcheting Up The Wells Fargo sanction -- called unprecedented by Fed officials -- arguably marks an apex for central-bank enforcement actions that have been ratcheting up in recent years. The Fed has at times put a bank's growth in check, such as in 2005 when it told Citigroup Inc (NYSE: C ). that it was expected to not undertake "significant expansion" until it addressed the issues that gave rise to numerous compliance failures. But before the 2008 financial crisis, the Fed wasn't known for punishing lenders. During former Chair Janet Yellen's tenure it changed course, routinely banning bankers from the industry who had been accused of misconduct and joining other regulators in imposing billions of dollars in fines on Wall Street firms.