Wells Fargo CEO John Stumpf resigned Wednesday as chairman and chief executive of the banking giant, effective immediately. Wells and Stumpf’s tenure there has come under fire in recent weeks after its controversial sales tactics were exposed, resulting in the firings of 5,300 employees. Last month, the bank agreed to a $185 million settlement with regulators for opening millions of accounts without customers’ knowledge. Stumpf attempted to defend the practices before Congress, but was famously called “gutless” by Sen. Elizabeth Warren, who additionally suggested he be under federal investigation for possible criminal activity. Stumpf will be succeeded as CEO by president and chief financial officer Timothy J. Sloan; and his board chairmanship will go to the bank’s independent chairman, Stephen Sanger.