Massachusetts Senator Elizabeth Warren is taking Wells Fargo's consumer accounts scandal straight to the top of the bank.
"There is a serious problem with senior management at Wells Fargo," Warren told CNBC Thursday. "There's a big problem at Wells Fargo."
Wells Fargo was fined a total of $185 million by regulatory agencies including the Consumer Financial Protection Bureau that accused the bank of creating as many as 1.5 million deposit accounts and 565,000 credit card accounts that consumers never asked for. The San Francisco-based banking giant fired 5,300 employees over the course of about five years as a result of the accounts.
As part of a settlement, Wells Fargo neither admitted nor denied the allegations.
Warren, a vocal critic of the big U.S. banks who originally proposed and later led the U.S. Consumer Financial Protection Bureau, said she is not satisfied with CEO John Stumpf's response to the crisis thus far.
"You can't have a scandal of this size and not have some senior management who are personally responsible," she said. "That's what I want to hear from him."
Earlier this week, in an interview with CNBC's Jim Cramer, Stumpf said he has no plans to step down as a result of the scandal, which has hammered Wells Fargo stock for more than 9 percent in the last week.
Representatives for Wells Fargo told CNBC on Thursday that Stumpf will respond to Warren next week, when he attends a Senate Banking Committee hearing in Washington. Warren is also a member of the Senate Banking Committee.
Wells Fargo on Tuesday announced that it will change the way it measures the performance of its retail bank staff. The bank said at a financial services conference in New York Tuesday that only around 10 percent of the fired employees were ranked branch managers or higher. Further, CFO John Shrewsberry said in a presentation on Tuesday, most of the staffers the bank cut for their behavior were under-performers.
On Wednesday, it was reported that federal prosecutors are taking a look at Wells Fargo in the wake of the regulatory action against the bank.
"All they do is fire the low-level employees," Warren said to CNBC. "You can't run a bank like that."