(Patrick Sison/AP)

This story has been updated.

Wells Fargo said Monday that two former senior executives, including its long-time CEO John Stumpf, must return an additional $75 million in compensation after a scathing internal report found the bad sales practices that have rocked the mega bank date back far longer than initially acknowledged.

Stumpf, who stepped down in October, had already agreed to give up $41 million in compensation as the scandal roiled the San Francisco bank. Now, Wells Fargo says it will “claw back” an additional $28 million from Stumpf. The former head of retail banking, Carrie Tolstedt,  who stepped down last year and agreed to give up $19 million in compensation, will lose an additional $47 million in stock options.

It is one of the largest clawbacks of compensation by a company in history and a sign that big U.S. banks feel increasingly under pressure to show the public that they can hold themselves accountable for wrongdoing.

The report was the culmination of a six-month investigation by the bank’s independent board members and comes as Wells Fargo struggles to move beyond the sales scandal. It indicates that the problems at Wells Fargo went on for far longer than originally acknowledged and likely involved more employees and customers.

Wells Fargo admitted last year, for example, that it had fired 5,300 employees over five years for opening accounts for customers who didn’t want the accounts or know about them. But the report found that Stumpf was notified of a problem at one of the bank’s Colorado branches in 2002 that led to a “mass termination” of bank employees, according to the report.

The roots of the problem, the report said, were the autonomy given to Wells Fargo’s community banking division and the apathy of senior executives who downplayed the illicit practices. The executives tended to view the sales abuses as largely “minor infractions and victimless crimes” committed by a relatively few bad apples, and clung to a sales culture that had helped the bank grow so large.

“The Community Bank identified itself as a sales organization, like department or retail stores, rather than a service-oriented financial institution. This provided justification for a relentless focus on sales, abbreviated training and high employee turnover,” the report said.

Wells Fargo has been in lawmakers’ crosshairs since acknowledging last year that some of its employees created as many as 2 million fake accounts — from credit cards to checking accounts — to meet sales goals. In some cases, Wells Fargo customers faced various fees for accounts they did not request, or bank employees took money from an authorized account to create a fake one.

In a tense exchange, Senator Elizabeth Warren badgered Wells Fargo CEO John Stumpf on why he had not offered to give up any of his compensation or to resign in the wake of the fake accounts controversy. (Reuters)

Tim Sloan, who replaced Stumpf as chief executive, escaped without much critique in the report. “We accept the Board’s findings as a critical part of our journey to rebuild trust,” Sloan said in a statement. ”The Board’s comprehensive findings provide another important opportunity to learn from our mistakes and take action to improve the way we operate, serve customers, and lead our team members.”

In addition to the investigation led by the bank’s independent board members, Wells Fargo is also being investigated by several regulators. Federal prosecutors are considering criminal or civil charges against the company, the Labor Department is investigating whether it illegally fired employees who reported the wrongdoing, and several cities and states, including California, have stopped doing business with the bank for now. The House Financial Services Committee is also reviewing thousands of pages of documents turned over by Wells Fargo.

The report is “grossly deficient,” said Dennis Kelleher, president of Better Markets, a nonprofit advocacy group.

“The self-investigation and actions reported today by the Board of Directors of Wells Fargo are grossly deficient. Thousands of Wells Fargo’s employees and officers engaged in serious criminal conduct ripping off millions of customers over many years,” he said. “It is laughable to claim that only two senior executives should be terminated and meaningfully held accountable.”