JPMorgan Chase executives faced a severe grilling by Senators Friday over more than $6.2 billion in losses on a derivatives portfolio, Bloomberg reports. 

Members of the Senate Permanent Subcommittee on Investigations put the executives on the defensive, often drawing statements of apology or great regret.

Ina Drew, who previously led the chief investment office responsible for the loss, said she did not know of the deceptive conduct until after she left the company, Bloomberg reports.

Other executives expressed their dismay about the situation.

“This whole thing is regrettable and unacceptable,” said Ashley Bacon, acting chief risk officer of the bank. “The onus of proof is on us now to demonstrate how this can’t happen in other places, how we weathered the financial crisis well everywhere else, and how we can make the entire firm a safer place to the satisfaction of you, everybody else and our regulators.”