FORTUNE — Citigroup appears to have evidence of wrongdoing at the bank.
On Friday, Citi (C) released a memo that CEO Michael Corbat sent to his staff two weeks ago saying he has knowledge of instances in which a number of the bank’s employees have “violated our Code of Conduct and disrespected our values.”
Corbat didn’t say specifically what activity he was referring to, how many employees at the bank were involved, or when it occurred. He just said that bank officials had uncovered the bad behavior over the past 16 months. Corbat said the activity was an ethical violation, but it wasn’t clear whether Citi had determined if its employees have broken the law. Corbat said if the situation warrants, the bank would refer the case to the proper authorities.
Citi released the memo on the same day that it had to restate its earnings due to a fraud that occurred at a company it lent money to in Mexico. The bank said an employee of its Mexican unit known as Banamex was involved in processing fraudulent documents that led to the bad loans. Citi said it is investigating and that it is working with Mexican authorities. In its most recent financial filing, Citigroup said it was being investigated by the civil division of the Department of Justice in connection with sales of mortgage bonds.
Still, it’s unusual for a bank’s CEO to admit wrongdoing before it has been officially charged. Here’s the whole memo: