(Reuters) - The Commodity Futures Trading Commission (CFTC) has reached out to a number of banks, including JPMorgan Chase ( JPM ), Bank of America ( BAC ) and Citigroup ( C/PN ) to see if they have been preventing would-be whistleblowers from speaking out, Bloomberg News reported on Wednesday.

CFTC is asking banks for non-disclosure agreements in their swaps and clearing businesses, and has also sought employment and customer agreements in those businesses, the report added, citing people familiar with the matter.

CFTC, JPMorgan ( JPM ), Citigroup ( C/PN ) did not immediately respond to Reuters requests for comment, while BofA declined to comment.

The top financial regulator joins the U.S. Securities and Exchange Commission, which has increased its oversight in this area and has levied fines against companies that don't comply.

In January, JPMorgan ( JPM ) agreed to pay a $18 million civil penalty to settle charges it violated whistleblower protection rules, the U.S. SEC said.

A top enforcer of criminal malfeasance on Wall Street, Damian Williams has also encouraged whistleblowers to come forward and report wrongdoing under a new program aimed at uncovering illegal activity.