The Fed sent the requests, known as tolling agreements, to at least two individuals in recent months, said the people, who asked not to be identified because the letters are private. The agreements would suspend the statute of limitations, usually five or ten years depending on the relevant law, which isn’t clear as no accusations have been made yet.

The move indicates the Fed — which is also in settlement talks with some banks in the matter — is weighing civil action against individuals. The U.S. Department of Justice is planning to file criminal charges against individuals in its currency-rigging probe next year, people with knowledge of the matter have said.

Criminal cases often take priority over civil actions, dragging those matters out. Authorities can ask for waivers as a way to preserve their ability to bring cases.

Corporations enter into tolling agreements because it “helps prevent hasty penalty decisions,” said Adam Kaufmann, a former chief of investigations at the Manhattan District Attorney’s Office. Individuals “often have an entirely different risk calculus. They don’t want to go to jail, or be prohibited from the industry, and so they are less likely to ‘toll the statute.’”

Looming Settlements

At least one trader has already refused to waive the statute of limitations. While tolling agreement requests are common place for U.S. agencies, the traders haven’t been contacted by other authorities, they said.

Regulators and prosecutors around the world are investigating whether foreign-exchange traders shared data about client orders with people at other firms to manipulate the $5.3 trillion-a-day currency market. The first settlements in the affair are expected this month with agencies including the U.K. Financial Conduct Authority. The Fed, the Office of the Comptroller of the Currency and Commodity Futures Trading Commission are also pressing to reach accords when the FCA does, people with knowledge of the matter have said.

The FCA could announce settlements with six banks as early as next week, with at least one of the U.S. agencies likely to reach a deal the same day, according to two people with knowledge of the negotiations. The involvement of a U.S. authority could push back the FCA date to later in the month, one person said.

‘Cultural Changes’

Barbara Hagenbaugh, a spokeswoman for the Fed, declined to comment.

The Fed has civil enforcement powers, which include fines and barring people from the industry. Actions against individuals are less common than bank-wide enforcement from the Fed. In 2010, a Standard Chartered Plc employee was barred from the industry for manipulating client account statements. The year before, an individual who worked at a U.S. unit of UBS AG was banned and fined for hiding losses from his proprietary trades. Employees at a Wells Fargo & Co. subsidiary received prohibition orders for improper handling of mortgages in 2009.

“It’s by going after the individuals that you get cultural changes,” said Cornelius Hurley, director of the Boston University Center for Finance, Law & Policy. The drawback is the regulators are often “dealing with people at the very lowest level.”