The name of the whistleblower was not disclosed.

"We take seriously the concerns of current and former team members," wrote Wells Fargo spokeswoman Richele Messick in an emailed statement to Reuters. "This decision is a preliminary order and to date there has been no hearing on the merits of this case. We disagree with the findings and will be requesting a full hearing of the matter."

Wells Fargo was fined last year for opening up to 2.1 million customer accounts without their knowledge over several years to meet aggressive sales targets.

The revelation damaged the bank's reputation, spurred investors to sell its shares for several weeks and led to the resignation of its chief executive last year.

Despite news reports and lawsuits claiming the bank had retaliated against whistleblowers, an investigative report by the bank's board of directors released on April 10 said "based on a limited review completed to date," outside law firm Shearman & Sterling had "not identified a pattern of retaliation" against employees in Wells Fargo's branch banking unit who complained about sales pressure or practices.

In a different case, the Department of Labor in April ordered Wells Fargo to reinstate a whistleblower, though that former staffer's concerns related to bank, mail and wire fraud -things that were not at issue in the sales practices scandal.

Wells Fargo still faces probes from federal, state and local government agencies including the U.S. Department of Justice, as well as a number of private lawsuits, according to its quarterly securities filing in May.

(Reporting by Dan Freed in New York; Editing by Bernadette Baum and Matthew Lewis)

By Dan Freed