The Consumer Financial Protection Bureau (CFPB) announced Thursday that it had fined Wells Fargo $100 million over charges that thousands of its employees opened up secret accounts in customers’ names to boost sales numbers.

“Wells Fargo employees secretly opened unauthorized accounts to hit sales targets and receive bonuses,” CFPB Director Richard Cordray said in a statement. “Because of the severity of these violations, Wells Fargo is paying the largest penalty the CFPB has ever imposed. Today’s action should serve notice to the entire industry that financial incentive programs, if not monitored carefully, carry serious risks that can have serious legal consequences.”

The bureau said that employees aimed to meet sales targets under compensation programs that rewarded them for encouraging customers to enroll in deposit accounts, credit and debit cards, and online banking.

Bank employees temporarily funded new accounts by transferring funds from customers’ existing accounts, a practice which dates back at least five years, the regulator said. The CFPB estimated the practice may have resulted in as many as 1.5 million deposit accounts and 565,000 credit cards that might not have been authorized by customers. Additionally, employees sometimes created phony email addresses to enroll customers in online banking, the bureau said.

In a statement, the bureau said that while compensation programs like the one described here are common and accepted, Wells Fargo “failed to monitor the implementation of these programs with adequate care.”

In addition to the $100 million paid to the CFPB’s Civil Penalty Fund, Wells Fargo was required to refund all the assorted fees associated with the unauthorized accounts, estimated to be at least $2.5 million. The bank also must hire an independent consultant to review and potentially overhaul its procedures. The will also pay $35 million to the Office of the Comptroller of the Currency and $50 million to the city and county of Los Angeles.