The interest credit card companies earn on their loans have hit an all-time high, the Consumer Financial Protection Bureau said on Thursday.

The average annual percentage rate (APR) on credit cards—or the interest firms charge their borrowers—increased to a record-high 22.8% in 2023 from 12.9% in 2013, according to the bureau.

Credit card companies typically form this APR by adding a rate on top of the prime rate. That additional rate is also called the APR margin.

According to the bureau, the average APR margin has also reached an all-time high, which contributed an additional $25 billion in revenue for the large credit card firms. "Increases to the average APR margin—despite lower charge-off rates and a relatively stable share of subprime borrowers—have fueled issuers’ profitability for the past decade," the bureau said. The bureau said it had found found high levels of concentration in the consumer credit card market and evidence of practices that inhibit consumers from finding alternative products. "These practices may help explain why credit card issuers have been able to prop up high interest rates to fuel profits," it said.

The issue of high rates charged by card companies has been in focus this week, after Capital One (COF) announced a $35.3 billion takeover of Discover (DFS), in a deal that would create the nation’s largest credit card lender by balance owed. The creation of bigger credit card companies could push interest rates even higher, consumer advocates have said.