Visa (NYSE:V) and Mastercard (NYSE:MA) shares fell over  5% on Tuesday, extending their recent losses after President Donald Trump reinforced his threat targeting credit card companies.

The payment processing giants faced renewed pressure after Trump voiced support for the bipartisan Credit Card Competition Act on his Truth Social platform. “Everyone should support great Republican Senator Roger Marshall’s Credit Card Competition Act, in order to stop the out of control Swipe Fee ripoff,” Trump wrote.

This legislation aims to limit the fees that banks and payment companies collect from merchants when consumers use credit cards at checkout. These interchange or “swipe” fees represent a significant revenue stream for payment processors and their banking partners.

Tuesday’s decline follows Monday’s selloff, which was triggered when Trump declared that credit card lenders would be “in violation of the law” if they don’t cap interest rates at 10% for one year.

The Credit Card Competition Act, if passed, would introduce more competition into the payment processing market by requiring banks to offer merchants multiple networks to process credit card transactions, potentially reducing the dominant position held by Visa and Mastercard.

The combined regulatory threats have investors concerned about potential impacts on the payment processors’ revenue models, contributing to the continued downward pressure on both stocks.