U.S. and UK financial stocks fell on Monday following President Donald Trump’s call for a 10 per cent cap on credit card interest rates, a move that threatens a key revenue stream for banks, according to Reuters.

Shares of top U.S. lenders JPMorgan Chase and Bank of America dropped 2.5 per cent and 1.6 per cent, respectively, while Citigroup fell 3.7 per cent and Wells Fargo declined 1.5 per cent. British bank Barclays’ shares also touched their lowest level in nearly a month, down 2.2 per cent.

Consumer finance companies were particularly hard hit. Shares of Synchrony Financial, Bread Financial, and Capital One fell between 8 per cent and 11 per cent, while American Express declined 3.8 per cent. Payment processors Visa and Mastercard slipped 1.8 per cent each, Reuters reported.

Analysts noted that Trump’s announcement, which proposed the 10 per cent cap starting 20 January, could face significant legal challenges, and any rate limit would likely require Congressional approval. “It would take an Act of Congress for such rate caps to be in place, given the overwhelming legal challenges an executive order would likely face,” UBS Global analysts said in a note cited by Reuters.

According to Reuters, market observers also warned that such a cap could force banks to reduce credit limits or close accounts for borrowers with lower credit scores, potentially driving consumers toward alternative, higher-cost lenders. Average U.S. credit card interest rates stood at 20.97 per cent in November, according to the Federal Reserve’s consumer credit report.

Investors will be closely watching commentary from bank executives as the U.S. financial sector begins reporting fourth-quarter earnings this week. JPMorgan is scheduled to report on Tuesday, followed by Bank of America, Citigroup, and Wells Fargo later in the week, Reuters reported.