Barclays shares fell 4% on Monday after U.S. President Donald Trump revived his plan to cap credit card interest rates at 10%. Trump announced the proposal on his social media platform, citing excessive rates that currently range from 20% to 30%. The measure, set to begin on January 20, lacks a clear path for implementation.

Banking groups, including the American Bankers Association, warned that a sudden cap could restrict credit access and push consumers toward riskier lending options. Barclays, though headquartered in the UK, maintains significant U.S. operations, making it sensitive to shifts in American financial policy. Investors reacted swiftly, concerned about compressed profit margins in credit card lending.

Trump’s proposal aligns with broader populist themes he has promoted since his first term. However, past efforts to legislate similar caps faced strong opposition from industry groups and stalled in Congress. The renewed push raises fresh questions about how, or whether, the administration can enforce such a cap without congressional support.

Market watchers expect continued volatility in banking stocks as the policy debate unfolds.