The pan-European STOXX 600 slipped 0.2% by 0807 GMT. Banks were the biggest drag on the index, dropping 1.1%.
Barclays fell 4.5%, hitting its lowest in nearly a month, and HSBC dropped about 1%.
On Friday, Trump called for a one-year cap on credit card interest rates at 10%, starting on January 20, but did not provide details.
Investors also fled to safe-haven assets after Trump’s officials threatened to indict Powell over comments to Congress about a building renovation project. Powell said it was an attempt to influence interest rates.
Meanwhile, AstraZeneca dropped nearly 1% after losing its spot in the Nasdaq-100 index.
French biotech Abivax surged 22.8%. In an interview with Bloomberg News, Abivax CEO Marc de Garidel said major pharmaceutical companies cannot ignore the potential of his company’s experimental inflammatory bowel disease drug.