Regional bank PacWest plunged 28 percent while Western Alliance fell 15 percent. Big banks were not immune, with JPMorgan Chase losing 1.6%, Bank of America 3%, Citigroup 2.7% and Wells Fargo 3.8%.

"It is obvious that concerns are re-emerging even after the takeover of First Republic, it is getting worse," said Karl Haeling of LBBW bank. "The market is telling us that it is chasing other banks," he warned, interviewed by AFP.