Large U.S. bank stocks collectively plunged, affected by Bank of America CEO's remarks and AI-themed trading.

Large U.S. bank stocks fell sharply on Monday after Bank of America said trading revenue would be "relatively flat" compared with the third quarter of last year. In addition, growing concerns about the artificial intelligence-themed trade also weighed on the financials sector. Bank of America's decline widened to as much as 5.7%. Chief Executive Officer Brian Moynihan said at the Barclays Global Financial Services Conference that the bank's third-quarter trading revenue would be "relatively flat" year over year. Among the large banks leading declines in the KBW Bank Index: Goldman Sachs fell 4.6%, Citigroup fell 3.5%, Morgan Stanley fell 4.1%, Wells Fargo fell 3.0%, Bank of New York Mellon fell 3.5%, and JPMorgan Chase fell 2.2%. Northern Trust shares fell as much as 4.9%. Chief Financial Officer Dave Fox expects the company's results this quarter to show a "seasonal decline."