Stocks Slump on Bank Report, Economic Doubts

Rotation from the five strongest stock performers year to date — Apple, Microsoft, Amazon, Facebook and Google/Alphabet — is also weighing on the market, according to Sonders. She noted that "the move toward more traditional cyclical leadership — materials and industrials — likely also will need support from an improving economic backdrop." Lacking that economic improvement the rotation could lead to "more broad-based selling of equities."

Another factor in today's market slide was a report from the International Consortium of Investigative Journalists on U.S. government documents revealing that several big banks including JPMorgan Chase, Bank of New York Mellon, HSBC and Deutsche Bank profited from business with "shadowy characters and criminal networks" even after they were fined for "earlier failures to stem flows of dirty money."