Wall Street's main indexes opened lower on Thursday as downbeat earnings from big U.S. banks JPMorgan Chase & Co and Morgan Stanley underscored concerns about a sharp economic downturn caused by aggressive monetary policy tightening.

As of 9:43 a.m. EST, the S&P 500 was down by 1.91%, Nasdaq had lost 1.71%, and the Dow Jones Industrial Average shed 1.94%, or 596.74 points.