The Dow Jones industrial average dropped 185.46 points, or 1.2 percent, to close at 15,451.09 — 225 points below its all-time closing high reached Wednesday after the Fed's announcement.
All 10 industry groups in the S&P 500 fell, led lower by telecom companies and utilities. The S&P also fell on Thursday, making this its first two-day decline in almost three weeks.
Until now, September defied the worriers. The stock market has bounced backed from an August swoon, despite a calendar loaded with potential rally killers.
Summers, a former Treasury secretary, was viewed as being more likely to rein in the Fed's massive stimulus program, which has kept interest rates low and boosted corporate profits.