Stocks extended their losses into a second day on Wednesday as railroad operator CSX had its biggest drop in 11 years, pulling other industrial companies down with it.
Banks also fell as investors worried that lower interest rates will hurt their profits going forward. Investors expect the Federal Reserve to cut interest rates for the first time in a decade at their next policy meeting in two weeks.
The yield on the 10-year Treasury fell to 2.05 percent from 2.12 percent late Tuesday as investors headed for less risky holdings. Utilities, which are also considered a safer bet, made late gains and held up better than any other industry.
Abbott Laboratories gained 3.1 percent and pushed health care stocks higher after the maker of infant formula and drugs raised its forecast for the year. UnitedHealth Group also rose.
Health care was the only sector other than utilities to finish with modest gains. Technology stocks gave up early gains and finished lower along with the rest of the market.
Corporate profits have so far been beating Wall Street forecasts. But investors are keeping a close watch on the picture that companies paint for the second half of the year.
"You're getting tempered guidance for the most part," said Lindsey Bell, investment strategist with CFRA Research. "It's more of a reality check. Second-half growth is not guaranteed at this point."
The S&P 500 fell 0.7 percent to 2,984.42. The Dow Jones Industrial Average fell 115.78 points, or 0.4 percent, to 27,219.85. The Nasdaq composite fell 0.5 percent to 8,185.21.