NEW YORK — A darkening outlook for companies from banks to retailers to energy producers pummeled Wall Street yesterday.

The Dow and the broader Standard & Poor's 500 index are down more than 9 percent in six sessions. The S&P 500, the gauge tracked by professional investors, has now given up half its gains since it closed at an 11-year low on Nov. 20.

A weak government report on retail sales touched off some of the market's latest turbulence. Wall Street knew retailers' cash registers weren't busy during the holiday season but the report was much worse than anticipated. The department said retail sales dropped 2.7 percent last month, more than double the 1.2 percent decline analysts forecast.