US STOCKS-Dow, S&P off to worst 4-day Jan start ever as China fears grow
* Oil prices near 12-year lows
* China stocks slide again, yuan currency also drops
* Indexes down: Dow 2.3 pct, S&P 2.4 pct, Nasdaq 3.0 pct (Updates with S&P has worst ever four-day start to the year)
By Caroline Valetkevitch
Jan 7 (Reuters) - U.S. stocks sold off further on Thursday, giving the Dow and S&P 500 their worst four-day starts to a year ever, dragged down by another drop in Chinese equities and oil prices at 12-year lows.
China allowed the biggest fall in its yuan currency in five months, adding to investor fears about the health of its economy, while Shanghai stocks were halted for the second time this week after another steep selloff.
Oil prices fell to 12-year lows and copper prices touched their lowest since 2009, weighing on energy and materials shares. Shares of Freeport McMoran dropped 9.1 percent to $5.61. All 10 S&P 500 sectors ended in the red, though, and the Nasdaq Biotech index fell 4.1 percent.
"People see the weakness in China and in the overall equity market and think there's going to be an impact on corporations here in the United States," said Robert Pavlik, chief market strategist at Boston Private Wealth in New York.
"When you have a market that begins a year with weakness, people are sort of suspect anyway. The economy isn't moving all that well, the outlook is modest at best, and they don't want to wait for the long term. China creates more uncertainty." Continuación...