NEW YORK (AP) – Investors have gotten used to bad news, but layoffs topping 600,000 a month still made for a volatile day on Wall Street.

The major indexes remain down sharply for the week and near 12-year lows. The Dow Jones industrial average is down 6.2 percent for the week, and the Standard & Poor’s 500 index is down 7 percent.

Many market watchers say there’s no reason stocks can’t slide further.

“My sense is we haven’t discounted all the negatives out there as of yet,” said Rob Lutts, president of Cabot Money Management.

Big institutional investors are still largely waiting for positive signs from the economy before making any major commitments. As a result, the market is largely being driven by “short” traders, who sell borrowed stock and then buy it back later in hopes that the price will decline in the meantime. That makes for a choppy, unpredictable market.

“The shorts are having a complete field day in this environment,” said Kent Engelke, managing director at Capital Securities Management in Glen Allen, Va. “Right now you have everybody so fearful, and these shorts are controlling the market.”

According to preliminary calculations, the Dow Jones industrial average rose 32.50, or 0.5 percent, at the 6,626.94. The Standard & Poor’s 500 index rose 0.83, or 0.12 percent, at 683.38, and the Nasdaq composite index fell 5.74, or 0.44 percent, at 1,293.85.

Three stocks fell for every two that rose on the New York Stock Exchange. Volume came to 1.77 billion shares.