Investors were in an optimistic mood yesterday, sending the Dow Jones Industrial Average surging past the 11,000 mark for the first time in more than four years.

The blue-chip average crossed the elusive barrier shortly after 1 p.m., the first time the Dow industrials had been above 11,000 since June 13, 2001. The DJIA then seesawed above and below the 11,000 mark through the afternoon before ending at 11,011.90, up 52.59, or 0.5%. It was the average’s first 11000-plus close since June 7, 2001.

The Dow’s ascent was boosted by a strong performance from General Motors, a Dow component. The auto maker’s stock rose $1.61, or 7.7%, to $22.41, lifted by an upgrade from Goldman Sachs. The investment bank raised its rating on GM shares to in line from underperform, citing valuation and the belief that GM doesn’t face an imminent bankruptcy. GM’s chief executive said on CNBC that the chances of a bankruptcy filing remain “remote.”

Other stock-market indexes also rose, as the rally that started 2006 continued. Much of the bullishness has been based on hopes that the Federal Reserve’s interest rates hikes soon will end. The Standard & Poor’s 500-Stock Index climbed 4.70,or 0.4%,to 1290.15. The Nasdaq Composite Index added 13.07, or 0.6%, to end at 2318.69.

Yesterday’s advance still left the Dow several hundred points short of its all-time high of 11,750.28, set on January 14, 2000. But rising back past the 11,000 level was seen as an important milestone for the stock market, which has performed well so far in January in what investors hope is a good omen for the remainder of the year. “It gives everyone a warm, fuzzy feeling,” the head trader at VFinance Investments, Bill Groeneveld, said.

To be sure, the stock market’s future course remains uncharted. Barry Hyman, equity market strategist at Ehrenkrantz King Nussbaum, said he has concerns about issues such as the economy as the year wears on. “We are bullish in the first half and cautious in the back half of the year,” he said.