With hundreds of companies reporting earnings this week and next, investors were cheered by results from Bank of America Corp., Wells Fargo & Co. and others, even as earnings from Dow component 3M Co. disappointed Wall Street.

This week's earnings reports will give Wall Street a much clearer picture of the economy, analysts said, and could draw even more investors back into the market if earnings reports and forecasts for the year ahead remain strong.

"I think there's a bias toward optimism on the part of investors, but mostly it's just wait and see," said Hugh Johnson, chief investment officer at First Albany Corp. "We've had good earnings, but it's only this week that we'll be getting into the real heart of earnings season."

The Dow Jones industrial average rose 70.79, or 0.67 percent, to 10,628.79.

Broader stock indicators moved substantially higher. The Standard & Poor's 500 index was up 11.46, or 0.97 percent, at 1,195.98, and the Nasdaq composite index gained 18.13, or 0.87 percent, to 2,106.04.

It was the first time in 2005 that the Dow, S&P and Nasdaq enjoyed back-to-back gains, having risen in Friday's session. The markets were closed yesterday for Martin Luther King Jr. Day.

A dip in crude futures also helped the buying after the major indexes start the session lower. Oil prices topped $49 per barrel in early trading, but slumped considerably by midday and fell below $48 by the afternoon. A barrel of light crude settled at $48.38, unchanged from the previous session, on the New York Mercantile Exchange.

"I think you saw a handful of investors deciding that the S&P, in particular, had gone down far enough and decided to place some big bets, and that started us off toward positive territory," said Brian Williamson, an equity trader at The Boston Company Asset Management. "And that move, with earnings going well and oil prices falling, kind of cascaded to the point we're at now."

The strong earnings reports from the financial sector led to optimism that the Federal Reserve — seeing confidence in corporate America and some strength in the dollar over the past week — would not abandon its gradual pace in raising interest rates.

Bank of America rose 84 cents to $45.73 after posting earnings of 94 cents per share, on par with analysts' expectations. The company said its integration of FleetBoston, which it purchased last year, remained on track.

Wells Fargo & Co. saw its profits rise 10 percent from a year ago, with revenues outstripping Wall Street's projections. However, its quarterly profit missed estimates by 2 cents per share. Wells Fargo climbed 77 cents to $61.46.

Charles Schwab Corp. rose 27 cents to $11.39 as the discount brokerage took $62 million in charges due to cost-cutting measures and the closure of its capital markets business. Without the charges, Schwab beat Wall Street profit expectations by a penny per share.

Ameritrade Holding Corp. surpassed profit forecasts by 3 cents per share in its latest quarter, buoyed by strong client balances and a positive interest rate environment. The online brokerage also increased its 2005 profit estimates. Ameritrade gained 42 cents to $12.85.

Industrial conglomerate 3M saw its earnings grow 16.3 percent in the fourth quarter, and its quarterly profits fell in line with Wall Street forecasts. The company also projected moderate profit growth in 2005. 3M dropped $1.95 to $82.02.

Drug maker Abbott Laboratories Inc. lost 21 cents at $46.04 after matching Wall Street's estimates. The company also reiterated its 2005 outlook, expecting sales growth of 10 percent to 12 percent.

Charter Communications Inc. announced that Carl Vogel, the company's president and chief executive, has resigned from the cable television giant. The resignation was by mutual agreement, the company said. Vogel also gave up his seat on Charter's board. The company was down 13 cents at $1.92.

Krispy Kreme Doughnuts Inc., facing a federal accounting investigation and sagging profits, said its CEO, Scott Livengood, is also retiring as part of an executive shakeup. The company reported an 18 percent drop in sales over the past two months. Krispy Kreme rose 89 cents, or 10.21 percent, to $9.61.

After the session, IBM Corp. released its quarterly earnings, which beat Wall Street forecasts by 6 cents per share as profits rose 12 percent from a year ago. IBM was up 80 cents at $94.90 in the regular session, then gained 49 cents to $95.39 in after-hours trading.

Advancing issues outnumbered decliners by nearly 9 to 4 on the New York Stock Exchange, where preliminary consolidated volume came to 2.03 billion shares, compared with 1.66 billion on Friday.

The Russell 2000 index of smaller companies was up 7.39, or 1.2 percent, at 624.87.