Another wave of corporate dealmaking stoked investors' confidence in the economy and carried stocks sharply higher Monday.

Analyst upgrades of Alcoa Inc. and Intel Corp. and positive momentum on President Obama's health care overhaul also helped drive a broad advance on the stock market. Major indexes closed off their highs of the day but still rose about 1 percent. The Dow Jones industrial average jumped into the black for the month.

Bond prices tumbled as stocks rose, pushing the yield on the benchmark 10-year Treasury note up to its highest level since August. The dollar strengthened, hurting commodities prices.

Stocks got an early boost Monday after French drug maker Sanofi-Aventis SA announced plans to buy U.S. health care products company Chattem Inc. for $1.9 billion, while mining equipment maker Bucyrus International Inc. said it planned to buy Terex Corp.'s mining equipment division for $1.3 billion. Dutch automaker Spyker Cars submitted a new offer to buy Saab from General Motors Co.

Robert Pavlik, chief market strategist at Banyan Partners, said the flurry of corporate deal activity is an encouraging sign of strength in the economy.

"Companies are revealing that they are in a better position financially," he said. "If they weren't feeling as confident, you wouldn't see this type of activity occurring."

The deals announced Monday follow Exxon Mobil Corp.'s $29 billion takeover of XTO Energy Inc. last week.

In other corporate news, aluminum maker Alcoa Inc. announced an $11 billion joint venture in Saudi Arabia. The deal, along with an analyst's upgrade of the stock, drove Alcoa shares up nearly 8 percent, making it the best performer among the 30 stocks that make up the Dow.

An upgrade of chip maker Intel Corp. helped boost technology stocks, while health care stocks rose broadly as a historic health bill moved closer to passage in the Senate.

Investors have been putting the brakes on stock buying since November, stepping back from the market following a historic rally over the past nine months. At the same time, prospects of an interest rate hike and a potential rebound in the dollar have dogged investors who spent the year taking advantage of low rates to borrow cheaply and invest in stocks and commodities.

The Dow rose 85.25, or 0.8 percent, to 10,414.14, after rising as much as 129 points earlier in the day. The Standard & Poor's 500 index rose 11.58, or 1.1 percent, to 1,114.05, while the Nasdaq composite index rose 25.97, or 1.2 percent, at 2,237.66.