NEW YORK ( TheStreet) -- Stocks posted solid gains Tuesday with the major indexes hitting two-year highs, buoyed by fresh deal-making activity and strong earnings reports. Concerns about debt problems in Europe also eased after China said it will support efforts to stem the crisis. All three indexes rose to levels unseen since the days leading up to the collapse of Lehman Brothers in September 2008. The Dow Jones Industrial Average climbed 55 points, or 0.5%, to close at 11,533, finishing within shouting distance of a session-high of 11,549. The S&P 500 advanced 8 points, or 0.6%, to close at 1,255, while the Nasdaq Composite jumped 18 points, or 0.7%, to settle the day at 2,668. Volume totaled around 810 million for the New York Stock Exchange, and 1.67 billion for the Nasdaq. Breadth was positive on both exchanges with advancers ahead of decliners by a more than 2-to-1 ratio. The Dow and the S&P 500 are now up about 10.6% and 12.5% year-to-date, respectively, while the Nasdaq has gained 17.6% so far in 2010, and market strategists are predicting 2011 will be another strong year for equities. "People are recognizing the underlying strength of the U.S. economy, "said Gary Flam, portfolio manager at Bel-Air Investment Advisors. "People who were underinvested in equities after the scars of 2008 and 2009 are coming back. We are beginning to see flows into equities after 18 months." Flam expects stocks will do well in 2011, though he conceded risks do remain. "We are wide-eyed bulls. There definitely are risks out there with Europe, high deficits on the federal, state and local level and a still-struggling housing market ." Basic materials, capital goods, energy and financial stocks led markets higher. Within the Dow, JPMorgan Chase ( JPM), American Express ( AXP) and Bank of America ( BAC) posted the biggest percentage gains. 3M ( MMM), Merck ( MRK) and Intel ( INTC) were among the handful of blue chips in the red. A plethora of M&A headlines contributed to Tuesday's bullishness. Massey Energy ( MEE) is weighing two takeover bids, according to a Wall Street Journal report, but the coal miner has yet to start a formal auction process. The stock closed up 1.2% at $52.45. Dutch chemicals company DSM offered to acquire Martek Biosciences ( MATK) for $31.50 per share, or $1.09 billion in cash. The board of Martek, a biotechnology company, recommended that shareholders approve the offer. Shares of Martek soared 35.6%, to $31.67.