Stocks were little changed on Monday as investors awaited companies' quarterly results to see if earnings would be strong enough to spark further gains in equities.

Alcoa Inc , a Dow component, unofficially launches the earnings season with the release of results after the market's close. While profits for S&P 500 companies are seen rising 11.4 percent from a year ago, according to Thomson Reuters data, some have speculated that the growth is already priced into shares.

Optimism over earnings has contributed to recent gains, despite turmoil in oil-producing regions and the disasters in Japan. The S&P 500 index is up 5.8 percent since the start of the year, but light trading volume has prompted questions about the rally's sustainability.

Alcoa slid 1.1 percent to $17.72 after rising earlier. The aluminum maker is seen posting growth in both earnings and revenue. JPMorgan Chase & Co and Google Inc are on tap to report later in the week.

There's a question of whether companies can meet the fairly optimistic expectations, said John Carey, portfolio manager at Pioneer Investment Management in Boston, which has about $260 billion in assets under management. There's potential for disappointment, but if they come in line or above the market could experience a continued rally.

Carey said he expects earnings to be strong, but there were a lot of odd things that happened during the quarter that could affect results, citing higher prices for raw materials.

The Dow Jones industrial average <.DJI> was up 5.03 points, or 0.04 percent, at 12,385.08. The Standard & Poor's 500 Index <.SPX> was down 2.78 points, or 0.21 percent, at 1,325.39. The Nasdaq Composite Index <.IXIC> was down 11.99 points, or 0.43 percent, at 2,768.43.

NYSE Euronext on Sunday rejected a joint buyout bid from Nasdaq OMX Group and IntercontinentalExchange and said it was sticking with an earlier bid from Deutsche Boerse AG . Nasdaq reaffirmed that its offer was superior to Deutsche Boerse's lower offer.

NYSE shares fell 2.1 percent to $37.90 while Nasdaq OMX fell 1.4 percent to $28.04 and ICE was 0.3 percent higher at $120.86.

Also in deal news, Endo Pharmaceuticals Holding Inc said it would buy American Medical Systems Holdings Inc for about $2.6 billion while Level 3 Communications Inc agreed to buy Global Crossing Ltd for $1.9 billion in stock.

Endo rallied 2,6 percent to $41.92 while American Medical jumped 32 percent to $29.46. Level 3 rose 8.7 percent to $1.57 and Global Crossing surged 55 percent to $23.00.

Biogen Idec Inc rose 6.5 percent to $78.04 and was the top percentage gainer on the Nasdaq 100 <.NDX> after the company's experimental multiple sclerosis drug met the main goal in the first of two important late-stage studies.

Flextronics International was the top percentage loser on the Nasdaq 100, falling 3.5 percent, after rival Benchmark Electronics Inc cut its first-quarter outlook, citing soft demand.

Tenet Healthcare Corp said it has sued its suitor, Community Health Systems Inc , claiming the rival hospital operator improperly admitted patients to overbill insurers, including Medicare.

Shares of Tenet sank 15.5 percent to $6.38 while Community slumped 34 percent to $26.45.

(Editing by Leslie Adler)