NEW YORK - Stocks ended flat Monday after expectations that a tax-cut package would pass the Senate kept shares higher for much of the day.

The tax-cut compromise brokered by the White House and Republicans underwent its first Senate vote late Monday and passed overwhelmingly in a test vote.

If enacted, the package would extend tax cuts passed during the Bush administration for all income levels for another two years. It also would extend unemployment benefits through next year and put in place a one-year reduction in Social Security taxes.

Traders were also encouraged by a handful of deals announced Monday. General Electric Co. is paying $1.3 billion to buy British oilfield company Wellstream Holdings P.L.C. and Dell Inc. is spending $960 million for network storage company Compellent Technologies Inc.

The S&P 500 index eked out a new 2010 high for the fourth time in four days. The index rose 0.06 point to 1,240.46.

Other indexes took a late afternoon spill. The Dow Jones industrial average closed with a gain of 18.24, or 0.16 percent, to 11,428.56, having been up as many as 70 points earlier. The Dow is now just 15.52 points from its 2010 closing high, reached Nov. 5.

The Nasdaq composite index fell 12.63, or 0.5 percent, to close at 2,624.91. That snapped a six-day streak in which the index notched new 2010 highs.

The tax plan has crushed the prices of Treasury bonds since it was announced last Monday.

World stock markets rose. China's benchmark Shanghai Composite Index gained 2.8 percent after Chinese authorities surprised investors by not raising interest rates. Investors had anticipated an interest rate increase to combat high inflation.

Blue-chip stocks in Europe rose 0.2 percent. The dollar fell 0.9 percent against an index of six currencies.

In corporate news, Hewlett-Packard Co. fell 2.1 percent to $41.65 after Goldman Sachs gave the hardware company a sell rating. Goldman's analysts see tablet computers, such as Apple Inc.'s iPad, taking business away from PCs.

Shares in Dionex Corp. shot up 20 percent to $117.83, after Thermo Fisher Scientific Inc. said Monday it planned to buy the maker of laboratory equipment for $2.1 billion. Thermo Fisher said it would pay $118.50 a share. Shares in Thermo Fisher rose 4.8 percent to $55.56.