Wall Street advanced on Tuesday after U.S. President Barack Obama signed a sweeping healthcare reform bill.

Obama's signature makes the bill, the same as the Senate passed in December, immediately become the law of the land. The historic 938-billion-dollar reform scheme is expected to bring health insurers 32 million subsidized customers by 2019.

Obama said it would take four years to fully implement some of the law's provisions.

Later in the day, the Senate began debating the House's package of revisions, known as a reconciliation bill, under a rule that permits passage with a simple majority.

Wall Street also got a boost from a report on existing home sales. The National Association of Realtors said in its latest report that sales of previously occupied homes fell 0.6 percent in February to an annual rate of 5.02 million units. The reading topped analysts' estimate of 5 million.

Lawrence Yun, NAR chief economist, said widespread winter storms in February may mask underlying demand.

Total housing inventory at the end of February rose 9.5 percent to 3.59 million existing homes available for sale, which represents an 8.6-month supply at the current sales pace, up from a 7.8-month supply in January.

The national median existing-home price for all housing types was 165,100 dollars in February, which is 1.8 percent below the February 2009 level, according to the report.

Investors accounted for 19 percent of transactions in February, compared with 17 percent in January. The remaining sales were to repeat buyers.

The Dow Jones industrial average gained 102.94, or 0.95 percent, to 10,888.83. The Standard & Poor's 500 index added 8.36, or 0.72 percent, to 1,174.17 and the Nasdaq was up 19.84, or 0.83 percent, to 2,415.24.