US STOCKS-Wall St turns negative after weak services data
* Private employers added 205,000 jobs in Jan. vs est 195,000
* Comcast rises; biggest boost to S&P 500, Nasdaq
* Match Group slumps after revenue misses estimates
* Indexes down: Dow 0.56 pct, S&P 0.98 pct, Nasdaq 1.31 pct (Adds details, changes comment, updates prices)
By Tanya Agrawal
Feb 3 (Reuters) - U.S. stocks gave up early gains and turned negative on Wednesday after data showed that the economy's service sector expanded at a slower-than-expected rate, raising concerns that weakness in manufacturing is spreading to other sectors.
The Institute for Supply Management (ISM) said its index of non-manufacturing activity fell to 53.5 in January from 55.8 in December. The reading was below expectations of 55.1.
Falling oil prices, tepid U.S. growth and fears regarding a China-led global slowdown have been major factors for a torrid start to the year for stocks. The S&P 500 is already down 6.9 percent this year.
"I think the next couple of quarters could be really volatile," said Bryce Doty, portfolio manager at Sit Investment Associates. Continuación...