* Disney gives back early gains
* Juniper down on U.S. probe into code
* Apple gives biggest boost to indexes
* Indexes up: Dow 0.42 pct, S&P 0.51 pct, Nasdaq 0.69 pct (Updates to afternoon)
By Noel Randewich
Dec 21 (Reuters) - U.S. stocks moved higher on Monday, helped by a bounce in Apple and a rally in hospital stocks after more Americans signed up for subsidized health insurance.
Shares of Apple Inc, under pressure in December over concerns that iPhone sales could miss estimates, rebounded 1 percent and gave a boost to major indexes.
Nine of the 10 S&P sectors were higher, led by a 0.75 percent rise in health and a 0.74 percent increase in technology.
About 6 million people have signed up for subsidized health insurance, often called Obamacare, including 2.4 million new customers, the U.S. government said.
Tenet Healthcare Corp jumped 9.5 percent and was headed for its best day since June. Universal Health Services Inc rose 3.4 percent.
With oil prices under pressure from global oversupply and tepid demand, the S&P energy sector was headed for its fourth losing day. Chevron Corp shed 1.35 percent.
Notwithstanding Monday's gains, many on Wall Street have acknowledged that 2015 looks to be a modest loss for stock investors, said Jennifer Ellison, a principal of San Francisco-based Bingham, Osborn & Scarborough.
Although the S&P 500 touched record highs in 2015, the index is down about 2.1 percent for the year as slowing growth in China, a slump in commodities and uncertainty over U.S. interest rates buffeted shares. The Dow Jones industrial average is down about 3.5 percent.
"It's going to be tough to get much of a rally now because it's so quiet and volume is already down," Ellison said. "Nobody's interested in anything except making some modest tweaks to their portfolios for year-end spit and polish."
At 2:03 p.m. the Dow Jones industrial average was up 0.42 percent at 17,200.99, and the S&P 500 gained 0.51 percent to 2,015.8.
The Nasdaq Composite added 0.69 percent to 4,956.82.
Trading volumes were expected to be light this week, with stock markets operating a shortened session on Thursday and closing on Friday for Christmas.
Juniper Networks Inc was down 4.7 percent after Reuters reported the U.S. government was investigating whether unauthorized code was inserted in its software, which could be used to spy on customers.
Walt Disney Co was down 1 percent, wiping out earlier gains after the box office-breaking opening weekend for the latest Star Wars movie.
Advancing issues outnumbered decliners on the New York Stock Exchange 1,903 to 1,118. On the Nasdaq, 1,648 issues rose and 1,158 fell.
The S&P 500 index showed two new 52-week highs and 16 new lows, while the Nasdaq recorded 32 new highs and 82 new lows. (Additional reporting by Abhiram Nandakumar in Bengaluru; Editing by Jeffrey Benkoe)