* Disney gives back early gains
* Juniper down on U.S. probe into code
* Apple gives biggest boost to indexes
* Indexes end higher: Dow 0.72 pct, S&P 0.78 pct, Nasdaq 0.93 pct (Updates to close)
By Noel Randewich
Dec 21 (Reuters) - U.S. stocks ended stronger on Monday, helped by bounces in Apple and Microsoft as well as 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, rose 1.23 percent and boosted major indexes.
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 on Friday.
Tenet Healthcare Corp jumped 11.6 percent, its best day since June. Universal Health Services Inc rose 3.64 percent.
Notwithstanding Monday's broad 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 1.8 percent for the year as slowing growth in China, a slump in commodities prices and uncertainty over U.S. interest rates buffeted shares. The Dow Jones industrial average is down about 3.2 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."
The Dow Jones industrial average rose 0.72 percent to end at 17,251.48 points and the S&P 500 gained 0.78 percent to 2,021.16.
The Nasdaq Composite added 0.93 percent to finish at 4,968.92, helped by a 1.29 percent gain in Microsoft.
All of the 10 S&P sectors ended higher, led by a 1.11 percent rise in telecoms and a 1.06 percent increase in technology.
The effects of the first Federal Reserve interest rate hike in almost a decade last week continued to resonate with investors.
"It reaffirms our view that the economy is doing really well," said Philip Orlando, chief equity market strategist at Federated Investors in New York.
With oil prices under pressure from global oversupply and tepid demand, the S&P energy sector ended 0.05 percent firmer after spending much of the day at a loss.
Volume on the U.S. exchanges was 6.8 billion shares, compared to a 7.55 billion average over the last 20 trading days, according to Thomson Reuters data.
Trading volumes were expected to be light for the rest of the week, with stock markets operating a shortened session on Thursday and closing on Friday for Christmas.
Juniper Networks Inc dropped 4.99 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 lost 1.05 percent as worries about the outlook for its ESPN sports network outweighed enthusiasm about the record-breaking opening weekend for the latest Star Wars movie.
Advancing issues outnumbered decliners on the New York Stock Exchange 2,013 to 1,041. On the Nasdaq, 1,764 issues rose and 1,095 fell.
The S&P 500 index showed two new 52-week highs and 20 new lows, while the Nasdaq recorded 40 new highs and 100 new lows. (Additional reporting by Abhiram Nandakumar in Bengaluru; Editing by Jeffrey Benkoe and Meredith Mazzilli)