US STOCKS-Wall St loses ground after mixed economic data

* Indexes off: Dow 0.42 pct, S&P 0.44 pct, Nasdaq 0.49 pct

By Chuck Mikolajczak

NEW YORK, Sept 25 (Reuters) - U.S. stocks were lower shortly after the open on Thursday, on the heels of the biggest gain for the S&P 500 in a month and following data on the labor market and durable goods.

Durable goods orders dropped 18.2 percent in August, the largest decline since the series started in 1992, which partially reversed the aircraft-driven 22.5 percent surge in the prior month. However, business spending plans rebounded.

Initial claims for state unemployment benefits increased 12,000 to a seasonally adjusted 293,000 for the week ended Sept. 20, below the 300,000 forecast, indicating an acceleration in job growth for the month.

"If you look at the jobless claims, it is still pretty much indicating that the jobs market expansion is continuing, and that is key," said Peter Cardillo, chief market economist at Rockwell Global Capital in New York.

The pace of growth in the U.S. services sector slowed in September compared with the previous month, dropping to its lowest level since May, a Markit (Stuttgart: A1139A - news) survey showed.

The S&P 500 had snapped a three-day losing streak on Wednesday in a broad advance, led by healthcare and biotech stocks, with gains in the housing sector also providing support after surprisingly strong data. The index managed to successfully hold its 50-day moving average around the 1,976 mark that was tested during the lows of the session.

"Yesterday, the markets certainly had a good day and indicated some of the lower levels around the S&P in the 1,970 to 1,980 region have held several times, this is an important factor," said Cardillo. "What the market is in tune to here is the fact that the pullbacks remain shallow."

The Dow Jones industrial average was falling 71.66 points, or 0.42 percent, to 17,138.4, the S&P 500 was losing 8.81 points, or 0.44 percent, to 1,989.49 and the Nasdaq Composite was dropping 22.11 points, or 0.49 percent, to 4,533.11.

Apple (NasdaqGS: AAPL - news) shares, down 1.4 percent to $100.37, were the biggest drag on both the S&P 500 and Nasdaq 100 indexes, after it pulled back an update to its new operating system.

The largest percentage gainer on the New York Stock Exchange was Magnum Hunter Resources (NYSE: MHR - news) , rising 13.74 percent, while the largest percentage decliner was Omnova Solutions (NYSE: OMN - news) , down 14.42 percent.

On the Nasdaq, Apple, CyberArk Software, up 15.3 percent to $34.50 and LipoScience (NasdaqGM: LPDX - news) were among the most actively traded.

Declining issues were outnumbering advancing ones on the NYSE by 1,826 to 800, for a 2.28-to-1 ratio on the downside; on the Nasdaq, 1,238 issues were falling and 791 advancing for a 1.57-to-1 ratio favoring decliners.

The benchmark S&P 500 index was posting 5 new 52-week highs and 3 new lows; the Nasdaq Composite was recording 13 new highs and 22 new lows.

(Reporting by Chuck Mikolajczak; Editing by Chizu Nomiyama and Nick Zieminski)