US STOCKS-Wall Street falls as oil prices drag

* Earnings season begins this week

* NPS Pharma climbs; to be acquired by Shire (Xetra: S7E.DE - news)

* Foundation Medicine (NasdaqGS: FMI - news) jumps; Roche to take majority stake

* Energy shares fall as oil tumbles

* Indexes off: Dow 0.46 pct, S&P 0.71 pct, Nasdaq 0.69 pct (Updates to late morning)

By Chuck Mikolajczak

NEW YORK, Jan 12 (Reuters) - U.S. stocks lost ground on Monday, extending a two-week decline for equities, as weakness in oil prices weighed on the energy sector ahead of the start of corporate earnings season.

Oil prices continued their downward march and were a drag on equities. Brent was down more than 5 percent to $47.44 and U.S. crude down 4.6 percent at $46.13, as Goldman Sachs slashed its short-term price forecasts and Gulf producers showed no signs of curbing output.

The S&P energy index was down 2.9 percent, easily the worst performer of the 10 major S&P sectors.

"People are truly becoming concerned about global growth stories here," said Keith Bliss, senior vice-president at Cuttone & Co in New York.

"People are getting a little bit ahead of this selloff in anticipation of fourth quarter earnings announcements and more worry about the large multinationals and what they are going to say about demand globally, as well as the impact of the dollar."

Alcoa (NYSE: AA - news) is scheduled to post quarterly earnings after the closing bell, with financials JPMorgan Chase, Wells Fargo, Goldman Sachs (NYSE: GS-PB - news) and Citigroup (NYSE: C - news) due to report later in the week. Dow component Intel Corp is expected to post earnings on Thursday.

Fourth-quarter earnings are expected to grow by 4 percent over the year-ago period, according to Thomson Reuters data.

The Dow Jones industrial average fell 81.33 points, or 0.46 percent, to 17,656.04, the S&P 500 lost 14.59 points, or 0.71 percent, to 2,030.22 and the Nasdaq Composite dropped 32.61 points, or 0.69 percent, to 4,671.46.

Since hitting a record high on Dec (Shanghai: 600875.SS - news) . 29, the S&P 500 has fallen about 2.6 percent on concerns about global growth, Greece's potential exit from the euro zone, and falling oil prices.

Tiffany slumped 11.6 percent to $91.42 after the upscale jeweler cut its full-year profit forecast, citing a disappointing holiday shopping season.

NPS Pharmaceuticals (NasdaqGS: NPSP - news) jumped 8.2 percent to $45.35 after Shire Plc agreed to acquire the company for $5.2 billion. U.S.-listed shares of Shire slipped 1.5 percent to $214.23.

Foundation Medicine surged 100.4 percent to $47.90 after Roche Holding (LSE: 0QOK.L - news) agreed to take a majority stake in the company for up to $1.18 billion.

Bristol-Myers Squibb climbed 3.8 percent to $62.64 as the best performer on the S&P 500 after the company said the independent data monitoring committee concluded a late stage study evaluating its Opdivo lung cancer drug met its endpoint.

Declining issues outnumbered advancing ones on the NYSE by 2,037 to 882, for a 2.31-to-1 ratio; on the Nasdaq, 1,688 issues fell and 847 advanced for a 1.99-to-1 ratio.

The S&P 500 was posting 25 new 52-week highs and 20 new lows; the Nasdaq Composite was recording 53 new highs and 70 new lows. (Editing by Bernadette Baum and Nick Zieminski)