By Ryan Vlastelica
NEW YORK, Sept 8 (Reuters) - U.S. stocks are lower in afternoon trading on Monday, with the Dow and S&P 500 adding to their earlier weakness and the Nasdaq turning negative as energy shares weigh on the market.
Energy shares are by far the weakest sector on the day, with the S&P energy index off 1.9 percent. Newfield Exploration is the S&P 500's biggest decliner, off 6 percent at $39.45, with Chesapeake Energy down 3.2 percent at $25.32.
The Nasdaq's losses are limited as tech shares continue to outperform; Yahoo Inc is up 4.1 percent at $41.22.
"It's very light on the economic news (and) with people returning from summer vacation, it's all about the valuations so they will make these little moves like we're seeing here," said Larry Peruzzi, senior equity trader at Cabrera Capital Markets Inc in Boston.
Recent market momentum has been driven by accommodative Federal Reserve policy, including bond purchases and low interest rates. However, research from the San Francisco Fed indicated investors expect rates to stay low for longer than the central bank itself does.
The Dow Jones industrial average is falling 57.99 points, or 0.34 percent, to 17,079.37, the S&P 500 is down 12.1 points, or 0.6 percent, to 1,995.61 and the Nasdaq Composite is dropping 12.28 points, or 0.27 percent, to 4,570.62.
The largest percentage gainer on the New York Stock Exchange is Silver Spring Networks, rising 8.73 percent, while largest percentage decliner Callon Petroleum is down 8.45 percent.
Among the most active stocks on the NYSE are Bank of America , up 1.68 percent to $16.29; Petroleo Brasil, down 5.16 percent to $18.38 and Ford Motor Co, down 2.28 percent to $16.75.
On the Nasdaq, Yahoo, Microsoft Corp, up 1.1 percent to $46.41 and Apple, down 0.8 percent to $98.14, are among the most actively traded.
Declining issues are outnumbering advancing ones on the NYSE by 2,054 to 899, for a 2.28-to-1 ratio on the downside; on the Nasdaq, 1,516 issues are falling and 1,177 advancing for a 1.29-to-1 ratio favoring decliners.
The broad S&P 500 index is posting 43 new 52-week highs and 3 new lows; the Nasdaq Composite was recording 67 new highs and 24 new lows.
(Editing by Meredith Mazzilli and Nick Zieminski)