* Second-qtr wage growth slowest in 33 years
* Exxon, Chevron fall as weak oil prices weigh on profits
* Expedia, YRC rise after results
* Dow down 0.33 pct, S&P down 0.09 pct, Nasdaq up 0.07 pct (Updates to open)
By Tanya Agrawal
July 31 (Reuters) - The Dow and S&P 500 were dragged down on Friday by weak earnings from oil producers Exxon Mobil and Chevron, while the Nasdaq edged up after Amgen's profit beat expectations.
Exxon Mobil shares fell 4 percent to $79.52 while Chevron was down 4.2 percent at $89.06 after quarterly profits slumped on falling oil prices.
Amgen rose 4.7 percent to $179.64 after the world's largest biotechnology company reported higher-than-expected second-quarter results.
Wall Street opened higher after an historically weak reading of U.S wage growth lent weight to the view that the Fed could delay a rate increase.
Positive commentary from the Fed about the economy is seen by many investors as a signal that a rate rise could come as early as September. That has led to a fall in U.S. equities' share in global portfolios as nervous investors started readying themselves for the first rate rise in almost a decade.
U.S. labor costs in the second quarter recorded their smallest increase in 33 years amid tepid gains in the private sector with the Employment Cost Index edging up 0.2 percent, compared with a 0.7 percent increase in the first quarter.
The U.S. Federal Reserve has said it will raise rates only when it sees a sustained recovery in the economy.
Oil prices fell after OPEC indicated there would be no output cuts despite a huge global oversupply, while copper was lower on lingering worries about demand in top consumer China.
A sharp selloff in Chinese shares over the past weeks has stoked concerns about a slowdown in growth in the world's second-biggest economy.
At 9:50 a.m. ET (1350 GMT), the Dow Jones industrial average was down 58.66 points, or 0.33 percent, at 17,687.32, the S&P 500 was down 1.85 points, or 0.09 percent, at 2,106.78 and the Nasdaq Composite was up 3.62 points, or 0.07 percent, at 5,132.41.
Seven of the 10 major S&P 500 sectors were higher with the utilities index's 1.13 percent rise leading the advancers. The energy index fell 1.9 percent.
Wall Street ended flat on Thursday as investors digested ho-hum corporate earnings and new data showed that economic growth accelerated in the second quarter.
With more than half of the S&P 500 companies having reported quarterly results, analysts expect overall earnings to edge up 1 percent and revenue to decline 3.6 percent, according to Thomson Reuters data.
"Earnings beating expectations is all well and good but revenue growth hasn't been encouraging and that's the real fly in the ointment, said Art Hogan, chief market strategist at Wunderlich Securities in New York.
Valuations remain a concern. The S&P 500 is trading near 16.8 times forward 12-month earnings, above the 10-year median of 14.7 times, according to StarMine data.
LinkedIn shares fell 9.4 percent to $206.19 after the operator of the biggest social networking site for professionals reported a bigger net loss.
Expedia rose 10.2 percent to $118.78 after the company posted a second-quarter profit above analysts' expectations and announced a larger dividend.
YRC Worldwide soared 24.5 percent to $19.02 a day after the trucking company reported better-than-expected second-quarter profit.
Advancing issues outnumbered decliners on the NYSE by 1,837 to 898. On the Nasdaq, 1,332 issues rose and 969 fell.
The S&P 500 index showed 30 new 52-week highs and three new lows, while the Nasdaq recorded 36 new highs and 31 new lows. (Editing by Don Sebastian)