* Caterpillar, the Dow's worst performer, falls for second day
* Facebook's best daily percentage gain boosts Nasdaq
* U.S. jobless claims rise modestly in latest week
* Dow up 0.1 pct, S&P 500 up 0.2 pct, Nasdaq up 0.7 pct
By Alison Griswold
NEW YORK, July 25 (Reuters) - The Nasdaq got a lift from Facebook shares on Thursday, but the Dow and the S&P 500 stumbled over mixed earnings and weakness in the cyclical sector.
Facebook Inc scored its biggest daily percentage gain ever a day after reporting a huge jump in mobile advertising revenue. Shares of the online social network company soared 28.7 percent to a session high of $34.12 and topped the Nasdaq's list of most actively traded names.
Disappointing earnings in the cyclical sector curbed the gains in both the Dow and the S&P 500. Concerns about China's growth also gave investors a reason for caution.
Caterpillar Inc, the world's largest maker of mining and construction equipment, extended a slide that began on Wednesday after the company cut its 2013 earnings forecast. The stock - the Dow's worst performer - slid 2 percent to $81.75.
General Motors and Dow Chemical reported profits that exceeded expectations, but that was not enough to help the S&P 500 make a major push into positive territory. GM's stock fell 0.7 percent to $36.88, after touching a two-year high of $37.70. Dow Chemical rose 1.8 percent to $35.
"The market is anticipating a pickup in corporate profits, looking to later parts of this year, but we're not seeing robust earnings in the here and now," said Kevin Caron, market strategist at Stifel, Nicolaus & Co in Florham Park, New Jersey.
"With stocks moving higher despite very slow earnings growth, the important takeaway is that investors are more comfortable with taking on more risks for the same amount of earnings."
The Dow Jones industrial average was up 12.00 points, or 0.08 percent, at 15,554.24. The Standard & Poor's 500 Index was up 3.93 points, or 0.23 percent, at 1,689.87. The Nasdaq Composite Index was up 24.20 points, or 0.68 percent, at 3,603.80.
Stocks have advanced steadily this year. The S&P 500 has climbed 18 percent in 2013 after hitting a number of record closing highs along the way. For July, the benchmark index has gained 4.9 percent.
With 47 percent of the S&P 500 companies having reported earnings so far, about 68 percent have topped profit forecasts, above the historical average of 63 percent. About 56 percent have reported better-than-expected revenue, a rate that is below the historical average.
TripAdvisor Inc shares surged 17.2 percent to $71.68 a day after the company reported a jump in quarterly profit and revenue from its travel website. The stock was the S&P 500's second-biggest percentage gainer in late afternoon trading.
Natural gas processor Oneok Inc leaped 24 percent to $53.11. The stock was the S&P 500's best performer after the company said it would separate its gas distribution business into a standalone publicly traded company called ONE Gas Inc.
In the latest economic snapshot, initial claims for U.S. jobless benefits rose to 343,000 in the latest week from 334,000 in the previous week, the Labor Department said. Economists were looking for a read of 340,000.
New orders for durable goods rose 4.2 percent in June, far stronger than the forecast for a growth rate of 1.3 percent.
Increasing worries about China's slowing growth also made U.S. investors nervous. A major index of Chinese stocks suffered its second straight loss on Thursday despite measures from China's government to spur the economy, including help for exports and railway investment. Data on Wednesday showed manufacturing in China running at an 11-month low in July.