* Initial jobless claims fall more than expected
* All 10 S&P 500 sectors higher; banks among leaders
* Pioneer Natural Resources jumps after results
* Indexes up: Dow 0.9 pct, S&P 1.2 pct, Nasdaq 1.2 pct
By Caroline Valetkevitch
NEW YORK, Aug 1 (Reuters) - U.S. stocks jumped on Thursday, pushing the S&P 500 above 1,700 for the first time, as data suggested the economy is still improving and as the Federal Reserve kept its stimulus plan in place.
Stocks were broadly higher, with all 10 S&P 500 sectors in the black, though growth-sensitive financials, industrials and consumer discretionary shares registered the biggest gains.
JPMorgan Chase, Bank of America and Wells Fargo were among the companies giving the greatest boost to the S&P 500. Shares of JPMorgan gained 1.6 percent to $56.61, Bank of America rose 2.3 percent to $14.94 and Wells Fargo added 1.7 percent to $44.24. The S&P 500 financial index was up 1.7 percent.
Data on weekly U.S. initial jobless claims and national manufacturing came in better than expected, while construction spending dropped 0.6 percent in June, below forecasts calling for a 0.4 percent rise.
They were the latest in a data-filled week. The drop in initial claims, coupled with Wednesday's better-than-expected ADP employment report, bodes well for July payrolls data on Friday.
The benchmark S&P rose to a new intraday high of 1,706.52, surpassing 1,700 early in the session after coming close but failing to break above that level on Wednesday.
"It keeps going higher in the face of skepticism," said Bruce Zaro, chief technical strategist at Delta Global Asset Management in Boston. "In my view, that is one of the positive longer-term signs."
The Dow Jones industrial average was up 133.94 points, or 0.86 percent, at 15,633.48. The Standard & Poor's 500 Index was up 19.98 points, or 1.19 percent, at 1,705.71. The Nasdaq Composite Index was up 44.49 points, or 1.23 percent, at 3,670.86.
In its latest policy statement on Wednesday, the Federal Reserve gave no hint that a reduction in the pace of its bond-buying program was imminent, as the economy continues to recover but is still in need of support.
Global central banks on Thursday also remained accommodative, with European Central Bank President Mario Draghi reiterating the ECB's rates will remain at their present level or lower for an "extended period."
Yelp Inc surged 25.6 percent to $52.51 after the consumer reviews website posted a smaller-than-expected quarterly loss and forecast third-quarter revenue above analysts' expectations.
Pioneer Natural Resources was the S&P 500's biggest percentage gainer after reporting second-quarter results. The company's shares jumped 13.5 percent to $175.65, after hitting an all-time high of $180.99 earlier in the session.
On the downside, Exxon Mobil Corp dipped 1.4 percent to $92.45, the biggest drag on the Dow and the S&P 500, after reporting a sharp drop in quarterly profit on lower oil and gas output production and weaker earnings from its refining business.