* Initial jobless claims fall more than expected
* All 10 S&P 500 sectors higher, financials leading gains
* Pioneer Natural Resources jumps after results
* Indexes up: Dow 0.8 pct, S&P 1.1 pct, Nasdaq 1.1 pct
By Alison Griswold
NEW YORK, Aug 1 (Reuters) - The S&P 500 surpassed 1,700 on Thursday and U.S. stocks rose after economic data pointed to a modestly improving economy and the Federal Reserve kept its massive monetary stimulus in place.
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" of time.
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.
"This morning we got some tremendous data in the U.S.," said John Brady, managing director at R.J. O'Brien & Associates in Chicago. "The ISM manufacturing number was very strong, and that's led to a further move upward in equity prices."
Stocks advanced broadly, with all of the 10 S&P 500 industry sectors moving higher. 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 1.7 percent to $56.70, Bank of America rose 2.2 percent to $14.92 and Wells Fargo added 1.6 percent to $44.21.
The S&P 500 financial index was up 1.6 percent.
The Dow Jones Industrial Average rose 123.22 points, or 0.79 percent, to 15,622.76. The Standard & Poor's 500 Index climbed 18.03 points, or 1.07 percent, to 1,703.76, and the Nasdaq Composite Index added 38.50 points, or 1.06 percent, to 3,664.87.
Earlier in the session, the benchmark S&P rose to a new intraday high of 1,704.97.
Yelp Inc surged 22.8 percent to $51.31 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 its second-quarter results. The company's shares jumped 13.3 percent to $175.35, after hitting an all-time high of $180.99 earlier in the session.
On the downside, Exxon Mobil Corp dipped 1.8 percent to $92.04, 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.
Of the 375 companies in the S&P 500 that have reported earnings for the second quarter, 67.5 percent have topped analyst expectations, in line with the average beat over the past four quarters, data from Thomson Reuters showed. About 55 percent have reported revenue above estimates, above the average beat of the past four quarters but below the historical average.
Weekly initial jobless claims data showed a drop of 19,000 to a seasonally-adjusted 326,000, the lowest since January 2008 and better than the 345,000 forecast.
The drop in initial claims, coupled with Wednesday's better-than-expected ADP employment report, bodes well for payrolls data on Friday.
The Institute for Supply Management said its index of national factory activity rose to 55.4 in July, its highest level since June 2011.
Financial data firm Markit said its final U.S. Manufacturing Purchasing Managers Index for July rose to 53.7, the highest since March.