(Adds Costco, Deckers up after the bell)
* Consumer discretionary tops gainers among S&P sectors
* Best Buy and PVH top of S&P after strong results
* Energy index down 1.8 pct following oil's decline
* Indexes up: Dow 0.3 pct, S&P 0.4 pct, Nasdaq 0.7 pct
NEW YORK, May 25 (Reuters) - The S&P 500 and Nasdaq hit record closing highs on Thursday, with the market propped up by gains in the consumer discretionary sector after strong reports from Best Buy and other retailers.
The discretionary index gained 0.9 percent, while the S&P 500 retail index was up 1.6 percent, its best day since Dec. 7.
Best Buy jumped 21.5 percent, hitting a record high and making it the top gainer on the S&P, after its comparable sales unexpectedly rose last quarter.
Tommy Hilfiger owner PVH was the second-biggest S&P gainer, with a 4.8-percent jump to a near 6-month high on strong results. Sears was up 13.5 percent after posting its first quarterly profit in nearly two years.
The reports follow mixed results this reporting period from other retailers, some of which continue to be hurt by competition from Amazon.com.
But they helped to give major indexes a sixth straight day of gains, more than making up for last week's selloff.
In addition, the CBOE Volatility Index, the most widely followed barometer of expected near-term stock market volatility, fell to a two-week low of 9.72 during the session.
"There's no clear and present danger on the horizon," said Jimmy Chang, chief investment strategist at Rockefeller & Co in New York. "The lack of fear, the complacency is supporting the market."
The Dow Jones Industrial Average rose 70.53 points, or 0.34 percent, to 21,082.95, the S&P 500 gained 10.68 points, or 0.44 percent, to 2,415.07 and the Nasdaq Composite added 42.23 points, or 0.69 percent, to 6,205.26.
Given relatively high valuations, further upside may be difficult for the market without progress on tax reform in Washington, Chang said.
He and other analysts also said the S&P 500's ability to remain above 2,400, after closing above it on Wednesday, also provided technical support.
Minutes from the Federal Reserve's May 2-3 meeting, released on Wednesday, continued to bolster sentiment. They showed policymakers view an interest rate hike coming soon, but that they agreed to hold off until it was clear a recent slowdown in the economy was temporary.
Fed officials also proposed a plan to wind down its $4.5 trillion of debt securities, including a limit on how much would be allowed to come off the balance sheet each month.
Limiting gains, the S&P energy index was down 1.8 percent following a nearly 5 percent drop in crude oil prices. OPEC agreed to extend output cuts, but not by as much as investors had hoped.
Also losing ground were shares of General Motors, down 1.8 percent to $32.60. GM was accused in a lawsuit of rigging hundreds of thousands of diesel trucks with devices, similar to those used by Volkswagen AG, to ensure they pass emissions tests.
Gains in retailers continued after the bell, with shares of Costco Wholesale up 2 percent and Deckers Outdoor up 13.3 percent, both following results.
Advancing issues outnumbered declining ones on the NYSE by a 1.08-to-1 ratio; on Nasdaq, a 1.15-to-1 ratio favored advancers.
The S&P 500 posted 92 new 52-week highs and 12 new lows; the Nasdaq Composite recorded 141 new highs and 66 new lows.
About 6.4 billion shares changed hands on U.S. exchanges, below the 6.8 billion daily average for the past 20 trading days, according to Thomson Reuters data.
(Additional reporting by Tanya Agrawal in Bengaluru; Editing by Nick Zieminski and Dan Grebler)