WASHINGTON (REUTERS) - The S&P 500 and the Dow Jones Industrial Average hit record intraday highs on Thursday as a rally in oil prices added to optimism about U.S. President Donald Trump's proposed tax reforms.

Oil prices surged 2 percent on Thursday after data showed a surprise decline in U.S. inventories, suggesting a global oversupply maybe be ending.

The S&P 500 energy index jumped 0.9 per cent, led by gains in Exxon and Chevron. The sector also provided the biggest boost to the broader index.

US stocks have been on a record-setting rally in the past two weeks after Mr Trump said his administration would make a major tax announcement in the coming weeks.

Treasury Secretary Steven Mnuchin told CNBC on Thursday that he expected a "very significant" tax reform to be enacted by Congress' August recess. "There is an incremental buy on the market everyday," said Drew Forman, co-head of sales and trading equity at Macro Risk Advisors in New York. "However, people are getting complacent ... and we're going to need to see some results from the president and the government on some of these policies before we see a huge breakout."

The S&P 500 has not moved more than 1 per cent in either direction since Dec. 7.

At 9:33 a.m. ET (10.33 pm Singapore time), the Dow Jones Industrial Average was up 38.11 points, or 0.18 per cent, at 20,813.71. The index has hit record highs in nine of the past 10 sessions. The S&P 500 was up 4.94 points, or 0.21 percent, at 2,367.76 and the Nasdaq Composite was up 2.30 points, or 0.04 percent, at 5,862.93.

All of the 11 major S&P 500 sectors were higher, with industrials and technology bringing up the rear.