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* China trade deal signing expected soon - White House adviser
* Tesla rival Nio jumps after strong quarterly sales
* Energy sector up on higher oil prices
* Dow Jones on track for worst day in nearly four weeks
* Indexes off: Dow 0.53%, S&P 0.51%, Nasdaq 0.72% (Updates prices)
Dec 30 (Reuters) - Wall Street slipped on Monday as investors booked profits on the penultimate day of the decade after optimism over improving U.S.-China trade relations fueled a stock market rally this month.
White House Trade Adviser Peter Navarro said on Monday the pact was likely to be signed in the next week, but added that confirmation would come from President Donald Trump or the Office of U.S. Trade Representative.
A South China Morning Post report earlier said Chinese Vice Premier Liu He would travel to Washington later this week to sign the deal.
The benchmark S&P 500 closed at all-time highs in nine of the past 11 sessions, also powered by improving global sentiment and a loose monetary policy by the Federal Reserve.
But with no other major updates on trade expected before the new year and thin trading volumes in a holiday-shortened week, some analysts expect the record run to lose steam further.
"It has been a pretty spectacular year, and Q4 especially has been really good, so a lot of times people might be inclined to take some profits," said Randy Frederick, vice president of trading and derivatives for Charles Schwab in Austin.
Tech stocks largely led the drop in the S&P 500, with Microsoft Corp and Apple Inc dragging the sector. Information technology stocks were the best performing among the 11 S&P 500 subsectors this year.
"It is also not uncommon for the leading sectors to pull back first when people start to sell because if it is an outperformer, then it warrants a lot more downside risk," Frederick said.
Conversely, Exxon Mobil Corp and Chevron Corp led gains on the benchmark index, tracking higher oil prices. Energy was the only S&P 500 sector in the black.
At 11:20 a.m. ET, the Dow Jones Industrial Average was down 152.05 points, or 0.53%, at 28,493.21, the S&P 500 was down 16.55 points, or 0.51%, at 3,223.47. The Nasdaq Composite was down 64.73 points, or 0.72%, at 8,941.89.
Nio Inc soared 43.6% after the Tesla rival beat quarterly revenue estimates on higher demand for its electric vehicles.
Declining issues outnumbered advancers for a 1.47-to-1 ratio on the NYSE and for a 1.65-to-1 ratio on the Nasdaq.
The S&P index recorded 12 new 52-week highs and no new low, while the Nasdaq recorded 48 new highs and 20 new lows. (Reporting by Manas Mishra in Bengaluru; Editing by Anil D'Silva, Maju Samuel and Shinjini Ganguli)