* Dow comes within 15 points of 20,000
* Twitter falls after CTO announces departure
* Accenture lower after forecast misses estimates
* Indexes down: Dow 0.09 pct, S&P 0.12 pct, Nasdaq 0.26 pct (Adds details, changes comment, updates prices)
By Tanya Agrawal
Dec 21 (Reuters) - U.S. stocks eased in muted pre-holiday trading on Wednesday as investors paused a day after the Nasdaq Composite and the Dow Jones Industrial Average hit record highs.
The Dow came within 15 points of hitting 20,000 level, the historic level it has threatened to breach for several days.
"The 20,000 mark is just a number, but it's also a nice chance to step back and plan for the coming year," said Ryan Detrick, senior market strategist at LPL Financial in Charlotte, North Carolina.
"We've had this huge eight-year bull market and now is an opportunity to think if this move and valuations are justified."
U.S. stocks have been roaring ahead since the election, with the Dow up about 9 percent and the S&P 500 6 percent on bets that President-elect Donald Trump's plans for deregulation and infrastructure spending will boost the economy.
Still, there are concerns that the recent rally has made stocks too expensive. The S&P 500 is trading at about 17 times expected 12-month earnings, well above the 10-year average of 14, according to Thomson Reuters Datastream.
"Valuations are definitely a little on the stretched side, but, at the same time, they're not historically high. So if earnings are going to accelerate in the next year, that can justify some of these valuations," said Detrick.
At 10:53 a.m. ET (1553 GMT) the Dow Jones industrial average was down 17.78 points, or 0.09 percent, at 19,956.84.
The S&P 500 was down 2.74 points, or 0.12 percent, at 2,268.02.
The Nasdaq Composite was down 14.07 points, or 0.26 percent, at 5,469.87.
Six of the 11 major S&P sectors were lower, with the health index's 0.53 percent fall leading the decliners.
Celgene fell 2.1 percent to $116.05. The stock was among the biggest drags on the Nasdaq.
Accenture fell 3.9 percent to $119.17 after the consulting and outsourcing software services provider's revenue forecast missed estimates. The stock was the biggest drag on the S&P.
Twitter fell 3.8 percent to $17.23 after its chief technology officer said he would be leaving the company.
FedEx fell 2.5 percent to $193.66 after the package delivery company's quarterly results missed expectations.
Advancing issues outnumbered decliners on the NYSE by 1,465 to 1,302. On the Nasdaq, 1,624 issues fell and 1,026 advanced.
The S&P 500 index showed 13 new 52-week highs and one new low, while the Nasdaq recorded 117 new highs and 24 new lows. (Reporting by Tanya Agrawal in Bengaluru; Editing by Anil D'Silva)