* Final Q3 GDP at 3.5 pct vs est. 3.3 pct
* Apple's fall weighs on S&P 500, Nasdaq
* S&P 500 up more than 10 pct so far in 2016
* Indexes down: Dow 0.07 pct, S&P 0.15 pct, Nasdaq 0.36 pct (Updates to afternoon)
By Noel Randewich
Dec 22 (Reuters) - U.S. stocks fell on Thursday as investors stepped back from a recent rally fueled by optimism that President-elect Donald Trump will invigorate economic growth.
The dip pulled the Dow Jones industrial average further away from the 20,000 mark after it nearly breached the level this week for the first time.
Following a sharp rally since the Nov. 8 U.S. election, the Dow is up about 14 percent for the year and the S&P 500 is 11 higher on bets that the economy will benefit from Trump's plans for deregulation and infrastructure spending.
Some investors believe that recent gains may have made stocks too expensive, and that Congress may water down or prevent major infrastructure spending or tax cuts proposed by Trump.
"There are issues hanging over the market," said Donald Selkin, chief market strategist at Newbridge Securities in New York. "You need to digest these gains, and once he becomes president, we'll see what is actually going to get passed."
Billionaire investor Carl Icahn, tapped by Trump on Wednesday as a special adviser for regulatory issues, said in an interview on CNBC that he was concerned about the stock market in the short term following its recent surge.
A report earlier showed that the U.S. economy grew faster than initially thought in the third quarter, notching its best performance in two years. Gross domestic product increased at a 3.5 percent annual rate instead of the previously reported 3.2 percent pace, the Commerce Department said.
Consumer spending, which accounts for more than two-thirds of U.S. economic activity, rose 0.2 percent in November, below the estimated 0.3 percent gain.
The Dow Jones Industrial Average was last down 0.07 percent at 19,928.76 points and the S&P 500 had lost 0.15 percent to 2,261.79.
The Nasdaq Composite dropped 0.36 percent to 5,451.49.
Seven of the 11 major S&P sectors were lower, with the consumer discretionary index's 0.94 percent fall leading the decliners. The discretionary sector was weighed by a 0.57 percent drop in Amazon shares.
The S&P telecommunications index led the gainers with a 1.08 percent rise.
Apple fell 0.74 percent after Nokia said it had filed a number of lawsuits against the iPhone maker for patent infringement. The stock was the biggest drag on the S&P 500 and Nasdaq.
ConAgra rose 3.30 percent after the packaged foods maker's quarterly profit beat estimates.
Red Hat slumped 12.6 percent after the Linux software distributor's quarterly revenue missed estimates.
Declining issues outnumbered advancing ones on the NYSE by a 1.26-to-1 ratio; on Nasdaq, a 1.55-to-1 ratio favored decliners.
The S&P 500 posted 11 new 52-week highs and 3 new lows; the Nasdaq Composite recorded 100 new highs and 43 new lows. (Additional reporting by Tanya Agrawal in Bengaluru; Editing by Meredith Mazzilli)