* Results by six biggest automakers miss expectations
* Late Thanksgiving date, bad weather hit December sales
* Industry sales in 2014 expected to rise as high as 16.5 mln vehicles
* GM's shares down 3 pct in afternoon
The U.S. auto industry raced to its best year since the boom times before 2008, but results came up short in December as consumers proved to be more focused on buying presents than new cars and trucks.
The tough sledding in December does not suggest a difficult 2014, however, as several executives and analysts expect auto industry growth to continue outpacing the overall U.S. economy as it has since the recession.
The December results were hit by the late Thanksgiving weekend that pulled more sales into November than usual, as well as snow and ice storms that kept consumers away from dealerships, several automakers and analysts said. The December results included Jan. 2 due to a quirk in the calendar that affected how automakers typically report monthly sales.
"Sales were pulled into November, but also people were more impacted by the compressed shopping season, most of which was in December," Kelley Blue Book senior analyst Karl Brauer said. "People were doing more Christmas shopping than car shopping."
He added that industry-watchers should not be overly concerned by a December that was affected by the timing of a holiday in the previous month.
Monthly auto sales are seen as an early indicator of consumer spending.
General Motors Co said that the U.S. auto industry's sales will finish December with an annual selling rate of 15.6 million vehicles, well below the 16 million expected by economists surveyed by Thomson Reuters. Morgan Stanley analyst Adam Jonas was more pessimistic, predicting 15.3 million.
The timing of Thanksgiving weekend had a greater impact on December sales than in recent years, causing automakers to miss expectations, said Mustafa Mohatarem, GM's chief economist.
The late December holiday season is generally one of the heaviest sales periods at U.S. auto dealerships. GM, Ford and Volkswagen AG each said the weather was less of a negative factor.
December sales were counted through Thursday, when much of the U.S. Midwest was buried in snow. The storm is now over the U.S. Northeast, but January sales will have time to recover from the current storm as the bulk of sales typically occurs later in the month, said Kurt McNeil, GM vice president of U.S. sales operations.
GM shares were down 3 percent at $39.71 and Ford shares were up 0.6 percent at $15.53 on Friday afternoon on the New York Stock Exchange.
BEST YEAR SINCE 2007
For all of 2013, U.S. auto sales are expected to finish near 15.6 million vehicles, up about 8 percent.
That would be the best sales year since 2007, when sales hit 16.1 million vehicles. Sales slumped as low as 10.4 million in 2009 before beginning their rebound.
While some economists and analysts expect 2014 sales to rise to between 16 million and 16.5 million vehicles, there is growing concern that competition will intensify, leading to higher incentives and lower profit for companies.
Research firm TrueCar.com said vehicle transaction prices fell by an average of $200 per vehicle in December, or 0.6 percent, over last year, while incentives were up $103 per vehicle, or 4 percent.
GM's December sales fell 6 percent, to 230,157 new vehicles, below analysts' expectations of a slight sales gain.
Sales of GM's Chevrolet Silverado full-size pickup truck fell 16 percent in the month as analysts said the automaker did not load incentives onto the redesigned vehicle to match what rival Ford was doing with its market-leading but older F-Series.
Ford's sales rose 2 percent to 218,058 vehicles, missing expectations. Its F-Series pickup truck, which finished as the best-selling vehicle in the U.S. market for the 32nd straight year, had an 8 percent sales gain.
Toyota's Camry finished as the top-selling passenger car for the 12th consecutive year.
GM introduced new versions of its Chevrolet Silverado and GMC Sierra pickup trucks last year while Ford will launch a redesign of its trucks later this year.
Toyota Motor Corp's U.S. December sales fell 1.7 percent to 190,843 vehicles, versus expectations of a slight gain.
Chrysler reported a 6 percent gain last month in its U.S. auto sales to 161,007 vehicles. That was the automaker's best December since 2007, but still narrowly missed analyst expectations. Ram pickup truck sales rose 17 percent.
Jeep sales rose 34 percent in the month, led by the new Cherokee, which sold four times as well in December as the vehicle it replaced, the Jeep Liberty, did a year earlier.
Honda Motor Co sales rose 2 percent to 135,255 vehicles, which also missed analysts' expectations.
Nissan Motor Co sales rose 10.5 percent in December, allowing the Japanese automaker to finish with its best year for U.S. sales ever.
Daimler AG's Mercedes-Benz won bragging rights as the top-selling luxury brand, edging BMW by a count of 312,534 vehicles to 309,280 vehicles.
Chrysler is majority-owned by Italy's Fiat SpA. Earlier this week, the two companies announced that Fiat would buy the remainder of Chrysler that is currently owned by a United Auto Workers healthcare trust, for $4.35 billion. That deal is expected to close by Jan. 20.