Chrysler reported a 6 percent gain in U.S. auto sales during last month, its best December since 2007, according to Reuters.

Despite the overall positive sales increase, the automaker still missed analyst expectations.

Five key analyst reported that Chrysler sales would increase about 7 percent compared to Dec. 2012.

Chrysler is the first major automaker based in the U.S. to report December sales numbers.

Jeep sales increased 34 percent last month, thanks to the new Cherokee, which sold "for times as well" last month as the vehicle it replaced, the Jeep Liberty, did in 2012.

Analyst have predicted that automakers in the U.S. will report an overall 4 percent increase in new vehicle sales, compared to numbers from last year.

In total, U.S. auto sales should finish around 15.6 million for 2013, which would be an increase of 8 percent, according to Reuters.

Some analyst are already making year end predictions for this year, claiming that 2014 sales could reach the 16 million to 16.5 million mark.

Vehicle transportation prices dropped $200 per vehicle last month, whereas incentives increased to $103 per vehicle, according to TrueCar.com.

Chrysler made headlines earlier this week reporting that Fiat would be purchasing the remainder of Chrysler, which is currently owned by a United Auto Workers healthcare trust, for approximately $4.35 billion, according to Reuters.

The Fiat deal will close around Jan. 20.

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