The year 2017 had proved a generally disappointing one for U.S. auto makers, being the first year since 2009 that vehicle sales had fallen from the previous year.
Ford Motor reported Wednesday that its new vehicle sales fell 1 percent, as did those of General Motors.
Fiat Chrysler did not release year-end figures, but its sales last month fell 11% to 171,946, a bit below the level projected by automotive information company Edmunds, but above the forecast by Kelley Blue Book.
"While we had a decline (in December) on a year-over-year basis, the strength during all of 2017 was such that we shattered the previous record, surpassing two million units for the first time ever", said Carlos Gomes, a senior economist and auto industry specialist at Scotiabank.
Sales of the Ford F-Series pickups rose 2.1% year over year in December to 89,385 units, and F-Series transaction prices rose $3,400 year over year to $47,800. Mercedes-Benz was the top selling luxury brand, even with a sales decline of 1 percent. But the influx of late-model used cars coming back on the market could also cut into sales of new vehicles.
And the USA auto industry continues to enjoy strong demand for larger vehicles, including SUVs, pickup trucks and "crossover" models. For the year, the company reported good news with total sales for 2017 increasing by 5.2% compared with 2016.
Most major automakers on Wednesday reported lower December US sales and forecast weaker overall sales in 2018, but investors bid up shares in the sector on a bet that high-margin pickup trucks and SUVs will pull Detroit's automakers through any downturn. But car-heavy brands like Chrysler, Dodge and Fiat all saw their sales drop by double-digit percentages. But most other automakers saw declines.
A promising note for FCA in December was that Alfa Romeo sold 2,034 units were up significantly compared with the same month a year ago and recorded its strongest monthly sales of 2017 and actually outsold the Fiat brand.
GM's overall December sales - retail and fleet - were down 3.3% and for the year, they fell 1.3% for the year. The company's Acura luxury division fell 12.2% in December and 4.2% for the full year. Honda division saw its sales drop last month by 6.3%, but came in with a 0.7% jump for all of 2017.
The winning streak "was the result of pent-up demand after the recession that's finally just running out", said Tim Fleming, an analyst at Kelley Blue Book.