2014 Mercedes-Benz CLA45 AMG. Photo: Mercedes-Benz. 

The race was close, and BMW (OTC:BAMXF) put forth a valiant effort. But it wasn't enough, and for 2013, Daimler's (OTC:DDAIF) Mercedes-Benz is officially the best-selling luxury brand in the United States.  Here's what else you need to know.

Mercedes take it home
At the beginning of December, I predicted that Mercedes would take home the award for best-selling luxury brand in the United States. And with a total of 312,534 units sold for the Mercedes-Benz brand, compared with 309,280 units sold for the BMW brand, that's exactly what happened. Moreover, for 2013, Mercedes saw its best sales year ever, and it saw a 14% Mercedes brand sales increase compared with 2012.

BMW 3 Series Gran Turismo-M Sport Package. Photo: BMW.

Not that BMW did poorly. In fact, BMW also saw its best sales year, ever, and it too had a strong BMW brand sales increase of 9.9% compared with 2012. Still, after holding on to the best-selling sales title for two years, BMW has to pass it on.

Why Mercedes won
For 2013, Mercedes' C-Class was the best selling vehicle, with 88,252 units sold -- that's an increase of 8% compared with 2012. However, it should be noted that Mercedes also saw a strong sales increase thanks to its all-new CLA, which was released for sale in the U.S. in September. 2013 U.S. year-to-date sales in for the CLA came to 14,113. Further, in July -- before the release of the CLA -- Daimler CEO Dieter Zetsche said he didn't expect Mercedes to outsell BMW in 2013.

What all this means for investors
Mercedes beat BMW's U.S. sales for 2013, and this is great news for Mercedes fans, and investors. But that doesn't mean BMW isn't also a great investment. Both Mercedes and BMW have an incredibly strong following, and strong sales. Further, 2014 looks like it could also be a good year for BMW and Mercedes. Consequently, both of these companies could make great additions to your portfolio if you're looking to buy auto stocks.