The Porsche Boxster made for a happy commute among luxury buyers in September.

Luxury auto sales shine in September

Traditionally, September is a busy month for both auto manufacturers and sellers alike.  For many luxury models – in particular, those made by German nameplates – it was yet again another big month.

For example, sales of BMW brand vehicles in September rose 4%, totaling 26,600 from the 25,600 that were sold last year during the same period, the German automaker reported. Three-quarters of the way through 2015, BMW has sold nearly a quarter-million vehicles nationally, up more than 5.5% versus the corresponding nine months of 2014.

"There's no doubt about the strength of the U.S. economy and that people continue to buy new cars as evidenced by the BMW record sales result in September," explained Ludwig Willisch, BMW North America president and CEO.

BMW SUV buys expected to increase
He added that with BMW expanding auto production in the months ahead, BMW's sport-utility vehicles – specifically the X3 and X5 – will likely be what buyers are looking to purchase as the cold weather settles in.

Speaking of sports cars, Porsche's sports car sales were robust in September, specifically the German automaker's 918 Spyder, 911, Boxster, and Cayman models. This fueled more than 4,400 vehicle purchases in the U.S., up 23% year-over-year, marking Porsche's best September sales month in recorded history.

Mercedes Benz records best-ever third quarter
The closing days of summer were also productive for Mercedes-Benz, as the luxury brand reported an all-time record of nearly 32,100 units sold during September, up 6% from 12 months prior. Leading the drive of Mercedes-Benz purchases was the Sprinter, as more than 2,300 units of the model were snapped during the month, 14% higher than last year.

Stephen Cannon, Mercedes-Benz USA president and CEO, noted that not only was September a record month, but it was a stellar quarter.

"Record September sales fueled the best-ever third-quarter results in our history," said Cannon. "The robust demand for SUVs continues with the strong performance of our new GLE and GLE-Coupe."

September is traditionally one of the busiest months of the year for auto sales, as automakers offer great discounts. These discounts, as well as incentive-filled packages to encourage consumers to buy, help make room for next year's inventory.