Editor's note: A previous version of this report incorrectly stated the percentage change in Lexus' sales. It has been corrected.
Despite a 5 percent U.S. sales decline in October, Mercedes-Benz remained No. 1 among luxury brands last month, extending its lead over BMW on the year.
Mercedes sold 27,537 vehicles in the month, excluding commercial vans.
Sales by the BMW brand rose 0.2 percent, or 54 units, to 23,262 in October. Lexus sales fell 0.8 percent to 22,716. Audi sales fell 17 percent to 16,056. Acura sales climbed 7.3 percent to 13,624 vehicles.
Year to date, Mercedes has sold 252,921 luxury vehicles, down 6.7 percent, compared with 248,327 for BMW, a 2 percent increase. Lexus trails both German brands with 236,340.
Overall, U.S. luxury sales fell nearly 3 percent to 158,694 vehicles in October. For the year to date, luxury sales fell 0.5 percent to 1.62 million units.
The industry had a stronger-than-expected October, indicating that consumer confidence remains healthy, said Akshay Anand, executive analyst at Kelley Blue Book.
"Even with luxury, the story is SUVs win, cars lose," Anand said. "Increasing gas prices and a bumpy stock market have not had a significant effect on sales, and luxury in particular may remain strong as we close out the year with sales events going on in November and December."
Mercedes is optimistic about a strong finish in 2018. It's chasing a third consecutive U.S. luxury crown.
"With increased availability of our MY2019 models over the past weeks, we expect continued momentum in the final months of the year," Mercedes-Benz USA CEO Dietmar Exler said in a statement.
Volume leaders for Mercedes in October included the GLC, C-class and E-class model lines. The GLC took the lead at 5,649, followed by 5,581 for the C class and 4,186 for the E class. October sales of Mercedes-AMG high-performance models totaled 1,000 units, with 21,738 vehicles sold year-to-date.
Mercedes' light trucks took a hit last month ahead of redesigns for the GLS SUV and GLE midsize crossover coming next year. GLS sales dropped 27 percent in October from the same time last year. The GLE saw a 24 percent decline, while GLA compact crossover sales fell 5.7 percent.
Rising competition in the luxury utility market also could be to blame. "Though SUVs are up significantly, more and more luxury SUV entrants are joining the fray, creating more crowding than ever," Anand said.
At BMW, crossovers accounted for nearly half of October sales. The X3 was the top-selling BMW model in the U.S. for the eighth consecutive month.
"There's no question the U.S. is becoming a tougher sales market," BMW North America CEO Bernhard Kuhnt said in a statement. "With only two months remaining in the year, November is important for BMW."
Electrified vehicles accounted for 7.4 percent of BMW Group's U.S. sales last month. Sales of electric vehicles and plug-in hybrids totaled 1,836 in October, down 8.5 percent from a year ago.
Porsche Cars North America reported October U.S. sales of 4,817 vehicles, a 2.2 percent uptick from the same time last year. Retail sales for the first 10 months climbed 3.2 percent to 47,443.
Porsche's October sales were fueled by demand for three model lines: Porsche 911 deliveries increased 14 percent year-over-year. The Macan was up 9.9 percent and the Cayenne, with the new generation now in showrooms, rose 1.1 percent. The Macan was the brand's top seller in October at 1,955 vehicles, or about 40 percent of all Porsches sold in the month.