BMW Group, the German car manufacturer, faces an investigation in the United States by the Securities and Exchange Commission, the company said Monday.

The inquiry is focusing on the company’s sales practices, and the commission contacted BMW within the last month, said a person briefed on the matter but not authorized to speak publicly about details of the investigation.

One sales practice drawing scrutiny, this person said, is “car punching,” in which some loaner vehicles delivered to dealerships are reported as purchases to improve sales figures.

A spokesman for the S.E.C. said regulators could neither confirm nor deny an investigation. The inquiry was reported earlier by The Wall Street Journal.