BMW has long called itself the ultimate driving machine, but lately some investors say the German luxury leader needs a shot in the arm.

The BMW brand has yet to regain the leading global sales position it lost in 2016 to competitor Mercedes-Benz.

To be fair, investors and analysts are quick to point out what while Mercedes is beating BMW in volume, BMW is ahead on other metrics, such as cash flow and profitability. Some say those numbers matter more.

But the automaker replaced its CEO in 2019 in what investors say is a move to reinvigorate a brand that might be growing a bit complacent.

Mercedes-Benz has more models available for buyers interested in stepping up into the luxury market, said RBC analyst Tom Narayan. That has enabled it to sell a larger number of cars.

Some also fear BMW's design and engineering have become a bit stale, and that the automaker might be losing its distinguishing identity as a luxury performance brand as its relies ever more heavily on sport utility sales. BMW's "sport activity vehicles" comprised over 37% of BMW's sales in 2018, up from just over a third of sales in 2017.

BMW is facing an investigation from federal securities regulators in the U.S. seeking to determine whether the automaker manipulated sales figures. The company is one of several automakers targeted by similar probes.

The automaker was not immediately available for comment on the investigation.