Tesla vs. BMW was close in 2021 — closer in 2022?

Tesla's new Texas factory is likely to spell the end of an era for the legacy brands that have dominated the U.S. luxury auto market.

New-vehicle registration data out last week suggests that Tesla came close last year to dethroning BMW as the premium-car sales leader — and did so relying solely on production from the EV automaker's plant in Fremont, Calif.

Now, Tesla CEO Elon Musk is promising a big volume increase with the imminent opening of the company's new plant near Austin. Tesla Texas will start making the Model Y, its volume leader, with an innovative new battery pack with larger "4680" cylindrical cells.

"So in Texas, we're building the Model Ys with the structural pack and the 4680 cells, and we'll start delivering after final certification of the vehicle, which should be fairly soon," Musk said on an earnings call last month.

Tesla's big sales surge in the final months of 2021 made the EV maker look like a sure bet to overtake BMW to become the U.S. luxury segment leader. But those results are a bit muddied by the fact that Tesla does not break out U.S. sales from its global numbers. Instead, analysts rely on new-vehicle registration data and third-party estimates.

U.S. vehicle registration data released last week by Experian indicated that BMW managed to hang on to its crown for 2021. Tesla came in at No. 2, ahead of Lexus and Mercedes-Benz.

Experian said in its report that BMW had 347,453 new vehicles registered in the U.S. in 2021, while Tesla had 342,412 — a difference of just 5,041 vehicles.

It has been a heated race.

Tesla registrations surged 71 percent over 2020, while BMW's grew 24 percent year over year, according to Experian. Those numbers suggest that Tesla has significant momentum going into 2022, although semiconductor shortages will likely play an important role in the luxury car race.

Sales and registration numbers don't track perfectly for a variety of reasons. Vehicles sold in one month can be registered in another, and some registration data may include estimates when exact numbers are unavailable, analysts said. Some industry estimates put Tesla sales higher than BMW for 2021.

"When the numbers are close, it's hard to declare a winner when you aren't always comparing apples to apples," said Jessica Caldwell, executive director of insights at Edmunds. Registration data is often useful when analyzing numbers not made public by automakers, such as fleet sales, she said.

BMW's own sales data put deliveries last year at 336,644. Lexus said it sold 304,475 vehicles and Mercedes reported official deliveries of 276,102.

But ultimately, manufacturer sales data is the official record because of the guesswork that goes into calculating Tesla's numbers.

For example, a 2021 sales estimate from Cox Automotive gave Tesla the edge over BMW with 352,471 U.S. deliveries.

"Tesla didn't only dominate the EV market, Tesla dominated the overall luxury market, outselling Audi, BMW, Lexus, and Mercedes-Benz in the U.S.," Cox said last month.

Musk has estimated that Tesla's global sales will rise by at least 50 percent this year as the new factory in Texas and another in Berlin come online in the first part of 2022.

Other details from this week's Experian registration report:

• The Model Y was the bestselling EV in the U.S. last year, with 169,325 registrations.
• The Tesla Model 3 sedan was No. 2 in EV sales, with 151,599 registrations.
• The Ford Mustang Mach-E was third, with 25,695, and the Chevrolet Bolt was in fourth place, with 23,078, Experian said.