Tax authorities in Seoul have slapped Mercedes-Benz Korea with an additional corporate tax of 50.1 billion won (about $43 million), according to a local news report on Tuesday.

Citing unnamed industry sources, Yonhap News reported that the National Tax Service notified the German carmaker’s Korean unit of its decision to impose the additional tax after its recent tax investigation into the company.

In response, the carmaker has requested a review of the legality of the imposition before taxation, according to the report. The additional corporate tax the carmaker may have to pay would be the largest of its kind levied on foreign carmakers here.

Last year, Mercedes-Benz Korea posted 3.14 trillion won in sales, a 42.5 percent increase from the previous year, and its operating profit hit 111.5 billion won.

The alleged tax imposition comes at a time when the foreign carmaker is facing a prosecution probe on charges of having installed automatic transmissions without proper authentication procedures.

The Transport Ministry said Tuesday that it has filed a complaint with the Seoul District Prosecutors’ Office against Mercedes-Benz Korea’s chief Dimitris Psillakis, accusing him of violating the automobile management and clean air conservation acts.

The carmaker failed to go through authentication procedures when it replaced existing 7-speed automatic transmission with 9-speed automatic transmission for its S350 series sold in December, according to officials. They noted that 98 cars were sold without going through the procedures.

“After finding out that some S350 diesel models were sold without proper authentication procedures, we voluntarily reported it to the ministry,” the German automaker said. “We respect the government’s decision and will actively cooperate for the investigation.”

By Shin Ji-hye (shinjh@heraldcorp.com)