Last week, President Donald Trump threatened to slap heavy tariffs on imported cars. The president asked Commerce Secretary Wilbur Ross to consider whether the imports of automobiles, including trucks and automotive parts, threaten U.S. national security. The move prompted an outcry from U.S. lawmakers as well as the foreign car companies. And investors reacted by selling shares of big European automakers, with both BMW and Daimler dropping on May 24 more than 3 percent in European trading on the news.

This week, German magazine Wirtschaftswoche reported that President Donald Trump told told French President Emmanuel Macron he wants German carmakers out of the U.S. all together, according to Reuters.

Here's what you should know about German automakers and their business in the U.S.:

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German brands dominate the U.S. luxury vehicle market

In 2017, Mercedes had about 17 percent of this market, BMW had 15 percent (about tied with Toyota Lexus) and Audi had 11 percent, according to Statista.

German carmakers are major U.S. job creators

They employ 36,500 U.S. workers. Another 80,000 work for suppliers, according to German auto industry group VDA.

German car companies export about 430,000 vehicles from U.S. factories to the rest of the world, the VDA said. And they sold some 1.35 million "light vehicles" -- cars, SUVs and trucks -- in the U.S. in 2017.

They have big U.S. plants, mostly in the South

BMW's Spartanburg, South Carolina, plant produced more than 371,000 BMW X3, X4, X5 and X6 models in 2017, according a BMW annual company report. BMW says the factory employs more than 10,000 people.

Mercedes-Benz, a brand of Daimler, made more than 286,000 vehicles at its Tuscaloosa, Alabama, plant in 2017, according the company's website. The plant employs more than 3,700 workers. More than 70 percent of the plant's SUVs are exported to 135 countries, making it the second-largest automotive exporter in the U.S., according to the company.

Mercedes last year announced plans for a $1 billion investment to start production of electric passenger cars there over the next decade.

Volkswagen's luxury brands include Audi, Bentley, Bugatti, Lamborghini and Porsche. VW's Chattanooga, Tennessee, plant makes Volkswagen's Passat model. That plant employs about 3,400 workers. The company is also planning an electric vehicle investment there.