Experts say the 25 percent import fee will make many cars more expensive, but it is not clear when, by how much or which models.

The threat came in a call earlier this month, leaving CEOs worried they would face punishment if prices increased.

President Donald Trump made official Wednesday his long-promised tariffs for the automotive industry, imposing a 25% import tariff on all cars, light-duty trucks and some car parts imported into the U.S. Trump argued the tariffs will boost domestic manufacturing by forcing American automakers to build cars in the U.S.