(Bloomberg) -- David Einhorn’s recovery this year, spurred partly by his big bet on General Motors Co., has been jolted by President Donald Trump’s threat of a trade war with Mexico. Einhorn’s hedge fund, Greenlight Capital, counts GM as its largest U.S. publicly disclosed position. The automaker’s stock is among the hardest hit in the industry after Trump said he would slap tariffs of as much as 25% on goods from Mexico, the largest source of U.S. vehicle and auto-parts imports.