A group of Swiss companies including energy trader Mercuria and private equity firm Partners Group has pledged over $6 billion in U.S. energy investments as part of efforts to lower U.S. tariffs on Switzerland, two people close to the matter said.

U.S. President Donald Trump in August stunned Switzerland by imposing 39% import tariffs on Swiss firms, justifying them by the size of the U.S. trade deficit with the Alpine country, which last year eliminated its industrial tariffs.