What if only a foreign company is infringing?-- If the foreign company makes and sells abroad a product covered by a US patent, there is no infringement. However, if a foreign company imports its infringing products into t8he U.S., we can pursue them here for patent infringement.
A U.S. patent cannot be infringed solely by acts performed abroad. A foreign company can freely make and sell a product covered by a U.S. patent anywhere outside the U.S. If they import infringing goods into the U.S., they may be sued here.