Billionaire Elon Musk has made a donation to a super PAC dedicated to electing Donald Trump to the White House, in a major move by the world's richest man to make his mark on US politics. Mr. Musk has donated to a low-profile group called the American Political Action Committee, according to people familiar with the matter, who spoke on the condition of anonymity to elaborate on his plans. It is not clear how much Mr. Musk has donated, but people familiar with the matter said it was substantial. The PAC will again disclose its donors on July 15.