Among recent secretaries of state, Hillary Clinton was one of the most aggressive global cheerleaders for American companies, pushing governments to sign deals and change policies to the advantage of corporate giants such as General Electric Co., Exxon Mobil Corp., Microsoft Corp. and Boeing Co.

At the same time, those companies were among the many that gave to the Clinton family’s global foundation set up by her husband, former President Bill Clinton. At least 60 companies that lobbied the State Department during her tenure...