Protecting Endowments from Our Adversaries Act This bill imposes an excise tax equal to 50% of the fair market values of certain investments made by private colleges and universities with assets or endowments exceeding $1 billion. It also taxes 100% of the net income of such investments held during a one-year period. These investments are in certain foreign persons or entities (e.g., Chinese or Russian companies) that are included on lists maintained by the Department of Commerce and the Federal Communications Commission that identify persons or entities engaged in human rights abuses or that pose a threat to U.S. national security.