The TSP Fiduciary Security Act of 2025 aims to enhance the responsibilities of fiduciaries managing the Thrift Savings Fund, a retirement savings plan for federal employees and military personnel. The legislation seeks to ensure that investments made by this fund do not jeopardize U.S. national security, particularly by preventing investments in companies linked to nations considered threats, such as China and Russia. Key provisions of the act mandate fiduciaries to avoid investments that could harm national security.