The Foreign Military Sales (FMS) program is a form of security assistance authorized by the Arms Export Control Act (AECA) and a fundamental tool of U.S. foreign policy.
Under Section 3, of the AECA, the U.S. may sell defense articles and services to foreign countries and international organizations when the President formally finds that to do so will strengthen the security of the U.S. and promote world peace.
Under FMS the US Government and a foreign government enter into a government-to-government sales agreement. The international agreement is called a Letter of Offer and Acceptance (LOA).
Secretary of State determines which countries will have programs. Secretary of Defense executes the program.
May be funded by country national funds or US Government funds.