This document provides guidance to U.S. Businesses and foreign persons that are parties to transactions that are covered by section 721 of the Defense Production Act of 1950, as amended by the Foreign Investment and National Security Act of 2007 (FINSA). Section 721 requires CFIUS to review covered transactions notified to it “to determine the effects of the transaction(s)  on the national security of the United States” but does not define “national security,” other than to note that the term includes issues relating to homeland security. Further information can be obtained from Nova Daly, Deputy Assistant Secretary, U.S. Department of the Treasury (Nova.Daly@do.treas.gov) or Welby Leaman, Senior Advisor (Welby.Leaman@do.treas.gov).