Illicit finance can be used by adversarial actors to conduct a range of hostile activities, such as interfering in another country’s political system, evading sanctions, funding armed operations or laundering tarnished reputations. Financial secrecy undermines a country’s ability to pursue a coherent security and foreign policy strategy. The lack of beneficial ownership transparency, the under-regulation of political finance, as well as the limited enforcement and prevention of financial crime help facilitate illicit financial flows that weaken national security. Policy responses to curb these illicit financial flows will have to start by addressing the gaps that are exploited by adversarial actors. This could include reforms that: strengthen beneficial ownership transparency, enhance the capacities of financial crime authorities, better regulate activities of foreign lobbyists, and create more substantive restrictions on political financing.