Proliferation financing refers to funding or assisting individuals, groups, or countries involved in acquiring, developing, or using weapons of mass destruction (WMDs) and their delivery systems (like missiles). This support often violates national and international laws aimed at preventing the spread of such weapons. 

Monitoring proliferation financing is crucial to deter the proliferation of WMDs. International efforts, such as UN Security Council Resolutions and the Proliferation Security Initiative, encourage countries to criminalize and prevent such financing within their borders. 

Many countries, including the U.S. with its Anti-Money Laundering Whistleblower Program, implement legal frameworks and programs to deter and prevent proliferation financing. These measures involve increased scrutiny, sanctions, and other controls on individuals and entities suspected of engaging in proliferation activities.