Policy programs on anti-money laundering and combating the financing of terrorism (AML/CFT) have largely called for preventive measures like keeping record of financial transactions and reporting suspicious ones. In this survey study, we analyze the extent of global money laundering and terrorist financing and discuss the preventive policies and their evaluations. Moreover, we investigate whether more effective tax information exchange would bolster AML/CFT policies in that it reduced tax evasion, thus the volume of transnational financial flows (i.e. to and from offshore financial centres) and thus in turn cover given to money laundering and terrorist financing. We conclude that such a strategy can reduce financial flows, yet due to a "weakest link problem" even a few countries not participating can greatly undo what others have achieved.