German newspaper Spiegel Online reports that the NSA has its own financial database to track money flows through a "tailored access operations" division.
According the newspaper, a special NSA branch called "Follow the Money" (FTM) "widely monitors international payments, banking and credit card transactions" around the world. The newspaper, which cites documents leaked by Edward Snowden as a source, claims that 84 percent of the collected data is from credit card transactions. Spiegel Online explains how VISA came under close scrutiny in particular:
NSA analysts at an internal conference that year described in detail how they had apparently successfully searched through the [VISA's] complex transaction network for tapping possibilities... Their aim was to gain access to transactions by VISA customers in Europe, the Middle East and Africa, according to one presentation. The goal was to "collect, parse and ingest transactional data for priority credit card associations, focusing on priority geographic regions."
The Brussels-based Society for Worldwide Interbank Financial Telecommunication (SWIFT)—a pervasive network used to securely wire money—was also a major target. Interestingly, though, it transpires that other intelligence agencies—like the UK's GCHQ—take a dim view on this particular aspect of the NSA's snooping, according to the Spiegel. Naughty NSA. [Spiegel Online]