As of 2018 it was the world's largest CSD by value of securities held, well ahead of the Depository Trust Company and of Euroclear Bank.
[1]: 69 The FSS started when the Federal Reserve began operating a book-entry system for U.S. Treasuries in 1968.
In 1985, mortgage-backed securities were also issued in book-entry form by Fannie Mae and Freddie Mac, followed by Ginnie Mae in 1986.
[3] Thus, the FSS has developed to provide issuance, maintenance, transfer and settlement services for all marketable U.S. Treasury securities and also some securities issued by other federal government agencies, government-sponsored enterprises, and international organizations such as the World Bank.
[4] The Fedwire Securities Service is also the key interbank settlement system for Fedwire-eligible securities.