This data series has been discontinued, please see series ID: https://fred.stlouisfed.org/series/WMTSEC1
Memorandum item: Securities Held in Custody for Foreign Official and International Accounts - Marketable U.S. Treasury Securities. For further information
on the changes to the H.4.1 Statistical Release please visit the following: http://www.federalreserve.gov/releases/h41/
Board of Governors of the Federal Reserve System (US), Memorandum Item: Marketable Securities Held in Custody for Foreign Official and International Accounts: U.S. Treasury Securities (DISCONTINUED) [WMTSEC], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/WMTSEC, April 25, 2018.