The line item for U.S. Treasury securities held in custody now excludes securities pledged by the Federal Reserve as collateral in reverse repurchase agreements conducted with foreign official and international
accounts and includes inflation compensation on Treasury Inflation-Protected Securities (TIPS), which captures the inflation adjustment to original face value of TIPS over time. Prior data included securities pledged as
collateral against reverse repurchase agreements with the Federal Reserve and excluded inflation compensation on TIPS. Information on the amount of foreign official and international reverse repurchase agreements is still
presented in table 1 and included in total reverse repurchase agreements in table 8 and table 9. For further information
on the changes to the H.4.1 Statistical Release please visit the following: http://www.federalreserve.gov/releases/h41/20121115/
Board of Governors of the Federal Reserve System (US), Memorandum Item: Securities Held in Custody for Foreign Official and International Accounts: Marketable U.S. Treasury Securities [WMTSEC1], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/WMTSEC1, May 20, 2018.