Foreign official deposits are balances of foreign central banks and monetary authorities, foreign governments, and other foreign official institutions with accounts at FRBNY. These balances usually are relatively small because the accounts do not bear interest. While transactions in these accounts are handled by FRBNY for balance sheet purposes, the deposits are allocated across all of the Reserve Banks based on each Reserve Bank's capital and surplus.
Board of Governors of the Federal Reserve System (US), Liabilities: Deposits with F.R. Banks, Other Than Reserve Balances: Foreign Official [WLFOL], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/WLFOL, May 25, 2018.