This series has been discontinued with a phase of the simplification of reserves administration (https://federalregister.gov/a/2012-8562). The simplification of reserves administration provides an opportunity to streamline the process of calculating the monetary base so that it reflects the fundamental concept of this measure. The fundamental concept of the monetary base, or "high-powered money," is the sum of total balances maintained by depository institutions at the Federal Reserve plus currency in circulation.
Please see the new monetary base at https://fred.stlouisfed.org/series/BOGMBASE.
Board of Governors of the Federal Reserve System (US), Board of Governors Monetary Base, Not Adjusted for Changes in Reserve Requirements (DISCONTINUED) [BOGUMBNS], retrieved from FRED, Federal Reserve Bank of St. Louis; https://fred.stlouisfed.org/series/BOGUMBNS, January 22, 2022.