Source: Board of Governors of the Federal Reserve System (US)  

Release: H.4.1 Factors Affecting Reserve Balances  

Units:  Billions of Dollars, Not Seasonally Adjusted

Frequency:  Weekly, Ending Wednesday

This series is calculated by the Federal Reserve Bank of St. Louis using historical data from the Board of Governors' H.4.1 press releases. The data include the value of primary, secondary, and seasonal credit, and other credit facilities and extensions. For historical changes to the data reported in Table H.4.1, see here.