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

Release: H.4.1 Factors Affecting Reserve Balances  

Units:  Millions of U.S. Dollars, Not Seasonally Adjusted

Frequency:  Weekly, As of Wednesday

Source: Federal Reserve Bank of St. Louis  

Release: H.3 Aggregate Reserves of Depository Institutions and the Monetary Base (data not included in press release)

Units:  Millions of Dollars, Not Seasonally Adjusted

Frequency:  Monthly

Notes:

The Board of Governors discontinued the H.3 statistical release on September 17, 2020. For more information, please see the announcement posted on August 20, 2020.

Series is calculated using data from the H.3 release as Total reserve balances maintained less Reserve balance requirements.

Please note though that this historical concept of "excess reserves" no longer has the same meaning following phase two of the simplification of reserves administration. For more information, see the Reserves Simplification Rule.