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

Release: H.4.1 Factors Affecting Reserve Balances  

Units:  Millions of Dollars, Not Seasonally Adjusted

Frequency:  Weekly, As of Wednesday

Notes:

This series has been discontinued and will no longer be updated. It was a duplicate of the following series, which will continue to be updated: https://fred.stlouisfed.org/series/WSHOMCB

The current face value of mortgage-backed obligations held by Federal Reserve Banks. These securities are guaranteed by Fannie Mae, Freddie Mac, or Ginnie Mae.

Source: U.S. Department of the Treasury. Fiscal Service  

Release: Treasury Bulletin  

Units:  Billions of Dollars, Not Seasonally Adjusted

Frequency:  Quarterly, End of Period

Notes:

The data is presented by the source as Public debt securities: Public issues held by Federal Reserve banks on TABLE OFS-1—Distribution of Federal Securities by Class of Investors and Type of Issues.

Public issues held by the Federal Reserve banks have been revised to include Ginnie Mae and exclude the following Government-Sponsored Enterprises: Federal National Mortgage Association, Federal Home Loan Mortgage Corporation, and the Federal Home Loan Bank System.