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

Primary credit is a lending program available to depository institutions that are in generally sound financial condition. Primary credit is available in terms from overnight to 28 days. In extending primary credit, Reserve Banks must judge that the borrower is likely to remain eligible for primary credit for the term of the loan.