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

After expenses are paid and the statutory cumulative 6 percent dividend on paid-in capital stock is met, Reserve Banks are required by law to pay a part of net earnings into surplus so that surplus equals the amount of capital paid in.