National banks taking out circulation are subject to a tax on the average amount outstanding. This tax is payable semiannually, and is at the rate of 1/2 per cent per annum on such notes as are secured by 2 per cent bonds, and 1 per cent per annum on the notes secured by bonds bearing higher interest rates. The Treasurer, when levying the tax, takes as the basis the average amount of notes that the bank has had in circulation during the six months previous to the assessment date. This estimate must be made by each bank and submitted, under the oath of the president or cashier, within 10 days from the first of January and 10 days from the first of July. If a bank fails to make a proper report on the average amount of circulation it has had outstanding for a period of six months, it is liable to a fine of $200, and the tax which must be paid by the bank is then assessed upon the amount of notes that have been delivered by the Comptroller instead of upon the average amount in circulation. A bank calculates the average amount outstanding during a period by taking the amount it has outstanding each day for the period and dividing by the exact number of days. Should a bank not keep a daily record of outstanding notes, but obtain its averages from weekly statements, it adds together the amounts outstanding weekly and divides by the number of weeks. If there is any fraction of a week, the amount that should be added for each day of such fraction is one-seventh of the balance for the week immediately preceding the odd number of days.

A bank may pay the amount of tax assessed on its circulating notes to the Treasurer of the United States, or to a federal reserve bank or to national bank depositories. When payments are so made, certificates are issued in triplicate, the original being forwarded to the Secretary of the Treasury, the duplicate to the Treasurer, and the triplicate being held by the paying bank as a voucher. If there is not a depository convenient, payment may be made by draft on New York, payable through the clearing house, to the order of the federal reserve bank, or by direct remittance to the Treasurer in lawful money or national bank notes.