Federal Reserve notes are obligations of the Reserve Banks.

This is interesting: The Reserve Banks secure the currency they issue with legally authorized collateral, most of which is in the form of U.S. Treasury securities held by the Reserve Banks.

Coin, unlike currency, is issued by the Treasury, not the Reserve Banks. The Reserve Banks order coin from the Treasury’s Bureau of the Mint and pay the Mint the full face value of coin, rather than the cost to produce it. The Reserve Banks then distribute coin to the public through depository institutions.

The Board of Governors of the Federal Reserve System shall have the right, acting through the Federal Reserve agent, to grant in whole or in part, or to reject entirely the application of any Federal Reserve bank for Federal Reserve notes; but to the extent that such application may be granted the Board of Governors of the Federal Reserve System shall, through its local Federal Reserve agent, supply Federal Reserve notes to the banks so applying, and such bank shall be charged with the amount of the notes issued to it and shall pay such rate of interest as may be established by the Board of Governors of the Federal Reserve system on only that amount of such notes which equals the total amount of its outstanding Federal Reserve notes less the amount of gold certificates held by the Federal Reserve agent as collateral security.

The withdrawal of the Gold Certificate