Iowa constitution
Article VIII
Section 8

If a general banking law shall be enacted, it shall provide for the registry and countersigning, by an officer of state, of all bills, or paper credit designed to circulate as money, and require security to the full amount thereof, to be deposited with the state treasurer, in United States stocks, or in interest paying stocks of states in good credit and standing, to be rated at ten per cent. below their average value in the city of New York, for the thirty days next preceding their deposit; and in case of a depreciation of any portion of said stocks, to the amount of ten per cent. on the dollar, the bank or banks owning such stock shall be required to make up said deficiency by depositing additional stocks: and said law shall also provide for the recording of the names of all stockholders in such corporations, the amount of stock held by each, the time of any transfer, and to whom.