According to previous studies, the demand-liability feature of national bank notes did not present a problem for note-issuing banks because the nonbank public treated notes and other currency as perfect substitutes. However, that view, when combined with nonbindingness of the collateral...

A current U.S. policy is to introduce a new style of currency that is harder to counterfeit, but not immediately to withdrawal from circulation all of the old-style currency. This policy is analyzed in a random-matching model of money, and its potential to decrease counterfeiting in the long run...