Monetary policy is analysed within a model that appeals to legal restrictions on private intermediation to explain the coexistence of currency and interest-bearing default-free bonds. The interaction between such legal restrictions and monetary policy is illustrated in a version of the overlapping generations model. The model shows that legal restrictions and the use of both currency and bonds permit the government to levy a nonlinear inflation tax and that such a tax may be better in terms of the Pareto criterion than a linear inflation tax.