摘要：Conventional discussion of the zero lower bound on nominal interest rates relies on static reasoning. According to the
conventional argument, people who are holding interest-bearing assets should switch to currency the instant that the
nominal interest rate falls below zero since currency has a fixed nominal rate of interest equal to zero. In this paper, I
argue that the presence of uncertainty about the expected future path of the nominal interest rate and the non-negative
fixed costs associated with the storage of cash require a dynamic rather than a static analysis. People who are holding
an interest-bearing asset have the option, but not the obligation to switch to currency at any point in time. The
economic decision is to determine at what point to exercise this option. I show that the lower bound on the nominal
interest rate in this context is below zero. This is true even if storage costs are approximately zero. Since my
calculation does not depend on storage costs, it implies that the effective lower bound on the nominal interest rate
might be considerably lower than previously thought.
