  In this paper we aim to find a measure for the diversity of cash flows
between agents in an economy. We argue that cash flows can be linked to
probabilities of finding a currency unit in a given cash flow. We then use the
information entropy as a natural measure of diversity. This leads to a
hirarchical inequality measure, which includes the well-known Theil index as a
special case, and a constraint on agent entropy differentials, i.e., the
difference between cash inflow and outflow entropies. The last result is
particularly intriguing as it formalises the fact that an economy must contain
both, cash flow aggregating and cash flow diversifying agents.
