The papers by Emery, “Risk, Return, and the Morphology of Commercial Banking,” and by Klein and Murphy, “The Pricing of Bank Deposits: A Theoretical and Empirical Analysis,” are impressive attempts to describe the rationale of banking behavior. They provide an interesting combination of contrast and similarity. Both derive a model of the individual bank—Emery credits Shull's descriptive model of multiple-product price discrimination, while Klein and Murphy assign no specific competitive category but provide rather a generalized mathematical construct. Emery then incorporates portfolio theory to determine the difference between the actual return on bank capital from an idealized rate. This difference, called rent, is posited as a measure of the extent to which the actual level of interbank competition differs from the ideal. Assuming that regulatory agencies aim to maximize competition and thus consumer welfare, the implication of positive or negative rent differentials is inefficient regulation.