Modeling Policy Response to Global Systemically Important Banks Regulation

In this paper we elaborate a simple model that allows for the predicting of possible reactions from financial institutions to more stringent regulatory measures introduced by the Basel Committee on Banking Supervision (BCBS) in regard to global systemically important banks (G-SIBs). The context is framed by a 2011 BCBS document that proposes higher capital requirements for global systemically important banks. We attempt to analyze bank interactions in an oligopolistic market that is subject to demand constraints on loan amounts and additional loss absorbency requirements introduced by the regulator. We distinguish between the bank’s announced funding cost that determines both the loan amount issued and the market interest rate, and the bank’s true funding cost that has a direct impact on retained earnings. We conclude that in a two-stage game both banks will announce the highest funding cost, thus reducing the amount of loans granted (in line with the regulator’s objective), but at the expense of a higher cost of borrowing established in the market. If the game is repeated, then both banks also choose lower loan amounts in the periods prior to the last one in which the declared funding cost is the lowest possible. It should be noted that the designated outcome also coincides with the findings of the Monetary Economic Department of the Basel Committee on Banking Supervision.