Adding it All Up : The Macroeconomic Impact of Basel III and Outstanding Reform Issues

As the Basel III package nears completion, the emphasis is shifting to monitoring its implementation and assessing the impact of the reforms. This paper presents a simple conceptual framework to assess the macroeconomic impact of the core Basel III reforms, including the leverage ratio surcharge that is being considered for global systemically important banks (G-SIBs). We use historical data for a large sample of major banks to generate a conservative approximation of the additional amount of capital that banks would need to raise to meet the new regulatory requirements, taking the potential impact of current efforts to enhance G-SIBs' total loss-absorbing capacity into account. To provide a high-level proxy for the effect of changes in capital allocation and bank business models on the estimated net benefits of regulatory reform, we simulate the effect of banks converging towards the "critical" average risk weights (or "density ratios") implied by the combined risk-weighted and leverage ratio-based capital requirements. While keeping in mind that quantifying the regulatory impact remains subject to caveats, the results suggest that Basel III can be expected to generate sizeable macroeconomic net benefits even after the implied changes to bank business models have been taken into account