Finance and Economics Discussion Series (FEDS)
July 2024
Optimal Design of Contingent Capital
Lionel Melin and Ahyan Panjwani
Abstract:
This paper proposes a parsimonious framework for designing contingent capital contracts (CoCos). CoCos designed this way (i) are either optimal or incentive compatible for equity holders, (ii) implement a unique equilibrium, and (iii) result in an optimal capital structure for the firm. We consider CoCos with equity conversion and write-down modalities. Equity conversion CoCos are optimal; write-down CoCos are incentive-compatible. Both types of CoCos can be implemented by exogenously specifying a capital ratio rule that triggers conversion and, hence, qualify as additional tier 1 (AT1) capital. A policymaker can use a normative criterion, e.g., capital ratio after conversion, to determine the desired capital ratio rule ex-ante. Given the policymaker's choice of the capital ratio rule, our model pins down the CoCo that respects (i), (ii), and (iii). We show that including such a CoCo in the firm's capital structure increases its optimal levered value while making it more resilient to bankruptcy. Lastly, CoCos in this framework are time-consistent. This characteristic alleviates the risk of renegotiation by stakeholders and removes the uncertainty of a discretionary trigger: precisely what spooked markets during the run on Credit Suisse in March 2023.
Keywords: Contingent convertible debt, Bail-in debt, Capital structure, Capital requirements, Bank regulation, Bank capital
DOI: https://doi.org/10.17016/FEDS.2024.051
PDF: Full Paper
Disclaimer: The economic research that is linked from this page represents the views of the authors and does not indicate concurrence either by other members of the Board's staff or by the Board of Governors. The economic research and their conclusions are often preliminary and are circulated to stimulate discussion and critical comment. The Board values having a staff that conducts research on a wide range of economic topics and that explores a diverse array of perspectives on those topics. The resulting conversations in academia, the economic policy community, and the broader public are important to sharpening our collective thinking.