Reproduction permitted only if source is stated.ISBN 978-3-95729-207-0 (Printversion) Non-technical summary
Research QuestionThe 2007-2009 financial crisis has raised fundamental questions about the effectiveness of the Basel II Securitization Framework, which regulates bank investments into asset-backed securities (ABS). The Basel Committee on Banking Supervision (2014) has identified "mechanic reliance on external ratings" and "insufficient risk sensitivity" as two major weaknesses of the framework. Yet, the full extent to which banks actually exploit these shortcomings and evade regulatory capital requirements is not known. This paper analyzes the scope of risk weight arbitrage under the Basel II Securitization Framework.
ContributionA lack of data on the individual asset holdings of institutional investors has so far prevented the analysis of the demand-side of the ABS market. I overcome this obstacle using the Securities Holdings Statistics of the Deutsche Bundesbank, which records the on-balance sheet holdings of banks in Germany on a security-by-security basis. I analyze investments in ABS with an external credit rating to uncover risk weight arbitrage on the demand-side of the ABS market.
ResultsThe analysis delivers three main results. First, I provide security-level evidence that banks arbitrage Basel II risk weights for ABS. Banks tend to buy the securities with the highest yields and the worst collateral in a group of ABS with the same risk weight (and, therefore, the same capital charge). My findings corroborate the hypothesis that institutional investors bought risky ABS to some extent for motives of regulatory arbitrage.Second, banks operating with low capital adequacy ratios close to the regulatory minimum requirement are found to arbitrage risk weights most aggressively. From a financial stability perspective this finding is troubling as it implies that the presumably more fragile banks are also most pervasively optimizing the very capital regulation designed to constrain them.Third, banks with tight regulatory constraints buy riskier ABS with lower capital requirements than other banks. The ABS bought by banks that arbitrage risk weights, promise an as much as four times higher return on required capital than the ABS bought by other banks. Arbitraging the Basel Securitization Framework:Evidence from German ABS Investment *
Matthias Efing Swiss Finance Institute & University of Geneva
AbstractThis paper provides evidence for regulatory arbitrage within the class of assetbacked securities (ABS) based on individual asset holding data of German banks. I find that those banks operating with tight regulatory constraints pick the securities with the highest yield and lowest collateral quality among ABS with the same regulatory risk weight. This ABS selection allows banks to increase the return on the capital required for an ABS investment by a factor of four.