IRB Model Regulatory Arbitrage and Profitability at European Banks by Giovanni Ferria, Valerio Pesicb Preliminary Draft (Version 28/10/17) – not for citation Abstract Internal Rating Based (IRB) models maneuvering evokes regulatory arbitrage allowing a bank to report Risk Weighted Assets (RWAs) below what stated by a similar bank disengaged from risk weights assuaging. Focusing on profitability distortions in a large sample of European banks, we find that reporting RWAs below our model prediction Granger-causes higher profitability among banks using IRB-Advanced approaches. Our results withstand a battery of robustness checks. Thus, regulatory arbitrage via IRB model calibration seems to significantly affect reported profitability at European banks. Authorities should either make IRB model validation more effective or consider phasing out IRB model discretion. JEL Classification codes: G2; G21; G28. Keywords: Banking; Regulatory arbitrage; Profitability; Risk Weighted Assets dispersion; IRB a LUMSA University, Via Pompeo Magno, 22, 00193 Rome, Italy. E-mail address: [email protected] b Sapienza University, Via del Castro Laurenziano, 9, 00161 Rome, Italy. E-mail address: [email protected] 1 1. Introduction A well established view in the economic banking literature asserts that “higher capital-asset ratio (CAR) is associated with a lower after-tax return on equity (ROE)” (Berger, 1995). The arguments behind this hypothesized negative relationship between capital and earnings have intuitive appeal and are consistent with “standard one-period models of perfect capital markets with symmetric information between a bank and its investors”. Higher capital ratios “reduce the risk on equity” and so “lower the equilibrium expected return on equity required by investors”. Also, higher CARs lower after-tax earnings by cutting the tax shield provided by the deductibility of interest payments. Despite these arguments, over time empirical evidence in the economics literature found support also for the opposite view. There are various potential explanations for a positive capital-earnings relationship, once the assumptions of the one-period model of perfect and symmetric information are relaxed. Relaxing the one-period assumption allows “an increase in earnings to raise the capital ratio, provided that marginal earnings are not fully paid out in dividends”. Relaxing the perfect capital markets assumption allows “an increase in capital to raise expected earnings by reducing the expected costs of financial distress including bankruptcy”. Finally, relaxing the assumption of symmetric information allows for “a signaling equilibrium in which banks that expect to have better performance credibly transmit this information through higher capital” (Berger, 1995). Banks capital level is particularly relevant for prudential regulators, who view an adequate level of capital as a key – even if no longer a sufficient per se – condition to pursue financial stability of a single bank and of the whole banking system. However, determining the right threshold of capital needed to ensure the soundness and stability of the international banking system – finding a correct measure of risk without jeopardizing banking profitability – remains a tough issue to solve. Being aware that the level of capital necessary to comply to the regulatory framework can hinder the profitability of banks – by enlarging (exogenously) the denominator of their Return on Equity ratio (ROE) – supervisors constantly engaged, since the first version of the 1988 Basel Accord, to cushion the negative effects of regulatory requirements on banks profitability. Over time, supervisors considered different tools to achieve that optimal threshold. They allowed (in the past) banks to include in regulatory capital resources other than common shares and retained earnings. They considered an increasing number of typologies of risks under the Risk Weighted Assets (RWA) formula, so to contemplate the evolution of banking activity and avoid regulatory obsolescence. They reviewed the modalities to compute capital requirements by different approaches, so to stimulate more sophisticated and relevant banks to invest in refined (and complex) methods of risk evaluation, supposedly achieving sounder risk management together with lower absorption of capital. Finally, within the last framework of Basel III, supervisors aimed to 2 make banking sectors more resilient by increasing the quality and quantity of the regulatory capital base, enhancing the risk coverage of the capital framework, proposing a new leverage ratio to protect against model risk and measurement error, and finally introducing a number of macro- prudential elements to dampen the pro-cyclicality of the prudential supervisory system. While there was wide consensus on the new framework, concerns emerged on the relevant efforts by the more sophisticated banks – which were in general those using most sources of funding other than common base – which could considerably impact their profitability profile. By this token, Basel III has been viewed as a possible new spur to improve these banks’ capital profile, inciting more discretionary use of the regulatory framework to further reduce capital absorption (Basel Committee on Banking Supervision, 2011). In the event, the potential bias is if the discretionary use of the regulatory framework moves from a “fair use” of the possibilities offered by regulators to new “enforcing interpretations” of regulatory discretion which might generate the suspicion of “regulatory arbitrage”. In this paper we investigate the potential nexus between regulatory arbitrage and profitability in a relatively large sample of European banks. Via a Granger analysis approach, we identify the effect that regulatory arbitrage can have at more sophisticated banks, the ones adopting Advanced IRB model, to save on capital and by this improve their level of profitability. The evidence supports our hypothesis. We also perform several robustness analyses confirming the main results. The rest of the paper is structured as follows. The available literature is surveyed in Section 2. Section 3 presents our methodology and describes the data that we meticulously collected. In Section 4 we report and comment the results of our econometric estimates. Finally, in Section 5 we summarize and evaluate the main implications for regulators. 2. Balancing banking stability and banking profitability in the economics literature Our paper tackles two streams of the economics banking literature. The first, and more recent, one considers the potential bias characterizing regulatory metrics (RWA dispersion) because of regulatory arbitrage, while the second, and more established, investigates the determinants of banks profitability and optimal capital structure. Since the dispersion among RWAs has become evident even across banks operating in the same jurisdiction and with similar business specialization, supervisors recently started to investigate regulatory arbitrage taking place at banks via RWA calculations [EBA (2013a, 2013b, 2013c, 2014); Basel Committee on Banking Supervision (2013a, 2013b, 2013c); Banco de Espana (2010, 2011, 2012); Banca d’Italia (2012); National Bank of Belgium (2014); IMF (2012a, 2012b, 2015)]. 3 More recently, Mariathasane & Merrouche (2014) and Ferri & Pesic (2016) study the determinants of RWA dispersion by focusing on the effect that the adoption of IRB methodologies can play in reducing capital absorption, via Basel risk-weights manipulation. They both conclude that regulatory arbitrage likely materializes with internal ratings-based (IRB) model adoption, especially among weakly capitalized banks. Specifically, Mariathasane & Merrouche (2014) study the relationship between banks’ approval for IRB methods under Basel II and the ratio of RWA to total assets. Instead, focusing on RWA/EAD, Ferri & Pesic (2016) are able to clean the risk weighted density from the roll-out effect generated by banks portfolio shift from Standard to IRB (Figure 1). Figure 1 – The Regulatory Capital Framework Puzzle Mix of Capital Sources Regulatory Capital Return ≥ 8% = RoE RWACRE + (MR + OR)*12.5 Equity Portfolio mix optimization Switch to Less Capital Switch to Less Capital Regulatory and risk reduction Consuming Methodologies Consuming Assets Arbitrage Retail EAD EAD EAD Other Control RWACRE Mortgage STD IRB CRE + → Variables Corporate EADCRE EADCRE Total Assets EADCRE … Fair use of Regulatory Option Regulatory Arbitrage Over time, significant efforts have been devoted to investigate both the determinants of banks profitability (Berger et al., 1995a; Albertazzi & Gambacorta, 2009; DeYoung & Rice, 2004; Fiordelisi & Molyneux, 2010) and banks capital level optimization decisions (Berger et al., 1995b; Blum, 1999; Estrella, 2004). In particular, the determinants of banks profitability emerge in the recent economics literature on bank business model investigating balance sheets characteristics (Altunbas et al., 2011), income and funding diversification (Demirgüc-Kunt and Huizinga, 2010; Köhler 2016), classification of financial institutions based on their asset and liability mix via cluster analysis (Ayadi et al., 2011) or factor analysis (Mergaerts & Vander Vennet, 2016). 4 It’s difficult to consider those elements together because of their reciprocal nexus of causation (Berger, 1995; Berger & DeYoung, 1997), especially when prudential regulation exogenously impacts capital structure decisions by the management (Kim & Santomero, 1988; Repullo,