The pernicious effects of contaminated data in risk management

Banks hold capital to guard against unexpected surges in losses and long freezes in financial markets. The minimum level of capital is set by banking regulators as a function of the banks’ own estimates of their risk exposures. As a result, a great challenge for both banks and regulators is to validate internal risk models. We show that a large fraction of US and international banks uses contaminated data when testing their models. In particular, most banks validate their market risk model using profit-and-loss (P/L) data that include fees and commissions and intraday trading revenues. This practice is inconsistent with the definition of the employed market risk measure. Using both bank data and simulations, we find that data contamination has dramatic implications for model validation and can lead to the acceptance of misspecified risk models. Moreover, our estimates suggest that the use of contaminated data can significantly reduce (market-risk induced) regulatory capital.     

Robust estimation of intraweek periodicity in volatility and jump detection

Opening, lunch and closing of financial markets induce a periodic component in the volatility of high-frequency returns. We show that price jumps cause a large bias in the classical periodicity estimators and propose robust alternatives. We find that accounting for periodicity greatly improves the accuracy of intraday jump detection methods. It increases the power to detect the relatively small jumps occurring at times for which volatility is periodically low and reduces the number of spurious jump detections at times of periodically high volatility. We use the series of detected jumps to estimate robustly the long memory parameter of the squared EUR/USD, GBP/USD and YEN/USD returns.     

Banking efficiency in transition economies

An increasing share of the banking sector is controlled by foreign capital in the majority of transition countries. To analyse the effects of this trend on the performance of the banking sector in these countries, this study conducts a comparative analysis of the performance of foreign‐owned and domestic‐owned banks operating in the Czech Republic and Poland. We use the stochastic frontier approach to compute cost efficiency scores. Following Mester (1996 ), financial capital is included in the cost frontier model to control for risk preferences. Our finding is that on average foreign‐owned banks are more efficient than domestic‐owned banks. We conclude, however, that this advantage does not result from differences in the scale of operations or the structure of activities.     

The endo–exo problem in high frequency financial price fluctuations and rejecting criticality

The endo–exo problem lies at the heart of statistical identification in many fields of science, and is often plagued by spurious strong-and-long memory due to improper treatment of trends, shocks and shifts in the data. A class of models that has shown to be useful in discerning exogenous and endogenous activity is the Hawkes process. This class of point processes has enjoyed great recent popularity and rapid development within the quantitative finance literature, with particular focus on the study of market microstructure and high frequency price fluctuations. We show that there are important lessons from older fields like time series and econometrics that should also be applied in financial point process modelling. In particular, we emphasize the importance of appropriately treating trends and shocks for the identification of the strength and length of memory in the system. We exploit the powerful Expectation Maximization algorithm and objective statistical criteria (BIC) to select the flexibility of the deterministic background intensity. With these methods, we strongly reject the hypothesis that the considered financial markets are critical at univariate and bivariate microstructural levels.     

Bond offerings in China

This study appraises the value created by a bond offering in China, where high levels of state ownership and insider ownership raise concerns about the use of the proceeds. To estimate the impact of a bond issue on the firm's value, we apply an event‐study methodology on a sample of 481 issues of 347 Chinese companies over the period 2009–2013. It turns out that state ownership has a positive impact on the value of a bond offering for shareholders, which is consistent with an implicit guarantee of the issue by the state. For privately owned companies, insider ownership exerts a nonlinear impact on the firm's value, supporting an aligning effect in the use of the proceeds. Overall, the study confirms the key role of ownership structure in Chinese firms.     

Does CEO gender matter for bank risk?

This paper addresses the relation between CEO gender and bank risk. We exploit a unique dataset of 365 Polish cooperative banks, 42% of which are run by female CEOs. We find that banks headed by female CEOs are less risky: they report higher capital adequacy and equity to assets ratios. Credit risk in female-led banks is not different from male-led banks, and therefore higher capital adequacy does not stem from lower asset quality and is likely to be linked to higher risk aversion of female CEOs. Our evidence supports the view that women are more risk averse bank CEOs than men. Our findings suggest that gender quotas in bank boards can contribute to reduce risk-taking behavior.