1 Introduction
The effect of bank competition on the risk taking behavior of banks has been at the
center of a discussion among regulators, policy makers and researchers for a long time.
Until recently, the general consensus among policy makers and researchers has been that
market power gives banks proper incentives to behave prudently. The central aim of
prudential bank regulation to reduce banks’ risk taking incentives therefore often coincides
with restricting competition among banks. Accordingly, the banking industry has
been exempted from competition law for a long time (Carletti and Vives (2008)). In
recent years, however, several theoretical and empirical studies have challenged the view
that monopoly power mitigates bank risk taking, instead arguing that higher competition
among banks leads to lower levels of bank risk. The recent financial crisis, which has also
been triggered by excessive bank risk taking, has again heightened interest in the relationship
between competition among banks, bank market structure and banking stability.
The competition-bank risk taking nexus has been extensively analyzed in the theoretical
banking literature. The predictions emerging from the theoretical models are ambiguous,
however. Models such as those of Keeley (1990), Allen and Gale (2004), Matutes and
Vives (2000), Hellmann, Murdock, and Stiglitz (2000) and Wagner (2010) all predict that
fiercer competition among banks will result in higher bank risk taking. The intuition
behind the result is straightforward: High market power at the bank level is associated
with high monopoly rents which the bank manager wants to protect by investing in safe
assets. By reversing the line of argument of the above models, Boyd and De Nicolo (2005)
show how higher competition among banks might lead to a reduction in the overall level
of bank risk taking: Higher competition reduces interest rate costs at the level of the borrowing
firm, leading the firm to choose a safer project which ultimately generates safer
banks. Martinez-Miera and Repullo (2010) build a model which predicts that the effect
of bank competition on bank risk taking is non-linear. Their model shows that under
specific circumstances higher bank competition first increases bank risk taking and then
reduces bank risk taking. Their model thus predicts a reversed u-shaped relationship
between bank competition and bank risk taking. Besides the theoretical literature, there
is abundant empirical work examining the effect of bank competition on stability and
bank risk. One strand of empirical research uses large aggregated cross-country datasets.
Beck, Demirguc-Kunt, and Levine (2006), using a logit probability model, find that more
concentrated banking systems are less likely to experience a banking crisis.