Do Board Gender Quotas Generate Horizontal Spillovers?

Using a panel of unlisted Italian banks over the period 2006-2018, we examine the extent to which a law that mandatorily introduced female quotas in the boards of Italian listed companies in 2012 had spillover effects on the boards of unlisted banks, which were not required to comply with the quota. Our results show that both the probability of having at least one woman on the board and the proportion of women on the boards of unlisted banks have been rising significantly after the passing of the law. These findings, which are robust to estimating different specifications and to using different estimation techniques, suggest that the quota law contributed to generating a fairer attitude towards women and, more in general, a change in social norms on gender equality. This may have, in turn, generated isomorphic pressures on unlisted banks, inducing them to mimic the board composition of their listed counterparts.