Analyzing spillover effects from data breaches to the US (cyber) insurance industry

As the US cyber insurance market is the largest worldwide, this paper presents an analysis of the effects of data breaches in the US financial services industry in relation to the stocks of US insurance companies. We conduct an event study, focusing on publicly announced data breaches that occurred between 2005 and 2018, and observe significant negative spillover effects for US insurers. However, in the subsample of non-announcing cyber insurers between 2015 and 2018, we not only find significant negative spillover effects especially for longer event windows, but also significant positive effects in case of ‘mega data breaches' with more than 1 million breached records, which may be due to an increasing demand for cyber insurance. To understand these findings in more detail, we further analyze event as well as firm characteristics and find that spillover effects are information-based rather than pure.