Data breaches in hospitals disrupt care, potentially leading to fatal consequences, violating privacy rights, and incurring significant costs to remedy. Mergers and acquisitions serve as an essential source of financing but also induce substantial management challenges. I study whether and how hospital mergers increase the probability of a data breach. Using proprietary hospital merger records and the archived data breach reporting from the Department of Health and Human Services from 2010 to 2022, I implement a stacked difference-in-differences estimation strategy to show that in the two-year window after hospital consolidation, incidents of data breaches in merger targets, buyers, and sellers more than double as compared to the pre-treated groups. The effect is robust to changes of the two-year window. The effect is also robust to the changes in sample size due to the data availability of the control variables and in how standard errors are clustered. The incompatibility of the merging information systems causes an increase in hacking in the post-signing period. Health systems, especially the large and experienced health systems, suffer greater such elevated post-signing breaches. In recent years, cyber attacks have shorter attack cycles than traditional malware attacks and catch hospitals that haven't gotten integration in order by surprise. The signaling effect that reduces hackers’ information asymmetry about the hospitals causes an even larger increase in pre-signing hacks, especially in recent years through ransomware attacks. Such signaling effect does not spill over to the post-signing period. Conversely, the complementary effect of organizational capital that improves internal risk control reduces the increase in data breaches. For example, mergers involving publicly traded hospitals can experience a decrease in data breaches during mergers. The dynamic analysis shows that the data breach situation during mergers is getting worse because of soaring cases of hacks, even though the insider misconduct have become less a problem since 2014.

Cloud services exist under a shared security environment with a dynamic nature; users trade fixed costs for variable costs over time and both cloud service providers (CSP) and users contribute to overall security. We investigate the nature of shared security in a dynamic game where users' security contribution takes into account both their users as well as competition with other CSPs. The Markov Perfect Equilibrium reveals the long-term time patterns of security of the cloud. In particular, we identify a novel form of time-path strategic complementary between usage and a CSP's Markov state of security. This implies cloud security is an unusual form of impure public good whereby individual contributions bolstering a CSP's security endow a selective incentive (private benefit) on others, rather than on the contributor alone. Since this increases usage, CSP vulnerability increases over time. At the same time, CSP competition on security may lead to both welfare improvements for users and lock-in.