A new study highlighted on the Harvard Law School Forum on Corporate Governance, and posted by Subodh Mishra, Global Head of Communications at ISS STOXX, on Tuesday, April 14, 2026, quantifies how cyber incidents can have sustained and measurable negative impacts on shareholder value. The report, based on research conducted by ISS STOXX and ISS-Corporate (the study), analyzed cyber incidents among companies in the Russell 3000 over a multi-year period. Its findings are stark: companies experiencing significant cyber incidents underperform the broader market by approximately 5% on average over a three-year time period.
As D&O Diary readers are aware, cybersecurity issues can be a source of D&O liability. The findings in this recent study pile on with findings that cybersecurity failures may also result in share underperformance for a broad period. The following discusses the findings of this most recent study, reasons for a longer tail and D&O liability and litigation implications.
Source: Cyber Incidents’ “Long Tail” Impact on Shareholder Value | The D&O Diary
