More than 95% of average data breach losses and 90% of average first-party losses are adequately covered by insurance, according to a report released Tuesday from Willis, an arm of WTW (WTW), the UK- and US-based insurance and risk-advisory service.

WTW based its conclusions on an analysis of 5,500 cyber claims occurring from January 2013 to January 2026 and across 95 nations, and which resulted in $1 billion in insurer payments, said the insurer.

Malicious data breaches are the most-often reported cyber-insurance loss, while ransomware triggered to largest financial losses, driven by the disrupted productivity and prolonged downtime that followed incidents, said WTW.

The average ransomware event lasts 25 days and the average loss is $5.3 million, with the largest single loss now exceeding $500 million, added WTW.