Cybercrime insurers largely avoided costly claims from the recent attacks that hit businesses around the globe. The next global virus could change that.

"It's exceptionally likely that we will see an event over the next months that will seriously affect insurers," Graeme Newman, chief innovation officer at CFC Underwriting, said in an interview. "It would only need a combination of WannaCry's wide reach and Petya's destructive force to cost cyber insurers something like $2.5 billion, or a full year of gross premium income in the market."

UK's Reckitt Benckiser Group cut its full-year sales forecast Thursday after a global cyberattack last month disrupted manufacturing and distribution for the maker of Air Wick fresheners and Dettol cleaners. It was the first detailed indication of the financial toll by a major company. Danish shipping giant A.P. Moller-Maersk, which had to shut down systems across its operations to contain the cyberattack, said it's too early to predict the impact on its results.