(Reuters) – A major, global cyber attack could trigger an average of $53 billion of economic losses, a figure on par with a catastrophic natural disaster such as U.S. Superstorm Sandy in 2012, Lloyd’s of London said in a report on Monday.

The report, co-written with risk-modeling firm Cyence, examined potential economic losses from the hypothetical hacking of a cloud service provider and cyber attacks on computer operating systems run by businesses worldwide.

Insurers are struggling to estimate their potential exposure to cyber-related losses amid mounting cyber risks and interest in cyber insurance. A lack of historical data on which insurers can base assumptions is a key challenge.

“Because cyber is virtual, it is such a difficult task to understand how it will accumulate in a big event,” Lloyd’s of London Chief Executive Inga Beale told Reuters.

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