Recent ransomware attacks including the WannaCry outbreak that crippled the UK’s public health system are likely to lead to increased demand for cyber insurance, Fitch says.

The ratings agency says insurers are in a unique position to assist customers, but warns caution is required in adding exposures because “there is considerable uncertainty in pricing and underwriting this risk”.

It says, for this reason, aggressive expansion in the sector could be credit negative.

US insurers wrote about $US1.3 billion ($1.75 billion) in cyber coverage last year, and the market could grow to $US14 billion ($18.87 billion) by 2022.

AM Best says the WannaCry attack highlights the need for technology companies and end users to mitigate potential losses.

“[WannaCry] could be a benefit to the insurance industry if it leads to a better ability to devise and craft appropriate policies with clear definitions and language, to attain the desired level of protection and coverage for policyholders,” it says.

AM Best says the attack was unique in terms of its scope, speed and reach.

However, it believes insured losses will be minimal “given the industry’s cautious and tepid position in cyber”.