This was second only to regulatory risk at 28%, according to a survey by BDO.
It found that 88% of CEOs feared that their businesses were unprepared for risks coming from failure to innovate or to adapt to technological changes. This concern was also held among other senior figures in business.
“The recent global cyber attacks highlight the changing risk landscape where threats that were once distant are now imminent and their consequences are reaching people, institutions and economies," said Nigel Burbidge, partner and global chair for risk and advisory services at BDO.
"Our research revealed three quarters of global chief risk officers are concerned about how cyber exposures could impact their business", Burbidge highlighted.
"We see big data breaches hit the headlines on a regular basis - something that can be detrimental to a business’ longer-term reputation.
"Cyber-crime can also cause a business severe financial strain, with the average breach in security costing a business $4m", he added.
The report revealed that ransomware attacks increased 6,000% in 2016, and “is on track to be a $1bn business by the end of the year".
“In a secure environment, executive boards allocate resources and provide management with the tools to identify cyber risks and apply appropriate mitigation”, Ophir Zilbiger, partner at BDO Israel’s cyber security centre said.
“Cyber-responsible boards do not just check policy but also oversee and verify the implementation of cyber security measures to ensure their effectiveness.”
Last week, the NHS was one of many global organisations that came under attack from ransomware, named WannaCry, which caused massive disruption to services.
"Cyber-attacks have entered a new dimension – and the attack on the NHS in the last week highlights the risks that come as part of our evolving technological landscape", said Burbidge.
“Ransomware presents a growing threat to every industry, but healthcare organisations are particularly vulnerable,” said Shahryar Shaghaghi, US head of international BDO cyber security.
In January, British companies reported more incidences of fraud and cyber crime than any other country in the world, behind only Colombia.