The specialist insurance company Hiscox has grown from one small office to a global brand by concentrating on specialist areas like cyber attack, terrorism and kidnap.
It also covers the homes and property of the rich and famous.
But given how unpredictable the terror threat is and how many different forms an attack can take, it is hard to price up the cost of insuring against it, says chief executive Bronek Masojada.
"Yes it is a bit arbitrary but people want the cover. It isn't the sort of thing like car accidents where there's lots of them and you can work it out," he told 5Live's Wake Up To Money.
"We don't want lots of terrorist events."
Read more: BBC News
