Legal experts are concerned that D&O cover has been hit following the US-led rise of a new policy exclusion.
According to several weekend reports, Robert Harrell, a partner in a US-based litigation practice is leading criticism of the "restatement exclusion".
The exclusion invalidates D&O cover if the director's company restates its published figures.
Harrell claimed this is "exactly the point" at which board members might need the insurance against lawsuits.
Harrell said: "There's a lot of choices in today's market that didn't exist 18 months ago and choices mean different coverage."
Underwriters are also concerned that companies could be hit by the rule since thousands of companies have to restate figures every year.
Evan Rosenberg, chief underwriting officer of executive protection products at Chubb said: "Simply because you have a restatement doesn't give you the right to rescind [the policy], because, unless there's fraud involved, that's what D&O insurance is for."
