Shareholders in Trinity Mirror are expected to demand greater openness from the newspaper group about the legal bill it faces over phone hacking.
The Local Authority Pension Fund Forum, which represents 60 public sector pension funds, plans to call for more transparency about phone hacking costs at a shareholder meeting in London .
Shareholder advisory body Pirc, which advises the forum, has called on shareholders to vote against Trinity Mirror's annual report in protest against "inadequate" disclosures on phone hacking.
In January journalist Dan Evans pleaded guilty to phone hacking while working at the Sunday Mirror and its rival, the now-defunct News of the World.
Pirc believes that the company is expecting further civil claims following Evans' admission. "Not reporting on these financial risks in our view is a material omission from the annual report," it said in a note to shareholders.
An ongoing phone-hacking trial was told on Wednesday that former NoW royal editor Clive Goodman hacked Kate Middleton's phone 155 times as part of a fishing expedition targeting the royal family.
In its latest annual report Trinity Mirror said "direct financial impact from legal claims" was a significant risk, the broadest statement it has ever made about how phone-hacking claims will damage it business. "Historical legal issues" have left the group open to financial claims and were a distraction to senior management, it said.
Pirc is also unhappy that Trinity Mirror has not set out its position on future press regulation, because it believes failure to sign up to a regulator underpinned by royal charter would leave the group open to higher costs when settling complaints.