Investors want changes at the company whose titles also include Scotland on Sunday, The Falkirk Herald, The Yorkshire Post and the ‘i’ newspaper.
Crystal Amber has been buying up shares in the London-based publisher and now has a 20.4% stake.
Talks are to take place this week with interim chairman Camilla Rhodes who has stepped in following the departure of former ScottishPower chief Ian Russell for personal reasons.
She is understood to have called in restructuring experts in an attempt to steer the company through a looming crisis.
Ms Rhodes, a former senior executive in Rupert Murdoch’s British newspaper operation, has asked Rothschild to examine its refinancing options, according to sources.
Crystal Amber will be calling for a shake-up of management amid concerns among other shareholders over the bonuses paid to executives while the valuation of the company has slumped alarmingly.
It paid £160m for The Scotsman titles in 2005, part of an acquisition spree that saw the business load its balance sheet with more than £300m of debt, but today the entire group is worth just £19m.
The company refinanced two years ago in order to reduce its interest payments and in April 2015 announced that Mr Highfield received a total pay and bonus package of £1.65 million including a £645,000 bonus.
This was more than three times the £592,000 pay package he received a year earlier.
The group subsequently bought the ‘i’ newspaper from the owner of The Independent, a deal that saw its debt rise again.
Figures published in November last year showed declining sales and circulation across the group which is being propped up by growth at the ‘i’ newspaper, which it bought in April last year.
It has been able to offset some of its borrowings after raising funds last week from the £17m sale of its titles in East Anglia.
Two weeks ago the company announced that Ian Stewart, editor of The Scotsman, would be leaving. The statement came just days before he featured in a documentary marking the paper’s 200th anniversary.
Crystal Amber is one of the most active shareholders in the market, buying up a 10% stake in STV in October and indicating it may want to double its holding.
Earlier this month it raised its holding in Johnston Press from 6.7% to 18.63% and has recently topped it up to more than 20%.