Troubled British publisher Pearson has cut its profit guidance for the next two years and lowered its 2017 dividend.
The company also said it may sell its stake in Penguin Random House to help battle "unprecedented" changes hitting its key markets.
Shares in Pearson, which has issued a string of profit warnings in recent years, plunged 23% as it announced its latest attempt to counter the disruption caused by the move to digital publishing.
This continues to pile pressure on CEO John Fallon.
The 173-year-old company sold the Financial Times newspaper and its stake in The Economist magazine in 2015 to concentrate on education.
But it has been hit by a recovering US economy which has encouraged more people to enter employment, hitting college enrolment numbers.
Students have also increasingly been using second-hand books and renting courseware, leading to a 30% decline in net revenues in the North American higher education courseware market in the final quarter of 2016.
"The education sector is going through an unprecedented period of change and volatility," John Fallon said.
"Our higher education business declined further and faster than expected in 2016," he added.
Pearson said cost cutting would enable it to hit 2016 operating profit guidance but that the 2017 figure would be around £180m lower than expected a year ago.
It sees 2017 operating profit between £570-630m, driving adjusted earnings per share (EPS) of between 48.5 pence and 55.5 pence.
Analysts had expected operating profit of £704m and earnings per share of 64 pence.
It has withdrawn its operating profit goal for 2018 and said it would have to "rebase" its dividend from 2017 onwards.
Pearson, which owns 47% of the Penguin Random House book venture with Bertelsmann, said it may seek to sell its stake or recapitalise the business and extract a dividend in order to protect its balance sheet.
Bertelsmann said it was open to increasing its stake.
