Maritime services group Boskalis has taken a massive €840m write down on its offshore operations, the Financieele Dagblad reported on Monday. The hit represents about 20% of total shareholders’ equity.

The company announced the move at the close of the bourse on Friday, writing off €380m on goodwill and €365m on its fleet, mostly on heavy sea transporter Dockwise. Another €90m was written off on Smit Lamnalco which the company acquired in 2010.

Boskalis enjoyed record earnings in 2014 and 2015 as the oil and gas sectors boomed. But there is now a structural imbalance between supply and demand particularly in heavy ocean transport, the company said in a statement.

This particularly affected Dockwise which Boskalis bought for €1.3bn five years ago. Nearly half of this has now been written off. Boskalis will open its books on 8 March when it will issue a strategy update.