Norway’s Equinor slumped to a marginal loss in the fourth quarter as it racked up heavy impairments mainly as a result of a tax revision in Norway and suffered lower revenue due to reduced oil and gas prices, despite lifting production.

The state-controlled operator reported a negative net result of $230 million in the quarter, reversing a year-earlier profit of $3.37 billion, after total revenue was slashed to $15.2 billion from $22.4 billion in the same period of 2018 as lower oil and gas prices impacted the top line.