Enquest shares tumbled 11% as investors took fright at its warning of lower production in 2023 allied to the impact of the energy profits levy.
North Sea-focused Enquest said 2023 output would be between 42-46,000 barrels daily in the current twelve months, compared to an average 47,259 in 2022.
It also said it was postponing new drilling at the Kraken field due to uncertainty over the impact of the EPL.
The oiler said after hedging it received US$89 per barrel on average last year, compared to operating expenditure of US$23 per barrel, up 12% on 2021 or US$400mln in total.
Debt at the 2022 year-end fell to US$700mln from US$1,2bn.
"In the immediate future, we remain focused on deleveraging and intend to prioritise organic investments with quick pay backs and accretive merger & acquisition opportunities that allow us to leverage our operating capability and tax loss position," said Amjad Bseisu, chief executive.
Shares fell 2.35p to 19p.