West Africa-focused Tullow Oil on Wednesday lowered its 2025 production forecast to account for the sale of its Gabonese assets, as the company continues to streamline its operations to boost performance, and reported a first-half loss.

Its shares fell 10% in early trading.

Tullow now expects output of 40,000-45,000 barrels of oil equivalent per day (boepd) for the year, down from 50,000-55,000 boepd projected earlier. It reported an average production of 40.6 kboepd in the first half, excluding Gabon.

"In the second half of the year we are focussed on refinancing our capital structure, production optimisation activities and continuing to optimise our cost base," finance chief and interim CEO Richard Miller said.

Miller added that Tullow had taken actions to address recent underperformance at its Jubilee oilfield in Ghana, with further "optimisation potential" identified.

Tullow operates mainly in Ghana, Gabon, Côte d’Ivoire, and a few other African countries, with most of its output coming from the Jubilee and TEN oilfields in Ghana.

The company reported a loss after tax of $80 million from continuing operations for the first half, compared with a profit of $106 million last year, driven by lower revenues, impairment charges and higher costs.