Shares of UK-based Tullow Oil Plc crashed by about 50% on Wednesday after Ghana won a long-running arbitration dispute over a $196.5 million corporate income tax assessment against the oil producer.
The decline followed Tullow’s disclosure on Wednesday, September 30, 2026, that an International Chamber of Commerce tribunal had delivered its award in the dispute and ruled that Ghana’s tax assessment did not breach the company’s petroleum agreements.
The dispute relates to insurance proceeds received by Tullow between 2016 and 2019 under its corporate Business Interruption insurance policy.
Tullow challenged the assessment through international arbitration after receiving the tax demand from the Ghana Revenue Authority in December 2022.
Tullow said the ICC tribunal upheld Ghana’s $196.5 million corporate income tax assessment relating to proceeds it received during the 2016 to 2019 financial years under its Business Interruption insurance policy.
The assessment dates back to December 2022, when the Ghana Revenue Authority issued Tullow Ghana Limited with a corporate income tax assessment and payment demand relating to the insurance proceeds. Tullow subsequently filed for ICC arbitration in February 2023.
Tullow said it would assess its options following further discussions with the Ghanaian government and provide an update in due course. Ghana’s government said it intends to implement the arbitration award in a manner that secures revenue owed to the country while allowing Tullow to continue operating and investing.
The arbitration ruling triggered a sharp selloff in Tullow’s London-listed shares, reversing a rally that had pushed the stock substantially higher in recent months, according to analyses by Nairametrics.
Despite the stronger revenue and gross profit, Tullow recorded a loss after tax of $101 million, widening from $80 million in the first half of 2025.
The arbitration outcome is particularly significant because Tullow has consolidated its business around its high-value Ghana assets following disposals in markets including Gabon, Equatorial Guinea, Kenya and Côte d’Ivoire, with the Jubilee and TEN fields remaining its principal producing assets.
The Tullow ruling comes as Ghana strengthens oversight of some of its most important natural resources while seeking to increase government revenue, local value addition and foreign-exchange reserves.
Against that backdrop, the Tullow arbitration victory gives Ghana another avenue to enforce revenue claims from one of the country’s most important oil producers, although the government has said implementation of the award will also take into account Tullow’s ability to continue investing and operating in the country.
