British energy major BP has agreed to sell a controlling stake in its Castrol lubricants business to U.S. investment firm Stonepeak, in a transaction that values the unit at approximately ten point one billion U.S. dollars, including debt.

Under the terms of the deal, Stonepeak will acquire sixty-five percent of the century-old brand, while BP will retain a thirty-five percent interest in a newly formed joint venture.

The sale is set to generate around six billion dollars in net proceeds for BP, including nearly eight hundred million dollars representing accelerated dividend payments tied to the minority stake.

BP has stated that it intends to apply the entirety of the proceeds toward reducing its net debt, which stood at twenty-six point one billion dollars at the end of the third quarter of two thousand twenty-five.

Completion of the transaction is expected by the end of two thousand twenty-six, subject to regulatory approvals.

Following a two-year lock-up period, BP will have the option to sell its remaining stake in Castrol.

The deal marks a significant step in BP’s broader strategic overhaul under new leadership, which has emphasised portfolio simplification and a focus on core operations.

The divestment also forms part of BP’s previously announced plan to divest twenty billion dollars’ worth of assets by the end of two thousand twenty-seven, with this transaction representing more than half of that targeted total.

Castrol, a globally recognised lubricants brand with operations spanning automotive, industrial, and specialty sectors, will continue under the joint venture structure.

Stonepeak’s acquisition reflects confidence in Castrol’s established market position and long-term growth prospects across multiple regions, including interests in India, Vietnam, Saudi Arabia, and Thailand.

BP’s board and interim management have described the agreement as an important milestone, strengthening the company’s balance sheet and aligning its business portfolio with strategic priorities going forward.