British energy major bp has completed the sale of a 65% stake in its industrial lubricants company, Castrol, to investment firm Stonepeak for $6 Bn in after-tax proceeds, the company said on November 2.

bp will use the proceeds to reduce its financial obligations as part of its efforts to strengthen its balance sheet, according to its statement.

It will retain a 35% stake in Castrol, which will operate as a standalone company.

bp CEO Meg O’Neill said the deal would provide significant cash proceeds while allowing the company to retain an interest in Castrol’s future growth.

Castrol CEO Michelle Jou commented that the business would work with Stonepeak and its new board to build on its existing strengths and pursue further growth.

The transaction includes minority interests in Castrol’s operations in several markets, including India, Vietnam, Saudi Arabia and Thailand.

bp said it could sell its remaining 35% stake after a two-year lock-up period. However, it does not expect to recognise earnings or receive dividends from the retained stake in the short to medium term, as Stonepeak has a preference on distributions.

The $6 Bn in after-tax proceeds include around $800 Mn related to the pre-payment of future dividend income on bp’s retained stake, alongside other customary transaction adjustments.

Castrol’s non-controlling interests’ share of net income averaged around $100 Mn per year between 2019 and 2025, according to bp.

As of September 30, 2026, these interests were recorded on bp’s balance sheet at around $450 Mn at historic cost, while Castrol’s debt-like obligations were recognised at around $300 Mn.

Castrol produces lubricants for automotive, industrial and marine applications. bp’s sale of a majority stake allows it to retain exposure to the business while prioritising debt reduction and balance-sheet strengthening.