BP Sum of the Parts: Why a Breakup Looks Best at the Top of the Refining Cycle

BP sum of the parts: what each segment earns

BP reports three operating segments. In the second quarter of 2026, gas & low carbon energy made an underlying profit before interest and tax of $2.1bn. Oil production & operations made $3.6bn. Customers & products, which holds refining, trading, fuel retail and Castrol, made $5.0bn.

In other words, the two upstream segments earned $5.7bn together and the downstream $5.0bn. So downstream supplied about 47% of segment profit, on our estimate. A year earlier, it made just $1.5bn, or about 28%. The swing came from refining. BP’s refining marker margin averaged $29.6/bbl in the quarter, against $11.9/bbl a year before.

Why the BP sum of the parts case looks strong

On today’s numbers, the market gives BP little credit for its windfall. Add net debt of about $14bn to the $129bn market value, and the enterprise value is roughly $143bn. That is about 3.5 times BP’s second-quarter 2026 underlying profit before interest and tax of $10.3bn, annualised, on our rough estimate. Clearly, investors doubt that these earnings will last, and a BP sum of the parts valuation is one way to make them look again.

Separately listed parts might be valued more clearly. For example, Stonepeak agreed in December 2025 to buy 65% of Castrol at an enterprise value of $10.1bn, about 8.6 times its past-year EBITDA. BP kept a 35% stake. Moreover, there is a precedent. In 2012, ConocoPhillips spun off its downstream arm as Phillips 66. In the third quarter of 2026, Phillips 66 alone earned $5.6bn; see our analysis of US refining margins.

Why the timing could mislead

However, the strength of downstream is partly a war premium. Refining and trading profits jumped after the Iran war effectively closed the Strait of Hormuz. If margins fall back towards 2025 levels, the downstream half would again earn far less than the upstream half. Therefore, a BP sum of the parts struck at the top of the refining cycle would flatter one part and leave the other exposed.

Debt is a second issue. BP said net debt should fall to $13.5-14.5bn at the end of September 2026, from $22.3bn at the end of June 2026. That already meets its 2027 target of $14-18bn. Yet a breakup would have to divide that debt and other liabilities between the parts. In addition, BP expects a further $3-4.5bn write-down on its clean energy businesses in the third quarter of 2026.

Finally, there is politics. BP is one of Britain’s largest listed companies. A split that led to a US listing would add to the London Stock Exchange’s losses, Semafor noted. Meanwhile, activist Elliott has asked for higher free cash flow and a sale of renewables, but has not pushed for a US relisting.

What to watch next

• Third-quarter 2026 results on 30 October 2026, for any comment on the report and on asset sales.
• The 15 December 2026 strategy update in New York, O’Neill’s first full plan.
• Refining margins into winter, which decide what the downstream half is worth.

For the news, read our report on the BP breakup claims.