Octopus Energy v British Gas: who is really winning the multi-billion pound energy war?

British Gas Trading, by £4,801m. Its most recent filed accounts show turnover of £14,523m for the year to December 2024, against £9,722m at Octopus Energy for the year to April 2025. That is a ratio of roughly 1.5 to 1.

The gap is smaller than the two companies' histories suggest. British Gas Trading was incorporated in 1995 and Octopus Energy in 2014, nineteen years apart, and the younger company now files turnover worth two thirds of the older one. Both file as single companies rather than as groups, so neither figure carries subsidiaries inside it.

In opposite directions on every movement figure in the filings. British Gas Trading turnover fell (32.1%) on the prior year, while Octopus Energy rose 21.9%. Those two movements sit 54.0 percentage points apart.

Profit follows the same pattern. British Gas Trading's estimated profit before tax of £477m compares with £1,370m reported the year before, a fall of (65.2%). Octopus Energy's £240m compares with £204m, a rise of 17.6%. On the latest filings the two profit figures are within a factor of two of each other, where the turnover figures are not.

Headcount moves the same way again. British Gas Trading grew employees 8.8% to 6,970. Octopus Energy grew 40.6% to 2,445, roughly a third of the British Gas payroll by number of people.

One caution on all of this. The periods are adjacent rather than identical, and wholesale energy costs moved considerably across the months that separate them, which affects a supplier's turnover line directly. A four month offset matters more in this sector than in most.

Almost all of it straight back out again. For every £100 of turnover, British Gas Trading keeps £3.28 as estimated profit before tax and spends £2.32 on staff. Octopus Energy keeps £2.47 and spends £0.98. Everything else, £94.40 and £96.55 respectively, leaves the business as the cost of buying and delivering energy and running the operation.

That is the real shape of retail energy supply, and it is the same shape on both sides. The visible difference between these two companies is not margin, it is how many people sit behind each £100 that passes through.

Almost completely differently, despite the similar trade. British Gas Trading carries £3,283m of net assets, 4.8 times the £681m at Octopus Energy, but it holds £1.0m in cash at the year end against £580m at Octopus.

The financing sits on opposite sides too. British Gas Trading shows estimated borrowings of £1,007m and Octopus Energy none. Interest received runs at £206m against £20m payable at British Gas, and £44m against £28m payable at Octopus. Neither company records a dividend in these filings.

Debtors are the largest current asset on both sides, £1,593m at British Gas and £939m at Octopus, which is what a supply book looks like when customers pay in arrears.

The charge registers point the same way. The charges listed against British Gas Trading are largely historic and discharged, from Bg PLC in 1997 and Centrica Pension Trustees in 2009, with a fixed charge to Nasdaq OMX Stockholm from 2011 still showing. Octopus Energy's live charges are more recent and commercial, to Shell Energy Europe in 2021 and 2023 and to Santander UK in 2026, with earlier charges to Octopus Capital and Origin Energy discharged. Both extracts are truncated at source, so treat them as indicative of the pattern rather than a complete list.

Both are wholly controlled subsidiaries, and both registered their controlling company on the same day. British Gas Trading Limited records GB Gas Holdings Limited (03186121) as a person with significant control in the 75 to 100% band, notified 6 April 2016. Octopus Energy Limited records Octopus Energy Group Limited (09718624) in the same band, notified 6 April 2016. PSC entries describe control bands, not exact stakes or prices.

The officer registers read very differently. Octopus Energy Limited still lists directors appointed in January 2016, among them Greg Sean Jackson, James Andrew Eddison, Christopher Robert Hulatt, Simon Andrew Rogerson and Stuart Keith Jackson, with John Bowie joining in 2022. British Gas Trading's register is a long corporate rotation, with Centrica Secretaries Limited appointed as secretary in 2000, Andrew James Kennedy resigning on 30 June 2026 and Arvind Philip Balan appointed the same day.

Registered property tells the same story of two ages of company. British Gas Trading's entries are infrastructure, gas governor sites, underground gas tanks and compound land across England and Wales, freehold and leasehold, none with a disclosed price. Octopus Energy's are two office leaseholds taken in 2020, at Queens Road Quadrant in Brighton and Colton Square in Leicester, also with no price disclosed.

Every figure quoted on this page, grouped and set side by side. Each column belongs to one company. No row is a total across the two.