Synthetic DNA developer 4basebio (LSE:4BB) reported a 2025 pre-tax loss of £17.3m on 20 May 2026 and followed with a wider first-half loss of £8.92m in late September. While Revenue rose 81% in 2025, first-half 2026 revenue was reported to have fallen sharply, leaving timing of clinical Supply contracts at the centre of the story.

What the company does

Cambridge-based 4basebio makes synthetic DNA for use in gene therapies and other advanced medicines. Its revenue comes from clinical-stage projects and DNA sales, and it has recently gained GMP accreditation, a requirement for supplying material used in human trials.

2025 results

Revenue for 2025 was £1.7m, up 81% from £933,000, with clinical-stage projects contributing £1.1m and DNA sales more than doubling. The pre-tax loss widened to £17.3m from £12.7m, and administrative expenses rose to £17.7m from £13.9m, reflecting Investment in commercial infrastructure, GMP capabilities and product development. Chief executive Amy Walker called 2025 a step-change year and said she expects significant revenue growth in 2026 and beyond.

Cash and funding

Cash was £17.8m at 31 December 2025, down from £34.6m a year earlier. In April 2026, LSE:4BB drew €7m under its Deutsche Balaton facility, which it said funds operations into late 2027. The terms of the Facility are worth examining in the full accounts.

New supply agreement

On the same day as the final results, 4basebio announced a clinical supply agreement with an unnamed cancer immunotherapy developer, covering synthetic DNA for a phase 2 trial. The company expects roughly seven-figure revenue from the contract over the following twelve months.

First-half 2026 results

The first-half loss was £8.92m, up from £7.80m, while revenue was £0.262m, down 77.6% from £1.17m. The report did not give a cash figure. The drop in revenue illustrates how lumpy project-based income can be and makes the second-half delivery of the new supply deal particularly important.

Sector and index context

Contract manufacturers of nucleic acids are positioned to benefit from the growth of gene and cell therapy, though funding for the biotech sector has been uneven. 4basebio is one of the more technology-focused life sciences names on the FTSE AIM All Share Index, and its valuation reflects expectations for growth rather than current earnings.

Key risks

Continued losses, the pace of revenue ramp-up, dependence on a small number of customers and trial outcomes beyond LSE:4BB's control are the main risks. Future funding needs, regulatory inspections and competition from larger manufacturers also matter.

What to watch next

Investors will follow new supply contracts, evidence of revenue recovery in the second half, GMP-related milestones, cash burn and the full-year trading update.

Reading the numbers

The scale of the losses relative to sales is the defining feature. A pre-tax loss of £17.3m on £1.7m of 2025 revenue means LSE:4BB spent roughly ten times what it earned. Cash fell by £16.8m during 2025, from £34.6m to £17.8m, which is close to the size of the loss, so the Business is effectively consuming its reserves. The April drawdown extends the horizon into late 2027, according to the company, but it is a debt-style facility rather than new shares. The supply agreement announced in May is therefore important as proof of repeatable commercial demand. Even if that contract delivers seven-figure revenue, as the company expects, it would remain small against the 2025 loss, so scaling beyond a handful of clinical projects is the real test. The first-half revenue of £0.262m, down from £1.17m, shows how far results can swing between periods when income depends on a few customers.