Sustainable Ventures opens Fund 8 to UK SEIS/EIS climate tech startups

Sustainable Ventures has opened applications for Fund 8, its eighth climate tech vehicle, aimed at UK early-stage startups that qualify for SEIS or EIS tax relief [Sustainable Ventures — 2026-05-15]. The offer pairs capital with a 12-month intensive programme of mentorship and 1:1 support designed to position companies for a follow-on round [Opportunities — funder-discovery — 2026-05-18].

The through-line: this is a structured accelerator-plus-investment route, not a grant. Eligibility is narrow — UK-incorporated, venture-scale impact thesis, and SEIS/EIS-compatible cap tables — so NGOs and non-UK ventures should deprioritise it. For founders who do qualify, the relevant signal is the portfolio's reported >£175M in follow-on funding, which suggests the programme is being run as a pipeline into later-stage climate capital rather than a one-off cheque [Sustainable Ventures — 2026-05-15].

Practical steps this week: confirm SEIS/EIS advance assurance status before applying, and prepare a clear venture-scale impact narrative rather than a generic sustainability pitch. Founders already mid-raise should weigh the 12-month time commitment against their runway.

Over the next 1–6 months, watch for Fund 8 cohort announcements, which typically telegraph which climate sub-sectors UK early-stage investors are leaning into, and for parallel SEIS/EIS-aligned programmes likely to open ahead of the UK tax year-end.