Carbon13 SEIS Fund X

Invest at the cutting-edge of climatetech innovation

Back the next generation of climatetech innovators, handpicked by specialist climatetech fund and venture builder, Carbon13.

Next deadlineOctober 2026

Target return3x (net of fees)

Min investment£10,000

Portfolio companies4-10 companies

Income tax relief50%

Reasons to invest

Returns with purpose

Build a portfolio of pre-seed stage businesses developing the latest technologies to protect Earth's vital systems.

Comprehensive SEIS tax reliefs

Claim up to 50% income tax relief on investments; no capital gains tax on growth; 50% capital gains tax relief, inheritance tax relief after 2 years, plus loss relief protection. Tax treatment subject to status and change.

Carbon13 expertise

Carbon13 launched its first programmes in 2021. Its companies have gone on to raise up-rounds totalling more than £50m. The average age of their cohort participants is 37, a quarter hold PhDs and 63% of their teams are mixed gender.

Carbon13's SEIS investment approach

Portfolio of four to ten companies.
Seeking an exclusive £1.2m.
Minimum investment of £10,000.
Seeking to deploy in 26/27 tax year.

Through catalytic programmes and founder-first investment, Carbon13 scales ventures with the power to transform industries and safeguard the Earth. Over the last four years, Carbon13 has supported more than 1,500 founders and helped build over 300 climate tech startups from day zero across the UK and Europe, with the explicit goal of launching hundreds of businesses capable of reducing gigatons of CO₂e emissions.

To date, Carbon13 has helped build more than 300 ventures, made over 90 investments, and invested a total of £13m. Half of the ventures supported by Carbon13 are deeptech companies, reflecting a strong focus on science and technology driven solutions. It invests across a broad range of climate-critical sectors — including energy, AI, the built environment, advanced materials, transport, carbon removal and food systems — so that founders can address the full system of challenges driving the climate crisis.

Carbon13’s Venture Builder Programme

Typically Carbon13 receives around 600 applicants to each of its Venture Builder programmes and selects 80 to join each programme through a highly competitive process. Each programme cohort can expect to see around 25% PhDs, average age 37, and half who have founded startups before. Each founder is judged to be an exceptional individual with the traits, skills and commitment to building a scalable mission-driven venture.

After six months, ventures pitch for pre-seed investment. Those who receive backing get exposed to stakeholders capable of supporting their next steps as well as opportunities to showcase their venture, including with Carbon13’s industry-leading corporate partners: Barclays, Siemens Energy, Arm, and Herbert Smith Freehills and additional contributions from Google Cloud Credits, Geovation, Honda Innovations and many others.

Carbon13 offers opportunities to speak to investors during the programme and showcases to pitch to a wider audience of investors and stakeholders. Some of their current co-investors include Ada Ventures, Cambridge University, G-Force, Pale Blue Dot, Climate VC, Octopus Ventures, Zero Carbon Capital, AgFunder, Plug & Play, DCVC and many more. Carbon13 is an Investor Partner with Innovate UK and assists companies to leverage non-dilutive grants.

Companies chosen for investment will participate in a final stage of the Venture Builder programme. This phase focuses on generating the proof points necessary around market, product, business model and strategy to prepare the venture for further seed-stage investment. We help the ventures to look at scaling strategies, managing growth pains and developing a funding strategy.

Our Venture Builder cohorts bring together operators, technologists, and scientists months before incorporation, and we observe team dynamics, commercial thinking, and execution tempo as they form.

By the time we invest we have seen how a team resolves disagreement, how quickly they run experiments, and whether their proposition survives stress-testing.

Dr Nicky Dee

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Co-founder of Carbon13

Tax Relief Benefits

Income Tax Relief

Claim up to 50% income tax relief on your investment in the year you invest or one year prior

Capital Gains Tax Exemption

Claim 50% relief on gains from other assets when you reinvest into SEIS

Reinvestment Relief

Claim up to 50% capital gains tax relief on gains arising that are reinvested in SEIS

Loss Relief

If your investment loses value, you can offset the loss against income tax or capital gains

Inheritance Tax Relief

Shares held for 2+ years qualify for 100% inheritance tax relief

Tax treatment depends on individual circumstances and may be subject to change.

The Team

Dr Nicky Dee

Co-founder and Chief Executive Officer

Nicky has pioneered many activities in the sustainability space to scale up impact from startups, including work with UNEP, Nesta, European Projects, Climate KIC, DfID and UK Gov.…

Michael Langguth

Co-founder & Chief Strategy Officer

Michael is a serial entrepreneur. His most recent start-up, Poq, is a London-based software-as-a-service platform for mobile shopping, powering the apps of some of the largest reta…

Min Dhillon

Principal

Min has extensive experience across partnership development, business strategy and go-to-market. Prior to joining Carbon13, he was the UK strategy lead at Eventbrite, pre and post…

Sara Jones

Head of Marketing

Sara joined Carbon13 as its first employee in 2020, responsible for launching the talent magnet for the Carbon13 Venture Builder. She now also covers comms, platform activities, in…

Investment Process

1

Registration

Complete our simple online registration form to create your investor account.

2

Complete your investment

Choose your investment amount and review the fund details.

3

Sign legal documents

Review and digitally sign the necessary legal documents.

4

Transfer funds and claim tax relief

Transfer your investment amount and receive your SEIS3 certificate.

Carbon13 Case Studies

Climatetech

MOIC: 8.68x

Cocoon

Cocoon are capturing CO₂ in industrial waste and upcycling this into a green cement alternative with the aim of decarbonising the steel and cement industries. This mineralisation process has been the focus of their Chief Science Officer’s research and they are now moving to commercialise at scale.

Current valuation

$54m

B2B

MOIC: 13.02x

Kita

Kita seeks to remove the carbon delivery risk from sellers and buyers in the market, using insurance products that guarantee the quality and delivery of carbon units and carbon removal solutions.

Current valuation

£20m

Climatetech

MOIC: 4.68x

Ki Hydrogen

The world's most affordable coproduction of green hydrogen and biogenic carbon as key building blocks for chemistry, products and fuels that power a decarbonised world.

Current valuation

£14.8m

Multiple on Invested Capital figures refer to gross performance and do not take into consideration fees, commissions or other costs. Actual returns may vary significantly. Past performance is not indicative of future performance.

Fund Documents

PDF

Information Memorandum| 4.9 MB

PDF

Brochure| 4.8 MB

PDF

Key Information Document| 1.3 MB

Charges

Setup Fee	2% drawn upfront from subscription
Annual Management Fees	Years 1-3: 2% per year retained upfront Years 4-7: 2% per year, deducted from distributions Years 8-10: 0.5% deducted from distributions
Performance Fee	20% with no hurdle on a portfolio basis

This SEIS fund is VAT exempt. If prevailing laws or HMRC guidance change, VAT may become applicable to the fees and you will be notified. Adviser fees for authorised financial advisers can be facilitated on application. These must be agreed with Investors and meet applicable FCA COBs rules.