# Third Sphere: investment profile

Published mandate, cheque sizes and source evidence for Third Sphere. Sources checked 2026-10-12.

Source: https://12inf.ai/resources/funds/third-sphere
Updated: 2026-10-14

Early-stage climate and sustainability investor aiming to be among a company's first investors at pre-seed and seed, with $250K-$1M initial checks and follow-ons for companies proving the thesis; promotes 'seedstrapping' with minimal equity.

## Published mandate

- **Stage:** Pre-seed, Seed

- **Cheque:** $250K–$1M

- **Geography:** US

- **Sectors:** Climate

## Notable investments

- [Return To Vendor](https://thirdsphere.substack.com/archive) — , 2026-03-30

- [Focal](https://thirdsphere.substack.com/archive) — , 2025-11-18

- [AccessGrid](https://thirdsphere.substack.com/archive) — , 2025-10-28

## Sources

Sources checked **2026-10-12**.

- [Third Sphere — Website](https://thirdsphere.com)

- [Third Sphere — About](https://thirdsphere.com/about)

- [Third Sphere — Funds](https://thirdsphere.com/funds)

- [Third Sphere — Contact](https://thirdsphere.com/contact)

- [Third Sphere — Portfolio](https://thirdsphere.com/portfolio)

- [thirdsphere.substack.com — Archive](https://thirdsphere.substack.com/archive)

## Related investor lists

- [Pre-seed investors](/resources/investors/pre-seed)

- [Seed investors](/resources/investors/seed)

- [Pre-seed investors in US](/resources/investors/pre-seed-us)

- [Seed investors in US](/resources/investors/seed-us)

- [Pre-seed Climate investors](/resources/investors/pre-seed-climate)

- [Seed Climate investors](/resources/investors/seed-climate)

## Check before outreach

- [How to read an investor match](/resources/how-to-read-an-investor-match)

- [Check-size reality](/resources/check-size-reality)

- [Portfolio conflicts](/resources/portfolio-conflicts)

- [All investor lists](/resources/investors)

[How we research investors](/resources/methodology)