Horizon 3 is an accelerator. Based in Los Altos, California, United States. The known portfolio counts 3 companies, including Cardiac Dimensions, Horizon3.ai and ChainCraft.
Is Horizon 3 a fit for your startup?
Paste your website. AI checks the fit and scores every other investor too.
Investment focus
- Sector
- AIHealthcareSaaS
Contacts
Who to pitch at Horizon 3
Horizon 3 portfolio companies (3)
- Cardiac Dimensions
- Horizon3.ai
- ChainCraft
Co-investors
Funds that share portfolio companies with Horizon 3.
Similar funds
Showing 20 of 100
About Horizon 3
The firm's listing covers sectors AI, Healthcare and SaaS, and focus areas AI Applications, Developer Tools, Enterprise SaaS and HR Tech; known deals cluster at Growth and Series A.
The contact to approach at Horizon 3 is Leonard Speiser (Founder & Managing Partner).
Across the known portfolio, 8 co-investors appear alongside Horizon 3, including Montgomery & Co, Lumira Ventures and Lumeira Ventures.
Frequently asked questions
What is Horizon 3?
Horizon 3 is an accelerator based in Los Altos, California, United States, with a known portfolio of 3 companies. The portfolio comes from public investment records rather than from the firm, so deals that never surfaced publicly are not in it.
What does Horizon 3 invest in?
Listed sectors include AI, Healthcare and SaaS; listed focus areas include AI Applications, Developer Tools, Enterprise SaaS and HR Tech. Those tags come from the portfolio attached to the firm, so they describe what has been backed rather than a stated mandate for what comes next.
What stage does Horizon 3 invest at?
The known deals of Horizon 3 include Growth and Series A rounds. Check that against your own round before reaching out: stage mismatch is the most common reason a well matched sector still goes nowhere.
Who should I pitch at Horizon 3?
One person at Horizon 3 is on file, listed as a contact for the firm, with their own profile page.
How do I contact Horizon 3?
Any email address on file for the firm is masked on this page and readable inside RaiseHunt after you create an account. The one person attached to the firm has their own page, which shows whether an address is on file for them.
Skip the browsing. Let AI find your ideal investors in one minute.
Paste your startup website and AI picks your best-fit investors out of 135,000+ profiles.
Data: RaiseHunt investor dataset · Snapshot 5 September 2026 · How this data is built · Report a correction or request removal