Stephen O'Brien
Investor & Head of Platform at MANTIS Venture Capital
Los Angeles, California
Stephen O'Brien, Investor & Head of Platform at MANTIS Venture Capital is an active investor based in Los Angeles, California. This profile covers what Stephen O'Brien backs, at which stage, and how founders can reach out in 2026.
Stephen O'Brien is an investor and Head of Platform at Mantis Venture Capital, passionate about startups, ESG, clean tech, and innovation.
- Investor type
- VC
- Stages
- SeedSeries A
- Invests in
- Climate & Energy
- Location
- Los Angeles, California
- Typical check
- $625K
How to reach Stephen O'Brien
Angels and operators like Stephen O'Brien reply to specific, personalized notes that show real traction, not mass blasts. Build a verified list, write a note that fits their thesis, and track replies, all on Round Funded.
Connect with Stephen O'Brien
About this profile
This profile is part of Round Funded, an investor database and outreach platform for founders. It covers 60,000+ active VCs, angels, family offices and accelerators with verified contacts, lets you send pitches from your own Gmail, and includes a free Data Room for your raise.
Frequently Asked Questions
What does Stephen O'Brien invest in?
Stephen O'Brien invests in Climate & Energy, typically at Seed and Series A. Match your sector and stage, then reach out with a personalized pitch.
What stage does Stephen O'Brien invest at?
Stephen O'Brien typically invests at Seed and Series A. Lead with traction that fits the stage when you reach out.
What is Stephen O'Brien's typical check size?
Stephen O'Brien typically writes checks around $625K. Use it as a signal for whether your raise fits their stage.
How do I contact Stephen O'Brien?
Unlock Stephen O'Brien's verified email on Round Funded and send a personalized pitch. We surface only deliverable contacts so your outreach lands.
What is Round Funded?
Round Funded is an investor database and outreach platform for startup founders. It lists 60,000+ active investors with verified contacts, filtered to recent investment activity, and lets founders send personalized pitches from their own Gmail, track replies, and share a free Data Room. Round+ starts at $99 per month with a 3-day trial.