Walter Kowtoniuk
Venture Partner at Third Rock Ventures
Boston, Massachusetts
Walter Kowtoniuk, Venture Partner at Third Rock Ventures is an active investor based in Boston, Massachusetts. This profile covers what Walter Kowtoniuk backs, at which stage, and how founders can reach out in 2026.
- Investor type
- VCPE
- Stages
- SeedSeries ASeries BLate Stage Venture
- Invests in
- Healthcare & BiotechBiotech & PharmaMedTech & Medical Devices
- Location
- Boston, Massachusetts
- Typical check
- $2M
- Past investments
- 57
Notable investments
Blueprint Medicines
Magenta Therapeutics
Larimar Therapeutics
Constellation PharmaceuticalsJounce Therapeutics
Motus Therapeutics
PanOptica
Warp Drive Bio
Editas Medicine
Ember Therapeutics
MOMA TherapeuticsHow to reach Walter Kowtoniuk
Angels and operators like Walter Kowtoniuk 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.
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Cite this page
Round Funded. "Walter Kowtoniuk." Round Funded investor database, updated October 19, 2026.
Stable URL, it will not change: https://www.roundfunded.com/en/investor/walter-kowtoniuk
Frequently Asked Questions
What does Walter Kowtoniuk invest in?
Walter Kowtoniuk invests in Healthcare & Biotech, Biotech & Pharma and MedTech & Medical Devices, typically at Seed, Series A, Series B and Late Stage Venture. Match your sector and stage, then reach out with a personalized pitch.
What stage does Walter Kowtoniuk invest at?
Walter Kowtoniuk typically invests at Seed, Series A, Series B and Late Stage Venture. Lead with traction that fits the stage when you reach out.
What is Walter Kowtoniuk's typical check size?
Walter Kowtoniuk typically writes checks around $2M. Use it as a signal for whether your raise fits their stage.
How do founders reach investors like this?
Round Funded lists active investors with verified, professional contact details for signed-up founders. Filter by sector, stage and location, then send a personalized pitch from your own inbox.
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.