Robbie Horwitz is a Partner at Addition, whose known portfolio counts 17 companies.
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Investment focus
Contacts
Affiliated funds' portfolios
Partner at Addition, whose known portfolio counts 17 companies
- Anthropic
- Stedi
- Snyk
- Chapter
- Airwallex
- Frore Systems
- Chainalysis
- Biologica
- CloudX
- Fauna
- Render
- Xscape Photonics
- and 5 more
Investor Profile
The listing covers sectors AI, Commerce, Education and FinTech, and focus areas Analytics, Biotech, Cloud Infrastructure and Creator Economy. Startups operating in these areas may find Robbie Horwitz relevant.
Stage-wise, the deals at Addition cluster around Growth, Seed and Series A rounds.
What the affiliated firm has backed is the closest available signal on whether Robbie Horwitz is worth approaching.
Colleagues at Addition
Zander Lurie
Operating Partner
Los Angeles, United States
Lee Fixel
Investor
New York, United States
Aaron Schildkrout
Partner
New York, United States
Todd Arfman
Partner
New York, United States
Brandon Sack
Investor
New York, United States
Jason Schneider
Investor
New York, United States
Jack Spiegel
Investor
New York, United States
Frequently asked questions
Who is Robbie Horwitz?
Robbie Horwitz is a private equity investor and venture capital investor based in New York, United States, listed as Partner at Addition. The known portfolio of that firm counts 17 companies. That portfolio belongs to the firm, not to Robbie Horwitz personally.
What does Robbie Horwitz invest in?
Listed sectors include AI, Commerce, Education and FinTech; listed focus areas include Analytics, Biotech, Cloud Infrastructure and Creator Economy. Those tags come from the portfolios of the firms this profile is attached to, so they read as a record of what has been backed rather than a stated preference for what comes next.
What stage does Robbie Horwitz invest at?
Addition appears in Growth, Seed and Series A rounds across its known deals, and Robbie Horwitz is listed there as Partner. Stage is the strongest single filter when you build a target list: an investor with no record at your stage rarely starts with you.
Which firm is Robbie Horwitz listed at?
Robbie Horwitz is listed as Partner at Addition. 7 other people in the database share a firm with Robbie Horwitz.
How do I contact Robbie Horwitz?
A LinkedIn page is on file for Robbie Horwitz. It is readable inside RaiseHunt after you create an account. The database holds no email address and no phone number for this profile.
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Data: RaiseHunt investor dataset · Snapshot 5 September 2026 · How this data is built · Report a correction or request removal