645 Ventures leads and participates in seed and Series A rounds through Fund IV. Its separate Select Fund I backs growth-stage follow-ons in top portfolio companies with larger checks.

Per the firm's public fund announcement, Fund IV targets roughly $1M–$5M at seed and $5M–$10M at Series A. Select Fund I writes growth follow-ons of about $10M–$15M in non-lead positions.

645 Ventures is headquartered in New York City with a San Francisco office. The firm invests across the U.S. in early-stage technology companies rather than limiting to a single metro.

645 Ventures is generalist within early-stage technology with emphasis on infrastructure software, SaaS, cybersecurity, and consumer technology. The firm is known for its proprietary Voyager data platform used in sourcing and portfolio support.

645 Ventures leads seed and Series A rounds and positions itself as an early partner that can follow on through growth via Select Fund I. They emphasize focused early-stage capital over multi-stage generalism.

In our directory, 645 Ventures is linked to Arbor (/startup/arbor), Sequence (/startup/sequence), and Setpoint (/startup/setpointio).

Warm introductions from founders, operators, or co-investors are the typical path. The firm does not publish partner cold-email lists; use the contact options on 645ventures.com and come with clear traction and sector fit.

See our articles on Fund IV and Select Fund I (/2026-645-ventures-347m-fund-iv-select-fund-i) and 645 leading Arbor's seed (/2026-645-ventures-leads-arbor-6-3m-seed).