B5 Capital is a Silicon Valley-based single-family office and family seed fund investing in pre-seed, seed, and Series A technology startups. The firm focuses on cash-efficient businesses across AI, cybersecurity, fintech, and climate tech, providing patient family capital to early-stage founders.
Their most common stage is seed (75% of deals). Average disclosed round size is $20.5M (across 7 rounds with reported amounts).
Portfolio
7
Fund Size
—
Top Stage
Seed
Last 12 Mo
0
Team
AB
Alex Bailey
Cofounder
MB
Mark Bailey
Founder and CEO
Portfolio Breakdown
Stage Distribution
Sector Distribution
Investment Activity
DealsAvg Round Size
Portfolio
8 investments
| Company | Round | Amount | Date |
|---|---|---|---|
| TTacta Systems | Series A | $64M | Jun 2025 |
 OpenInfer | Seed | $8M | Feb 2025 |
 Neo Cybernetica | Seed | $30M | Feb 2022 |
| Neo Cybernetica | Seed | $30M | Jan 2022 |
 Dobby | Seed | $1.7M | Dec 2020 |
 Wardstone | Seed | $5M | — |
 Tacta | Series A | — | — |
 Wardstone | Seed | $5M | — |
Top Co-Investors
B Capital4 shared
Tyche Partners2 shared
EDBI2 shared
America's Frontier Fund2 shared
Sojitz Corporation2 shared
SBVA2 shared
Liquid 2 Ventures2 shared
Y Combinator2 shared
Nova Threshold2 shared
New Enterprise Associates2 shared
Cortical Ventures2 shared
Tau Ventures1 shared
StemAI1 shared
Cota Capital1 shared
Operator Stack1 shared
Future Fund1 shared
Gokul Rajaram1 shared
Essence VC1 shared
SilverCircle1 shared
Gemini Frontier Fund1 shared
Last updated: 20 October 2026