ClearSky is a venture capital and growth equity firm investing in innovative companies in the cybersecurity and energy transition sectors. The firm has managed approximately $1 billion in capital commitments across multiple funds, including ClearSky Security Fund I and ClearSky Power & Technology Fund II.
Deal activity decreased year-over-year (1 deals in the last 12 months vs 3 prior). Average disclosed round size is $39.3M (across 41 rounds with reported amounts).
Portfolio
35
Fund Size
$1B
Top Stage
Series B
Last 12 Mo
2
Team
AW
Alex Weiss
CEO, Co-Founder & Managing Partner
JH
James Huff
Co-Founder & Managing Partner
OS
Owen Santos
Analyst
Portfolio Breakdown
Stage Distribution
Sector Distribution
Investment Activity
DealsAvg Round Size
Portfolio
45 investments
| Company | Round | Amount | Date |
|---|---|---|---|
 Ubicquia | Series D | $106M | Feb 2026 |
| UUbicquia, Inc | Series D | $106M | Jan 2026 |
 Guardz | Series B | $56M | Jun 2025 |
| GGuardz Cyber Ltd | Series B | $56M | Jun 2025 |
| MMitiga Security Inc | Series B | $30M | Jan 2025 |
| MMitiga Security Inc | Growth | $30M | Jan 2025 |
 HUMAN | Growth | $50M | Oct 2024 |
 Hatz AI | Seed | $2.5M | Jan 2024 |
 EdgeQ | Series B | $75M | Apr 2023 |
 Mitiga | Series A | $45M | Mar 2023 |
| RRevelstoke Security | Series B | $20M | Mar 2023 |
| Guardz | Series A | $18M | Jan 2023 |
 OhmConnect | Series D | $55M | Jun 2022 |
 Appomni | Series C | $70M | Jun 2022 |
 T-REX | Series C | $40M | Jan 2022 |
| TT-REX Group, Inc. | Series C | $40M | Jan 2022 |
| CCleartrace Technologies Inc | Unknown | $20M | Jan 2022 |
| Mitiga | Series A | — | Dec 2021 |
 Query.ai | Series A | $15M | Oct 2021 |
 SecZetta | Series B | $20M | Sep 2021 |
| Mitiga | Series A | $25M | Jun 2021 |
 Mainspring | Series D | $95M | May 2021 |
| Appomni | Series B | $40M | Apr 2021 |
 Climatetrade | Series A | — | Jan 2021 |
| AAppomni Inc | Series B | — | Jan 2021 |
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Top Co-Investors
SYN Ventures7 shared
Glilot Capital Partners7 shared
Scale Venture Partners6 shared
Atlantic Bridge5 shared
DNX Ventures5 shared
Blackstone Inc.5 shared
Salesforce Ventures5 shared
MassMutual5 shared
Costanoa Ventures4 shared
Intel Capital4 shared
Bessemer Venture Partners3 shared
Hanaco Ventures3 shared
Bain Capital Ventures3 shared
CRV3 shared
Mayfield Fund3 shared
General Catalyst2 shared
Inner Loop Capital2 shared
Silicon Valley Data Capital2 shared
ServiceNow Ventures2 shared
Thoma Bravo2 shared
Last updated: 8 September 2026