Clearsky Advisors LLC
SEC exempt reporting adviser (venture capital exemption).
- Website
- https://www.clear-sky.com/
- HQ
- FL
Clearsky Advisors LLC is a venture capital and growth equity firm that invests in innovative companies in the cybersecurity and energy transition sectors. Alex Weiss serves as CEO, Co-Founder and Managing Partner, and James Huff is also a Co-Founder and Managing Partner. The firm's portfolio includes companies such as Altamira, Inky, EdgeQ, Diamanti and Sceye.
01 · Says / Does
| Tag | Says | Does | Historically (to 2020) |
|---|---|---|---|
| Stages | Series B | Not enough dated deals | Series A, Growth, Series B |
| Sectors | Cybersecurity, Energy | Not enough dated deals | Cybersecurity, Enterprise SaaS, Data analytics, Hardware |
| Regions | Not stated | Not enough dated deals | CA, NY |
Says: what the firm's funds state. Does: from 0 dated deals in the last 24 months.
Historical focus (through 2020), derived from historical deal data.
| Year | Deals | Top sectors |
|---|---|---|
| 2012 | 1 | Data analytics, Hardware |
| 2017 | 1 | Cybersecurity |
| 2018 | 12 | Cybersecurity, Data analytics, Enterprise SaaS |
| 2019 | 11 | Cybersecurity, Enterprise SaaS, Data analytics |
| 2020 | 6 | Cybersecurity, Enterprise SaaS |
Stage mix over time
- Pre-seed
- Seed
- Series A
- Series B
- Growth
| Year | Pre-seed | Seed | Series A | Series B | Growth |
|---|---|---|---|---|---|
| 2012 | 0 | 0 | 0 | 1 | 0 |
| 2013 | 0 | 0 | 0 | 0 | 0 |
| 2014 | 0 | 0 | 0 | 0 | 0 |
| 2015 | 0 | 0 | 0 | 0 | 0 |
| 2016 | 0 | 0 | 0 | 0 | 0 |
| 2017 | 0 | 0 | 1 | 0 | 0 |
| 2018 | 0 | 0 | 3 | 3 | 4 |
| 2019 | 0 | 1 | 3 | 2 | 3 |
| 2020 | 0 | 0 | 4 | 1 | 0 |
| 2021 | 0 | 0 | 0 | 0 | 0 |
| 2022 | 0 | 0 | 0 | 0 | 0 |
| 2023 | 0 | 0 | 0 | 0 | 0 |
| 2024 | 0 | 0 | 0 | 0 | 0 |
| 2025 | 0 | 0 | 0 | 0 | 0 |
| 2026 | 0 | 0 | 0 | 0 | 0 |
02 · Fund history
| Fund | Year | Size | Status |
|---|---|---|---|
| Mainspring Funding II LLC ClearSky is a venture capital and growth equity firm investing in innovative companies in the cybersecurity and energy transition sectors, focusing on technology solutions that power the energy transition and disruptive cybersecurity technologies. Inferred from the firm's website | 2026 | $2.93M to $20M (Form D) | Raising |
| XGS Funding LLC ClearSky is a venture capital and growth equity firm investing in innovative companies in the cybersecurity and energy transition sectors, focusing on technology solutions that power the energy transition and disruptive cybersecurity technologies. Inferred from the firm's website | 2026 | $6.18M to $20M (Form D) | Raising |
| ClearSky Fund IV International LP ClearSky is a venture capital and growth equity firm investing in innovative companies in the cybersecurity and energy transition sectors, focusing on technology solutions that power the energy transition and disruptive cybersecurity technologies. Inferred from the firm's website | 2025 | $38.5M to $500M (Form D) | Raising |
| ClearSky Fund IV LP ClearSky is a venture capital and growth equity firm investing in innovative companies in the cybersecurity and energy transition sectors, focusing on technology solutions that power the energy transition and disruptive cybersecurity technologies. Inferred from the firm's website | 2025 | $58.4M to $500M (Form D) | Raising |
| MAINSPRING FUNDING LLC ClearSky is a venture capital and growth equity firm investing in innovative companies in the cybersecurity and energy transition sectors, focusing on technology solutions that power the energy transition and disruptive cybersecurity technologies. Inferred from the firm's website | 2023 | $6.83M to $10M (Form D) | Open, writing first checks |
03 · People across funds
- Alexander Weiss, Manager of the Manager of the Issuer
Mainspring Funding II LLC (Named on Form D); XGS Funding LLC (Named on Form D); ClearSky Fund IV International LP (Named on Form D); ClearSky Fund IV LP (Named on Form D); MAINSPRING FUNDING LLC (Named on Form D)
- James Huff, Co-Founder & Managing Partner
Mainspring Funding II LLC (Named on Form D); XGS Funding LLC (Named on Form D); ClearSky Fund IV International LP (Named on Form D); ClearSky Fund IV LP (Named on Form D); MAINSPRING FUNDING LLC (Team)
- Alex Weiss, CEO, Co-Founder & Managing Partner
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Anjali Nagaraja, Associate
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Austin Summers, Senior Vice President
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Daniel Furey, Partner, Head of Global Capital Formation
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Erik Straser, Partner
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Guy Nizan, Venture Partner
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Howard Shecter, Executive Partner
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Joseph Wright, Chairman of the Investment Committee
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Nick-Anthony Buford, Managing Director & General Counsel
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Owen Santos, Analyst
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Robert Rauch, Partner
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Ryan Crum, Partner
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Vince Nicchi, Controller
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
- Zach Weiss, Analyst
Mainspring Funding II LLC (Team); XGS Funding LLC (Team); ClearSky Fund IV International LP (Team); ClearSky Fund IV LP (Team); MAINSPRING FUNDING LLC (Team)
04 · Recent deals
No dated deals found yet.
05 · Latest from the firm
No news from the firm's website yet.
06 · Sources
- https://www.clear-sky.com/
- https://www.clear-sky.com/team/
- https://www.clear-sky.com/about/spring-2026-newsletter/
Fund dates and sizes are from SEC Form D filings.
Last verified: Oct 28, 2026