Investors / United States / StoneMill Ventures
StoneMill Ventures
Venture capital · VA, United States · North America
StoneMill Ventures is an investment firm that invests in disruptive cyber security companies, primarily at the seed stage. It is an active investor that looks for founding teams seeking mentorship alongside financial capital.
Invests inCybersecurityAI & Machine Learning
In its own wordscybersecurityseed stagesecurity-as-a-servicecloud securitysaas securityendpoint security
Your fit with StoneMill Ventures
Four questions about your startup
See how your round matches what it backs, point by point.
Or find every investor that fitsStoneMill Ventures lists 21 checked portfolio companies on its own site. Its largest themes are Cybersecurity (49%), AI & Machine Learning (34%) and Space & Defense (6%). 80% of its companies are based in United States. It invests most often alongside Blu Ventures, CRV and MACH37.
No funding round on record names StoneMill Ventures yet, so the figures come from its portfolio page.
Round figures show recent activity, not StoneMill Ventures' whole history. Rounds on record name 0 companies; its own site lists 21. Funding rounds are complete from mid-2025, so counts and the yearly trend undercount a firm that invested before then. The portfolio, themes and places come from its own site and are not affected.
Investment themes
share of its checked companiesThis firmAll checked companies
Show as a table
| This firm | All checked companies | |
|---|---|---|
| Cybersecurity | 49% | 4% |
| AI & Machine Learning | 34% | 18% |
| Space & Defense | 6% | 3% |
| Enterprise Software | 3% | 8% |
| Legal & Compliance | 3% | 2% |
| Education | 3% | 7% |
| Fintech | 3% | 12% |
Its portfolio companies
where they are based, and what their own sites showSite status
- Site answers1781%
- No longer answers00%
- Points to another company419%
- Parked or sold domain00%
A site that stops answering three checks in a row is counted as no longer answering; that is not proof of closure. A site that points to another company is often an acquisition.
Investor profile
percentile among all firmsShow as a table
| Measure | Percentile of all firms | Value |
|---|---|---|
| Portfolio size | 53th | 21 companies |
| Recent activity | 46th | 0 rounds in 12 months |
| Early stage | 54th | 0% of entries at pre-seed or seed |
| Evidence | 52th | 0% of companies confirmed by a round |
| Sector focus | 82th | 49% in its largest sector |
| Reach | 42th | 2 countries |
Co-investor network
who it backs companies with, and who they back togetherCompare StoneMill Ventures head to head
portfolio size, rounds, entry stages, themes and the companies both backThree or more firms at once: portfolio overlap.
Portfolio
21 companies checked against their own sites| Company | What it does | Themes | First round with it | Evidence |
|---|---|---|---|---|
| Anno AI provides testing infrastructure for autonomous platforms used in commercial and defense ecosystems | AI & Machine LearningAI & Machine Learning | Portfolio page | ||
| Atomicorp provides security solutions for cloud, server, and endpoint protection and compliance | CybersecuritySpace & Defense | Portfolio page | ||
| Binarly helps product security and engineering teams uncover and remediate vulnerabilities in third-party software, firmware, and binaries before and after release. | CybersecurityFintech | Portfolio page | ||
| Cybrary provides online cybersecurity courses and training | EducationCybersecurity | Portfolio page | ||
AI & Machine LearningSpace & Defense | Portfolio page | |||
| Deepsig develops AI/ML foundational software components and products that improve commercial and private wireless communication systems. | AI & Machine LearningCybersecurity | Portfolio page | ||
| Feroot Security provides automated compliance and security solutions for websites and mobile apps | CybersecurityLegal & Compliance | Portfolio page | ||
| Fixify solves routine tickets start to finish inside a company's PSA, under their brand | AI & Machine LearningCybersecurity | Portfolio page | ||
| FleetDM provides device management services for various operating systems, including macOS, Linux, Windows, iOS, and Android. | CybersecurityEnterprise Software | Portfolio page | ||
| GreyNoise provides real-time network threat intelligence and blocklists to stop attackers | Cybersecurity | Portfolio page | ||
| GroupSense provides digital risk protection services, including dark web monitoring and threat intelligence | Cybersecurity | Portfolio page | ||
| Portfolio page | ||||
| Huntress Labs provides a managed security platform with various services including endpoint visibility, threat response, and security awareness training. | CybersecurityAI & Machine Learning | Portfolio page | ||
| LimaCharlie provides a security infrastructure platform for managing and automating security operations | CybersecurityAI & Machine Learning | Portfolio page | ||
| Lucata delivers massive scalability and performance improvements for graph analytics, machine learning and AI with a next-generation computing architecture | CybersecurityAI & Machine Learning | Portfolio page | ||
Cybersecurity | Portfolio page | |||
| SCYTHE provides a platform for adversarial exposure validation and managed purple teaming services to help organizations validate their detection and response capabilities against real adversary behavior. | CybersecurityAI & Machine Learning | Portfolio page | ||
CybersecurityAI & Machine Learning | Portfolio page | |||
| Portfolio page | ||||
| Todyl delivers unified cybersecurity to help professionals defend against threats, manage risk, and stay compliant. | CybersecurityAI & Machine Learning | Portfolio page |
About this data
site last read 5 Nov 2026- Site
- stonemillventures.com
- Last read
- 5 Nov 2026
- Watching since
- 6 Nov 2026
- Companies checked
- 21
Rates come from what VCinfo has observed since observation_start. Firms tend to remove companies that closed, so early rates understate reality. A company leaving a portfolio page does not mean it closed or exited. An unreachable site means our checks failed, nothing more.
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