StoneMill Ventures
Angel networkWashington · Seed–Series A
Investment thesis
StoneMill Ventures backs disruptive cybersecurity companies, primarily at the seed stage. The firm positions itself as an active, hands-on investor that looks for founding teams who can benefit from its operating experience building pioneering security companies. It concentrates its activity in the Washington, DC metro area where it can be closely involved, but will invest globally when the right opportunity arises. Beyond capital, the firm offers mentorship, seeking passionate entrepreneurs aiming to disrupt key parts of the security ecosystem.
Source: firm website, verified Aug 7, 2026.
What they invest in
from 27 of 37 portfolio companiesCybersecurity ×21Enterprise Software ×17SaaS ×17AI & Machine Learning ×11Cloud Computing ×6Data & Infrastructure ×4Defense Tech ×3Developer Tools ×2
HQs:United States×15Canada×1
Who they back
founder profiles across 18 portfolio companiesFounding team size:solo founder×102 founders×63 founders×14+ founders×1
Investments · 37 tracked
founders shown can be your intro pathBy year:2024 · 22021 · 13 dated
Test range infrastructure for autonomous vehicles (unmanned aerial, ground, and marine systems) serving commercial and defense sectors.
Defense TechHardwareRoboticsDuluth, US
Matt Thomasson(Executive Officer)Steven Witt(Executive Officer, Director)Michael Cutrone(Director)Laura Barr(Director)
BoardCyndi Gula(Director)in
PartnerMichael· solo GP
Co-investorsCapital InnovatorsGula Tech AdventuresPerot JainPJC
Atomicorp provides security and compliance automation for workloads deployed across cloud and datacenter environments, built on the OSSEC open source foundation.
Cloud ComputingCybersecurityDeveloper ToolsEnterprise SoftwareSaaS
Scott Shinn(CTO and co-founder)Michael Shinn(CEO and co-founder)in
PartnerMichael· solo GP
Co-investorsLeawood Venture Capital Llc
PartnerMichael· solo GP
Co-investorsMaryland TEDCOOld Line Capital PartnersTEDCO
Santa Monica, US
Alex Matrosov(Founder)
PartnerMichael· solo GP
Co-investorsCanaan PartnersTwo Bear Capital
Cybrary provides online cybersecurity training courses, certification prep programs, and hands-on labs for individuals and enterprise teams.
CybersecurityEdTechSaaSRiverdale, US
Ryan J. Cory(Executive Officer, Director)Ralph, Jr. P. Sita(Executive Officer, Director)inJeremy Gehring(Executive Officer, Director)
BoardKlee Kleber(Executive Officer, Director)inRon Gula(Director)inJim Curry(Director)in
PartnerMichael· solo GP
Co-investorsBuildGroupGula Tech AdventuresInner Loop CapitalNew Stack VenturesArthur Ventures
DeepSig develops AI/ML software components and products, including OmniPHY-5G for the 5G RAN and OmniSIG for real-time spectrum awareness, to improve commercial and private wireless communication systems.
AI & Machine LearningDeep TechDefense Tech
PartnerMichael· solo GP
Co-investorsLeawood Venture Capital Llc
Feroot discovers and monitors third-party scripts, tags, and trackers on websites to detect malicious or unwanted code and block threats.
CybersecurityEnterprise SoftwareSaaSToronto, CA
Ivan Tsarynny(Founder)inVitaliy Lim(Founder)in
PartnerMichael· solo GP
Co-investorsTrue VenturesY CombinatorPreface Ventures
Fixify provides an AI-assisted IT service desk that integrates with a customer's existing ticketing and productivity tools to automate routine support tasks, backed by a human team that handles designated issue categories.
AI & Machine LearningEnterprise SoftwareSaaS
PartnerMichael· solo GP
Co-investorsAviso VenturesDecibel PartnersPaladin Capital GroupScale Venture PartnersCostanoa Ventures
Fleet Device Management is the company behind an open-source device management platform that enrolls millions of laptops, servers, and other devices across Apple, Linux, Windows, and Android.
CybersecurityDeveloper ToolsEnterprise Software
Zach Wasserman(Cofounder)inMike McNeil(CEO)in
PartnerMichael· solo GP
Co-investorsCRV (Charles River Ventures)Moonfire VenturesOpen Core VenturesTen ElevenGTMfund
Gradient Works provides a territory design platform that connects account scoring, territory planning, book management, lead routing, and pipeline analytics for B2B commercial sales teams.
AI & Machine LearningEnterprise SoftwareSaaSSales TechAustin, US
Hayes Davis(Co-Founder & CEO)
Co-investorsStage 2 CapitalAnthos CapitalGula Tech Adventures
GreyNoise collects primary scanning and exploitation data to provide actionable threat intelligence for cybersecurity defenders.
CybersecurityData & InfrastructureEnterprise SoftwareWashington, US
Andrew Morris(Executive Officer, Director)in
PartnerMichael· solo GP
Co-investorsCRV (Charles River Ventures)Gula Tech AdventuresIn-Q-TelInner Loop CapitalPaladin Capital GroupRadian Capital
Grip provides security tooling that discovers and classifies risk across SaaS services and web apps, identifying risky identities and accounts to help security teams close gaps, prioritize access controls, and maintain SaaS and identity compliance.
AI & Machine LearningCloud ComputingCybersecurityEnterprise SoftwareSaaS
Lior Yaari(Founder)in
PartnerMichael· solo GP
Co-investorsIntel CapitalThird Point VenturesYL Ventures
GroupSense develops patented cyber reconnaissance and threat intelligence technology to help organizations manage the volume of threat intelligence data.
CybersecurityEnterprise SoftwareSaaSArlington, US
Kurtis Minder(Executive Officer, Director, Promoter)inKelly Milan(Executive Officer, Director)Deborah Pearce(Executive Officer)Tom Richards(Executive Officer)Michael Kostoff(Director)Adam Bregenzer(Executive Officer)in
PartnerMichael· solo GP
Co-investorsIrishAngelsThree Tree Ventures
HPE Aruba Networking, formerly Aruba Networks, is Hewlett Packard Enterprise's enterprise wired, wireless and security networking unit.
Co-investorsAmplify PartnersArtis VenturesAsset Management CompanyGolub GrowthICCP Venture PartnersiGlobe Partners+6 more
Huntress provides endpoint detection and response (EDR), identity threat detection and response (ITDR), managed SIEM, and security posture management solutions for organizations of all sizes, protecting against threats through AI-driven threat hunting and 24/7 managed response.
CybersecurityEnterprise SoftwareSaaS
PartnerMichael· solo GP
Co-investorsBroad Street AngelsForgePoint Capital
LimaCharlie provides security infrastructure for MSSPs and enterprise security teams, using AI "agentic operators" that connect to clients' existing tools via API to automate queue work such as email quarantine, endpoint approvals, DLP violations, and alert triage.
AI & Machine LearningCybersecuritySaaS
PartnerMichael· solo GP
Co-investorsHumba VenturesIronGate Capital AdvisorsStrategic Cyber VenturesStreamlined VenturesCoFound Partners VentureLong Journey Ventures+6 more
Link Labs builds IoT-based real-time location and asset-tracking systems that provide indoor and outdoor visibility of equipment, inventory, and personnel for manufacturing and logistics operations.
Advanced ManufacturingIoTLogistics & Supply ChainAnnapolis, US
Robert B. Proctor(Executive Officer, Director)Brian E. Ray(Executive Officer, Director)in
BoardChristopher G. College(Director)
Co-investorsTCP Venture Capital
New York, US
Edwin Upchurch(Executive Officer, Director)Peter Kogge(Executive Officer, Director)Jay Brockman(Executive Officer)Michael J Maulick(Executive Officer, Director)Martin Deneroff(Executive Officer)
BoardJames Hunt(Director)
PartnerMichael· solo GP
Co-investorsIrishAngels
Orca Security offers an agentless cloud security platform (CNAPP) that scans cloud accounts, code, containers, and AI workloads to detect, prioritize, and remediate risks from development through runtime.
Cloud ComputingCybersecuritySaaSPortland, US
Gil Geron(CEO & Co-founder)inAvi Shua(Chief Innovation Officer & Co-founder)inEty Spiegel Hubara(Founder)inLiran Antebi(Founder)inMatan Ben Gur(Founder)inShay Filosof(Founder)in
PartnerMichael· solo GP
Co-investorsCapitalGCisco InvestmentsFlyover CapitalHarmony PartnersICONIQLauder Partners+4 more
RackTop Systems develops BrickStor, a cyberstorage platform that actively defends data against ransomware, insider threats, and data theft through inline inspection and real-time response at the storage layer.
CybersecurityData & InfrastructureDefense TechWashington, US
Eric Bednash(Co-founder)inJonathan Halstuch(Co-founder)in
PartnerMichael· solo GP
Co-investorsEastward Capital PartnersGrotech VenturesGula Tech AdventuresMaryland TEDCORazor's Edge VenturesTEDCO+1 more
SCYTHE is a continuous Adversarial Exposure Validation (AEV) platform that emulates real adversary techniques (mapped to MITRE ATT&CK) against an organization's actual IT, cloud, and OT/ICS environments to validate that detection, alerting, and response controls work.
AI & Machine LearningCybersecurityEnterprise SoftwareSaaSArlington, US
Bryson Bort(Chief Executive Officer)in
PartnerMichael· solo GP
Co-investorsEnergy Impact PartnersGula Tech AdventuresEvolution Equity PartnersSaas Ventures, L.L.C.Inner Loop CapitalAlumni Ventures
A data security platform that detects sensitive data, monitors its movement across endpoints, browsers, SaaS, GenAI workflows and cloud environments, and blocks unauthorized data exfiltration.
Cloud ComputingCybersecurityData & InfrastructureEnterprise SoftwareSaaS
PartnerMichael· solo GP
PartnerMichael· solo GP
Tidal Cyber develops tools and services that help enterprises adopt MITRE ATT&CK framework for threat-informed defense.
CybersecurityEnterprise Software
Rick Gordonin
PartnerMichael· solo GP
Co-investorsAccess Venture PartnersBright Pixel CapitalDreamit VenturesGlasswing VenturesTFX CapitalAccess Ventures+8 more
Todyl provides a unified cybersecurity platform for MSPs, IT, and security professionals to defend against threats, manage risk, and maintain compliance.
CybersecurityEnterprise SoftwareSaaSDenver, US
John G. Nellen III(Executive Officer, Director)
BoardSaid Mohammadioun(Director)in
PartnerMichael· solo GP
Co-investorsTechOperators Venture CapitalTechnology Operators
Weehawken, US
Nazario Parsacala(Founder)
PartnerMichael· solo GP
Co-investorsCanaan PartnersEvolution Equity PartnersLytical VenturesShasta Ventures
Valence provides a SaaS security platform that builds a complete inventory of sanctioned, unsanctioned, and shadow IT and AI applications, detecting risky integrations, OAuth tokens, service accounts, and non-SSO access.
AI & Machine LearningCybersecurityEnterprise SoftwareSaaS
Yoni Shohet(Founder)in
PartnerMichael· solo GP
Co-investorsM12 (Microsoft's Venture Fund)YL Ventures
Verisign operates critical internet infrastructure, serving as the registry for the .com and .net top-level domains and as the Root Zone Maintainer for the global Domain Name System.
Cloud ComputingCybersecurityData & InfrastructureEnterprise Software
Jim Bidzos(CEO)in
Co-investorsBessemer Venture PartnersEverest GroupKleiner PerkinsVedanta Capital
VISO TRUST is an AI-powered third-party risk management (TPRM) platform that helps security teams assess and monitor vendor cyber risk across 3rd, 4th, and nth parties.
AI & Machine LearningCybersecuritySaaS
Paul Valente(Founder)in
PartnerMichael· solo GP
Co-investorsCisco InvestmentsGTM CapitalLytical VenturesRecall CapitalSierra VenturesWork-Bench
Tenable provides an AI-powered exposure management platform that unifies security visibility, insight, and action across an organization's entire attack surface, including infrastructure, cloud, identity, and operational technology environments.
AI & Machine LearningCybersecurityEnterprise Software
PartnerMichael· solo GP
Co-investorsDawn CapitalTen ElevenWipro Ventures
Zscaler operates a cloud-based cybersecurity platform built on Zero Trust architecture to protect users, workloads, branches, and devices across an inline security cloud.
Cloud ComputingCybersecurityEnterprise SoftwareSan Jose, US
Jay Chaudhry(Executive Officer, Director)inRobert Schlossman(Executive Officer)inRemo Canessa(Executive Officer)inSyam Nair(Executive Officer)inCharles Giancarlo(Director)Karen Blasing(Director)
Co-investorsAlphaDriveAnsa CapitalaVentureBright Pixel CapitalCapitalGDell Technologies Capital+3 more
Exits · 1
IPOs and acquisitions across the tracked portfolioVulcanacq. by Tenable
Portfolio news
latest coverage across their companiesZscaler · tickerreport.com · Aug 22, 2026
Gradient · thesaasnews.com · Jun 4, 2026
Tidal · esgtoday.com · May 29, 2026
GroupSense · bankinfosecurity.com · May 23, 2025
Frequently asked questions
- How many investments has StoneMill Ventures made?
- StoneMill Ventures has 36 tracked investments, 1 of which have exited via acquisition or IPO.
- What stage does StoneMill Ventures invest at?
- StoneMill Ventures invests at the Seed, Series A stages.
- What is StoneMill Ventures's typical check size?
- StoneMill Ventures typically writes checks of $100K – $1M.
- What sectors does StoneMill Ventures focus on?
- StoneMill Ventures focuses on Consumer, Cybersecurity, Data & Infrastructure, Enterprise Software, Hardware, SaaS.
- Where is StoneMill Ventures located?
- StoneMill Ventures is headquartered in Washington, US.
- Does StoneMill Ventures lead rounds?
- StoneMill Ventures typically participates in rounds rather than leading them.
- Who does StoneMill Ventures co-invest with?
- StoneMill Ventures most often shares deals with Gula Tech Adventures, Inner Loop Capital, YL Ventures, among 88 tracked co-investors.
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