# Alex Stamos

> Alex Stamos is a Series A investor at SentinelOne (San Francisco) backing Security and Software. See 4 investments, check sizes, portfolio. Updated Aug 2026.

- Type: Angel Investor
- Fund: [SentinelOne](https://shizune.co/investors/profile/sentinel)
- Location: San Francisco, United States
- Total investments: 4
- Last investment: May 2020
- Lead investor: 0%
- Last updated: Aug 2026
- LinkedIn: http://www.linkedin.com/in/alexstamos
- X (Twitter): http://twitter.com/alexstamos
- Website: http://unhandled.com/
- Facebook: https://www.facebook.com/alex.stamos

Alex Stamos is a Series A investor at SentinelOne in San Francisco focused on Security and Software. Alex Stamos is the current Chief Information Security Officer of SentinelOne. He previously worked at Krebs Stamos Group LLC as a Partner. Alex Stamos attended the University of California, Berkeley.

## Round sizes

| Stage | Round size |
| --- | --- |
| Series A | $9M–$16M |

## Investment focus

### Industry

| Industry | Investments | Share |
| --- | --- | --- |
| Security | 3 | 75% |
| Software | 3 | 75% |
| Cyber Security | 3 | 75% |
| Information Technology | 3 | 75% |
| Internet | 2 | 50% |

13 industries tracked in total.

### Stage

| Stage | Investments | Share |
| --- | --- | --- |
| Series A | 3 | 75% |
| Seed | 1 | 25% |

### Country

| Country | Investments | Share |
| --- | --- | --- |
| United States | 3 | 75% |
| Ireland | 1 | 25% |

## Investments

| Company | Description | Amount | Stage | Date | Website |
| --- | --- | --- | --- | --- | --- |
| Evervault | Encryption infrastructure for developers. | $16.2M | Series A | May 21, 2020 |  |
| Cyberhaven | Cyberhaven is the data security company revolutionizing how companies protect their important information from theft and misuse.Security products only recognized and protected a limited range of data types because they relied on finding patterns in the content itself. Data tracing technology analyzes billions of events surrounding every piece ofdata to better understand and classify it, allowing for the protection of a broader range of sensitive data in any form, anywhere it goes. | $13M | Series A | Dec 05, 2019 |  |
| Altitude Networks | Altitude Networks protects cloud collaboration software (SharePoint, OneDrive, Google Drive) from unauthorized data access, sharing to unintended individuals, and data theft. With their DLP application, the client can quickly identify, remediate, and prevent data loss in the cloud with one click. Altitude Networks is deployed at companies as smallas 50 employees and as big as thousands of employees. The solution focuses on simplicity, ease of use, and remediation by leveraging automatic file sensitivity classification, identity mapping to uncover backdoor cloud access via personal accounts of employees, and one click remediation to protect files. | $9M | Series A | Jul 31, 2019 |  |
| Signal Sciences | Signal Sciences is the fastest growing web application security company in the world. With its award-winning next-gen WAF and RASP solution, Signal Sciences protects more than 40,000 applications and over a trillion production requests per month. Signal Sciences’ patented architecture provides organizations working in a modern developmentenvironment with comprehensive and scalable threat protection and security visibility. The company works with some of the world’s most recognizable companies, like Under Armour, Aflac and WeWork, across industries, including financial services, retail, healthcare, media and entertainment, and government, among others. Signal Sciences is the only vendor to win the Gartner Peer Insights Customers' Choice Award for WAF two times in a row. In addition to customer recognition, Signal Sciences was also named a Visionary in the 2019 Gartner Magic Quadrant for Web Application Firewalls report. The company also won Technology of the Year from InfoWorld and Computing's DevOps Excellence Award for Best DevOps Security Tool. For more information, visit Signal Sciences or follow @SignalSciences. | $2M | Seed | May 20, 2014 |  |

4 of 4 investments shown.

## Co-investors
- [Costanoa Ventures](https://shizune.co/investors/profile/costanoaventures) — VC Fund, 1 deal together
- [Crane Venture Partners](https://shizune.co/investors/profile/crane-venture-partners) — VC Fund, 1 deal together
- [Cyber Mentor Fund](https://shizune.co/investors/profile/cyber-mentor-fund) — VC Fund, 1 deal together
- [Frontline Ventures](https://shizune.co/investors/profile/frontline-ventures) — VC Fund, 1 deal together
- [Index Ventures](https://shizune.co/investors/profile/index-ventures) — VC Fund, 1 deal together
- [Kleiner Perkins](https://shizune.co/investors/profile/kleiner-perkins-caufield-byers) — VC Fund, 1 deal together

## About SentinelOne

VC Fund · Mountain View, United States

SentinelOne delivers autonomous endpoint protection that prevents, detects, and responds to attacks across all major vectors.The company aims to shape the future of endpoint security with an integrated platform that combines behavioral-based detection, advanced mitigation, and forensics to stop threats in real time. Specializing in attacks thatutilize evasion techniques, SentinelOne is a vendor that offers complete protection against malware, exploit, and insider-based attacks. This led Gartner to recognize SentinelOne as a Visionary in their recent Endpoint Protection Magic Quadrant. SentinelOne is also a next-generation endpoint protection company to be independently certified as a true antivirus replacement for Windows, OS X, and Linux, including certification for both HIPAA and PCI. SentinelOne was formed by an elite team of cybersecurity and defense experts from IBM, Intel, Check Point Software Technologies, Cylance, McAfee, and Palo Alto Networks.SentinelOne was named the seventh fastest-growing company in North America in 2019, the fastest-growing in Silicon Valley, and was the only cybersecurity company recognized in the top 10 of the Deloitte Technology Fast 500™. SentinelOne was also the only endpoint protection company on the Forbes AI 50 list, recognizing the 50 most promising companies using AI as a core part of its business model and success.

5 contacts available at SentinelOne.

| Name | Title | Profile |
| --- | --- | --- |
| Alex Stamos | CISO | https://shizune.co/investors/profile/alex-stamos |
| Benny Yashinovsky | Principal Software Engineer | https://shizune.co/investors/profile/benny-yashinovsky-c3f7 |
| David Kellenberger | Senior Director | https://shizune.co/investors/profile/david-kellenberger |
| Evan Davidson | VP of Asia Pacific Japan | https://shizune.co/investors/profile/evan-davidson |
| Jared Phipps | Vice President Worldwide Sales Engineering | https://shizune.co/investors/profile/jared-phipps |

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## FAQ

### What does Alex Stamos invest in?

Alex Stamos invests primarily in Security, Software and Cyber Security startups, most often at Series A and Seed stage. Most of the 4 investments tracked by Shizune back companies in United States. The Investment Focus section breaks down every industry, stage and country in the portfolio.

### What is Alex Stamos's check size?

Alex Stamos typically joins rounds of $9M–$16M at Series A. These ranges are 10th–90th percentile round sizes calculated from confirmed public funding rounds, so they are a realistic guide to the rounds Alex Stamos participates in.

### When did Alex Stamos last invest?

The most recent investment recorded for Alex Stamos closed in May 2020. Shizune tracks 4 investments in total for this profile, including round sizes, stages and portfolio companies, all sourced from confirmed public funding rounds and refreshed monthly.

### Is Shizune's investor data accurate?

Yes — every stat on this profile is calculated from confirmed public funding rounds monitored across hundreds of sources since 2020. This profile was last refreshed in Aug 2026 and is updated monthly. Spotted something off? Use the “Suggest an edit” link near the top of the page.

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