# Ramu Arunachalam

> Ramu Arunachalam is a Series A investor at A.Capital Ventures backing Internet and Software. See 3 investments, check sizes, portfolio. Updated Aug 2026.

- Type: Angel Investor
- Fund: [A.Capital Ventures](https://shizune.co/investors/profile/capital-partners-l-p)
- Location: San Francisco, United States
- Total investments: 3
- Last investment: Jul 2021
- Lead investor: 33%
- Last updated: Aug 2026
- LinkedIn: http://www.linkedin.com/in/ramuarunachalam
- X (Twitter): http://twitter.com/ra2w
- Website: https://x.com/ra2w

Ramu Arunachalam is a General Partner at A.Capital. He was most recently a Partner at Andreessen Horowitz where he worked on over a dozen investments in the enterprise software space. In addition, he helped shape the firm’s investment thesis in Cloud infrastructure and Big Data. Past investments include Instart Logic, Databricks, Mesosphere,Illumio, and Cumulus Networks. A computer scientist by training, Ramu has over a decade of operating experience in product management and engineering at both startups and public companies. Prior to Andreessen Horowitz, Ramu led new product initiatives in Big Data for Aster Data (acquired by Teradata). Earlier in his career, Ramu was an engineer at VMware and part of the team that developed the industry’s first virtual switch for VMware’s flagship ESX server product line.Ramu holds an MBA from the Kellogg School of Management at Northwestern University, an MS in Computer Science from the University of Maryland, and a BS in Electrical and Computer Engineering (with University Honors) from Carnegie Mellon University.

## Investment focus

### Industry

| Industry | Investments | Share |
| --- | --- | --- |
| Internet | 1 | 33% |
| Software | 1 | 33% |
| Agentic AI | 1 | 33% |
| Compliance | 1 | 33% |
| Cyber Security | 1 | 33% |

10 industries tracked in total.

### Stage

| Stage | Investments | Share |
| --- | --- | --- |
| Series A | 2 | 67% |
| Series B | 1 | 33% |

## Investments

| Company | Description | Amount | Stage | Date | Website |
| --- | --- | --- | --- | --- | --- |
| Unit21 | Unit21 is the leader in AI Risk Infrastructure for fraud prevention and AML monitoring. Trusted by over 200 institutions, including Intuit, Chime, and Sallie Mae, our platform unifies detection, investigation, and decisioning in a single system built on data-agnostic architecture. Powered by agentic AI, Unit21 doesn’t just summarize alerts; itexecutes the full investigation workflow, reducing false positives by up to 93% and accelerating handle times by 80%. By automating repetitive tasks while maintaining full regulator-ready auditability, Unit21 empowers banks and fintechs to operate proactively and focus on real risk. | $34M | Series B | Jul 07, 2021 |  |
| Unit21 | Unit21 is the leader in AI Risk Infrastructure for fraud prevention and AML monitoring. Trusted by over 200 institutions, including Intuit, Chime, and Sallie Mae, our platform unifies detection, investigation, and decisioning in a single system built on data-agnostic architecture. Powered by agentic AI, Unit21 doesn’t just summarize alerts; itexecutes the full investigation workflow, reducing false positives by up to 93% and accelerating handle times by 80%. By automating repetitive tasks while maintaining full regulator-ready auditability, Unit21 empowers banks and fintechs to operate proactively and focus on real risk. | $13M | Series A | Oct 19, 2020 |  |
| Armorblox | Armorblox is a venture-backed stealth cybersecurity startup that secures the human layer by using the latest techniques in machine learning (ML) and artificial intelligence (AI) to protect organizations against identity-based attacks and data loss. | $16.5M | Series A | Feb 20, 2019 |  |

3 of 3 investments shown.

## Co-investors
- [Gradient](https://shizune.co/investors/profile/gradient-ventures) — VC Fund, 3 deals together
- [South Park Commons](https://shizune.co/investors/profile/south-park-commons) — VC Fund, 2 deals together
- [Tiger Global Management](https://shizune.co/investors/profile/tiger-global) — VC Fund, 2 deals together
- [Trajectory Ventures](https://shizune.co/investors/profile/trajectory-ventures) — VC Fund, 2 deals together
- [Core Innovation Capital](https://shizune.co/investors/profile/core-innovation-capital) — VC Fund, 1 deal together
- [General Catalyst](https://shizune.co/investors/profile/general-catalyst-partners) — VC Fund, 1 deal together

## About A.Capital Ventures

VC Fund · Menlo Park, United States

A.Capital Ventures is an early-stage investment firm that finances consumer and enterprise technology companies. It was founded in 2014 by Ronny Conway. A.Capital Ventures is based in Menlo Park, California.

5 contacts available at A.Capital Ventures.

| Name | Title | Profile |
| --- | --- | --- |
| Brad Strader | Talent Partner | https://shizune.co/investors/profile/brad-strader |
| Carrie Farrell | Talent Partner | https://shizune.co/investors/profile/carrie-farrell |
| Zach Miller | COO | https://shizune.co/investors/profile/zach-miller |
| Kartik Talwar | General Partner | https://shizune.co/investors/profile/kartik-talwar |
| Ramu Arunachalam | General Partner | https://shizune.co/investors/profile/ramu-arunachalam |

## Similar investors

### Similar stage
- [Antler](https://shizune.co/investors/profile/antler-be9c) — VC Fund
- [Alumni Ventures](https://shizune.co/investors/profile/alumni-ventures-group) — VC Fund
- [General Catalyst](https://shizune.co/investors/profile/general-catalyst-partners) — VC Fund

## FAQ

### What does Ramu Arunachalam invest in?

Ramu Arunachalam invests primarily in Internet, Software and Agentic AI startups, most often at Series A and Series B stage. Most of the 3 investments tracked by Shizune back companies in United States. The Investment Focus section breaks down every industry, stage and country in the portfolio.

### When did Ramu Arunachalam last invest?

The most recent investment recorded for Ramu Arunachalam closed in Jul 2021. Shizune tracks 3 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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