# J. Stein

> J. Stein is a seed investor at Span (San Francisco) backing Software and Artificial Intelligence. See 7 investments, check sizes, portfolio. Updated Aug 2026.

- Type: Angel Investor
- Fund: [Span](https://shizune.co/investors/profile/span-3dd1)
- Location: San Francisco, United States
- Total investments: 7
- Last investment: Oct 2025
- Lead investor: 29%
- Last updated: Aug 2026
- LinkedIn: https://www.linkedin.com/in/jzacstein/
- Facebook: https://www.facebook.com/jzac.stein

J. Stein is a seed investor at Span in San Francisco focused on Software and Artificial Intelligence. J Zac Stein is based out of San Francisco, California and is the co-founder of Span. J Zac Stein attended the Harvard University.

## Round sizes

| Stage | Round size |
| --- | --- |
| Seed | $1.1M–$3.8M |
| Series B | $24M–$110M |

## Investment focus

### Industry

| Industry | Investments | Share |
| --- | --- | --- |
| Software | 5 | 71% |
| Artificial Intelligence | 4 | 57% |
| SaaS | 2 | 29% |
| B2B | 1 | 14% |
| Legal | 1 | 14% |

16 industries tracked in total.

### Stage

| Stage | Investments | Share |
| --- | --- | --- |
| Seed | 3 | 43% |
| Series B | 2 | 29% |
| Pre-Seed | 1 | 14% |
| Series A | 1 | 14% |

### Country

| Country | Investments | Share |
| --- | --- | --- |
| United States | 5 | 71% |
| New Zealand | 1 | 14% |

## Investments

| Company | Description | Amount | Stage | Date | Website |
| --- | --- | --- | --- | --- | --- |
| Starbridge | Starbridge is an AI-powered platform that enables businesses to efficiently secure contracts in the state, local, and education sectors, allowing governments to solve problems faster and more effectively. | $42M | Series A | Oct 21, 2025 |  |
| VXT | VXT is a telecommunications and software firm that provides telephone systems and contact management solutions. Customers utilize VXT applications for making phone calls, conducting video conferences, and facilitating internal communication with their teams. Additionally, VXT enhances these services with industry-specific automation through the useof integrations and artificial intelligence tools. | $1.1M | Seed | Apr 12, 2024 |  |
| Outset | AI-powered user research | $3.8M | Seed | Oct 26, 2023 |  |
| Parabola | Parabola is the spreadsheet alternative where you combine the data running throughout your company and create automated processes.Pull in data from any source you can imagine—from scattered spreadsheets and tools, to emails and PDFs—and build logic that replicates the manual work you do every day. Use our canvas to combine and transform yourdata, and surface the results to the right people at the right time so you can do more with the data you rely on. In the process, you’ll codify the steps for every workflow you manage so they become repeatable, shareable, and usable for the whole team.Create solutions for the problems you’ve always wanted to solve, and make your work more shareable and impactful along the way.Parabola is proud to serve companies like Flexport, Sonos, Uber Freight, Brooklinen, and Chubbies and is backed by OpenView Partners, Matrix Partners, Thrive Capital and more. | $24M | Series B | Jun 28, 2023 |  |
| Vanta | Vanta provides an AI-powered Trust Management Platform that automates compliance, security, and risk management for businesses. It helps companies achieve and maintain compliance with various frameworks, streamlining the audit process. The platform also offers solutions for vendor risk management and questionnaire automation, helping businessesbuild and prove trust continuously. | $110M | Series B | Jun 08, 2022 |  |
| Thena | Thena is a new-age customer support platform purpose-built for B2B teams. Thena AI connects to the modern communication stack like Slack, MS Teams, In-app chat and email. Join bold modern B2B teams from Vercel, Amplitude, FOX, Etsy, and LaunchDarkly. Founded by Ankit Saxena, Mike Molinet and Govind Kavaturi. Backed by First Round Capital andLightspeed. | $2.2M | Pre-Seed | May 01, 2022 |  |
| Doorbell Health | Your front door to home health. | $2.5M | Seed | Dec 01, 2020 |  |

7 of 7 investments shown.

## Co-investors
- [Pear VC](https://shizune.co/investors/profile/pejman-mar-ventures) — VC Fund, 3 deals together
- [Goat Ventures](https://shizune.co/investors/profile/goat-ventures) — VC Fund, 2 deals together
- [Pioneer Fund](https://shizune.co/investors/profile/pioneer-fund) — VC Fund, 2 deals together
- [Y Combinator](https://shizune.co/investors/profile/y-combinator) — VC Fund, 2 deals together
- [20SALES](https://shizune.co/investors/profile/20sales) — VC Fund, 1 deal together
- [Adverb Ventures](https://shizune.co/investors/profile/adverb-ventures) — VC Fund, 1 deal together

## About Span

VC Fund · San Francisco, United States

Span is AI platform that helps software engineering leaders cut coordination costs and drive performance at scale.

2 contacts available at Span.

| Name | Title | Profile |
| --- | --- | --- |
| J. Stein | Co-Founder | https://shizune.co/investors/profile/j-zac-stein |
| Stephen Poletto | CTO | https://shizune.co/investors/profile/stephen-poletto |

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## FAQ

### What does J. Stein invest in?

J. Stein invests primarily in Software, Artificial Intelligence and SaaS startups, most often at Seed and Series B stage. Most of the 7 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 J. Stein's check size?

J. Stein typically joins rounds of $1.1M–$3.8M at Seed and $24M–$110M at Series B. These ranges are 10th–90th percentile round sizes calculated from confirmed public funding rounds, so they are a realistic guide to the rounds J. Stein participates in.

### When did J. Stein last invest?

The most recent investment recorded for J. Stein closed in Oct 2025. Shizune tracks 7 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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