# Hartmut Ostrowski

> Hartmut Ostrowski is a seed investor in Bielefeld backing Audio and Sports. See 5 investments, check sizes, portfolio and contact details. Updated Aug 2026.

- Type: Angel Investor
- Location: Bielefeld, Germany
- Total investments: 5
- Last investment: Nov 2021
- Lead investor: 40%
- Last updated: Aug 2026

Hartmut Ostrowski is a seed investor in Bielefeld focused on Audio and Sports. Hartmut Ostrowski is Members of the Supervisory Board at Bertelsmann.

## Contacts

5 contacts available for Hartmut Ostrowski: work email, personal email, work phone, personal phone and socials. Sign up free to unlock them: https://app.shizune.co/sign-up/investor-profiles/find-email/hartmut-ostrowski?utm_source=investor_profile

## Round sizes

| Stage | Round size |
| --- | --- |
| Seed | $219k–$290k |

## Investment focus

### Industry

| Industry | Investments | Share |
| --- | --- | --- |
| Audio | 1 | 20% |
| Sports | 1 | 20% |
| Big Data | 1 | 20% |
| Software | 1 | 20% |
| Marketing | 1 | 20% |

12 industries tracked in total.

### Stage

| Stage | Investments | Share |
| --- | --- | --- |
| Seed | 4 | 80% |
| Pre-Seed | 1 | 20% |

## Investments

| Company | Description | Amount | Stage | Date | Website |
| --- | --- | --- | --- | --- | --- |
| AreaOne | Matchingmaking for your perfect home | $290K | Seed | Nov 01, 2021 |  |
| mycrocast | mycrocast brings people together through audio. Whether for the inclusion of visually impaired fans, the increased engagement of existing fans or the acquisition of new fans in an emotionally native way. | $219K | Seed | Nov 12, 2020 |  |
| mycrocast | mycrocast brings people together through audio. Whether for the inclusion of visually impaired fans, the increased engagement of existing fans or the acquisition of new fans in an emotionally native way. | $236.1K | Pre-Seed | Nov 12, 2020 |  |
| AddApptr | AddApptr GmbH is operates a supply side platform for mobile applications. It offers AddApptr SDK, a solution for mobile developers and publishers to monetize their advertising spaces in applications. The company’s solution supports iOS and Android phones and tablets. |  | Seed | Jul 29, 2013 |  |
| 360report |  |  | Seed | Dec 17, 2012 |  |

5 of 5 investments shown.

## Co-investors
- [High Rise Ventures](https://shizune.co/investors/profile/high-rise-ventures) — VC Fund, 1 deal together
- JJE Venture — VC Fund, 1 deal together
- SHIM Beteiligung — VC Fund, 1 deal together

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## FAQ

### What does Hartmut Ostrowski invest in?

Hartmut Ostrowski invests primarily in Audio, Sports and Big Data startups, most often at Seed and Pre-Seed stage. Most of the 5 investments tracked by Shizune back companies in Germany. The Investment Focus section breaks down every industry, stage and country in the portfolio.

### What is Hartmut Ostrowski's check size?

Hartmut Ostrowski typically joins rounds of $219k–$290k at Seed. These ranges are 10th–90th percentile round sizes calculated from confirmed public funding rounds, so they are a realistic guide to the rounds Hartmut Ostrowski participates in.

### How do I contact Hartmut Ostrowski?

For a verified work email and phone number, create a free Shizune account — contact data is searched across 20+ sources and validated before delivery, so your outreach lands in the right inbox.

### When did Hartmut Ostrowski last invest?

The most recent investment recorded for Hartmut Ostrowski closed in Nov 2021. Shizune tracks 5 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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