---
title: "BLAVATNIK LEN — Ownership Dossier"
canonical: https://whiteintel.dev/entity/9b09a8c6-eb8b-51ee-9fa0-e19ebc0e40cd
json: https://whiteintel.dev/api/public/dossier/9b09a8c6-eb8b-51ee-9fa0-e19ebc0e40cd
identifier: sec:0001326628
jurisdiction: US
risk: Low
source: WhiteIntel corporate-ownership graph
---

# BLAVATNIK LEN

**Type:** Company  
**Jurisdiction:** [US](https://whiteintel.dev/jurisdictions/us)  
**Identifier:** `sec:0001326628`  
**Risk level:** Low  
**Canonical dossier:** https://whiteintel.dev/entity/9b09a8c6-eb8b-51ee-9fa0-e19ebc0e40cd  
**Structured JSON / MCP:** https://whiteintel.dev/api/public/dossier/9b09a8c6-eb8b-51ee-9fa0-e19ebc0e40cd  

## Ownership & control

### Holdings / subsidiaries

- **OnKure Therapeutics, Inc.** (tenpercentowner) — https://whiteintel.dev/entity/af2b92dc-19f8-5b2c-8dde-04696e432088
- **Day One Biopharmaceuticals, Inc.** (tenpercentowner) — https://whiteintel.dev/entity/f84c84e2-4e61-565b-94e2-fe9a1c41646f
- **Warner Music Group Corp.** (tenpercentowner) — https://whiteintel.dev/entity/9bf8e2f0-451e-5260-9856-dc9399a6ea1d
- **DigitalOcean Holdings, Inc.** (other) — https://whiteintel.dev/entity/739bb02d-67b1-5c60-a886-19319ee518b4
- **HEMAB THERAPEUTICS HOLDINGS, INC.** (tenpercentowner) — https://whiteintel.dev/entity/9e165d1b-994a-5fc3-9fb5-032c0017644f
- **LyondellBasell Industries N.V.** (tenpercentowner) — https://whiteintel.dev/entity/158e1df0-7159-5b0e-af2a-45ba9d87ee9c
- **Zura Bio Ltd** (tenpercentowner) — https://whiteintel.dev/entity/4c696d46-221f-5975-a485-bcbbe749a021
- **Disc Medicine, Inc.** (tenpercentowner) — https://whiteintel.dev/entity/6d317465-e113-5fee-9632-915c2579af2d
- **Warner Music Group Corp.** (other) — https://whiteintel.dev/entity/9bf8e2f0-451e-5260-9856-dc9399a6ea1d
- **Upstream Bio, Inc.** (tenpercentowner) — https://whiteintel.dev/entity/d4a67260-0136-5e37-912a-3a65173d819d
- **Warner Music Group Corp.** (director) — https://whiteintel.dev/entity/9bf8e2f0-451e-5260-9856-dc9399a6ea1d
- **Day One Biopharmaceuticals, Inc.** (other) — https://whiteintel.dev/entity/f84c84e2-4e61-565b-94e2-fe9a1c41646f

…and **11** more subsidiaries/holdings. Resolve the full list with `get_dossier` on the WhiteIntel MCP (`npx -y @whiteintel/mcp-server`) or a one-off dossier — https://whiteintel.dev/pricing.

## Get the full, resolved dossier (agent-callable)

The above is the free teaser. The resolved **multi-hop UBO chain**, ownership **%**, full **financial history**, itemised **assets** and the hop-by-hop **exposure path** are the paid depth — callable as tools from your agent:

```bash
npx -y @whiteintel/mcp-server   # then: get_dossier · trace_ownership_path · check_offshore_exposure
```

Or unlock a one-off cited dossier for **BLAVATNIK LEN** — https://whiteintel.dev/entity/9b09a8c6-eb8b-51ee-9fa0-e19ebc0e40cd · pricing https://whiteintel.dev/pricing.

---

_This is the markdown-for-agents view of the WhiteIntel dossier for **BLAVATNIK LEN**. Human view: https://whiteintel.dev/entity/9b09a8c6-eb8b-51ee-9fa0-e19ebc0e40cd · Structured JSON: https://whiteintel.dev/api/public/dossier/9b09a8c6-eb8b-51ee-9fa0-e19ebc0e40cd._

_Risk levels are heuristic investigative leads, not legal determinations of beneficial ownership. Every claim carries a source; an absent edge means "not yet observed in current sources", not "does not exist"._