Quick Takeaways
- WELLINGTON MANAGEMENT GROUP LLP filed SCHEDULE 13G/A for MBX Biosciences, Inc. Common Stock (MBX).
- Disclosed ownership: 11%.
- Date of event: 30 Sep 2025.
WELLINGTON MANAGEMENT GROUP LLP - 30 Sep 2025 SCHEDULE 13G/A Report for MBX Biosciences, Inc. Common Stock (MBX)
- Filing Manager
- WELLINGTON MANAGEMENT GROUP LLP
- Reporting Manager
- Wellington Management Group LLP
- Security
- MBX Biosciences, Inc. Common Stock
- Symbol
- MBX
- Shares outstanding
- 44,660,519 shares
- Disclosed Ownership
- 4,823,336 shares
- Ownership
- 11%
- Form type
- SCHEDULE 13G/A
- Filing time
- 06 Oct 2025, 12:22:32 UTC
- Date of event
- 30 Sep 2025
- Previous filing
- 12 Aug 2025
- Next filing
- 10 Feb 2026
- SEC
- View on sec.gov
Quoteable Key Fact
"WELLINGTON MANAGEMENT GROUP LLP disclosed 11% ownership in MBX Biosciences, Inc. Common Stock (MBX) on 30 Sep 2025."
What Changed
- Previous schedule filing date: 12 Aug 2025.
- Current filing was accepted on 06 Oct 2025, 12:22.
Why This Matters
- This page explains what this Schedule 13D/13G filing tells you before manager-level rows.
- You can verify ownership claims directly against the original SEC filing.
Source Evidence
Backed by Schedule 13D/13G
See Original Filing
Beneficial ownership values are sourced from the original SEC Schedule 13D/13G filing.
Reporting Managers (4)
| Name | Ownership | Shares Owned | sole voting power | shared voting power | Signature | Title | CIK |
|---|---|---|---|---|---|---|---|
| Wellington Management Group LLP | 11% | 4,823,336 | 0 | 4,558,297 | Taisia Lowe | Regulatory Analyst | |
| Wellington Group Holdings LLP | 11% | 4,823,336 | 0 | 4,558,297 | Taisia Lowe | Regulatory Analyst | |
| Wellington Investment Advisors Holdings LLP | 11% | 4,823,336 | 0 | 4,558,297 | Taisia Lowe | Regulatory Analyst | |
| Wellington Management Company LLP | 11% | 4,823,336 | 0 | 4,556,077 | Taisia Lowe | Regulatory Analyst |