---
schema_version: "secwatch.filing_event.v1"
accession: "0001193125-26-018700"
form_type: "8-K"
ticker: "MBX"
cik: "0001776111"
company_name: "MBX Biosciences, Inc."
filed_at: "2026-01-22T23:59:59+00:00"
generated_at: "2026-05-16T08:50:27.328243+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.4
calibrated_materiality_score: 0.4
confidence: "high"
source: SEC EDGAR
---

# MBX Biosciences appoints Laurie Stelzer as independent director and audit committee chair

## Summary
- Laurie Stelzer appointed as Class I director effective Jan. 20, 2026, filling an existing board vacancy.
- Stelzer will serve as chair of the Audit Committee, replacing Ed Mathers on that committee.
- She brings CFO experience from Kailera, Orna, Mirati, Arena, Halozyme, and board roles at Sionna, PMV, Spyre.
- Board size increased to eight directors; Stelzer is independent under Nasdaq standards.

## SEC filing metadata
- accession: 0001193125-26-018700
- form_type: 8-K
- ticker: MBX
- cik: 0001776111
- company_name: MBX Biosciences, Inc.
- filed_at: 2026-01-22T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.4
- calibrated_materiality_score: 0.4
- confidence: high
- sec_items: 5.02, 7.01, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1776111/000119312526018700/0001193125-26-018700-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1776111/000119312526018700/mbx-20260120.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001193125-26-018700
- JSON: https://secwatch.observer/filing/0001193125-26-018700.json
- Plain text: https://secwatch.observer/filing/0001193125-26-018700.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.