---
schema_version: "secwatch.filing_event.v1"
accession: "0000950170-23-030535"
form_type: "8-K"
ticker: "RLYB"
cik: "0001739410"
company_name: "Rallybio Corp"
filed_at: "2023-06-29T23:59:59+00:00"
generated_at: "2026-06-13T14:58:14.202719+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.75
calibrated_materiality_score: 0.75
confidence: "high"
source: SEC EDGAR
---

# Rallybio appoints Stephen Uden as CEO effective Aug 1; Martin Mackay becomes Executive Chairman

## Summary
- Stephen Uden, current President and COO, named CEO effective Aug 1, 2023; will also join the Board.
- Co-founder Martin Mackay transitions from CEO to Executive Chairman, remains full-time employee focusing on strategy and IR.
- Phase 1 multiple dose cohort data for RLYB212 and initial data for RLYB116 expected in Q4 2023.
- Board size increased to 11 directors; Uden appointed as Class II director with term through 2026 annual meeting.
- Uden's base salary stays at $530,000, target bonus 45%; Mackay's compensation unchanged; severance terms similar.

## SEC filing metadata
- accession: 0000950170-23-030535
- form_type: 8-K
- ticker: RLYB
- cik: 0001739410
- company_name: Rallybio Corp
- filed_at: 2023-06-29T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.75
- calibrated_materiality_score: 0.75
- confidence: high
- sec_items: 5.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1739410/000095017023030535/0000950170-23-030535-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1739410/000095017023030535/rlyb-20230628.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0000950170-23-030535
- JSON: https://secwatch.observer/filing/0000950170-23-030535.json
- Plain text: https://secwatch.observer/filing/0000950170-23-030535.txt

## Key facts
- Executive change
  Stephen Uden was appointed as Chief Executive Officer at Rallybio Corp.
  - Action: appointed
  - Role: Chief Executive Officer
  source text: On June 28, 2023, the Board of Directors (the Board) of Rallybio Corporation (Rallybio) appointed Stephen Uden, M.D., Rallybio’s President, Chief Operating Officer and Co-Founder since January 2018, to Chief Executive Officer, effective August 1, 2023.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1739410/000095017023030535/0000950170-23-030535-index.htm
- Executive change
  Martin Mackay was appointed as Executive Chairman at Rallybio Corp.
  - Action: appointed
  - Role: Executive Chairman
  source text: Dr. Mackay, who has served as Chief Executive Officer and Chairman of the Board since 2018, has been appointed to Executive Chairman, effective August 1, 2023.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1739410/000095017023030535/0000950170-23-030535-index.htm

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