---
schema_version: "secwatch.filing_event.v1"
accession: "0001819142-23-000078"
form_type: "8-K"
ticker: "SES"
cik: "0001819142"
company_name: "SES AI Corp"
filed_at: "2023-09-22T23:59:59+00:00"
generated_at: "2026-06-10T09:49:35.074476+00:00"
event_type: "leadership"
sentiment: "neutral"
materiality_score: 0.5
calibrated_materiality_score: 0.5
confidence: "high"
source: SEC EDGAR
---

# SES AI CTO Yongkyu Son resigns effective Sept 30; interim team assigned

## Summary
- Yongkyu Son resigned as CTO effective Sept 30, 2023, citing personal reasons.
- No disagreement with management, board, operations, policies, or practices.
- Hong Gan (Chief Science Officer) and Daniel Li (Chief Manufacturing Officer) assume interim CTO responsibilities.
- Company has commenced a search for a permanent successor.

## SEC filing metadata
- accession: 0001819142-23-000078
- form_type: 8-K
- ticker: SES
- cik: 0001819142
- company_name: SES AI Corp
- filed_at: 2023-09-22T23:59:59+00:00
- event_type: leadership
- sentiment: neutral
- materiality_score: 0.5
- calibrated_materiality_score: 0.5
- confidence: high
- sec_items: 5.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1819142/000181914223000078/0001819142-23-000078-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1819142/000181914223000078/ses-20230919x8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001819142-23-000078
- JSON: https://secwatch.observer/filing/0001819142-23-000078.json
- Plain text: https://secwatch.observer/filing/0001819142-23-000078.txt

## Key facts
- Executive change
  Yongkyu Son resigned as Chief Technology Officer at SES AI Corp.
  - Action: resigned
  - Role: Chief Technology Officer
  source text: On September 19, 2023, Yongkyu Son informed SES AI Corporation (the “Company”) of his decision to resign from his position as Chief Technology Officer of the Company, effective September 30, 2023.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1819142/000181914223000078/0001819142-23-000078-index.htm
- Executive change
  Hong Gan changed role as Interim Chief Technology Officer at SES AI Corp.
  - Action: assumed interim CTO responsibilities
  - Role: Interim Chief Technology Officer
  source text: Mr. Son’s prior responsibilities shall be assumed by Hong Gan and Daniel Li, the Company’s Chief Science Officer and Chief Manufacturing Officer, respectively.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1819142/000181914223000078/0001819142-23-000078-index.htm
- Executive change
  Daniel Li changed role as Interim Chief Technology Officer at SES AI Corp.
  - Action: assumed interim CTO responsibilities
  - Role: Interim Chief Technology Officer
  source text: Mr. Son’s prior responsibilities shall be assumed by Hong Gan and Daniel Li, the Company’s Chief Science Officer and Chief Manufacturing Officer, respectively.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1819142/000181914223000078/0001819142-23-000078-index.htm

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