---
schema_version: "secwatch.filing_event.v1"
accession: "0001104659-23-033374"
form_type: "8-K"
ticker: null
cik: "0001839185"
company_name: "Summit Healthcare Acquisition Corp."
filed_at: "2023-03-16T23:59:59+00:00"
generated_at: "2026-06-18T00:58:14.068331+00:00"
event_type: "m_and_a"
sentiment: "neutral"
materiality_score: 0.9
calibrated_materiality_score: 0.9
confidence: "high"
source: SEC EDGAR
---

# Summit Healthcare completes de-SPAC merger with YS Biopharma; shares begin trading March 17

## Summary
- Business combination closed March 16, 2023; YS Biopharma Ordinary Shares and Warrants to trade under YS and YSBPW.
- 19,388,769 Summit Class A shares redeemed at ~$10.10/share, totaling ~$195.8M in redemptions.
- SPAC Class A exchange ratio of 1.4286; up to 1,708,497 YS Biopharma shares issued to non-redeeming holders.
- All Summit directors and officers resigned; Yi Zhang (YS Biopharma chairman) becomes sole director of surviving entity.
- Summit's securities delisted from Nasdaq; Form 25 filed; deregistration to follow.

## SEC filing metadata
- accession: 0001104659-23-033374
- form_type: 8-K
- cik: 0001839185
- company_name: Summit Healthcare Acquisition Corp.
- filed_at: 2023-03-16T23:59:59+00:00
- event_type: m_and_a
- sentiment: neutral
- materiality_score: 0.9
- calibrated_materiality_score: 0.9
- confidence: high
- sec_items: 2.01, 3.01, 3.03, 5.01, 5.02, 9.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/tm239524d2_8k.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001104659-23-033374
- JSON: https://secwatch.observer/filing/0001104659-23-033374.json
- Plain text: https://secwatch.observer/filing/0001104659-23-033374.txt

## Key facts
- Executive change
  Ken Poon departed as Director at Summit Healthcare Acquisition Corp..
  - Action: ceased
  - Role: Director
  source text: each of Bo Tan, Ken Poon, Ian Stone, Thomas Folinsbee and Tao Bai ceased to be a director of Summit
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- Executive change
  Bo Tan departed as Director at Summit Healthcare Acquisition Corp..
  - Action: ceased
  - Role: Director
  source text: each of Bo Tan, Ken Poon, Ian Stone, Thomas Folinsbee and Tao Bai ceased to be a director of Summit
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- Executive change
  Yi Zhang was appointed as Sole Director at Summit Healthcare Acquisition Corp..
  - Action: appointed
  - Role: Sole Director
  source text: Mr. Yi Zhang, the chairman and director of YS Biopharma will serve as the sole director of Merger Sub II, the surviving entity after the Second Merger.
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- Executive change
  Ken Poon resigned as President, Co-Chief Investment Officer at Summit Healthcare Acquisition Corp..
  - Action: resigned
  - Role: President, Co-Chief Investment Officer
  source text: Ken Poon resigned as President, Co-Chief Investment Officer
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- Executive change
  Ian Stone departed as Director at Summit Healthcare Acquisition Corp..
  - Action: ceased
  - Role: Director
  source text: each of Bo Tan, Ken Poon, Ian Stone, Thomas Folinsbee and Tao Bai ceased to be a director of Summit
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- Executive change
  Bo Tan resigned as Chief Executive Officer, Co-Chief Investment Officer at Summit Healthcare Acquisition Corp..
  - Action: resigned
  - Role: Chief Executive Officer, Co-Chief Investment Officer
  source text: Bo Tan resigned as Chief Executive Officer, Co-Chief Investment Officer
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- Executive change
  Tao Bai departed as Director at Summit Healthcare Acquisition Corp..
  - Action: ceased
  - Role: Director
  source text: each of Bo Tan, Ken Poon, Ian Stone, Thomas Folinsbee and Tao Bai ceased to be a director of Summit
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- Executive change
  Thomas Folinsbee departed as Director at Summit Healthcare Acquisition Corp..
  - Action: ceased
  - Role: Director
  source text: each of Bo Tan, Ken Poon, Ian Stone, Thomas Folinsbee and Tao Bai ceased to be a director of Summit
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm
- M&A Transactions
  Summit Healthcare Acquisition Corp. underwent a change of control involving YS Biopharma (closed 2023-03-16).
  - Action: change of control
  - Counterparty: YS Biopharma
  - Closing: 2023-03-16
  source text: On March 16, 2023 (the “Closing Date”), pursuant to the Business Combination Agreement, immediately prior to the effective time of the First Merger (the “First Merger Effective Time”)
  evidence_url: https://www.sec.gov/Archives/edgar/data/1839185/000110465923033374/0001104659-23-033374-index.htm

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