[Form 4] Cannabist Co Holdings Inc. Insider Trading Activity

Rhea-AI Filing Summary

Cannabist Co Holdings Inc. (CBSTF) reporting person Rosemary Mazanet notified the company that she ceased to be a director on September 24, 2025. The Form 4 contains no reported purchases or sales of issuer securities; the filing is signed by an attorney-in-fact on behalf of Ms. Mazanet on September 26, 2025.

Positive

• No securities transactions reported in this Form 4, indicating no insider purchases or sales were disclosed with the director's departure

Negative

• Reporting person ceased to be a director of the issuer on September 24, 2025, which is a material governance change disclosed in the filing

Insights

Corporate Governance Expert

TL;DR: A director resignation was disclosed with no insider trades reported, a routine governance update that may have limited market impact.

The filing conveys a straightforward governance change: the reporting person ceased to be a director on September 24, 2025. No non-derivative or derivative transactions are reported, which indicates no immediate insider trading activity tied to the departure in this Form 4. For investors, the item is a disclosure of leadership change without accompanying material financial transactions or clarifying rationale in the filing.

Securities Analyst

TL;DR: No trades were reported alongside the director exit, so direct financial effects from this filing are limited.

The Form 4 shows the reporting person ceased to be a director effective September 24, 2025, and the document lists no acquisitions or dispositions of securities. The absence of transaction data means there is no change in reported beneficial ownership to evaluate here. This filing is primarily administrative and does not provide financial metrics or transactional detail for valuation impact.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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X

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person^*

MAZANET ROSEMARY

(Last) (First) (Middle)

C/O THE CANNABIST COMPANY HOLDINGS INC.

321 BILLERICA ROAD

(Street)

CHELMSFORD MA 01824

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cannabist Co Holdings Inc. [ CBSTF ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
	Officer (give title below)	X	Other (specify below)
			former Director

3. Date of Earliest Transaction (Month/Day/Year)
09/24/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

Remarks:

The Reporting Person ceased to be a director of Issuer on September 24, 2025.

	/s/ David Sirolly as attorney-in-fact for Rosemary Mazanet	09/26/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did the Form 4 for CBSTF report?

The Form 4 reports that Rosemary Mazanet ceased to be a director on September 24, 2025 and shows no purchases or sales of securities.

Were any insider trades reported on the Form 4 for CBSTF?

No. The filing contains no non-derivative or derivative securities transactions.

When did the reporting person cease to be a director?

Effective date: September 24, 2025, as stated in the filing remarks.

Who signed the Form 4 for Rosemary Mazanet?

The form was signed by David Sirolly as attorney-in-fact for Rosemary Mazanet on September 26, 2025.

Does the Form 4 explain why the director left?

No. The filing only states the reporting person ceased to be a director and provides no reason.