Milestone Pharmaceuticals Inc. reporting persons led by Adage Capital Management, L.P. state beneficial ownership of 8,000,000 shares, representing 6.37% of the class, issuable upon exercise of warrants. The percentage is calculated using 117,667,277 Common Shares outstanding as of March 20, 2026.
The filing identifies the reporting persons and their shared voting and dispositive power with respect to the warrants and notes the address and CUSIP 59935V107.
Positive
None.
Negative
None.
Insights
Adage discloses a 6.37% position via warrants exercisable into 8,000,000 shares.
Adage's position is reported as shared voting and dispositive power over 8,000,000 Common Shares issuable upon exercise of warrants. The 6.37% stake is calculated using March 20, 2026 outstanding shares of 117,667,277.
Timing and exercise decisions by the warrant holder will determine if and when these shares enter the market; cash‑flow treatment and exercise timing are not specified in the provided excerpt.
Filing clarifies attribution and shared control across related Adage entities and individuals.
The statement attributes the shares to ACP with ACM as investment manager and names Robert Atchinson and Phillip Gross as related managing members. It includes standard disclosure language about inquiries and that filing does not itself admit beneficial ownership.
Reviewers should note the filing is an amendment and cites the Form 10-K outstanding share count; subsequent filings may update outstanding shares or percentages.
Key Figures
Shares issuable upon exercise:8,000,000 sharesPercent of class:6.37%Shares outstanding used for calculation:117,667,277 shares+1 more
4 metrics
Shares issuable upon exercise8,000,000 sharesReported as issuable upon exercise of warrants
Percent of class6.37%Calculated assuming exercise using 117,667,277 shares outstanding as of March 20, 2026
Shares outstanding used for calculation117,667,277 sharesAs of <date>March 20, 2026</date> per company's Form 10-K
CUSIP59935V107Milestone Pharmaceuticals common shares
Key Terms
warrants, beneficial ownership, shared dispositive power
3 terms
warrantsfinancial
"Reflects Common Shares issuable upon exercise of warrants."
Warrants are special documents that give you the right to buy a company's stock at a set price before a certain date. They are often used as a way for companies to attract investors or raise money, and their value can increase if the company's stock price goes up.
beneficial ownershipregulatory
"Amount beneficially owned: The information required by Item 4(a) is set forth"
Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.
shared dispositive powerregulatory
"Shared Dispositive Power 8,000,000.00"
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 1)
Milestone Pharmaceuticals Inc.
(Name of Issuer)
Common Shares, no par value
(Title of Class of Securities)
59935V107
(CUSIP Number)
03/31/2026
(Date of Event Which Requires Filing of this Statement)
Check the appropriate box to designate the rule pursuant to which this Schedule is filed:
Rule 13d-1(b)
Rule 13d-1(c)
Rule 13d-1(d)
schemaVersion:
SCHEDULE 13G
CUSIP Number(s):
59935V107
1
Names of Reporting Persons
Adage Capital Management, L.P.
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
DELAWARE
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
8,000,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,000,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,000,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
6.37 %
12
Type of Reporting Person (See Instructions)
IA, PN
Comment for Type of Reporting Person: Reflects Common Shares (as defined in Item 2(a)) issuable upon exercise of warrants.
SCHEDULE 13G
CUSIP Number(s):
59935V107
1
Names of Reporting Persons
Robert Atchinson
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
8,000,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,000,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,000,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
6.37 %
12
Type of Reporting Person (See Instructions)
HC, IN
Comment for Type of Reporting Person: Reflects Common Shares issuable upon exercise of warrants.
SCHEDULE 13G
CUSIP Number(s):
59935V107
1
Names of Reporting Persons
Phillip Gross
2
Check the appropriate box if a member of a Group (see instructions)
(a)
(b)
3
Sec Use Only
4
Citizenship or Place of Organization
UNITED STATES
Number of Shares Beneficially Owned by Each Reporting Person With:
5
Sole Voting Power
0.00
6
Shared Voting Power
8,000,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
8,000,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
8,000,000.00
10
Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)
11
Percent of class represented by amount in row (9)
6.37 %
12
Type of Reporting Person (See Instructions)
HC, IN
Comment for Type of Reporting Person: Reflects Common Shares issuable upon exercise of warrants.
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Milestone Pharmaceuticals Inc.
(b)
Address of issuer's principal executive offices:
1111 Dr. Frederik-Philips Boulevard, Suite 420, Montreal, Quebec CA H4M 2X6.
Item 2.
(a)
Name of person filing:
This statement is filed by:
(i) Adage Capital Management, L.P., a Delaware limited partnership ("ACM"), as the investment manager of Adage Capital Partners, L.P., a Delaware limited partnership ("ACP"), with respect to the common shares, no par value ("Common Shares") of Milestone Pharmaceuticals Inc., a Quebec corporation (the "Company") issuable upon exercise of warrants directly held by ACP;
(ii) Robert Atchinson ("Mr. Atchinson"), as (1) managing member of Adage Capital Advisors, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACA"), managing member of Adage Capital Partners GP, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACPGP"), general partner of ACP and (2) managing member of Adage Capital Partners LLC, a Delaware limited liability company ("ACPLLC"), general partner of ACM, with respect to the Common Shares issuable upon exercise of warrants directly held by ACP; and
(iii) Phillip Gross ("Mr. Gross"), as (1) managing member of ACA, managing member of ACPGP and (2) managing member of ACPLLC, general partner of ACM, with respect to the Common Shares issuable upon exercise of warrants directly held by ACP.
The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party.
The filing of this statement should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of the securities reported herein.
(b)
Address or principal business office or, if none, residence:
The address of the business office of each of the Reporting Persons is 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116.
(c)
Citizenship:
ACM is a limited partnership organized under the laws of the State of Delaware. Messrs. Gross and Atchinson are citizens of the United States.
(d)
Title of class of securities:
Common Shares, no par value
(e)
CUSIP No.:
59935V107
Item 3.
If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)
Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)
Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)
Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)
Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)
An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)
An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)
A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)
A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)
A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)
A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
(k)
Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.
Ownership
(a)
Amount beneficially owned:
The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 117,667,277 Common Shares outstanding as of March 20, 2026, as reported in the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the Securities and Exchange Commission on March 20, 2026, and assumes the exercise of the warrants held by ACP.
(b)
Percent of class:
6.37%
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(ii) Shared power to vote or to direct the vote:
The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iii) Sole power to dispose or to direct the disposition of:
The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iv) Shared power to dispose or to direct the disposition of:
The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
Item 5.
Ownership of 5 Percent or Less of a Class.
Not Applicable
Item 6.
Ownership of more than 5 Percent on Behalf of Another Person.
If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required.
See Item 2(a).
Item 7.
Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
Not Applicable
Item 8.
Identification and Classification of Members of the Group.
Not Applicable
Item 9.
Notice of Dissolution of Group.
Not Applicable
Item 10.
Certifications:
By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.
SIGNATURE
After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.
Adage Capital Management, L.P.
Signature:
/s/ Robert Atchinson
Name/Title:
By: Adage Capital Partners LLC, its General Partner, By: Robert Atchinson, its Managing Member
What stake does Adage report in Milestone Pharmaceuticals (MIST)?
Adage reports beneficial ownership of 8,000,000 shares, representing 6.37% of the class, issuable upon exercise of warrants, based on March 20, 2026 outstanding shares.
How was the 6.37% figure calculated for MIST?
The percentage uses an aggregate share base of 117,667,277 Common Shares outstanding as of March 20, 2026 from the company’s Annual Report on Form 10-K.
Who are the reporting persons named in the filing for MIST?
The filing lists Adage Capital Management, L.P., and individuals Robert Atchinson and Phillip Gross as reporting persons tied to the Adage entities that manage the warrants.
Are the reported shares currently outstanding or only issuable?
The filing states the 8,000,000 shares are issuable upon exercise of warrants; they are not described as currently outstanding in this excerpt.
Does the filing state who would receive proceeds if warrants are exercised?
The excerpt does not specify proceeds recipients or cash‑flow treatment for potential exercises; the filing focuses on ownership and control attributes.
