ProMIS Neurosciences (PMN): Wellington group discloses 7.77% ownership stake

Rhea-AI Filing Summary

ProMIS Neurosciences, Inc. has a Schedule 13G/A filed by several Wellington entities reporting a passive ownership position in the company’s common stock as of June 30, 2026. Wellington Management Group LLP and related holding and advisory entities report beneficial ownership of 696,378 shares of ProMIS common stock, representing 7.77% of the class. The Wellington entities report no sole voting or dispositive power, but shared voting and shared dispositive power over all 696,378 shares. The shares are held of record by clients of one or more Wellington investment advisers, including certain Wellington Biomedical Innovation Master Investors funds that may each hold more than five percent of the class at the client level.

Key Figures

Shares beneficially owned: 696,378 shares Percent of class: 7.77% Shared voting power: 696,378 shares +3 more

6 metrics

Shares beneficially owned 696,378 shares Beneficially owned by Wellington entities as of June 30, 2026

Percent of class 7.77% ProMIS Neurosciences common stock held by Wellington entities

Shared voting power 696,378 shares Shares over which Wellington entities have shared voting power

Shared dispositive power 696,378 shares Shares over which Wellington entities have shared dispositive power

Ownership threshold exceeded 5% Schedule 13G/A filing triggered by holding more than 5% of class

Reporting entities 4 entities Wellington Management Group LLP and three related entities reporting

Key Terms

beneficially owned, shared voting power, shared dispositive power, parent holding company, +1 more

5 terms

beneficially owned financial

"Amount beneficially owned: See the responses to Item 9 on the attached cover pages."

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

shared voting power financial

"Shared Voting Power 696,378.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"Shared Dispositive Power 696,378.00"

parent holding company financial

"Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company"

investment advisers financial

"The securities as to which this Schedule is filed are owned of record by clients of one or more investment advisers"

FAQ

What ownership stake in ProMIS Neurosciences (PMN) do the Wellington entities report?

The Wellington entities report beneficial ownership of 696,378 shares of ProMIS Neurosciences common stock, representing 7.77% of the outstanding class as of June 30, 2026, held for various advisory clients.

Which Wellington entities are listed as reporting persons for ProMIS Neurosciences (PMN)?

The filing lists Wellington Management Group LLP, Wellington Group Holdings LLP, Wellington Investment Advisors Holdings LLP, and Wellington Management Company LLP as reporting persons, reflecting the Wellington ownership and advisory structure over the ProMIS position.

How much voting power do the Wellington entities have over ProMIS Neurosciences (PMN) shares?

The Wellington entities report 0 shares with sole voting power and 696,378 shares with shared voting power, indicating voting authority is shared, typically with advisory clients or related entities, rather than held solely by a single Wellington entity.

Do Wellington’s clients, rather than Wellington itself, own the ProMIS Neurosciences (PMN) shares?

Yes. The shares are owned of record by clients of one or more Wellington investment advisers. Those clients have the right to receive dividends and sale proceeds, while Wellington reports beneficial ownership through its advisory and holding structure.

Which Wellington client funds may each hold over 5% of ProMIS Neurosciences (PMN)?

The filing notes that no client is known to hold over 5% of the class, except potentially Wellington Biomedical Innovation Master Investors (Cayman) II L.P. and Wellington Biomedical Innovation Master Investors (Cayman) II, L.P..

Is the Wellington stake in ProMIS Neurosciences (PMN) reported as passive or activist?

This is filed on Schedule 13G/A, which is typically used for passive beneficial ownership rather than an activist position, indicating Wellington’s stake is reported in a non-control, investment capacity.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/13/2026 - 04:06 PM Accepted by SEC EDGAR 08/13/2026 - 04:05 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

ProMIS Neurosciences, Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

74346M505

(CUSIP Number)

06/30/2026

(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): 74346M505

1

Names of Reporting Persons

Wellington Management Group LLP

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

MASSACHUSETTS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 696,378.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 696,378.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

696,378.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP Number(s): 74346M505

1

Names of Reporting Persons

Wellington Group Holdings LLP

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 696,378.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 696,378.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

696,378.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP Number(s): 74346M505

1

Names of Reporting Persons

Wellington Investment Advisors Holdings LLP

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 696,378.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 696,378.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

696,378.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP Number(s): 74346M505

1

Names of Reporting Persons

Wellington Management Company LLP

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 696,378.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 696,378.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

696,378.00

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)

7.8 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: ProMIS Neurosciences, Inc.
(b)	Address of issuer's principal executive offices: Suite 200, 1920 Yonge Street, Toronto ON M4S 3E2
Item 2.
(a)	Name of person filing: Wellington Management Group LLP Wellington Group Holdings LLP Wellington Investment Advisors Holdings LLP Wellington Management Company LLP
(b)	Address or principal business office or, if none, residence: c/o Wellington Management Company LLP, 280 Congress Street, Boston MA 02210
(c)	Citizenship: Wellington Management Group LLP - Massachusetts Wellington Group Holdings LLP - Delaware Wellington Investment Advisors Holdings LLP - Delaware Wellington Management Company LLP - Delaware
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 74346M505
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: See the responses to Item 9 on the attached cover pages.
(b)	Percent of class: 7.77 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: See the responses to Item 6 on the attached cover pages.
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: See the responses to Item 8 on the attached cover pages.
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. The securities as to which this Schedule is filed are owned of record by clients of one or more investment advisers identified in Item 7 directly or indirectly owned by Wellington Management Group LLP. Those clients have the right to receive, or the power to direct the receipt of, dividends from, or the proceeds from the sale of, such securities. No such client is known to have such right or power with respect to more than five percent of this class of securities, except as follows: Wellington Biomedical Innovation Master Investors (Cayman) II L.P. Wellington Biomedical Innovation Master Investors (Cayman) II, L.P.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Pursuant to the instructions in Item 7 of Schedule 13G, the following lists the identity and Item 3 classification of each relevant entity that beneficially owns shares of the security class being reported on this Schedule 13G. Wellington Group Holdings LLP - HC Wellington Investment Advisors LLP - HC Wellington Management Global Holdings, Ltd. - HC One or more of the following investment advisers (the "Wellington Investment Advisers"): Wellington Management Company LLP - IA Wellington Management Canada LLC - IA Wellington Management Singapore Pte Ltd - IA Wellington Management Hong Kong Ltd - IA Wellington Management International Ltd - IA Wellington Management Japan Pte Ltd - IA Wellington Management Australia Pty Ltd - IA The securities as to which this Schedule is filed by Wellington Management Group LLP, as parent holding company of certain holding companies and the Wellington Investment Advisers, are owned of record by clients of the Wellington Investment Advisers. Wellington Investment Advisors Holdings LLP controls directly, or indirectly through Wellington Management Global Holdings, Ltd., the Wellington Investment Advisers. Wellington Investment Advisors Holdings LLP is owned by Wellington Group Holdings LLP. Wellington Group Holdings LLP is owned by Wellington Management Group LLP.
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.

Wellington Management Group LLP

Signature:	Matthew Revell
Name/Title:	Compliance Manager
Date:	08/14/2026

Wellington Group Holdings LLP

Signature:	Matthew Revell
Name/Title:	Compliance Manager
Date:	08/14/2026

Wellington Investment Advisors Holdings LLP

Signature:	Matthew Revell
Name/Title:	Compliance Manager
Date:	08/14/2026

Wellington Management Company LLP

Signature:	Matthew Revell
Name/Title:	Compliance Manager
Date:	08/14/2026