Vanguard reports 5.19% stake in SELLAS Life Sciences

Vanguard Capital Management filed a Schedule 13G reporting beneficial ownership of 9,666,278 securities of SELLAS Life Sciences Group Inc, representing 5.19% of the common stock class identified by CUSIP 81642T209 as of June 30, 2026.

Rhea-AI Filing Summary

Vanguard Capital Management filed a Schedule 13G reporting beneficial ownership of 9,666,278 securities of SELLAS Life Sciences Group Inc, representing 5.19% of the common stock class identified by CUSIP 81642T209 as of June 30, 2026. Vanguard reports sole voting power over 1,400,173 securities and sole dispositive power over all 9,666,278 securities, with no shared voting or dispositive power. The position is held by Vanguard Capital Management LLC together with specified affiliates and business divisions, and consists of warrants, even though the CUSIP corresponds to the issuer’s ordinary shares. Vanguard notes that various Vanguard funds and managed accounts have the right to receive dividends or sale proceeds on these securities, but no other single person has an interest in more than 5% of the class.

Key Figures

Beneficially owned securities: 9,666,278 Percent of class: 5.19% Sole voting power: 1,400,173 +5 more

8 metrics

Beneficially owned securities 9,666,278 Amount beneficially owned by Vanguard Capital Management as reported in Schedule 13G

Percent of class 5.19% Portion of SELLAS Life Sciences common stock class represented by Vanguard’s holdings

Sole voting power 1,400,173 Number of SELLAS securities over which Vanguard has sole power to vote

Shared voting power 0 Number of SELLAS securities over which Vanguard has shared voting power

Sole dispositive power 9,666,278 Number of SELLAS securities over which Vanguard has sole power to dispose

Shared dispositive power 0 Number of SELLAS securities over which Vanguard has shared dispositive power

CUSIP 81642T209 CUSIP assigned to SELLAS Life Sciences ordinary shares referenced in the filing

Signature date 07/31/2026 Date the Schedule 13G was signed by Vanguard’s authorized signatory

Key Terms

beneficially owned, dispositive power, Schedule 13G, Investment Company Act of 1940, +1 more

5 terms

beneficially owned financial

"this reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard"

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.

dispositive power financial

"Sole Dispositive Power 9,666,278.00 8 | Shared Dispositive Power 0.00"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

Schedule 13G regulatory

"Vanguard Capital Management filed a Schedule 13G reporting beneficial ownership"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

Investment Company Act of 1940 regulatory

"investment companies registered under the Investment Company Act of 1940 and other managed accounts"

A U.S. federal law that sets the rulebook for pooled investment vehicles such as mutual funds, exchange-traded funds and similar money managers, requiring them to register with regulators, disclose holdings and fees, limit conflicts of interest, and follow governance standards. It matters to investors because these protections and transparency rules act like a referee and scoreboard, helping people compare funds, trust that managers follow fair practices, and spot hidden costs or risks.

warrants financial

"The holdings reported herein are in the form 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.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What percentage of SELLAS Life Sciences Group (SLS) does Vanguard Capital Management report owning?

Vanguard Capital Management reports beneficial ownership of 5.19% of SELLAS Life Sciences Group’s common stock class. This percentage is based on 9,666,278 securities deemed beneficially owned as of June 30, 2026.

How many SELLAS (SLS) securities does Vanguard Capital Management beneficially own?

Vanguard Capital Management reports beneficial ownership of 9,666,278 SELLAS securities. The filing explains these holdings are in the form of warrants, even though the CUSIP listed is assigned to the issuer’s ordinary shares.

What voting power does Vanguard Capital Management have over SELLAS (SLS) shares?

Vanguard Capital Management reports sole voting power over 1,400,173 SELLAS securities and no shared voting power. It also reports sole dispositive power over all 9,666,278 securities with no shared dispositive power.

Which Vanguard entities are included in the SELLAS (SLS) Schedule 13G filing?

The beneficial ownership reflects holdings of Vanguard Capital Management LLC and affiliates or business divisions, including Vanguard Asset Management Limited, Vanguard Fiduciary Trust Company, Vanguard Global Advisers, LLC, and Vanguard Investments Australia Ltd.

Are Vanguard’s SELLAS (SLS) holdings on behalf of other investors?

Yes. Vanguard Capital Management states that investment companies registered under the Investment Company Act of 1940 and other managed accounts have rights to dividends or sale proceeds, though no other single person has over 5% interest.

What type of SELLAS (SLS) securities does Vanguard Capital Management hold?

The filing states that the holdings are in the form of warrants. The CUSIP 81642T209 used in the report is the CUSIP assigned to SELLAS’s ordinary shares, but the position itself consists of warrants.

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

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Available on EDGAR 07/31/2026 - 09:08 AM Accepted by SEC EDGAR 07/31/2026 - 09:07 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

SELLAS Life Sciences Group Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

81642T209

(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): 81642T209

1

Names of Reporting Persons

Vanguard Capital Management

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

PENNSYLVANIA

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 1,400,173.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 9,666,278.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

9,666,278.00

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)

5.19 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by Vanguard Capital Management LLC and the following affiliates of Vanguard Capital Management LLC or business divisions of such affiliates: Vanguard Asset Management Limited, Vanguard Fiduciary Trust Company, Vanguard Global Advisers, LLC and Vanguard Investments Australia Ltd. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Capital Management LLC exercises dispositive power, in addition to securities held by clients over which the affiliates or business divisions of such affiliates indicated above exercise dispositive and/or voting power. This Schedule 13G does not include securities, if any, beneficially owned by other subsidiaries or affiliates of Vanguard Capital Management LLC, or business divisions of such subsidiaries, whose ownership of securities is disaggregated from that of the reporting business unit in accordance with such release. The holdings reported herein are in the form of warrants. The CUSIP Number listed throughout this filing is the CUSIP assigned to the Ordinary Shares of the Issuer.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: SELLAS Life Sciences Group Inc
(b)	Address of issuer's principal executive offices: 15 West 38th Street, 10th Floor, New York, NY, 10018
Item 2.
(a)	Name of person filing: Vanguard Capital Management
(b)	Address or principal business office or, if none, residence: 100 Vanguard Blvd,, Malvern, PA, 19355
(c)	Citizenship: PA
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 81642T209
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: 9666278
(b)	Percent of class: 5.19 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 1400173
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 9666278
	(iv) Shared power to dispose or to direct the disposition of: 0
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. Vanguard Capital Management, including investment companies registered under the Investment Company Act of 1940 and other managed accounts, have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the securities reported herein.No one other person's interest in the securities reported herein is more than 5%.
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.

Vanguard Capital Management

Signature:	My Trieu-Gatt
Name/Title:	Authorized Signatory, Head of Global Fund Administration
Date:	07/31/2026