Two Seas Capital (QMCO) discloses 6.3% Quantum Corporation ownership via master fund

Rhea-AI Filing Summary

Quantum Corporation has a significant shareholder group led by Two Seas Capital LP, which, together with Two Seas Capital GP LLC and Sina Toussi, reports beneficial ownership of 2,488,535 shares of common stock as of June 30, 2026. This represents 6.3% of the 39,375,000 shares of common stock outstanding on that date.

The shares are held by Two Seas Global (Master) Fund LP, for which Two Seas Capital LP acts as investment adviser with investment discretion, including voting and disposition decisions. Two Seas Capital GP LLC serves as the general partner of Two Seas Capital LP, and Sina Toussi is the chief investment officer of Two Seas Capital LP and managing member of Two Seas Capital GP LLC. The reporting persons have sole voting and dispositive power over all 2,488,535 shares and no shared voting or dispositive power.

Key Figures

Beneficial ownership: 2,488,535 shares Ownership percentage: 6.3% Shares outstanding: 39,375,000 shares +2 more

5 metrics

Beneficial ownership 2,488,535 shares Shares of Quantum Corporation common stock beneficially owned as of June 30, 2026

Ownership percentage 6.3% Percent of Quantum Corporation common stock class as of June 30, 2026

Shares outstanding 39,375,000 shares Quantum Corporation common stock outstanding as of June 30, 2026

Sole voting power 2,488,535 shares Shares over which reporting persons have sole power to vote

Sole dispositive power 2,488,535 shares Shares over which reporting persons have sole power to dispose

Key Terms

beneficially owned, sole voting power, sole dispositive power, investment discretion, +1 more

5 terms

beneficially owned financial

"Amount beneficially owned as of June 30, 2026"

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.

sole voting power financial

"had sole power to vote or to direct the vote of 2,488,535 shares"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

sole dispositive power financial

"had sole power to dispose or to direct the disposition of 2,488,535"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

investment discretion financial

"has been granted investment discretion over portfolio investments"

investment adviser financial

"principal business of TSC is providing investment advice as a registered investment adviser"

An investment adviser is a person or firm that professionally manages money and gives recommendations about buying, selling, or holding investments. Like a financial coach or guide, they have a legal duty to act in a client's best financial interest, so their advice, fees and potential conflicts can directly affect returns and risk — making their role important for investors who want informed, accountable help with portfolios.

FAQ

How much of Quantum Corporation (QMCO) does Two Seas Capital beneficially own?

Two Seas Capital and related reporting persons beneficially own 2,488,535 shares of Quantum Corporation common stock, representing 6.3% of the 39,375,000 shares outstanding as of June 30, 2026, held through Two Seas Global (Master) Fund LP.

Who are the reporting persons in this Quantum Corporation (QMCO) Schedule 13G?

The reporting persons are Two Seas Capital LP, Two Seas Capital GP LLC, and Sina Toussi. They report beneficial ownership of Quantum Corporation common stock held by Two Seas Global (Master) Fund LP, over which they exercise investment discretion and voting authority.

What percentage of Quantum Corporation (QMCO) is owned by the Two Seas entities and Sina Toussi?

Each reporting person—Two Seas Capital LP, Two Seas Capital GP LLC, and Sina Toussi—reports beneficial ownership of 6.3% of Quantum Corporation’s common stock, based on 39,375,000 shares outstanding as of June 30, 2026.

Who holds the Quantum Corporation (QMCO) shares reported by Two Seas Capital?

The 2,488,535 shares of Quantum Corporation common stock are held by Two Seas Global (Master) Fund LP. Two Seas Capital LP serves as investment adviser to this fund and has investment discretion, including voting and disposition power over these shares.

What voting and dispositive powers do the reporting persons have over Quantum Corporation (QMCO) shares?

As of June 30, 2026, the reporting persons have sole power to vote and dispose of 2,488,535 shares of Quantum Corporation common stock, with 0 shares under shared voting or shared dispositive power.

Where are the reporting persons for Quantum Corporation (QMCO) based?

The principal business office of the reporting persons—Two Seas Capital LP, Two Seas Capital GP LLC, and Sina Toussi—is located at 32 Elm Place - 3rd Floor, Rye, New York 10580, while Quantum Corporation’s principal executive offices are in Centennial, Colorado.

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Available on EDGAR 08/14/2026 - 04:51 PM Accepted by SEC EDGAR 08/14/2026 - 04:50 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Quantum Corporation

(Name of Issuer)

Common Stock, $0.01 par value per share

(Title of Class of Securities)

747906600

(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): 747906600

1

Names of Reporting Persons

Two Seas Capital LP

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 2,488,535.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,488,535.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,488,535.00

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)

6.3 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP Number(s): 747906600

1

Names of Reporting Persons

Two Seas Capital GP LLC

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 2,488,535.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,488,535.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,488,535.00

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)

6.3 %

12

Type of Reporting Person (See Instructions)

OO, HC

SCHEDULE 13G

CUSIP Number(s): 747906600

1

Names of Reporting Persons

Sina Toussi

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 2,488,535.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,488,535.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,488,535.00

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)

6.3 %

12

Type of Reporting Person (See Instructions)

IN, HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Quantum Corporation
(b)	Address of issuer's principal executive offices: 10770 E. Briarwood Avenue, Centennial, Colorado, 80112
Item 2.
(a)	Name of person filing: The Statement is filed on behalf of each of the following persons (collectively, the "Reporting Persons") (i) Two Seas Capital LP ("TSC"); (ii) Two Seas Capital GP LLC ("TSC GP"); and (iii) Sina Toussi. This statement relates to the Common Stock, $0.01 par value per share (the "Common Stock"), of Quantum Corporation (the "Issuer") held by Two Seas Global (Master) Fund LP (the "Global Fund"). The principal business of TSC is providing investment advice as a registered investment adviser and serving as investment manager to the Global Fund. As such, TSC has been granted investment discretion over portfolio investments, including the Common Stock, held by or for the account of the Global Fund, including the Global Fund's voting and discretionary decisions. TSC GP serves as general partner of TSC. Sina Toussi serves as the chief investment officer of TSC and managing member of TSC GP.
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the Reporting Persons is 32 Elm Place - 3rd Floor, Rye, New York 10580.
(c)	Citizenship: (i) Two Seas Capital LP is a Delaware limited partnership; (ii) Two Seas Capital GP LLC is a Delaware limited liability company; and (iii) Sina Toussi is a United States citizen.
(d)	Title of class of securities: Common Stock, $0.01 par value per share
(e)	CUSIP Number(s): 747906600
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: Amount beneficially owned as of June 30, 2026: TSC - 2,488,535 shares of Common Stock TSC GP - 2,488,535 shares of Common Stock Sina Toussi - 2,488,535 shares of Common Stock
(b)	Percent of class: Percent of class as of June 30, 2026: TSC - 6.3% TSC GP - 6.3% Sina Toussi - 6.3% The shares of Common Stock reported for Item 4 total 2,488,535 shares of Common Stock held by the Global Fund. TSC may be deemed to have sole power to vote and sole power to dispose of the Common Stock held by the Global Fund, through its capacity as investment adviser of the Global Fund. TSC GP may be deemed to have sole power to vote and sole power to dispose of the Common Stock held by the Global Fund, through its capacity as general partner of TSC. Sina Toussi may be deemed to have sole power to vote and sole power to dispose of the Common Stock owned by the Global Fund, through his capacity as Managing Member of TSC GP. The percentages reported for Item 4(b) are calculated based on a total of 39,375,000 shares of Common Stock outstanding on June 30, 2026, as disclosed in the Issuer's Form 10-Q filed with the Securities and Exchange Commission on August 11, 2026.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: As of June 30, 2026, the Reporting Persons had sole power to vote or to direct the vote of 2,488,535 shares of Common Stock.
	(ii) Shared power to vote or to direct the vote: As of June 30, 2026, the Reporting Persons had shared power to vote or to direct the vote of 0 shares of Common Stock.
	(iii) Sole power to dispose or to direct the disposition of: As of June 30, 2026, the Reporting Persons had sole power to dispose or to direct the disposition of 2,488,535 shares of Common Stock.
	(iv) Shared power to dispose or to direct the disposition of: As of June 30, 2026, the Reporting Persons had shared power to dispose or to direct the disposition of 0 shares of Common Stock.
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 disclosure in Item 4, which is incorporated by reference herein.
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. See disclosure in Item 2, which is incorporated by reference herein.
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.

Two Seas Capital LP

Signature:	/s/ Sina Toussi
Name/Title:	Sina Toussi / Managing Member of Two Seas Capital GP LLC, its General Partner
Date:	08/14/2026

Two Seas Capital GP LLC

Signature:	/s/ Sina Toussi
Name/Title:	Sina Toussi / Managing Member
Date:	08/14/2026

Sina Toussi

Signature:	/s/ Sina Toussi
Name/Title:	Sina Toussi / Self
Date:	08/14/2026