GCI Liberty (GLIBA): Southeastern, Longleaf report 5.4% ownership of Series C shares

Rhea-AI Filing Summary

Southeastern Asset Management, Inc., together with Longleaf Partners Small-Cap Fund, reports beneficial ownership of Series C GCI Group Common Stock of GCI Liberty, Inc. The filing states that Southeastern beneficially owns 1,935,424 shares, representing 5.4% of this class.

Within this amount, 3,224 shares are reported with sole voting and dispositive power by Southeastern, while 1,932,200 shares are held with shared voting and dispositive power by Southeastern and Longleaf. Longleaf is reported as beneficially owning 1,932,200 shares, also representing 5.4% of the class. O. Mason Hawkins is listed as a reporting person but reports 0 shares beneficially owned and no voting or dispositive power.

The reporting persons enter a joint filing agreement under Rule 13d-1(k), confirming this Schedule 13G is filed on behalf of all three reporting persons.

Key Figures

Southeastern beneficial ownership: 1,935,424 shares Longleaf beneficial ownership: 1,932,200 shares Ownership percentage of class: 5.4 % +3 more

6 metrics

Southeastern beneficial ownership 1,935,424 shares Series C GCI Group Common Stock reported as beneficially owned by Southeastern

Longleaf beneficial ownership 1,932,200 shares Series C GCI Group Common Stock reported as beneficially owned by Longleaf

Ownership percentage of class 5.4 % Percent of Series C GCI Group Common Stock class reported by Southeastern and Longleaf

Sole voting power (Southeastern) 3,224 shares Shares of Series C stock over which Southeastern has sole voting and dispositive power

Shared voting power (Southeastern & Longleaf) 1,932,200 shares Shares with shared voting and shared dispositive power between Southeastern and Longleaf

O. Mason Hawkins beneficial ownership 0 shares Shares of Series C stock reported as beneficially owned by O. Mason Hawkins

Key Terms

beneficially owned, Sole Voting Power, Shared Dispositive Power, Schedule 13G, +2 more

6 terms

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned:"

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

"5 | Sole Voting Power 3,224.00 6 | Shared Voting Power"

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.

Shared Dispositive Power financial

"8 | Shared Dispositive Power 1,932,200.00"

Schedule 13G regulatory

"agree to the joint filing on behalf of each of them of this with respect"

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.

joint filing agreement regulatory

"Joint Filing Agreement In accordance with Rule 13d-1 (k)"

percent of class financial

"11 5.4 % 12"

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

FAQ

What percentage of GCI Liberty (GLIBA) Series C stock does Southeastern Asset Management report owning?

Southeastern Asset Management reports beneficial ownership of 5.4% of GCI Liberty’s Series C GCI Group Common Stock, corresponding to 1,935,424 shares, including 3,224 with sole voting power and 1,932,200 with shared voting power and dispositive power.

How many GLIBA Series C shares does Longleaf Partners Small-Cap Fund hold?

Longleaf Partners Small-Cap Fund reports beneficial ownership of 1,932,200 shares of GCI Liberty’s Series C GCI Group Common Stock, representing 5.4% of that class, all with shared voting and shared dispositive power alongside Southeastern Asset Management.

What voting powers over GLIBA shares does Southeastern Asset Management have?

Southeastern Asset Management reports sole voting power over 3,224 shares and shared voting power over 1,932,200 shares of GCI Liberty’s Series C GCI Group Common Stock, and the same split between sole and shared dispositive power over these shares.

Does O. Mason Hawkins personally own any GLIBA Series C shares in this Schedule 13G?

O. Mason Hawkins is listed as a reporting person but reports 0 shares beneficially owned, with no sole or shared voting power and no sole or shared dispositive power over GCI Liberty’s Series C GCI Group Common Stock.

What is the relationship between Southeastern, Longleaf, and GLIBA in this filing?

Southeastern Asset Management and Longleaf Partners Small-Cap Fund enter a joint filing agreement to file this Schedule 13G for GCI Liberty’s Series C shares, with Southeastern serving as the investment adviser to Longleaf and reporting shared voting and dispositive power over Longleaf’s holdings.

Where are the principal offices of the GLIBA issuer and the reporting persons located?

GCI Liberty’s principal offices are at 12300 Liberty Blvd, Englewood, CO 80112. All reporting persons share a principal business office at 5100 Poplar Avenue, Suite 2450, Memphis, TN 38137, as disclosed in the Schedule 13G.

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Available on EDGAR 08/14/2026 - 04:18 PM Accepted by SEC EDGAR 08/14/2026 - 04:10 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

GCI Liberty, Inc.

(Name of Issuer)

Series C GCI Group Common Stock

(Title of Class of Securities)

36164V800

(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): 36164V800

1

Names of Reporting Persons

Southeastern Asset Management, Inc.

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

TENNESSEE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 3,224.00
6	Shared Voting Power 1,932,200.00
7	Sole Dispositive Power 3,224.00
8	Shared Dispositive Power 1,932,200.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,935,424.00

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)

5.4 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP Number(s): 36164V800

1

Names of Reporting Persons

Longleaf Partners Small-Cap Fund

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 1,932,200.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,932,200.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,932,200.00

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)

5.4 %

12

Type of Reporting Person (See Instructions)

IV

SCHEDULE 13G

CUSIP Number(s): 36164V800

1

Names of Reporting Persons

O. Mason Hawkins

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: GCI Liberty, Inc.
(b)	Address of issuer's principal executive offices: 12300 Liberty Blvd, Englewood, CO, 80112
Item 2.
(a)	Name of person filing: (1) Southeastern Asset Management, Inc., ("Southeastern") (2) Longleaf Partners Small-Cap Fund, ("Longleaf") (3) Mr. O. Mason Hawkins, ("Mr. Hawkins")
(b)	Address or principal business office or, if none, residence: For all Reporting Persons: 5100 Poplar Avenue, Suite 2450, Memphis, TN 38137
(c)	Citizenship: (1) Southeastern - Tennessee (2) Longleaf - Massachusetts (3) Mr. Hawkins - United States of America
(d)	Title of class of securities: Series C GCI Group Common Stock
(e)	CUSIP Number(s): 36164V800
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: (1) Southeastern - 1935424 (2) Longleaf - 1932200 (3) Mr. Hawkins - 0
(b)	Percent of class: 5.4 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: (1) Southeastern - 3224 (2) Longleaf - 0 (3) Mr. Hawkins - 0
	(ii) Shared power to vote or to direct the vote: (1) Southeastern - 1932200 (2) Longleaf - 1932200 (3) Mr. Hawkins - 0
	(iii) Sole power to dispose or to direct the disposition of: (1) Southeastern - 3224 (2) Longleaf - 0 (3) Mr. Hawkins - 0
	(iv) Shared power to dispose or to direct the disposition of: (1) Southeastern - 1932200 (2) Longleaf - 1932200 (3) Mr. Hawkins - 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. Not Applicable.
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. Not Applicable.
Item 8.	Identification and Classification of Members of the Group.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(K), so indicate under Item 3(k) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. Not Applicable.
Item 9.	Notice of Dissolution of Group.
	Notice of dissolution of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5. 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.

Southeastern Asset Management, Inc.

Signature:	/s/ Andrew R. McCarroll
Name/Title:	Andrew R. McCarroll, General Counsel
Date:	08/14/2026

Longleaf Partners Small-Cap Fund

Signature:	/s/ Andrew R. McCarroll
Name/Title:	Andrew R. McCarroll, General Counsel
Date:	08/14/2026

O. Mason Hawkins

Signature:	/s/ O. Mason Hawkins
Name/Title:	O. Mason Hawkins, Individually
Date:	08/14/2026

Exhibit Information

Joint Filing Agreement In accordance with Rule 13d-1 (k) under the Securities Exchange Act of 1934, the persons or entities named below agree to the joint filing on behalf of each of them of this Schedule 13G with respect to the Securities of the Issuer and further agree that this joint filing agreement be included as an exhibit to this Schedule 13G. In evidence thereof, the undersigned hereby execute this Agreement as of August 14, 2026. Southeastern Asset Management, Inc. By /s/ Andrew R. McCarroll Andrew R. McCarroll, General Counsel Longleaf Partners Small-Cap Fund By: Southeastern Asset Management, Inc. /s/ Andrew R. McCarroll Andrew R. McCarroll, General Counsel O. Mason Hawkins, Individually /s/ O. Mason Hawkins