PRIMECAP reports 47.07M shares (9.58%) in Southwest

Southwest Airlines Co. reported a Schedule 13G/A showing PRIMECAP MANAGEMENT CO/CA/ beneficially owns $0 — actually 47,069,495 shares representing 9.58% of common stock as disclosed in the filing.

Rhea-AI Filing Summary

Southwest Airlines Co. reported a Schedule 13G/A showing PRIMECAP MANAGEMENT CO/CA/ beneficially owns $0 — actually 47,069,495 shares representing 9.58% of common stock as disclosed in the filing. The filing states PRIMECAP has sole voting power for 46,915,716 shares and sole dispositive power for 47,069,495 shares. The Schedule 13G/A, signed by the filer’s Deputy Chief Compliance Officer on 05/12/2026, lists Vanguard PRIMECAP Fund as an entity holding more than 5% on behalf of others.

Insights

Institutional Ownership Analyst

PRIMECAP holds a sizeable passive stake in Southwest at 9.58%.

PRIMECAP Management reports 47,069,495 shares beneficially owned with 46,915,716 shares of sole voting power. The Schedule 13G/A classification implies a passive investment posture rather than an activist intent.

Impact depends on PRIMECAP’s voting and disposition decisions; filings note Vanguard PRIMECAP Fund as a >5% interest holder. Subsequent filings would disclose any change in intent or active engagement.

Corporate Governance Specialist

Filing shows concentrated passive ownership with near-complete sole voting control reported.

The reporting entity declares sole voting power for 46,915,716 shares and sole dispositive power for 47,069,495, indicating control over voting instructions and disposition decisions for the stake disclosed.

Because this is a Schedule 13G/A, the filing is consistent with passive investor status. Any shift to active intent would require an updated Schedule.

Key Figures

Beneficially owned shares: 47,069,495 shares Percent of class: 9.58% Sole voting power: 46,915,716 shares +2 more

5 metrics

Beneficially owned shares 47,069,495 shares Reported in Schedule 13G/A

Percent of class 9.58% Percent of common stock reported

Sole voting power 46,915,716 shares Shares with sole power to vote

Sole dispositive power 47,069,495 shares Shares with sole power to dispose

Filing signature date 05/12/2026 Date signature was provided on Schedule 13G/A

Key Terms

Schedule 13G/A, beneficially owned, sole dispositive power

3 terms

Schedule 13G/A regulatory

"Amendment No. 20) Southwes... Schedule 13G/A"

A Schedule 13G/A is an amended public filing with the U.S. securities regulator that updates a previous Schedule 13G, disclosing when an individual or group holds a substantial (typically over 5%) stake in a company and is claiming a passive, non‑controlling intent. Investors monitor these updates because rising or falling holdings can signal changing confidence, potential future moves, or shifts in voting power — like watching a public ledger where large shareholders quietly adjust their positions.

beneficially owned financial

"Item 4. | Ownership (a) | Amount beneficially owned: 47,069,495"

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 dispositive power financial

"(iii) Sole power to dispose or to direct the disposition of: 47,069,495"

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.

FAQ

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

What stake does PRIMECAP Management report in Southwest Airlines (LUV)?

PRIMECAP reports beneficial ownership of 47,069,495 shares, which the filing labels as 9.58% of Southwest Airlines’ common stock. The filing also reports sole voting power for 46,915,716 shares.

Does the Schedule 13G/A indicate PRIMECAP is an active or passive investor in LUV?

The filing is a Schedule 13G/A, which is used by passive investors; the document’s classification and signature indicate a passive reporting posture rather than an expressed intent to influence management.

Who is listed as holding >5% on behalf of others in the filing?

The filing identifies Vanguard PRIMECAP Fund as having an interest of more than five percent of Southwest Airlines’ outstanding common stock, reported as holdings on behalf of other persons.

What voting and dispositive powers does PRIMECAP report for its LUV position?

PRIMECAP reports sole voting power for 46,915,716 shares and sole dispositive power for 47,069,495 shares, indicating the filer asserts direct control over voting and disposition of the reported shares.

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

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Accepted by SEC EDGAR 05/13/2026 - 09:34 AM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 20)

Southwest Airlines Co.

(Name of Issuer)

COM

(Title of Class of Securities)

844741108

(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): 844741108

1

Names of Reporting Persons

PRIMECAP MANAGEMENT CO/CA/

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 46,915,716.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 47,069,495.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

47,069,495.00

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)

9.58 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Southwest Airlines Co.
(b)	Address of issuer's principal executive offices: P.O. Box 36611, Dallas, TEXAS 75235-1611
Item 2.
(a)	Name of person filing: PRIMECAP MANAGEMENT CO/CA/
(b)	Address or principal business office or, if none, residence: 177 EAST COLORADO BLVD. 11TH FLOOR PASADENA, California 91105
(c)	Citizenship: PRIMECAP MANAGEMENT CO/CA/ - UNITED STATES
(d)	Title of class of securities: COM
(e)	CUSIP No.: 844741108
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: 47,069,495
(b)	Percent of class: 9.58 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: PRIMECAP MANAGEMENT CO/CA/ - 46,915,716
	(ii) Shared power to vote or to direct the vote: PRIMECAP MANAGEMENT CO/CA/ - 0
	(iii) Sole power to dispose or to direct the disposition of: PRIMECAP MANAGEMENT CO/CA/ - 47,069,495
	(iv) Shared power to dispose or to direct the disposition of: PRIMECAP MANAGEMENT CO/CA/ - 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. Various Persons have the right to receive, or the power to direct the receipt of, dividends from, or proceeds from the sale of, with respect to the securities as to which this Schedule is filed. No one Person here has an interest more than five percent of this class of securities except as follows: Vanguard PRIMECAP Fund has an interest of more than five percent of the total outstanding common stock of Southwest Airlines Co.
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.

PRIMECAP MANAGEMENT CO/CA/

Signature:	Jorge A. Rodriguez
Name/Title:	Deputy Chief Compliance Officer
Date:	05/12/2026