Vanguard Portfolio Management (MGEE) reports 7.34% stake in MGE Energy

Rhea-AI Filing Summary

Vanguard Portfolio Management reports beneficial ownership of 2,686,624 shares (7.34%) of MGE Energy Inc common stock as of 03/31/2026. The filing shows sole dispositive power over 2,686,624 shares and sole voting power over 23,523 shares. The disclosure states these holdings include shares held for Vanguard funds and managed accounts over which Vanguard Portfolio Management LLC or its affiliates exercise dispositive power. The schedule is signed by Ashley Grim, Head of Global Fund Administration, on 04/29/2026.

Insights

Institutional Ownership Analyst

Large passive holding noted: Vanguard reports 7.34% ownership.

Vanguard Portfolio Management reports beneficial ownership of 2,686,624 shares, representing 7.34% of MGE Energy Inc as of 03/31/2026. The filing attributes dispositive control to Vanguard and notes inclusion of holdings across Vanguard funds and managed accounts.

Institutions holding >5% are routinely disclosed; this position signals material passive stake but does not, by itself, indicate changes in voting strategy or corporate control. Subsequent filings would show any active proposals or voting coordination.

Corporate Governance Specialist

Disclosure clarifies voting vs. dispositive power.

The schedule differentiates sole voting power: 23,523 shares from sole dispositive power: 2,686,624 shares, reflecting that Vanguard can direct sales while limited voting authority is exercised directly. The filing cites SEC Release No. 34-39538 to explain aggregated reporting across affiliates.

For governance impact, the small voting slice versus larger dispositive control suggests passive investment via funds; any future changes to voting power would be material and reported in amendments.

Key Figures

Beneficial ownership: 2,686,624 shares Percent of class: 7.34% Sole voting power: 23,523 shares +3 more

6 metrics

Beneficial ownership 2,686,624 shares as of 03/31/2026

Percent of class 7.34% percent of common stock

Sole voting power 23,523 shares shares Vanguard has sole power to vote

Sole dispositive power 2,686,624 shares shares Vanguard has sole power to dispose

Reporting date 03/31/2026 ownership as of this date

Signature date 04/29/2026 signed by Ashley Grim

Key Terms

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

4 terms

beneficially owned regulatory

"reflects the securities beneficially owned, or deemed to be 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 dispositive power regulatory

"Sole power to dispose or to direct the disposition of: 2686624"

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.

Schedule 13G regulatory

"Item 1. (a) Name of issuer: MGE Energy Inc"

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.

dispositive power regulatory

"exercises dispositive power over shares held by Vanguard funds"

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.

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

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Accepted by SEC EDGAR 04/29/2026 - 02:18 PM Learn about SEC filing dates

FAQ

What stake does Vanguard Portfolio Management hold in MGE Energy (MGEE)?

Vanguard Portfolio Management reports beneficial ownership of 2,686,624 shares, equal to 7.34% of MGE Energy common stock as of 03/31/2026. The figure includes holdings across Vanguard funds and managed accounts over which the firm exercises dispositive power.

How much voting power does Vanguard have in MGEE?

Vanguard reports sole voting power for 23,523 shares of MGE Energy. The filing separates voting authority from dispositive power, noting Vanguard has sole dispositive power over 2,686,624 shares, reflecting control over sale decisions.

Does the Schedule 13G filing indicate Vanguard controls MGEE?

No explicit control is stated; the filing discloses a 7.34% beneficial ownership stake as of 03/31/2026. It notes holdings span Vanguard funds and managed accounts, without stating coordinated control or active governance actions.

When was the MGEE 13G signed and filed by Vanguard?

The Schedule 13G is signed by Ashley Grim, Head of Global Fund Administration, on 04/29/2026, and reports beneficial ownership figures as of 03/31/2026, per the filing content.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

MGE Energy Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

55277P104

(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): 55277P104

1

Names of Reporting Persons

Vanguard Portfolio 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 23,523.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 2,686,624.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,686,624.00

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)

7.34 %

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 Portfolio Management LLC and the following affiliates of Vanguard Portfolio Management LLC or business divisions of such affiliates: Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. This Schedule 13G includes securities held by Vanguard funds, or sleeves thereof, over which Vanguard Portfolio 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 Portfolio 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.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MGE Energy Inc
(b)	Address of issuer's principal executive offices: 133 South Blair Street, Madison, WI, 53788
Item 2.
(a)	Name of person filing: Vanguard Portfolio 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): 55277P104
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: 2686624
(b)	Percent of class: 7.34 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 23523
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 2686624
	(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 Portfolio 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 Portfolio Management

Signature:	Ashley Grim
Name/Title:	Head of Global Fund Administration
Date:	04/29/2026