Dimensional Fund Advisors (NYSE: MDU) lists 10.29M shares, 5.0% stake

Rhea-AI Filing Summary

MDU Resources Group Inc reported that Dimensional Fund Advisors LP beneficially owns 10,285,747 shares of common stock, representing 5.0% of the class as of 03/31/2026. The filing states Dimensional furnishes investment advice to registered funds that own these shares and disclaims beneficial ownership; voting and dispositive powers are shown in the schedule.

Key Figures

Beneficial ownership: 10,285,747 shares Percent of class: 5.0% Sole voting power: 10,136,321 shares +3 more

6 metrics

Beneficial ownership 10,285,747 shares Amount beneficially owned as of 03/31/2026

Percent of class 5.0% Percent of common stock class as reported

Sole voting power 10,136,321 shares Sole power to vote as reported in the schedule

Sole dispositive power 10,285,747 shares Sole power to dispose as reported in the schedule

As-of date 03/31/2026 Reporting date for ownership figures

Signature date 04/09/2026 Date filing was signed by compliance officer

Key Terms

Schedule 13G, beneficially owned, Investment Company Act, sole dispositive power

4 terms

Schedule 13G regulatory

"Dimensional Fund Advisors files this Schedule 13G reporting 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.

beneficially owned financial

"Amount beneficially owned: 10,285,747"

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.

Investment Company Act regulatory

"investment companies registered under the Investment Company Act of 1940"

The Investment Company Act is a law that sets rules for businesses whose main activity is managing and selling pooled money, such as mutual funds and other investment funds. It matters to investors because it requires clear reporting, limits managers from putting their own interests ahead of clients, and mandates safekeeping and oversight of assets—similar to safety inspections and traffic rules that help keep shared vehicles reliable and trustworthy.

sole dispositive power financial

"Sole power to dispose or to direct the disposition of: 10,285,747"

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.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

MDU Resources Group Inc

(Name of Issuer)

Common Stock

(Title of Class of Securities)

552690109

(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): 552690109

1

Names of Reporting Persons

Dimensional Fund Advisors 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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 10,136,321.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 10,285,747.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

10,285,747.00

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)

5.0 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MDU Resources Group Inc
(b)	Address of issuer's principal executive offices: 1200 West Century Avenue, Bismarck, ND 58503
Item 2.
(a)	Name of person filing: Dimensional Fund Advisors LP
(b)	Address or principal business office or, if none, residence: 6300 Bee Cave Road, Building One, Austin, TX 78746
(c)	Citizenship: Delaware Limited Partnership
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 552690109
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: 10,285,747 ** see Note 1 ** ** Note 1 ** Dimensional Fund Advisors LP, an investment adviser registered under Section 203 of the Investment Advisors Act of 1940, furnishes investment advice to four investment companies registered under the Investment Company Act of 1940, and serves as investment manager or sub-adviser to certain other commingled funds, group trusts and separate accounts (such investment companies, trusts and accounts, collectively referred to as the "Funds"). In certain cases, subsidiaries of Dimensional Fund Advisors LP may act as an adviser or sub-adviser to certain Funds. In its role as investment advisor, sub-adviser and/or manager, Dimensional Fund Advisors LP or its subsidiaries (collectively, "Dimensional") may possess voting and/or investment power over the securities of the Issuer that are owned by the Funds, and may be deemed to be the beneficial owner of the shares of the Issuer held by the Funds. However, all securities reported in this schedule are owned by the Funds. Dimensional disclaims beneficial ownership of such securities. In addition, the filing of this Schedule 13G shall not be construed as an admission that the reporting person or any of its affiliates is the beneficial owner of any securities covered by this Schedule 13G for any other purposes than Section 13(d) of the Securities Exchange Act of 1934.
(b)	Percent of class: 5.0 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 10,136,321** see Note 1 **
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 10,285,747** see Note 1 **
	(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. The Funds described in Note 1 above have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of the securities held in their respective accounts. To the knowledge of Dimensional, the interest of any one such Fund does not exceed 5% of the class of securities. Dimensional Fund Advisors LP disclaims beneficial ownership of all such securities.
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.

Dimensional Fund Advisors LP

Signature:	Selwyn Notelovitz
Name/Title:	Global Chief Compliance Officer
Date:	04/09/2026

FAQ

What stake does Dimensional Fund Advisors hold in MDU (MDU)?

Dimensional Fund Advisors reports beneficial ownership of 10,285,747 shares, equal to 5.0% of MDU common stock as of 03/31/2026. The shares are held by funds advised by Dimensional; Dimensional disclaims beneficial ownership in the filing.

How much voting power does Dimensional have over MDU shares?

Dimensional reports sole voting power over 10,136,321 shares per the schedule. Shared voting power is listed as 0, and sole dispositive power is 10,285,747 shares as of the reported date.

Who actually owns the MDU shares reported by Dimensional?

The filing states the shares are owned by investment companies, commingled funds, group trusts and separate accounts (the "Funds") advised or sub-advised by Dimensional. Dimensional disclaims beneficial ownership and reports voting/investment power in its advisory role.

When was the Schedule 13G signed for Dimensional's MDU disclosure?

The Schedule 13G was signed by Selwyn Notelovitz, Global Chief Compliance Officer, on 04/09/2026. The ownership figure is reported as of 03/31/2026 in the filing.