[Form 4] MDU Resources Group, Inc. Insider Trading Activity

Rhea-AI Filing Summary

Jason L. Vollmer, Chief Financial Officer of MDU Resources Group, Inc. (MDU) reported an open-market purchase of 5,000 shares of MDU common stock on 09/08/2025 at a reported price of $16.075 per share. After this transaction Mr. Vollmer directly beneficially owned 344,548.197 shares. He also has indirect beneficial ownership of 8,394.3379 shares held in a 401(k) account by a trustee. The Form 4 was signed by Anthony D. Foti as attorney-in-fact on 09/09/2025. The filing states the purchase was executed in the open market.

Positive

• Insider purchase disclosed: CFO purchased 5,000 shares in an open-market transaction on 09/08/2025 at $16.075 per share.
• Complete post-transaction holdings reported: Direct beneficial ownership updated to 344,548.197 shares and indirect 401(k) holdings of 8,394.3379 shares.
• Procedural compliance: Form 4 signed and filed with attorney-in-fact signature dated 09/09/2025, providing required disclosure details.

Negative

• None.

Insights

Financial Analyst

TL;DR: A routine open-market purchase by the CFO; transaction size is disclosed and ownership totals updated.

The Form 4 documents a 5,000-share open-market buy by CFO Jason Vollmer at $16.075 per share on 09/08/2025, increasing his direct beneficial holdings to 344,548.197 shares and confirming 8,394.3379 indirect shares in a 401(k). This is a transparent, standard Section 16 disclosure that updates insider holdings and provides price and quantity details required for market oversight. No options or derivative transactions are reported.

Corporate Governance Expert

TL;DR: Filing is a standard, properly executed insider reporting of an open-market purchase signed by an attorney-in-fact.

The report includes requisite details: reporting person identity, relationship to issuer (CFO), transaction date, transaction code (P), number of shares, price per share, and post-transaction holdings. The signature by an attorney-in-fact and explicit statement that the purchase was open market meet procedural disclosure norms. The filing does not show any compensatory grants, dispositions, or derivative activity.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Vollmer Jason L

(Last) (First) (Middle)

1200 WEST CENTURY AVENUE

(Street)

BISMARCK ND 58503

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
MDU RESOURCES GROUP INC [ MDU ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	CFO

3. Date of Earliest Transaction (Month/Day/Year)
09/08/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	09/08/2025		P(1)		5,000	A	$16.075	344,548.197	D
Common Stock - 401(k)								8,394.3379	I	By Trustee

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Mr. Vollmer purchased these shares in an open market transaction.

	Anthony D. Foti, Attorney-in-Fact for Jason L. Vollmer	09/09/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Jason L. Vollmer (MDU) report on the Form 4?

The Form 4 reports an open-market purchase of 5,000 shares of MDU common stock on 09/08/2025 at a price of $16.075 per share.

How many MDU shares does Jason L. Vollmer beneficially own after the transaction?

Following the reported purchase, Mr. Vollmer directly beneficially owns 344,548.197 shares and indirectly owns 8,394.3379 shares in a 401(k) account.

What transaction code is used on the Form 4 for this purchase?

The transaction is reported with code P, indicating an open-market purchase executed on 09/08/2025.

Was the Form 4 signed by the reporting person?

The Form 4 was signed by Anthony D. Foti, Attorney-in-Fact for Jason L. Vollmer on 09/09/2025.

Does the filing report any derivative or option transactions?

No. Table II for derivative securities shows no entries; only a non-derivative common stock purchase is reported.