William Mathis Increases BSM Stake by 2,378 Units at $13.14

Rhea-AI Filing Summary

Director William N. Mathis reported a non-derivative acquisition of 2,378 common units of Black Stone Minerals, L.P. (BSM) on 10/03/2025 at a price of $13.14 per unit, increasing his direct holdings to 246,200 units. The Form 4 shows multiple indirect holdings tied to family trusts and affiliated entities, the largest being 842,637 units held by WM Capital Partners, L.P., and other indirect holdings ranging from 10,436 to 324,763 units. The filing states the acquisition resulted from electing to receive common units in lieu of a cash board retainer for service as a director.

Positive

• Director elected equity compensation, acquiring 2,378 units at $13.14, aligning interests with limited partners
• Direct beneficial ownership increased to 246,200 units, while larger indirect holdings show sustained family/affiliate exposure (e.g., 842,637 units via WM Capital Partners, L.P.)

Negative

• None.

Insights

Corporate Governance Analyst

Small director equity award shows alignment with limited partner interests.

The reported purchase of $13.14-priced common units reflects an election to take board compensation in equity rather than cash, which increases the director's direct stake to 246,200 units and preserves liquidity for the partnership. This form lists several indirect ownership vehicles, indicating consolidated family and affiliate ownership across trusts and partnerships.

Key dependencies include future unit price movement and distributions; monitor subsequent Forms 4 for additional elections or disposals over the next 12 months to see if this pattern of equity compensation continues or changes.

Insider Transactions Specialist

This is a routine, non-derivative acquisition under a compensation election, not a sale or exercise.

The transaction code and the explanation confirm the units were received in lieu of a cash retainer, a common practice that produces a small, incremental increase in direct beneficial ownership without exercising options or using derivative instruments. The price per unit reported is $13.14, and the Form 4 was signed on 10/07/2025.

Investors tracking insider behavior should note the transaction type and review future filings for any material changes in holdings; absent additional filings, this single equity retainer is not a material shift in control.

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

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

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^*

Mathis William N.

(Last) (First) (Middle)

1001 FANNIN STREET, SUITE 2020

(Street)

HOUSTON TX 77002

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Black Stone Minerals, L.P. [ BSM ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
10/03/2025

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 units representing limited partner interests	10/03/2025		A(1)		2,378	A	$13.14	246,200	D
Common units representing limited partner interests								324,763	I	By Travis A. Mathis Special Trust
Common units representing limited partner interests								842,637	I	By WM Capital Partners, L.P.
Common units representing limited partner interests								295,574	I	By William Mathis 2012 Trust
Common units representing limited partner interests								295,573	I	By Travis Mathis 2012 Trust
Common units representing limited partner interests								10,436	I	By William Mathis 2012 GSTE
Common units representing limited partner interests								10,437	I	By Travis Mathis 2012 GSTE
Common units representing limited partner interests								12,153	I	By W2M Limited
Common units representing limited partner interests								54,690	I	By Willen Partners LP
Common units representing limited partner interests								178,913	I	By Conti Street Partners, L.P.

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. Pursuant to a previous arrangement, the Reporting Person elected to receive common units in lieu of a cash retainer for service on the Board of Directors of the Partnership's General Partner.

Remarks:

	/s/ Steve Putman, attorney-in-fact for William N. Mathis	10/07/2025
	** 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 William N. Mathis report on his Form 4 for BSM?

He reported acquiring 2,378 common units of Black Stone Minerals, L.P. on 10/03/2025 at $13.14 per unit, increasing his direct holdings to 246,200 units.

Why were the units acquired by the director?

The filing states the units were received because the reporting person elected to receive common units in lieu of a cash retainer for board service.

Does the Form 4 show indirect holdings for the reporting person?

Yes. The Form 4 lists multiple indirect holdings through trusts and affiliated entities, including 842,637 units by WM Capital Partners, L.P. and other holdings between 10,436 and 324,763 units.

When was the Form 4 signed and filed?

The Form 4 was signed by an attorney-in-fact on 10/07/2025; the reported transaction date is 10/03/2025.

Is this transaction a derivative or an exercise of options?

No. The Form 4 lists the acquisition as a non-derivative transaction of common units, not a derivative security or option exercise.