Black Stone Minerals (BSM) chair adds 67,758 units in three open-market purchases

Filing Impact

(Very High)

Filing Sentiment

(Positive)

Form Type

Rhea-AI Filing Summary

Black Stone Minerals, L.P. Executive Chairman Carter Thomas L Jr reported buying additional common units representing limited partner interests in three open-market purchases. He acquired 23,604 units on May 8 at a weighted average price of $13.3186, 25,000 units on May 11 at $13.4742, and 19,154 units on May 12 at $13.4754 per unit. After these transactions, he directly owns 3,681,604 common units, indicating a net increase in his personal stake.

Insights

Executive Chairman makes routine open-market net purchases, modestly increasing his direct stake.

The Executive Chairman of Black Stone Minerals, L.P., Carter Thomas L Jr, completed three open-market purchases totaling 67,758 common units at weighted average prices between $13.3186 and $13.4754. These are straightforward buy transactions, not option exercises or tax-related movements.

Following the purchases, he directly holds 3,681,604 common units. The added units are a small portion of his disclosed holdings, which suggests a routine increase rather than a transformative position change. No Rule 10b5-1 trading plan or indirect ownership structures are referenced in the excerpt.

Because there are no derivative positions listed in the derivative summary and all trades are simple open-market buys, the filing mainly updates the market on incremental alignment between the Executive Chairman and other unitholders, without signaling a major shift in control or capital structure.

Insider Trade Summary

Net Buyer: 67,758 shares ($909,335)

Net Buy 3 txns

Insider Carter Thomas L Jr

Role Executive Chairman

Bought 67,758 shs ($909K)

Type	Security	Shares	Price	Value
Purchase	Common units representing limited partner interests	19,154	$13.4754	$258K
Purchase	Common units representing limited partner interests	25,000	$13.4742	$337K
Purchase	Common units representing limited partner interests	23,604	$13.3186	$314K

Holdings After Transaction: Common units representing limited partner interests — 3,681,604 shares (Direct, null)

Footnotes (1)

The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.29 to $13.34, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of common units purchased at each separate price within the ranges set forth in this footnote. The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.44 to 13.48, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of common units sold at each separate price within the ranges set forth in this footnote. The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.42 to $13.50, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of common units purchased at each separate price within the ranges set forth in this footnote.

Key Figures

Units bought May 8: 23,604 units at $13.3186 Units bought May 11: 25,000 units at $13.4742 Units bought May 12: 19,154 units at $13.4754 +2 more

5 metrics

Units bought May 8 23,604 units at $13.3186 Open-market purchase of common units on May 8, 2026

Units bought May 11 25,000 units at $13.4742 Open-market purchase of common units on May 11, 2026

Units bought May 12 19,154 units at $13.4754 Open-market purchase of common units on May 12, 2026

Total net units bought 67,758 units Sum of three reported open-market purchases

Units owned after transactions 3,681,604 units Direct common units beneficially owned after May 12, 2026

Key Terms

open-market purchase, weighted average price, common units representing limited partner interests, beneficially owned

4 terms

open-market purchase financial

"transaction_action: open-market purchase"

An open-market purchase is when an investor or a company buys shares on a public stock exchange at the going market price, rather than through a private deal. It matters to investors because these purchases change how many shares are available, can push the stock price up or signal confidence from large buyers, and often affect per-share metrics like earnings—think of it like someone buying lots of apples off a grocery shelf, reducing supply and potentially raising the price.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

common units representing limited partner interests financial

"security_title: Common units representing limited partner interests"

beneficially owned financial

"number of units beneficially owned following the last transaction"

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.

Form 4 Insider Transactions: What Each Field Means →

05/12/2026 - 05:02 PM

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^*

Carter Thomas L Jr

(Last)

(First)

(Middle)

1001 FANNIN STREET, SUITE 2020

(Street)

HOUSTON

TEXAS

77002

(City)

(State)

(Zip)

UNITED STATES

(Country)

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
X	Officer (give title below)	Other (specify below)
	Executive Chairman

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/08/2026

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

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

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

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)
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	Code	V	Amount	(A) or (D)	Price		6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
Common units representing limited partner interests	05/08/2026		P		23,604	A	$13.3186⁽¹⁾	3,637,450	D
Common units representing limited partner interests	05/11/2026		P		25,000	A	$13.4742⁽²⁾	3,662,450	D
Common units representing limited partner interests	05/12/2026		P		19,154	A	$13.4754⁽³⁾	3,681,604	D

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)
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)	Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	8. Price of Derivative Security (Instr. 5)		10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)

Explanation of Responses:

1. The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.29 to $13.34, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of common units purchased at each separate price within the ranges set forth in this footnote.

2. The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.44 to 13.48, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of common units sold at each separate price within the ranges set forth in this footnote.

3. The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.42 to $13.50, inclusive. The reporting person undertakes to provide to the issuer, any security holder of the issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of common units purchased at each separate price within the ranges set forth in this footnote.

Remarks:

	/s/ Steve Putman, attorney-in-fact for Thomas L. Carter, Jr.	05/12/2026
	** 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.
* Form 4: SEC 1474 (03-26)

Source: View Original Filing on SEC EDGAR

FAQ

What did Black Stone Minerals (BSM) Executive Chairman buy in this Form 4?

The Executive Chairman bought common units representing limited partner interests. He made three open-market purchases totaling 67,758 units at weighted average prices between $13.3186 and $13.4754, increasing his direct ownership position in Black Stone Minerals, L.P.

Over what dates did Carter Thomas L Jr purchase BSM units?

He purchased units on May 8, May 11, and May 12. Each date reflects a separate open-market transaction, with 23,604, 25,000, and 19,154 common units acquired, respectively, at different weighted average prices disclosed in the Form 4.

What is Carter Thomas L Jr’s total BSM ownership after these transactions?

After the reported purchases, he directly owns 3,681,604 common units. This total is shown in the Form 4 as the number of units beneficially owned following the last transaction, updating investors on his current direct equity stake.

Were the BSM insider transactions open-market buys or option exercises?

All three insider transactions were open-market purchases of common units. The Form 4 identifies each with transaction code P and describes them as open-market purchases, with no derivative exercises or option-related activity shown in the derivative summary.

What price ranges did the BSM insider pay for the purchased units?

Weighted average prices were $13.3186, $13.4742, and $13.4754 per unit. Footnotes explain these averages reflect multiple trades in ranges, including $13.29–$13.34, $13.44–$13.48, and $13.42–$13.50, and detailed breakdowns are available upon request.