BSM · Black Stone Minerals, L.P.

The Reporting Person has indicated that Eagle Gathering System Ltd., Lacy Properties Ltd., and R. Lacy Services Ltd. Retirement Plan plan to divest their common-unit positions by year-end 2026 for estate-planning and diversification purposes; the reported sales are part of that divestment plan.

The Reporting Person has indicated that Eagle Gathering System Ltd., Lacy Properties Ltd., and R. Lacy Services Ltd. Retirement Plan plan to divest their common-unit positions by year-end 2026 for estate-planning and diversification purposes; the reported sales are part of that divestment plan.

The units were acquired as part of a liquidating distribution from a family limited partnership over which the Reporting Person exercised no investment or voting control.

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.

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.

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.

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.

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.

The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.54 to $13.695, 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 $13.42 to $13.56, 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 $13.19 to $13.205, 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 $13.49 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.

The price reported in Column 4 is a weighted average price. These common units were sold in multiple transactions at prices ranging from $13.41 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.

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 $13.29 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 sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on December 4, 2025.

The price reported in Column 4 is a weighted average price. These common units were sold in multiple transactions at prices ranging from $13.56 to 14.11, 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.

On April 7, 2026, the reporting person filed a Form 4 that inadvertently omitted the 10b5-1 checkbox and plan adoption date. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 plan adopted by the reporting person on December 4, 2025.

The price reported in Column 4 is a weighted average price. These common units were sold in multiple transactions at prices ranging from $14.31 to 14.64, 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.

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.

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.

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.

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.

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.

On March 6, 2026, the reporting person filed a Form 4 that inadvertently omitted the plan adoption date. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 plan adopted by the reporting person on December 4, 2025.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Represents settlement of performance units awarded under the Issuer's Long-Term Incentive Plan. For tax withholding purposes, the value of the common units was deemed to be equal to the closing price of BSM common units on February 24, 2026.

Common units subject to a restricted unit award issued pursuant to the Black Stone Minerals, L.P. 2025 Long-Term Incentive Plan (the "LTIP"). Except as otherwise provided in the LTIP or the award agreement governing the award, the common units will vest in three equal installments on each of January 7, 2027, January 7, 2028, and January 7, 2029, so long as the Reporting Person remains continuously employed by the Issuer, Black Stone Minerals GP, L.L.C. (the "General Partner"), or any of their respective affiliates through each such vesting date.

Common units subject to a restricted unit award issued pursuant to the Black Stone Minerals, L.P. 2025 Long-Term Incentive Plan (the "LTIP"). Except as otherwise provided in the LTIP or the award agreement governing the award, the common units will vest in three equal installments on each of January 7, 2027, January 7, 2028, and January 7, 2029, so long as the Reporting Person remains continuously employed by the Issuer, Black Stone Minerals GP, L.L.C. (the "General Partner"), or any of their respective affiliates through each such vesting date.

Common units subject to a restricted unit award issued pursuant to the Black Stone Minerals, L.P. 2025 Long-Term Incentive Plan (the "LTIP"). Except as otherwise provided in the LTIP or the award agreement governing the award, the common units will vest in three equal installments on each of January 7, 2027, January 7, 2028, and January 7, 2029, so long as the Reporting Person remains continuously employed by the Issuer, Black Stone Minerals GP, L.L.C. (the "General Partner"), or any of their respective affiliates through each such vesting date.

Common units subject to a restricted unit award issued pursuant to the Black Stone Minerals, L.P. 2025 Long-Term Incentive Plan (the "LTIP"). Except as otherwise provided in the LTIP or the award agreement governing the award, the common units will vest in three equal installments on each of January 7, 2027, January 7, 2028, and January 7, 2029, so long as the Reporting Person remains continuously employed by the Issuer, Black Stone Minerals GP, L.L.C. (the "General Partner"), or any of their respective affiliates through each such vesting date.

Common units subject to a restricted unit award issued pursuant to the Black Stone Minerals, L.P. 2025 Long-Term Incentive Plan (the "LTIP"). Except as otherwise provided in the LTIP or the award agreement governing the award, the common units will vest in three equal installments on each of January 7, 2027, January 7, 2028, and January 7, 2029, so long as the Reporting Person remains continuously employed by the Issuer, Black Stone Minerals GP, L.L.C. (the "General Partner"), or any of their respective affiliates through each such vesting date.

Common units subject to a restricted unit award issued pursuant to the Black Stone Minerals, L.P. 2025 Long-Term Incentive Plan (the "LTIP"). Except as otherwise provided in the LTIP or the award agreement governing the award, the common units will vest in three equal installments on each of January 7, 2027, January 7, 2028, and January 7, 2029, so long as the Reporting Person remains continuously employed by the Issuer, Black Stone Minerals GP, L.L.C. (the "General Partner"), or any of their respective affiliates through each such vesting date.