X0306 4 2015-08-21 0001621434 Black Stone Minerals, L.P. BSM 0001639921 Stuart Alexander D. 1001 FANNIN STREET, SUITE 2020 HOUSTON TX 77002 true false false false Common units representing limited partner interests 2015-08-21 4 P false 50 13.99 A 288198 D Common units representing limited partner interests 2015-08-24 4 P false 6950 13.7145 A 295148 D Common units representing limited partner interests 2072350 I By North Star Oil & Gas Common units representing limited partner interests 914682 I By Topsfield Energy, Ltd. Common units representing limited partner interests 541885 I By RDS Investments, L.P. Common units representing limited partner interests 78265 I By R D Stuart Jr 1996 Trust The price reported in Column 4 is a weighted average price. These common units were purchased in multiple transactions at prices ranging from $13.688 to $13.777, 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. /s/Steve Putman, Attorney-in-Fact for Alexander D.Stuart 2015-08-25