X0306 4 2019-09-16 1 0001489136 SemGroup Corp SEMG 0001712611 Buffalo Investor II, L.P. C/O ALINDA CAPITAL PARTNERS, 100 WEST PUTNAM AVENUE GREENWICH CT 06830 0 0 1 0 0001712612 Buffalo Investor II GP, LLC C/O ALINDA CAPITAL PARTNERS, 100 WEST PUTNAM AVENUE GREENWICH CT 06830 0 0 1 0 Class A Common Stock 2019-09-16 4 S 0 2821204 16.61 D 4524925 I See Footnotes Class A Common Stock 2019-09-16 4 S 0 2821204 16.61 D 2216567 I See Footnotes These securities are directly held by Buffalo Investor I, L.P. Buffalo Investor I GP LLC is the general partner of Buffalo Investor I, L.P. Alinda GP II, L.P. is the sole member of Buffalo Investor I GP LLC. Alinda GP of GP II LLC is the general partner of Alinda GP II, L.P. Mr. Christopher W. Beale is the managing member of Alinda GP of GP II LLC. These securities are directly held by Buffalo Investor II, L.P. Buffalo Investor II GP LLC is the general partner of Buffalo Investor II, L.P. Alinda Parallel Fund GP II, L.P. is the sole member of Buffalo Investor II GP, LLC. Alinda Parallel Fund GP II, Ltd is the general partner of Alinda Parallel Fund GP II, L.P. Mr. Christopher W. Beale is a director of Alinda Parallel Fund GP II, Ltd. Due to the limitations of the electronic filing system certain Reporting Persons are filing a separate Form 4. Each of the Reporting Persons (other than to the extent it directly holds securities reported herein) disclaims beneficial ownership of the securities held by the other Reporting Persons, except to the extent of such Reporting Person's pecuniary interest therein, and, pursuant to Rule 16a-1(a)(4) under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), each of the Reporting Persons (other than to the extent it directly holds securities reported herein) states that the inclusion of these securities in this report shall not be deemed an admission of beneficial ownership of all of the reported securities for purposes of Section 16 or for any other purpose. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $16.50 to $16.8975, inclusive. The Reporting Persons undertake 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 shares sold at each separate price in the range set forth above. BUFFALO INVESTOR II, L.P., By: BUFFALO INVESTOR II GP, LLC, its general partner, By: /s/ Christopher W. Beale, Name: Christopher W. Beale, Title: President 2019-09-18 BUFFALO INVESTOR II GP, LLC, By: /s/ Christopher W. Beale, Name: Christopher W. Beale, Title: President 2019-09-18