X0206 3 2019-05-20 0 0001489136 SemGroup Corp SEMG 0001555729 Warburg Pincus (Bermuda) Private Equity GP Ltd. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001728684 WP SemGroup Holdings L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001783661 WP Cayman SemGroup Holdings L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001722343 Warburg Pincus (Europa) Private Equity XII (Cayman), L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001722309 Warburg Pincus (Cayman) XII, L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001722306 Warburg Pincus (Cayman) XII GP LLC C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001658820 Warburg Pincus Partners II (Cayman), L.P. C/O WARBURG PINCUS & CO. 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001239318 KAYE CHARLES R C/O WARBURG PINCUS LLC 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 0001220638 Landy Joseph P. C/O WARBURG PINCUS LLC 450 LEXINGTON AVENUE NEW YORK NY 10017 0 0 1 0 Series A Cumulative Perpetual Convertible Preferred Stock 2019-07-19 Class A Common Stock, $0.01 Par Value 10051574 I See Footnotes This Form 3 is filed on behalf of WP SemGroup Holdings, L.P., a Delaware limited partnership ("WP SemGroup LP"), WP Cayman SemGroup Holdings, L.P., a Delaware limited partnership and general partner of WP SemGroup LP ("WP Cayman SemGroup LP"), Warburg Pincus (Europa) Private Equity XII (Cayman), L.P., a Cayman Islands exempted limited partnership and the general partner of WP Cayman SemGroup LP ("WP Europa PE XII LP"), Warburg Pincus (Cayman) XII, L.P., a Cayman Islands exempted limited partnership and the general partner of WP Europa PE XII LP ("WP Cayman XII LP"), Warburg Pincus (Cayman) XII GP LLC, a Delaware limited liability company and the general partner of WP Cayman XII LP ("WP Cayman XII GP LLC"), Warburg Pincus Partners II (Cayman), L.P., a Cayman Islands exempted limited partnership and sole member of WP Cayman XII GP LLC ("WPP II Cayman LP"), (Continued from footnote 1) Warburg Pincus (Bermuda) Private Equity GP Ltd., a company registered in the Islands of Bermuda and general partner of WPP II Cayman LP ("WP Bermuda PE GP"), Charles R. Kaye and Joseph P. Landy. Messrs. Kaye and Landy are the sole Directors and Co-Chairmen of WP Bermuda PE GP. WP SemGroup LP directly beneficially owns 300,000 shares of Series A Cumulative Perpetual Convertible Preferred Stock, par value $0.01 per share (the "Series A Preferred"), of SemGroup Corporation, a Delaware corporation (the "Company"). By reason of the provisions of Rule 16a-1of the Exchange Act, WP Cayman SemGroup LP, WP Europa PE XII LLP, WP Cayman XII LP, WP Cayman XII GP LLC, WPP II Cayman LP, WP Bermuda PE GP, Mr. Kaye and Mr. Landy may be deemed to be the beneficial owners of an indeterminate portion of the Securities that may be deemed to be beneficially owned by WP SemGroup LP. WP Cayman SemGroup LP, WP Europa PE XII LLP, WP Cayman XII LP, WP Cayman XII GP LLC, WPP II Cayman LP, WP Bermuda PE GP, (Continued from footnote 3) Mr. Kaye and Mr. Landy may be deemed to have an indirect pecuniary interest in an indeterminate portion of the Securities that may be deemed to be beneficially owned by WP SemGroup LP. Each of WP Cayman SemGroup LP, WP Europa PE XII LLP, WP Cayman XII LP, WP Cayman XII GP LLC, WPP II Cayman LP, WP Bermuda PE GP, Mr. Kaye and Mr. Landy disclaim beneficial ownership of all Securities that may be deemed to be beneficially owned by WP SemGroup LP, except to the extent of any indirect pecuniary interest therein. On or after July 19, 2019 (the eighteen month anniversary of the issue date of the Series A Preferred), each share of Series A Preferred is convertible into such number of shares of class A common stock of the Company, par value $0.01 ("Common Stock"), as is equal to the accreted value of such share of Series A Preferred divided by a conversion price, initially $33.00 (subject to adjustment pursuant to the terms of the Series A Certificate of Designations). WARBURG PINCUS (BERMUDA) PRIVATE EQUITY GP LTD. By: /s/ Robert B. Knauss, Name: Robert B. Knauss, Title: Authorised Signatory 2019-07-25