Effective January 29, 2018, and pursuant to a stockholders agreement by and among ProPetro Holding Corp. and Energy Capital Partners II, LP, Energy Capital Partners II-A, LP, Energy Capital Partners II-B, LP, Energy Capital Partners II-C (Direct IP), LP, Energy Capital Partners II-D, LP and Energy Capital Partners II (Midland Co-Invest), LP, Matt Himler resigned as a director of ProPetro Holding Corp. In connection with the resignation of Mr. Himler, Anthony Best was appointed as a director by ProPetro Holding Corp.’s Board of Directors on January 29, 2018. In connection with his appointment, Mr. Best was also named to the Audit Committee and the Compensation Committee of the Board of Directors. Mr. Best, 68, has over thirty-five years of experience in the energy industry, and has served as a Senior Advisor for Quantum Energy Partners since August 2015.