X0306 4 2016-10-19 0 0001679268 Mammoth Energy Services, Inc. TUSK 0000874499 GULFPORT ENERGY CORP 14313 N MAY AVE # 100 OKLAHOMA CITY OK 73134 1 0 1 0 Common Stock 6667 I See footnote Common Stock 2016-10-19 4 S 0 76250 14.0625 D 9080417 D On October 19, 2016, the closing date (the "Closing Date") of the initial public offering of common stock, par value $0.01 per share (the "IPO"), of Mammoth Energy Services, Inc. (the "Issuer"). Gulfport Energy Corporation ("Gulfport"), on behalf of services of Aaron Gaydosik, a director of the Issuer, was granted 6,667 restricted stock units ("RSUs") under the Issuer's 2016 Equity Incentive Plan. 2,223 RSUs vested on the Closing Date of the IPO, and the remaining 4,444 RSUs will vest in two equal annual installments beginning on October 19, 2017. Each RSU represents a contingent right to receive one share of common stock of the Issuer. Mr. Gaydosik reported the acquisition of the RSUs on a Form 4 filed on the date hereof and indicated that these RSUs were assigned to Gulfport under the terms of his employment with Gulfport. These shares of comon stock were sold by Gulfport to the underwriters in the IPO at a price of $14.0625 per share. Of these securities, 9,073,750 shares of common stock were received by Gulfport in connection with Gulfport's contribution of its membership interests in Mammoth Energy Partners LLC to the Issuer, which was completed prior to the IPO and approved by the board of directors of the Issuer in advance. /s/ Aaron Gaydosik, Chief Financial Officer 2016-10-21