X0306 4 2019-02-18 0 0001587732 ONE Gas, Inc. OGS 0001595607 McCormick Joseph L 15 E. 5TH STREET TULSA OK 74103 0 1 0 0 See Remarks Common stock, par value $0.01 2019-02-18 4 M 0 8857 83.94 A 56057 D Common stock, par value $0.01 2019-02-18 4 F 0 3922 83.94 D 52135 D Common stock, par value $0.01 2019-02-18 4 M 0 1100 83.94 A 53235 D Common stock, par value $0.01 2019-02-18 4 F 0 544 83.94 D 52691 D Common stock, par value $0.01 2959 I by 401(k) Plan Performance Units 2016 2019-02-18 4 M 0 4125 83.94 D Common stock, par value $0.01 4125 0 D Restricted Units 2016 2019-02-18 4 M 0 1025 83.94 D Common stock, par value $0.01 1025 0 D Performance Units 2019 2019-02-18 4 A 0 4051 83.94 A Common stock, par value $0.01 4051 4051 D Restricted Units 2019 2019-02-18 4 A 0 1013 83.94 A Common stock, par value $0.01 1013 1013 D Performance units awarded under Issuer's Equity Compensation Plan. The award vested on February 18, 2019, and was certified by the Executive Compensation Committee of the Board of Directors on February 18, 2019. The award vested in an amount equal to 200% of the performance units awarded based upon Issuer's total shareholder return compared to total shareholder return of a selected peer group plus accrued dividends of 607 shares. The award was payable one share of Issuer's common stock for each vested performance unit and accrued dividends. Restricted units awarded under Issuer's Equity Compensation Plan. The award vested on February 18, 2019. The award was payable one share of Issuer's common stock for each vested restricted unit and accrued dividends of 75 shares. Performance units awarded under the Issuer's Amended and Restated Equity Compensation Plan (2018). The award will vest on February 19, 2022, for a percentage (0% to 200%) of the performance units awarded based upon the Issuer's total shareholder return compared to total stockholder return of a selected peer group. During the 3-year vesting period, the award will be credited with dividend equivalents that will be paid out in shares of common stock at the time the underlying units vest and shares are issued. The award and credited dividend equivalents will be payable one share of the Issuer's common stock for each vested performance unit and dividend equivalent. Restricted units awarded under the Issuer's Amended and Restated Equity Compensation Plan (2018). The award vests on February 19, 2022. During the 3-year vesting period, the award will be credited with dividend equivalents that will be paid out in shares of common stock at the time the underlying units vest and are issued. The award and credited dividend equivalents will be payable one share of the Issuer's common stock for each vested restricted unit and dividend equivalent. Senior Vice President, General Counsel and Assistant Secretary /s/ Brian K. Shore, Attorney-in-Fact for Joseph L. McCormick 2019-02-20