X0306 4/A 2018-01-17 2018-01-17 0 0001084991 NATURAL GAS SERVICES GROUP INC ngs 0001340731 Hazlett James R 2208 S.C.R. 1084 1/2 MIDLAND TX 79706 0 1 0 0 VP -- Technical Services Common Stock 2018-01-17 4 S 0 1349 29.01 D 45282 D On January 17, 2018, the reporting person filed a Form 4 reporting the sale of 1,688 shares of common stock. The reporting person's broker subsequently acknowledged that 339 of such 1,688 shares were erroneously sold by the broker. The sale of the 339 shares was unwound through the broker's error account and therefore did not occur for purposes of the reporting person's account. This Form 4 amends the foregoing transaction. The remainder of the transactions reported in the January 17, 2018, Form 4 are unchanged and remain as originally reported. James R. Hazlett 2018-01-26