X0306 4 2021-11-08 0000749251 GARTNER INC IT 0001198849 HALL EUGENE A 56 TOP GALLANT ROAD P.O. BOX 10212 STAMFORD CT 06904-2212 1 1 CEO Common Stock 2021-11-08 4 M 0 81987 114.26 A 1229503 D Common Stock 2021-11-08 4 D 0 28061 333.85 D 1201442 D Common Stock 2021-11-08 4 F 0 24989 333.85 D 1176453 D Common Stock 2021-11-09 4 S 0 8740 339.08 D 1167713 D Common Stock 2021-11-09 4 S 0 4335 337.83 D 1163378 D Common Stock 2021-11-09 4 S 0 5138 337.07 D 1158240 D Common Stock 2021-11-09 4 S 0 5324 335.56 D 1152916 D Common Stock 2021-11-09 4 S 0 4600 334.89 D 1148316 D Common Stock 2021-11-09 4 S 0 800 334.18 D 1147516 D Stock Appreciation Rights 114.26 2021-11-08 4 M 0 81987 0 D 2019-02-08 2025-02-08 Common Stock 81987 27329 D Represents shares acquired upon exercise of SARs. Represents shares withheld that had an aggregate value, based on the market price on the date of exercise, substantially equal to the aggregate exercise price of the SARs. Represents shares withheld from the settlement of the SARs for the payment of applicable income and payroll tax withholding due upon exercise. This transaction was executed in multiple trades at prices ranging from $338.51 to $339.49. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $337.48 to $338.46. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $336.47 to $337.46. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $335.32 to $336.31. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $334.36 to $335.31. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. This transaction was executed in multiple trades at prices ranging from $333.91 to $334.29. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected. These SARs were part of an award that becomes exercisable in four substantially equal annual installments, commencing on February 8, 2019. /s/ Kevin Tang for Eugene A. Hall 2021-11-10