X0508 4 2026-03-11 0000749251 GARTNER INC IT 0001185567 GRABE WILLIAM O 56 TOP GALLANT RD P.O. BOX 10212 STAMFORD CT 06904-2212 1 0 Common Stock 2026-03-11 4 J 0 2100 160.01 D 47900 I 2025 GRAT Common Stock 2026-03-11 4 J 0 2100 160.01 A 2214 D Common Stock 2026-03-11 4 G 0 235 0 D 1979 D Common Stock 2026-03-11 4 G 0 235 0 A 235 I Family Trust 1 Common Stock 2026-03-11 4 G 0 235 0 D 1744 D Common Stock 2026-03-11 4 G 0 235 0 A 235 I Family Trust 2 Common Stock 2026-03-11 4 G 0 1410 0 D 334 D Common Stock 2026-03-11 4 G 0 1410 0 A 1410 I Family Trust 3 Pursuant to a power of substitution, the reporting person, who is the trustee of the 2025 GRAT (see footnote 2 below for more information about the 2025 GRAT), transferred the shares from the 2025 GRAT to himself in exchange for a contribution of $336,021 by the reporting person to the 2025 GRAT. The transfer resulted in a decrease in the number of shares the reporting person beneficially owns indirectly through the 2025 GRAT and a corresponding increase in the number of shares the reporting person beneficially owns directly. The reporting person believes that this transfer of shares from the 2025 GRAT constitutes a change in form of beneficial ownership of the shares, exempted by Rule 16a-13 under the Securities Exchange Act of 1934. These shares are held in a grantor retained annuity trust created on August 22, 2025 when the reporting person transferred 50,000 Gartner shares to the trust (the "2025 GRAT"). These shares are held in trust for the benefit of the reporting person and his children. The reporting person is the Trustee of the 2025 GRAT. The reporting person transferred the shares to a family trust, Family Trust 1 ("Family Trust 1"). The reporting person disclaims beneficial ownership of the shares held by Family Trust 1 except to the extent, if any, of his pecuniary interest therein. The reporting person transferred the shares to a family trust, Family Trust 2 ("Family Trust 2"). The reporting person disclaims beneficial ownership of the shares held by Family Trust 2 except to the extent, if any, of his pecuniary interest therein. The reporting person transferred the shares to a family trust, Family Trust 3 ("Family Trust 3"). The reporting person disclaims beneficial ownership of the shares held by Family Trust 3 except to the extent, if any, of his pecuniary interest therein. /s/ Kevin Tang for William O. Grabe 2026-03-13