Who Owns the Stack? A Per-Country Quantification of Critical-Component Supplier Concentration behind Gulf AI Data-Centre Build-out

The six Gulf Cooperation Council (GCC) states have announced AI data-centre programmes. A 2026 Abha Foundation review puts them at about 12.8 GW in Saudi Arabia, 8.1 GW in the United Arab Emirates and 1.8 GW in Qatar. Their electricity and water implications have been studied in detail. Who supplies the physical components that this capacity depends on has been discussed mainly in qualitative, geopolitical terms. This paper builds a replicable, per-country indicator of import-supplier concentration for four critical component classes: (A) compute and network equipment, (B) high-voltage power equipment, (C) cooling equipment, and (D) water-treatment machinery used in desalination. Each class is mapped to HS 6-digit codes checked against the official descriptions returned by UN Comtrade. Using reporter-by-partner import data for the six GCC states, we compute Herfindahl–Hirschman indices (HHI) and top-1 and top-3 partner shares. In the 2023 preliminary sample, 5 of 24 reporter–class cells are highly concentrated (HHI > 2,500), and 8 are moderately concentrated. Because several HS codes mix data-centre and non-data-centre goods, the values describe concentration in the trade channel through which components arrive. They are not measures of data-centre procurement as such. They should be read as bounds and indicators, not as ownership shares. We do not re-model power or water demand. Capacity figures are taken as exogenous scenario inputs from published sources.