EXHIBIT 8.1
Principal subsidiaries

The following is a list of Ternium’s subsidiaries at December 31, 2025.
CompanyCountry of OrganizationMain activityPercentage of ownership at December 31,
202520242023
Ternium S.A.LuxembourgHolding100.00 %100.00 %100.00 %
Ternium Investments S.à.r.l.LuxembourgHolding, financial services and agency trading activities100.00 %100.00 %100.00 %
Ternium Internacional España S.L. (1)SpainHolding and marketing of steel products100.00 %100.00 %100.00 %
Ternium Solutions S.A. (1)UruguayOther services100.00 %100.00 %100.00 %
Ternium Internationaal B.V. (1)NetherlandsMarketing of steel products100.00 %100.00 %100.00 %
Ternium USA Inc. (2) USAManufacturing and selling of steel products100.00 %100.00 %100.00 %
Ternium Argentina S.A. (3)ArgentinaManufacturing and selling of flat steel products 62.57 %62.57 %62.57 %
Prosid Investments S.A. (4)UruguayHolding62.58 %62.58 %62.58 %
Ternium Mexico S.A. de C.V. (5)MexicoManufacturing and selling of steel products89.25 %89.25 %89.25 %
Las Encinas S.A. de C.V. (6)MexicoExploration, exploitation and pelletizing of iron ore89.25 %89.25 %89.25 %
Ferropak Comercial S.A. de C.V. (6)MexicoScrap services company89.25 %89.25 %89.25 %
Transamerica E. & I. Trading Corp. (6)USAScrap services company89.25 %89.25 %89.25 %
Galvacer Chile S.A. (6)ChileDistributing company89.25 %89.25 %89.25 %
Ternium Gas México S.A. de C.V. (7)MexicoEnergy services company89.25 %89.25 %89.25 %
Consorcio Minero Benito Juarez Peña Colorada S.A.de C.V. (8)MexicoExploration, exploitation and pelletizing of iron ore44.62 %44.62 %44.62 %
Exiros B.V. (8)NetherlandsProcurement and trading services50.00 %50.00 %50.00 %
Servicios Integrales Nova de Monterrey S.A. de C.V. (9)MexicoMedical and Social Services66.49 %66.49 %66.49 %
Ternium Internacional Nicaragua S.A. NicaraguaManufacturing and selling of steel products99.38 %99.38 %99.38 %
Ternium Internacional Honduras S.A. de C.V. HondurasManufacturing and selling of steel products99.18 %99.18 %99.18 %
Ternium Internacional El Salvador S.A. de C.V.El SalvadorManufacturing and selling of steel products99.92 %99.92 %99.92 %
Ternium Internacional Costa Rica S.A. Costa RicaManufacturing and selling of steel products99.98 %99.98 %99.98 %
Ternium Internacional Guatemala S.A. (10)GuatemalaManufacturing and selling of steel products99.98 %99.98 %99.98 %
Ternium Colombia S.A.S. (11)ColombiaManufacturing and selling of steel products100.00 %100.00 %100.00 %
Ternium del Atlántico S.A.S (11)ColombiaManufacturing and selling of steel products100.00 %100.00 %100.00 %
Ternium Procurement S.A. (11)UruguayMarketing of steel products and procurement services100.00 %100.00 %100.00 %
Technology & Engineering Services S.A. (11)UruguayEngineering and other services100.00 %100.00 %100.00 %
Ternium Brasil Ltda. (12)BrazilManufacturing and selling of steel products100.00 %100.00 %100.00 %
Tenigal S. de R.L. de C.V. (13)MexicoManufacturing and selling of steel products51.00 %51.00 %51.00 %
Soluciones Integrales de Gestión S.A. (14)ArgentinaOther services100.00 %100.00 %100.00 %
Usinas Siderúrgicas de Minas Gerais S.A. (15)BrazilManufacturing and selling of steel products23.30 %23.30 %23.30 %
Mineração Usiminas S.A. (16)BrazilExploration, exploitation and pelletizing of iron ore16.31 %16.31 %16.31 %
Soluções Em Aço Usiminas S.A. (17)BrazilManufacturing and selling of steel products16.05 %16.05 %16.05 %
Usiminas Mecânica S.A. (18)BrazilEngineering and other services23.30 %23.30 %23.30 %
Usiminas International S.À R.L. (19)LuxembourgHolding23.30 %23.30 %23.30 %
Usiminas Participações E Logística S.A. (20)BrazilLogistics and distribution of steel-derived products17.48 %17.48 %17.48 %
Metalcentro Ltda. (21)BrazilOther services23.30 %23.30 %23.30 %
Vientos de Olavarría S.A. (22)ArgentinaRenewable energy projects.062.57 %62.57 %
Ternium del Cauca S.A.S. (23)ColombiaManufacturing and selling of steel products0100.00 %100.00 %
Rios Unidos logistica e transporte de açõ Ltda. (24)BrazilLogistics and distribution of steel-derived products0023.30 %
(1) Indirectly through Ternium Investments S.à.r.l. Total voting rights held: 100.00%.
(2) Indirectly through Ternium Internacional España S.L. Total voting rights held 100.00%.
(3) Indirectly through Ternium Internacional España S.L. Total voting rights held 62.57%.
(4) Indirectly through Ternium Argentina S.A. and Ternium Procurement S.A. Total voting rights held 100.00%.
(5) Indirectly through Ternium Argentina S.A. and Ternium Internacional España S.L. Total voting rights held 100.00%.



(6) Indirectly through Ternium Mexico S.A. de C.V. Total voting rights held: 100.00%.
(7) Indirectly through Ternium Mexico S.A. de C.V. and Tenigal S. de R.L. de C.V. Total voting rights held: 100.00%.
(8) Total voting rights held: 50.00%. The Company recognizes the assets, liabilities, revenue and expenses in relation to its interest in the joint operation.
(9) Indirectly through Ternium Mexico S.A. de C.V. Total voting rights held: 74.50%.
(10) Indirectly through Ternium Internacional España S.L. and Ternium Mexico S.A. de C.V. Total voting rights held: 100.00%.
(11) Indirectly through Ternium Internacional España S.L. Total voting rights held: 100.00%.
(12) Indirectly through Ternium Internacional España S.L. Total voting rights held: 100.00%.
(13) Indirectly through Ternium Internacional España S.L. Total voting rights held: 51.00%.
(14) Indirectly through Ternium Investments S.à r.l. and Ternium Internacional España S.L. Total voting rights held 100.00%.
(15) Indirectly through Ternium Investments S.à r.l., Prosid Investments S.A. and Ternium Argentina S.A. Total voting rights held 42.57%.
(16) Indirectly through Usinas Siderúrgicas de Minas Gerais S.A. Total voting rights held 29.80%.
(17) Indirectly through Usinas Siderúrgicas de Minas Gerais S.A. Total voting rights held 29.32%.
(18) Indirectly through Usinas Siderúrgicas de Minas Gerais S.A. Total voting rights held 42.57%.
(19) Indirectly through Usinas Siderúrgicas de Minas Gerais S.A. Total voting rights held 42.57%.
(20) Indirectly through Usinas Siderúrgicas de Minas Gerais S.A. and Mineração Usiminas S.A. Total voting rights held 36.20%.
(21) Indirectly through Usinas Siderúrgicas de Minas Gerais S.A. and Usiminas Mecânica S.A. Total voting rights held 42.57%.
(22) This company was merged into Ternium Argentina S.A effective as of January 1, 2025.
(23) This company was dissolved as of June 4, 2025.
(24) This company was merged into Usinas Siderúrgicas de Minas Gerais S.A. as of April 25, 2024.