PUBLICLY-HELD COMPANY COMPANY REGISTRY (NIRE): 313.000.363-75
CORPORATE TAXPAYER'S ID (CNPJ/MF): 17.281.106/0001-03
Companhia de Saneamento de Minas Gerais - COPASA MG (B3: CSMG3) ("COMPANY" or "COPASA"), in compliance with CVM Resolution 44/2021, and further to the execution of the Agreement Instrument ("Agreement Instrument") entered into between the Company and the Municipality of Belo Horizonte ("MUNICIPALITY"), disclosed in a Material Fact on December 05, 2025, hereby informs its shareholders and the market in general that it formalized an amendment ("Amendment") to the cooperation agreement with the MUNICIPALITY.
The Amendment reflects the terms agreed upon in the Agreement Instrument, the measures for the continuity and universalization of services, and the assurance of economic and financial balance. Accordingly, the amended cooperation agreement shall remain in force until February 07, 2073, in order to promote the affordability of the single tariff and the alignment of contractual terms within the COPASA System.
The Amendment also provides, among other obligations and responsibilities, that the COMPANY shall transfer to the MUNICIPALITY, between 2026 and 2028, the total amount of R$1,300,000,000.00, which shall be incorporated into the Regulatory Remuneration Base, due to its contribution to tariff affordability in the shared provision of public services.
The Amendment maintains the agreement under the regulation of the Minas Gerais State Water and Sewage Regulatory Agency - ARSAE MG and it further establishes the following basic rules of the regulatory model to be observed by the Agency in tariff reviews and adjustments until the expiration of the agreement: (i) adoption of the pre-tax methodology for calculating the Weighted Average Cost of Capital (WACC), which is the rate of return on the Regulatory Asset Base (RAB) to be applied in tariff review proceedings; (ii) application of the Rolling Forward method, with annual updating of the regulatory asset base, considering the preservation of a ring-fenced asset base, whereby the updated asset base amount shall serve as the reference for calculating remuneration and amortization installments, and its effects shall be reflected annually in the tariff; (iii) determination of efficient costs and prudent investments based on COPASA's historical performance, taking into account its technological, operational, territorial and environmental legislation specificities; and (iv) partial sharing with users of COPASA's operational efficiency gains, to be calculated as of the next periodic tariff review, in accordance with the following proportions: 25% for the tariff cycle as of the 4thPeriodic Tariff Review; 50% for the tariff cycle as of the 5thPeriodic Tariff Review; 75% for the tariff cycle as of the 6thPeriodic Tariff Review, and as of the 7thPeriodic Tariff Review onwards, the sharing with users shall correspond to 90% of the operational efficiency gains.
Through the Amendment, the COMPANY and the MUNICIPALITY also undertook to settle, by mutual agreement, the dispute underlying Public Civil Action 5004577-94.2018.8.13.0024, which has already become final and unappealable, through the payment of any reimbursements (the amount of which shall be incorporated into the Regulatory Remuneration Base).
In addition, the concession agreement was executed and shall become effective in the event of the COMPANY'S privatization, pursuant to State Law 25,664/2025. Should the privatization process be completed, the concession agreement shall preserve the regulatory model established in the Amendment, among other enhancements, considering the change in the legal framework resulting from the privatization.
Considering the provisions of State Law 25,668/2025, which addresses the regionalization of sanitation services in the State, the MUNICIPALITY undertook to join the Regional Unit for Potable Water Supply, Sanitary Sewage, Urban Rainwater Drainage and Stormwater Management - URAED 1, subject to the applicable deadlines and other measures required for its establishment.
Lastly, it is clarified that the results of the 3rd Periodic Tariff Review are not affected by the execution of the Amendment.
The Company will keep the market informed of any relevant developments regarding the matter addressed in this Material Fact.
Belo Horizonte, March 26, 2026.
Adriano Rudek de Moura
Chief Financial and Investor Relations Officer