Notice to the Market - Fitch Rating

Publicly Held Company Corporate Registry (NIRE) 313.000.363-75

CNPJ No. 17.281.106/0001-03

Companhia de Saneamento de Minas Gerais - COPASA MG (B3: CSMG3) hereby informs its shareholders and the public in general that the Agency Fitch Ratings ("Fitch" or "Agency") published, on this date, a report affirming the Company's National Long-Term Rating and the ratings of its 14th, 17th, 20thand 22ndunsecured debenture issuances at 'AAA(bra)', with a stable outlook.

According to Fitch, COPASA MG's rating reflects the expectation that it will maintain its robust credit profile, with expanded margins and stronger operating cash generation to support higher investments and the payment of the grant for the extension of the agreement with the Municipality of Belo Horizonte. The rating also incorporates the solid fundamentals of the basic sanitation sector, with resilient demand and operations based on long-term agreements with most of the served municipalities.

The Company also states that the aforementioned report is available on the electronic systems of the CVM (Brazilian Securities and Exchange Commission) and B3 S.A. - Brasil, Bolsa, Balcão, as well as on the Investor Relations website.

Belo Horizonte, April 2, 2026.

Adriano Rudek de Moura

Chief Financial and Investor Relations Officer