The Central Bank of Brazil has opened Public Consultation No. 129/2026 on draft amendments to the regulation annexed to Resolution BCB No. 304/2023, which sets the operating rules for Institutions Operating Financial Market Systems (IOSMF) within the Brazilian Payment System (SPB). The proposal would update the regulatory framework applicable to these operators, including governance and risk requirements relevant to core financial market infrastructures. The draft highlights changes to IOSMF authorisation requirements, corporate governance rules and criteria for appointing administrators. It also strengthens operational risk provisions, covering cybersecurity, contracting of material technology services abroad, business continuity and information technology management, and adds more detailed requirements for interconnection and interoperability between financial market systems. Further detail is proposed on credit and liquidity risk management requirements and on central counterparties’ margin models. The consultation will run for 90 days to collect input from IOSMF, system participants and the public. Accounting standardisation measures, including more detailed calculation of minimum net worth and adoption of the Cosif chart of accounts, are planned to enter into force in 2027.