The BIS Committee on Payments and Market Infrastructures and the International Organization of Securities Commissions have launched a consultation on targeted amendments to their central counterparty resilience guidance and public quantitative disclosure standards to implement earlier policy proposals on initial margin in centrally cleared markets. The proposed updates would embed measures on initial margin transparency and responsiveness into the existing Principles for Financial Market Infrastructures framework and are presented as clarifications on acceptable approaches rather than new standards for CCPs. The amendments would revise the 2017 guidance on the resilience of central counterparties and the 2015 public quantitative disclosure standards for CCPs. They incorporate relevant elements from the January 2025 BCBS-CPMI-IOSCO final report on transparency and responsiveness of initial margin, covering margin simulation tools, methods to measure initial margin responsiveness, governance frameworks for margin models, margin model overrides and expanded public disclosures by CCPs. Proposals on simulation tools, responsiveness measurement, governance and overrides would be implemented through additions to the resilience guidance, while disclosure-specific proposals would be implemented through revisions to the quantitative disclosure standards, including new or more granular reporting on initial margin components, backtesting, variation margin and a standardised margin responsiveness metric. Comments are due by 30 June 2026. CPMI-IOSCO said CCPs would be encouraged to implement the disclosure changes within 12 months after publication of the final report.