Payments Canada's latest rule updates streamline operations and global alignment

Interest rate consistency and ISO 20022 lead key changes.

Payments Canada has implemented a comprehensive set of amendments to its Automated Clearing Settlement System (ACSS) and Lynx Rules. These changes, effective as of November 24, 2025, aim to enhance operational efficiency, align with global standards and ensure rules remain consistent across Payments Canada's payment systems.

Changes include: 

• Interest rate calculation (ACSS Rule J10 and Lynx Rule 14): The changes ensure consistency in interest rate calculations between ACSS and Lynx, aligning them with the Bank of Canada's updated monetary policy, where the deposit rate is now lower than the policy rate.
• Decommissioning of Lynx MT format: In alignment with Swift's global mandate for wire payments to transition to the ISO 20022 messaging standard and its final adoption deadline in November 2025, Payments Canada has removed all references to the Swift MT format from the affected rules. Payments Canada, as the manager of ISO 20022 guidelines for Lynx payments in Canada, updated these rules to reflect the end of the Swift MT/MX coexistence period for financial payment messages. The following rules have been updated to reflect this change: ACSS Rules G12, H6, J10; Lynx Rules 1, 2, 3, 6, 8, 9, 10, 11, 12, 14, 16, and TSPs 001, 002, 003, 005.
• Return messaging policy (Lynx Rule 10): A new policy has been implemented to standardize how Canadian financial institutions initiate the return of a Lynx payment message. The amended rule now clarifies that participants are to use the specific ISO 20022 payment return message (pacs.004) to promote standardization.
• ACSS and Lynx rules cleanup: These improvements are largely editorial and operational, focusing on stylistic corrections, capitalizing defined terms and confirming or correcting by-law and rule references to ensure consistency and accuracy. Cleanup efforts are reflected in the following rules ACSS (A3, J7, J10, K4, K5, K6, K8, L1, L2, L3) and Lynx (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 and TSPs 001, 002, 003, 004, 005).

Rules, standards, technical specifications and procedures (TSPs) and by-laws are reviewed and, if necessary, amended through processes that involve Payments Canada members, the Bank of Canada, the Payments Canada Board of Directors, the Department of Finance and the Department of Justice, as required.

Payments Canada’s legal framework is made up of by-laws, rules, standards, technical specifications and procedure documents that support and ensure the safety, soundness, security and operational resilience of our payment systems. By-laws, rules and standards lay out the roles, responsibilities and obligations of our member financial institutions on the appropriate handling of payment items exchanged, cleared and settled via our payment systems.

For full versions of amendments and rules and to learn more about Payments Canada’s rules, by-laws and the amendment or development process, please visit our Rules and documentation webpage.