In December 2023, the United States Securities and Exchanges Commission published their Final Rule prescribing mandatory clearing for “eligible secondary market transactions” involving US Treasury Securities. In-scope transactions must be cleared and settled through a central clearing agency. The rule extends to those who are a party to “eligible secondary market transactions” regardless of their jurisdiction. This includes market participants in the UK, the European Union, APAC and other jurisdictions in addition to the US. The purpose of this article is to examine the requirements of the clearing mandate, to review the legal issues and documentation requirements which it raises.