Biography
John Siena, based in London, is Associate General Counsel, Co-Head Global Regulatory Strategy, for Brown Brothers Harriman (BBH). John formerly was Head of Asia Legal at BBH; Head of External and Regulatory Affairs, EMEA, at BNY Mellon; Assistant General Counsel, EMEA, at Brown Brothers Harriman; and Senior Legal Counsel at The Northern Trust Company.
John chairs the Association of Global Custodian-European Focus Committee (AGC-EFC) and in this capacity represents the custody industry to EU, national and global competent authorities and supervisory bodies in connection with all post-trade and related matters. John sits on various European cross-sector steering and working groups focusing on post-trade matters as well as on the European Central Bank’s Advisory Group on Market Infrastructures (AMI-SeCo) and Corporate Events Group (CEG). He is Co-Chair of the Legal/Regulatory Workstream of the UK Accelerated Settlement Taskforce Technical Group, sponsored by HM Treasury and is a member of the American Bar Association’s Business Law Section Task Force on Securities Holding Infrastructure, which is expected to publish its Report in the ABA’s The Business Lawyer in 2024.
Recent focus has been particularly on securities settlement acceleration and other post-trade matters such as the the EU's CSDR settlement discipline regime and custody of assets utilizing digital ledger technology under law and regulation.
John co-wrote the book, Financial Collateral, Oxford University Press (2020), and contributed to The Alternative Investment Fund Managers Directive, Wolters Kluwer, 3rd Ed. (2020), which is planned to be updated in a fourth edition in 2024. John wrote Digital Ledger Technology: Cutting through the Paradox, published in the Journal of Securities Operations and Custody (vol. 15, Spring 2023) and in 2023 co-chaired the development of a Report on digital asset custody (DAC) sponsored jointly by the International Securities Services Association (ISSA) and Global Digital Finance (GDF), which may be found at: https://www.gdf.io/working-group/custody/
John for many years has lectured on financial services law at Leiden University, The Netherlands and King’s College, London, well as in Ireland’s Certified Investment Fund Director Institute.
John is admitted to the Illinois Bar (1988).