The International Organization of Securities Commissions (IOSCO) has published a thematic review assessing how market authorities have implemented IOSCO’s 2013 recommendations on technological challenges to effective market surveillance. The IOSCO Assessment Committee reviewed outcomes across 34 member jurisdictions and found that most authorities have implemented the recommendations and made significant progress, particularly in more complex markets. The review identifies concerns where some regulators still lack the organisational and technical capabilities needed to conduct effective surveillance amid rapid technological developments, and where surveillance capabilities are not subject to regular review. It also notes persistent challenges in markets with multiple trading venues, including difficulties collecting and comparing data across venues, and weaknesses in mapping cross-border surveillance capabilities in an increasingly globalised financial landscape.