The European Securities and Markets Authority (ESMA) has published a report examining Maximal Extractable Value (MEV) and its implications for decentralised finance (DeFi) and broader crypto markets. MEV refers to the value that blockchain participants, such as validators or block proposers, can extract by reordering, inserting or excluding transactions within a block. The report notes that MEV is prevalent on Ethereum and appears to be increasing on other blockchains, although data remain limited. While some MEV practices, such as arbitrage and liquidations, may contribute to market efficiency, others—particularly front-running and sandwich attacks—raise concerns around transparency, fairness and user outcomes. The report also highlights that MEV can increase transaction costs and reduce trust in DeFi protocols.