[co-author: Nazia Sohail] Summary Diverging approaches to Share Trading Obligations from the FCA and ESMA pose challenges for investment firms in a post-Brexit Europe. With 1 January 2021 creeping closer and the hope of securing an effective Brexit deal seemingly drifting ever further away, there is continued ambiguity when it comes to the future of financial services across Europe. How the Share Trading Obligation (“ STO”) will operate in practice in a post-Brexit world is no exception to this state of uncertainty. The Current STO Under Article 23 of the Markets in Financial Instruments Regulation (“ MiFIR”), EU investment firms are only permitted to trade shares on an EU trading venue (i.e. regulated markets and multilateral trading facilities), an EU systemic internaliser (“