The automatic exchange of information on bank accounts held by non-residents is considered a major breakthrough in the fight against tax evasion. Its multilateral adoption in 2014 obliged tax havens around the world to abolish banking secrecy, providing tax authorities with unprecedented access to data on their taxpayers’ foreign accounts. While analysts usually trace the emergence of this new regime to a credible sanction threat from the United States, they continue to debate the preconditions for this threat, how concessions granted to the United States translated into a multilateral regime, and to what degree targeted jurisdictions retain room for resistance. This chapter reviews these debates, provides a consolidated account of the emergence and current shape of the AEoI regime, and identifies avenues for future research.