AEOI refers to the Automatic Exchange of Information between international tax authorities in an effort to reduce global tax evasion and increase tax transparency. This includes information relating to Financial Accounts, tax rulings, cross-border arrangements, etc.
The Automatic Exchange of Information specifically relating to Financial Accounts held by individuals, corporations, partnerships, trusts, etc. is governed by the FATCA and CRS regimes.
The exchange of information under FATCA and CRS is typically achieved by requiring local country Financial Institutions (as defined) to provide information on in-scope Account Holders to their local country tax authority (however this process can differ across countries). The local country tax authority in turn exchanges information on such Account Holders with the tax authorities in each relevant foreign jurisdiction, provided that the foreign jurisdiction has signed up to the applicable FATCA/CRS regime.