Luxembourg and Austria have lifted a longstanding objection to an EU law aimed at curbing banking secrecy.
The directive, blocked by both countries since 2008, requires all EU member states to automatically share information on bank accounts held by their citizens abroad inside the bloc.
Luxembourg and Austria gave the green light after Brussels promised to push Switzerland and four other countries into signing a similar deal soon.
The measures, which will be adopted next Monday and become national law across the EU over the next two years, aim to make it harder for tax cheats to squirrel away funds.
EU Council chief Herman Van Rompuy described the deal as indispensable, claiming banking secrecy was about to die.
Under current rules, EU states do not share data on interest earned from financial products linked to investment funds, pensions or trusts.