Guernsey has agreed to comply with a new EU tax law after being told Gibraltar will have to follow suit.
Gibraltar had threatened to opt out of the European Savings Directive (ESD) which forces overseas account holders to reveal confidential information.
But at a meeting of senior politicians in the Isle of Man, the UK's Paymaster General assured Guernsey that Gibraltar would be forced to sign up.
The ESD agreement came into force earlier this month.
The agreement, between EU members and UK Crown dependencies, allows the exchange of information about customers who earn savings income in one EU Member State, but reside in another.