Bern

Switzerland and the United States have signed a treaty to increase the amount of tax information they share to help crack down on tax evasion, Swiss officials said Wednesday.

The agreement follows a model set out by the Paris-based Organization for Economic Co-operation and Development designed to make it harder for taxpayers to hide money in offshore tax havens.

U.S. tax authorities will be able to request information on Americans suspected of concealing Swiss bank accounts, the Swiss Finance Ministry said.

The treaty forbids so-called 'fishing expeditions,' meaning U.S. authorities have to provide specific details on the person they are seeking further information about and can't simply ask for wholesale lists of Americans with Swiss accounts, the ministry said.

The agreement, which comes into force immediately, won't be retroactive.