European private banks are closing their doors to wealthy expatriate Americans to avoid falling foul of new US rules on tax evasion. Last month, four Credit Suisse bankers were charged with helping Americans evade taxes as part of the US Internal Revenue Service’s crackdown. By 2013, all banks outside the US will have to comply with the new act signed by President Barack Obama a year ago. The regulations oblige international financial institutions to reveal all accounts held by U.S. citizens that contain more than $50,000. Banks that do not comply will be subject to a 30% withholding tax on all payments made to them in the US. David Treitel, a tax director at UK and Switzerland-based US Tax & Financial Services, said up to 20% of his 1,000 US clients have had their bank accounts closed since the legislation was announced.