HSBC apologized to customers and investors on Sunday for past practices at its Swiss private bank after allegations that it helped hundreds of wealthy clients dodge taxes.

Europe's largest bank said in full-page advertisements in British newspapers that recent media coverage that focused on the Swiss operation and financial affairs of some of its clients had been a painful experience and that standards in place today "were not universally in place" in the past.

"We therefore offer our sincerest apologies," the advertisment said. It is addressed to customers, shareholders and colleagues and is signed by Chief Executive Stuart Gulliver.