A German newspaper has reported that authorities have purchased confidential data on suspected tax evaders who were clients of British private bank Coutts' Swiss unit.
The Financial Times Deutschland reports that officials in the western state of North Rhine-Westphalia paid £2.75 million for a CD containing the names of some 1,000 rich German clients.
Coutts, which has served as banker to the British royal family since the 18th century, said it had no evidence that client confidentiality had been breached.
Tax authorities in North Rhine-Westphalia couldn't immediately be reached.
Germany has irked Switzerland by repeatedly buying stolen bank data in its pursuit of suspected German tax evaders.
A deal between the two countries to end the tax spat is being blocked by opposition-controlled German states such as North Rhine-Westphalia.