RBS Coutts Bank Ltd., the private banking arm of the Royal Bank of Scotland Group PLC, has lost about 70 people from its Singapore office and a number of them will likely join Swiss private bank BSI AG (Generali), a person familiar with the situation said Tuesday.

"Many of them have offers from BSI," the person said, adding that the mass resignation followed the departure of Raj Sriram, the former head of RBS Coutts' Southeast Asia unit, who joined BSI earlier this year.