Sainsbury's Bank plc is a British bank wholly owned by Sainsbury's. The bank began trading on 19 February 1997 as a joint venture between Sainsbury's and Bank of Scotland. Sainsbury's took full ownership of the bank in January 2014. From Wikipedia
The transfer of 1.8 million accounts and £5.1 billion in assets is underway, with customers advised to monitor account terms and loyalty points.