The price is made up of £193m in cash which will be paid when the deal is finalised early next year, as well as £55m of loan stock.
Sainsbury’s plans to pump an extra £100m in capital into the unit.
It is transferring its operating systems from Lloyds’ setup to a new system provided by tech firm FIS.
The focus will be on credit cards, savings, personal loans and travel money, rather than current accounts and mortgages which the group fears would ramp costs up too high.
“The sort of transition Tesco is trying to go through – by building a current account offering is a lot more complex,” said chief finance officer John Rogers. “We are taking a more simple set of products and putting them onto a new platform.”
Former Barclays UK head Roger Davis was appointed non-executive chairman.