Ex-Lloyds executive Graham Allatt and former Close Brothers director Mary McNamara have both joined the bank’s board.
McNamara was formerly the group’s commercial division, and previously worked at GE Capital.
OneSavings Bank is seeking a valuation of up to £600m when it lists on LSE. The initial sale will be at least 30 per cent of its shares.
The lender is owned by private equity firm JC Flowers, which rescued the Kent Reliance Building Society in a recapitalisation deal in 2010.