Royal Bank of Scotland is understood to have appointed its finance director, Bruce van Saun, to head its US arm, Citizens, ahead of its planned float.
The state-backed bank is thought to have lined up Nathan Bostock, Abbey National's former finance director, to replace Mr van Saun.
The changes are expected to be announced in the next few weeks, although the move is unlikely to happen until much later this year, while the plan could still be changed.
RBS declined to comment on reports of the proposed changes.
Mr Bostock is head of risk and restructuring at RBS, a position he has held since joining from Abbey National in June 2009.
Mr van Saun is an American who has been RBS's finance director since 2009, a role which has seen him leading the move to improve the bank's struggling balance sheet.
RBS was bailed out with £45bn of taxpayers' money in 2008. Having posted losses for much of the past four years, analysts say the bank is back on track.