Challenger bank Secure Trust is weighing up a bid for Royal Bank of Scotland arm Williams & Glyn, according to City AM.
Santander and BBVA are also tipped to bid for Williams & Glyn, which has 300 UK branches.
RBS must sell Williams & Glyn by the end of 2017 under the conditions of its 2008 bailout.
Last year RBS told investors it wanted to sell the subsidiary in the first quarter of next year.
Solihull-based Secure Trust is listed on the Alternative Investment Market and is a subsidiary of the Arbuthnot Banking Group.
Last year the bank made a £16m pre-tax profit in the first half, up 40 per cent year-on-year.
Secure Trust’s income reached £62.2m between January and June, up from £43.8m in the first half of 2014.
Secure Trust Bank is also considering an entry into the UK mortgage market.