Metro Bank (LSE:MTRO) said it has received a takeover approach from US private equity firm Carlyle Group.
The dog-friendly bank added that it has "engaged" with Carlyle about its possible offer and will make a further announcement "as and when appropriate".
Carlyle has a 'put up or shut up' deadline of 5pm on 2 December, where it must either announce a firm intention to make a takeover offer or walk away.
Shares in Metro Bank (LSE:MTRO) PLC had shot up 40% to 143.09p by just after midday on Thursday, still well off their 200p level at the start of 2020 and £40 high in 2018.
Carlyle, which has more than US$160bn of assets under management from owning over 260 portfolio companies from Addison Lee to McDonald's franchise in China , recently lost out on the acquisition of inhaler maker Vectura to Phillip Morris International.