Standard Life Aberdeen has taken a 5 per cent stake in OneSavings Bank.
According to a regulatory announcement, funds operated by the group have increased their stake in the company.
The bank listed on the stock exchange in June 2014. Since then its share price has more than doubled from 170p to 398p.
Standard Life Aberdeen is not the only institution to have taken an interest in the challenger bank.
Its largest shareholder is asset management group Old Mutual, which holds a 14 per cent stake in the business.
Also among the largest shareholders are JP Morgan Asset Management, Legal & General Investment Management and Santander Asset Management.