HSBC will take legal action to recover £4.3m loaned to Independent Insurance chief executive Michael Bright.
Bright is believed to have taken out the loan late last year.
He used his 6.8% shareholding in the company as security, but these shares are now considered worthless following the company's liquidation and he has repaid only £5,000 of the loan.
HSBC has retained legal firm Eversheds to act for it in the case and confirmed it is asking Bright for £850 a day in interest but would not comment further on the action.
HSBC took a number of blows from Independent's crash: its investment arm was an adviser to the insurer and HSBC Asset Management owned a 4% shareholding in the company.