Portuguese bank 3.6bn euros loss 'deeply concerning'
1 August 2014 Last updated at 12:16 BST
The share price of Portugal's largest private lender, Banco Espirito Santo, dropped by more than 40% on Thursday after the bank posted a record loss of 3.6 billion for the first half of the year.
The troubled bank said "extraordinary events" had resulted in costs totalling 4.25bn euros during the period.
Bill Blain, chief strategist at Mint Partners, said the bank's loss is "deeply concerning" and could lead to a "reignition" of the sovereign debt crisis seen in Europe from 2010-12.
First broadcast on BBC Radio 4's Today programme on Friday 1 August.