Pre-tax losses for the first six months of the year were £204.2m, compared with losses of £77m a year earlier. The figure was slightly better than expected.
It included losses of £38.2m on sales of assets needed to reduce the bank’s overall levels of debt.
The BBC reports that the bank said it was now in better shape to withstand economic stresses.
The Co-op Bank was owned by the Co-operative Group, but in 2013 it contributed £2.1bn of losses of £2.3bn – the largest in the Co-operative Group’s 150 year history.
It then had to be rescued by investors, including US hedge funds, after a £1.5bn black hole was discovered in its accounts. The Co-op now owns just a third of the bank.
The black hole has been linked to losses on commercial property loans, stemming from Co-op Bank’s 2009 merger with the Britannia building society.
A number of top executives then left the bank, including former chairman Paul Flowers who left the bank following a drugs scandal.
At the end of last year, the bank failed a Bank of England stress test, designed to test banks’ ability to withstand another financial crisis.
And last week, a regulatory report criticised the bank for misleading investors. The bank escaped a fine, however, because the regulator said it needed all the money it has to strengthen its balance sheet.
While announcing the 2015 losses, the Co-op’s current chief executive, Niall Booker, said the bank’s work to “improve resilience and reduce costs” was “on course”.