The mutual revealed pre-tax losses of £132 million for 2016 as it took a £185m hit after slashing the value of its 20 per cent holding in the Co-operative Bank to zero.
The Co-operative Bank has been put up for sale amid concerns over its balance sheet strength as it continues to suffer following its 2013 rescue after the discovery of a £1.5 billion black hole in its finances, which left it majority controlled by US hedge funds.
Losses at the Co-op Group come against profits of £23m in 2015 and mark the first time it has fallen back into the red for three years, when it was plunged into crisis as the full scale of the woes at the banking business emerged.
It said the move to write off its stake in the Co-op Bank was a “prudent valuation” amid “volatility” caused by the ongoing sale process.
The group had already marked down the value of the shareholding to £140m at its half-year results, from £185m in 2015. But it said the hit would not disrupt its overhaul of the mutual and investment plans.
On an underlying basis, pre-tax profits fell to £59m from £81m in 2015.
Steve Murrells, group chief executive of the Co-op, said: “We’ve made great progress in rebuilding our Co-op, with all our businesses delivering strong performances.
“While much remains to be done, our rebuild plans have really started to deliver value for our customers, our members and their communities.”