Britain’s biggest building society said the additional tax cost was equivalent to the capital used to fund £10 billion of lending.
Nationwide chief executive Graham Beale said the changes to the existing bank levy and new 8% bank surcharge, which were announced by Chancellor George Osborne in last month’s summer budget, would help international banking groups, but unfairly impact building societies.
“This represents a missed opportunity to support diversity by acknowledging that building societies are different to banks and to recognise the contribution Nationwide and other mutuals make by lending to the UK economy, and the housing market in particular,” he said.
He said the Government should have lowered the rate of the new surcharge for mutuals, or entirely scrapped the bank levy for the building society sector.
His comments came as Nationwide reported a 52% hike in underlying pre-tax profits to £400 million for its first quarter to June 30.
On a bottom line basis, pre-tax profits rose 50% to £379 million.
Nationwide said its net mortgage lending - gross lending, less repayments - surged 23.5% to £2.1 billion in the three months, meaning it accounted for more than a quarter of net lending in the UK.