Mutuals took a 22% market share of gross lending in September, up from 17% in September 2011, and took a 21% share of lending in the first nine months of the year.
Net mortgage lending by mutuals was £0.5bn in September, and £4.9bn in the first nine months of the year.
However retail savings balances at mutuals fell by £0.2bn in September 2012, compared to an increase of £0.6bn in the same month last year. In the third quarter savings balances held with mutuals increased by £2.2bn, compared to a £1.6bn increase in the third quarter of 2011.
Adrian Coles, director-general of the Building Societies Association, said: "The funds from the Bank of England's Funding for Lending Scheme will take some time to be drawn and flow through into the mortgage market.
“As the scheme is favourable to institutions which are looking to increase their lending, it will clearly appeal to many mutual lenders.
"Savings balances at mutuals fell slightly in September, which follows two consecutive months of particularly strong inflows into deposit accounts.
“Conditions in the labour market appear to be improving and consumer price inflation has reduced over recent months.
“Both these factors should reduce the pressure on household finances and help households to save more in coming months."
