Joe Garner, chief executive of Nationwide Building Society, said: "We finished the year financially and operationally strong, and well-placed to support our members in future."
Nationwide Building Society has published its financial results, showing that its mortgage balances reached £191bn in the 2021 financial year, up from £188.8bn in 2020.
The society's mortgage balance accounts for 12.5% of market share, down from 12.9% in the previous year.
Gross mortgage lending for the year was valued at £29.6bn, a decrease from £30.9bn in the previous financial year - dropping from 11.4% of market share to 11.1%.
The proportion of residential mortgage accounts on Nationwide's books three months or more in arrears was 0.43%, compared to 0.41%.
The average loan-to-value (LTV) of new lending over the financial year to April 2021 was 70%, down from 72%; meanwhile, the average across the society's books was 56% LTV, down from 58%.
Joe Garner, chief executive of Nationwide Building Society, said: "This year has shown the financial strength of the building society mutual model.
"It has been a tough year, one that tested the resilience of people and businesses.
"Given the profound uncertainties we faced, we focused on the things that were most important in times of crisis: namely to keep our people and members safe and our society strong.
"We entered the crisis in a position of financial strength and, in the face of a highly uncertain environment, we took steps to protect our finances.
"This meant we could stand by our members, colleagues and communities when they needed us most.
"From payment holidays and socially distanced services, to personal assistance for the most vulnerable and remote working for all our office employees, we responded with flexibility and humanity.
"We also continued to help members achieve their financial goals.
"We supported homebuyers by lending responsibly, including at 90% LTV, and more recently at 95% LTV."
He added: "We finished the year financially and operationally strong, and well-placed to support our members in future."
Chris Rhodes, chief financial officer at Nationwide, said: "Our longstanding prudent approach to managing our finances proved its worth in this crisis
year."
He added: "On financial performance, our interest income and margin improved and we also reduced our costs.
"Although arrears remain low today, unsurprisingly, provisions for loans that might not be repaid have remained elevated, in light of the uncertain economic times ahead.
"Our member financial benefit – the extra value we give to members as a mutual – was lower than our £400m target, having significantly exceeded it in recent years.
"In the medium term, we expect member financial benefit to exceed £400m a year again.
"Our profitability recovered, enhancing our financial strength at a time of uncertainty.
"We face the future from a position of strength."
