Britain's bellwether mortgage lender, Nationwide Building Society, has reported a 21% fall in profits for the first nine months of the year after ramping up its investment in digital banking.
The lender is investing to make sure its systems can cope with more customers.
It is building up its business banking capabilities and providing better and simpler digital services, the company's chief operating officer Tony Prestedge said.
Nationwide reported statutory profits of £703m for the nine months to December, compared to £886m the same time a year earlier. It booked a £167m charge for technology investment.
"The technology investment programme is around £1.3 billion in magnitude, we are still at the early stages of the cash spend," Nationwide's chief executive Joe Garner said.
Nationwide is the third largest provider of home loans in Britain with a market share of around 13%. It said it expects its retail lending margins to continue to shrink.
The firm's net interest margin - a closely-watched measure of underlying lender profitability - fell to 1.26%, compared to 1.33% a year ago, amid intense competition in the home loans market.
It has decided not to provide updates on its results for the first and third financial quarters in the future, saying such regular reporting is not consistent with its longer-term strategy.
Unlike rival listed banks such as Lloyds and Barclays, the company is not under pressure to deliver ever higher profits as it operates as a society owned by its customers.
Nationwide has said it is comfortable keeping annual profits at between £0.9 billion and £1.3 billion a year.
In the bank's first half results in November, it reported a 17% drop in profits to £516m, which it said was largely down to making a £135m investment in improving its digital banking services.
