In Q1 the lender reported gross lending of £5.8bn compared to £6.4bn in Q1 2013 and a decline in market share from 15.5% to 11.4% for the same period.
A spokesperson from Nationwide said: “Our historic market share has typically been between 10 and 11% and we have been performing above that for some time, and are still doing so.
“With a number of competitors, who have been less active for some while, but now coming back into the mortgage market we have seen more of a normalisation of our market share but we have continued to report strong lending figures.
“We are really happy with our performance over that period where we have continued to lend to first-time buyers and provide funding for the housing market.”
Net lending fell to £1.7bn compared to £2.6bn in Q1 2013. The average loan-to-value of new residential lending remained the same at 67% while the average loan-to-value of its overall lending book dropped from 48% to 46% LTV year-on-year.
Nationwide accounts for 15% of all new first-time buyer loans.
In June this year the Post Office launched its intermediary range in a bid to increase its market share while the National Counties Building Society launched the Family Building Society one month later aimed at helping families support each other.
TSB started mortgage lending in September last year and has announced plans for mortgage distribution through intermediaries at the beginning of 2015.
Nationwide’s Q1 reporting period runs later than the other big lenders which report Q1 figures for the three months to the end of March.
The lender pointed to seasonal factors which have had an added cooling effect on market share and indicated that Autumn lending figures would give a better reflection of actual market share.