Coventry Building Society’s mortgage lending fell in the first half of 2017 from the corresponding period a year ago.
The society lent £4.4bn on a gross basis and £1.6bn on a net basis, down from £4.8bn and £2bn in the first half of 2016.
Despite the slowdown it increased its share of the UK mortgage market in the first five months of 2017.
Coventry also upped statutory profit by 2% from £110m to £112.4m.
Mark Parsons, chief executive of the society, said: “The mortgage market in the first half of 2017 has been markedly different from 12 months ago, when we saw significant volumes of property purchases in the buy-to-let sector ahead of changes to stamp duty.
“It has, though, continued to see resurgence in remortgages as more homeowners and landlords seek to take advantage of current borrowing rates.
“Our strong product and service offering has allowed us to benefit from this shift, and as a result over the last year we have grown our mortgage balances by 10%.
“In the first five months of 2017 our mortgage balances grew over four times faster than the market growth rate, further increasing our share of the UK market.”