The figures showed the network had handled 50% more mortgage completions by the end of May this year than it had over the first five months of last year.
Richard Adams, managing director of Stonebridge Group, said: “As we near the halfway point of the year we are justifiably proud of the strong start we have made to 2013 and hope to continue this level of performance over the coming months.
"The success is partly attributable to the fact we have increased the number of appointed representative firms within the network but also to the fact that the market seems to have turned a corner in terms of borrower demand, lending supply and general confidence."
Adams said initiatives such as Funding for Lending and the Help to Buy scheme are only likely to improve things further.
The most recent monthly statistics available, for May 2013, show that the value of cases is 68% higher than the same month a year ago and the volume of cases is up by 48%.