The value of mortgage applications placed through the firm rose to £6.29bn, an increase of 12% on the previous period.
The group will announce its full-year results in January.
The group also announced strong quarter-on-quarter growth in completions, with mortgages in quarter three up seven per cent on quarter two at £1.74bn, life completions up three per cent at £4bn, and GI business up 19% at £290k.
In October, Stonebridge saw its highest monthly mortgage application tally of the year so far and its best ever completion tally.
Life application figures for October 2018 were its best of 2018. Its life completions for the month were also the third highest since the start of the year.
Stonebridge has added 17 advisers to the group during the quarter – its biggest quarterly growth of 2018 – and recruited a further 10 advisers during October which it says bodes well for further growth during quarter four and into 2019.
The network now has 584 active advisers, spread across 279 Appointed Representative (AR) partner firms.
Total life business volumes from both appointed representative (AR) firms also increased, with £13.43m of life application commissions, up five per cent and £10.98m of life completion commissions, up four per cent.
In total, the network’s advisers completed £768k of general insurance during the three quarter, up 17% on 2017.
Jo Carrasco, business partnerships director at Stonebridge Group, said:
“The first three quarters of 2018 have proved a particularly strong nine-month period for the entire group, especially in our core mortgage, life and GI product sectors. It is very satisfying to see significant growth from all our adviser members and this has also been carried forward into October and November which bodes well for a quarter four improvement which will round off a highly positive year for the Group in 2018.”
Carrasco suggested 2019 will bring some ‘major challenges’ including the low level of purchase activity across the UK and the UK leaving the EU.
Carrasco said: “From a Stonebridge perspective, we are preparing with our members for all eventualities and we will be seeking to promote the opportunities we have for them, and to introduce new ones which should help them improve activity and volume.”