In the 13 weeks to the end of December overall income was 6.3% lower than the 14-week period to the end of December 2010.
But on a like-for-like basis, income was up 0.8%, which the firm said represented a "resilient performance in the current environment".
Commission income for the period was £17.5m, down from £24.9m, a 24.4% drop, while income from financial planning and trail fees was up 26.6% at £9.3m, from £7.9m a year earlier.
Investment management fees had also increased substantially, up at £28.5m from £26.5m in the same period in 2010.
Brewin said subdued market activity in the previous quarter had continued into January 2012, but other income had held up well "benefiting from the scale of the business".
Discretionary funds under management saw a boost of 5.1% to sit at £16.4bn at 31 December, while advisory funds posted a more muted increase of 1.2% to £8.5bn.