Wealth management group Rathbone Brothers said total assets under management rose 15.6 per cent in nine months to stand at 20.8bn pounds at the end of September. The growth outperformed a 9.6% increase in the FTSE 100 index over the same period.The company reported net operating income in Rathbone Investment Management rose 12.7% to £123.3m after investment management fee income jumped 15.7% to £76.7m. Funds under management at Rathbone Unit Trust Management stood at £1.6bn at the end of September up 23.1% from £1.3bn at the end of 2012. This follows net inflows of £157m year-to-date including £59m from a new mandate from Scottish Life in the third quarter.Shares in Rathbone Brothers were up 2.41% at 14:39 at £15.74.TB