IG Group has backed up its bullish trading update last month by confirming that revenues jumped 26% in the first quarter ended 31 August, a like-for-like increase of 30%.The FTSE 250 spread-betting firm said on 22 August that it expected revenues in the three month period to exceed £94m, from £79m in the first quarter of last year. However, the group confirmed on Tuesday that sales actually reached £100m.IG said that growth was driven by heightened levels of market volatility over the summer, with August being a record month for the group in terms of both revenue and client activity. The firm recorded a 20% increase in active clients and 8% higher revenue per client during the quarter."The effect of heightened volatility on revenue per client was less pronounced in the UK and Europe than in Australia and Singapore, due to the seasonal impact of holidays."Australia saw revenues jump 51% to £17m, while Rest of World (Singapore, US and South Africa) recorded a 79% increase to £7.2m. UK revenues rose by 22%.IG said that while the volatility has somewhat tailed off somewhat since August, markets still remain more volatile than September of last year, which is likely to benefit revenues in the second quarter."The group continues to see progressive growth in active client numbers in all of the markets in which it operates, which is the key driver of the long term revenue growth in the business. This growth is in turn underpinned by the on-going significant investment the group makes in its technology platforms and systems."BC