Swiss franc shock strikes IG

That hit partly reflects losses on clients' bad debts, but management also attributes it to losses incurred when IG voluntarily closed customer positions at a time when the liquidity wasn't available. Analysts expect the final loss to be less than £30m, but it will still hit second-half earnings, and could have implications for the final dividend. Management has already said that the full-year payout will be maintained at last year's level if full-year earnings are reduced because of losses on the Swiss franc trade.

Still, analysts think the strong first half and third-quarter trading trends should offset most of the loss. UBS is forecasting full-year adjusted EPS of 38.8p - down just 3 per cent - and 48.6p for 2015-16.

Increased volatility - which is driving more trading activity - helped IG's revenues grow particularly strongly in its more mature markets. They rose over 14 per cent in the UK, for instance, and nearly 7 per cent in Australia. Analysts are consequently bullish about future prospects: Numis Securities reckons "the volatility seen since the end of US quantitative easing is more representative of normal market conditions". IG also boasts a commanding 40 per cent slice of the UK’s spread-betting market, and the launch of a UK stockbroking business last September also offers promise.