The UK’s biggest spread-betting firm, IG Group, said yesterday that it would “learn lessons” from last week’s stunning reversal by the Swiss National Bank (SNB), which cost it £30m.

IG is nursing £18m in client losses from the SNB’s shock scrapping of the franc’s cap against the euro, as well as £12m in market exposure. IG honoured the loss limits of clients but was unable to close its hedging positions on bets because of the extreme volatility, which saw the euro tumble 30 per cent against the “Swissie” at one stage.

The company intends to maintain the dividend at last year’s level. “Although this was because of an unprecedented and unforeseeable degree of movement in a major global currency, and only a few hundred clients were affected, we will seek to learn lessons from this incident which we can incorporate into our risk-management approach,” the company said.

The Swiss blow took the gloss off strong results from the company, which has seen 1,700 clients sign up to a new stockbroking account. IG generated its highest monthly revenue in October, when global markets sank on growth fears, helping half-year profits up 2.8 per cent to £101.4m.

Another victim of the SNB’s currency earthquake, the US broker FXCM, also revealed the punishing terms of a $300m (£198m) rescue loan from investment firm Leucadia National, owner of a wide range of companies that includes broker Jefferies.

FXCM will pay an eye-watering 10 per cent annual interest on the loan, with the rate increasing by 1.5 per cent a quarter up to a maximum of 17 per cent, to encourage a sale of the business within three years. Leucadia will get half the proceeds on a sale of FXCM after the loan is repaid, although it will claim an even bigger share on a sale above $500m.

Danish investment bank and broker Saxo said it would incur losses from the SNB move but that its capital position was not in peril. The firm gave its clients less leverage to bet on the currency last year, reducing its exposure.