The shock occurred after the Swiss central bank declared that it would stop pegging the franc against the euro, causing the currency to temporarily gain 30 percent against other currencies while the euro plunged against the franc and the dollar, according to Australian ABC News. The losses came due to many brokerage clients betting against the franc, and then losing those positions after the currency' surge.
The head of the US currency brokerage FXCM told Bloomberg that, offering traders leverage is necessary because of generally low volatility in the currency markets.
Yet another broker, Alpari UK, part f the global Alpari group of companies, declared itself insolvent as a result of the franc surge, as its capital was declared insufficient for regulatory requirements according to the London Evening Standard.