Swiss Franc and Euro banknotes of several values lie on a table in a Swiss bank in BernThe Swiss franc shock reverberated through currency trading firms around the world on Friday, wiping out many small-scale investors and the brokerages that cater to them and forcing regulators to take a closer look at the sector. Some major banks also lost out when the Swiss National Bank lifted its cap on the franc against the euro without warning on Thursday, including Britain’s Barclays which lost “tens of millions” of dollars, an industry source said. Retail broker Alpari UK filed for insolvency on Friday, while New York-listed FXCM Inc, one of the biggest platforms catering to online and retail currency traders, said it may be in breach of some regulatory capital requirements after its clients suffered $225 million of losses. The company is talking to investment bank Jefferies about a possible rescue deal, sources told Reuters on Friday. In the past 15 years, retail currency trading has grown quickly, attracting individuals staking their own money with long trading hours, low transaction costs and the ability to take on huge risks for a relatively small sum. More