At 9:30 a.m. today, trading floors across the City of London erupted.

Outbursts of obscenities and confusion followed the Swiss central bank’s surprise decision to abolish its three-year-old policy of capping the Swiss franc against the euro, according to traders in London’s financial district. The U-turn sent the franc as much as 41 percent up against the euro, the biggest gain on record, a move that one trader estimated may cause billions of dollars of losses for banks and their customers.

Dealers at banks including Deutsche Bank AG (DBK), UBS Group AG (UBSG) andGoldman Sachs (GS) Group Inc. battled to process orders amid a flood of customer calls and trade requests, according to people with direct knowledge of the events. At least one electronic currency-trading system temporarily halted transactions, adding to the mayhem.

“This is the biggest currency shocker in years and it’s likely to create more volatility in the short term,” said James Stanton, head of foreign exchange at deVere Group, a financial adviser that oversees about $10 billion. “Trading positions are extremely vulnerable and volume has gone through the roof.”

Deutsche Bank was among currency dealers to suffer disruptions to electronic trading, with its Autobahn platform temporarily ceasing to provide quotes, according to a dealer from outside the bank. The Frankfurt-based lender is among the four biggest dealers in the $5.3 trillion-a-day foreign-exchange market, along with Citigroup Inc.,Barclays Plc (BARC) and UBS, according to Euromoney Institutional Investor.

Spokesmen for Deutsche Bank, Zurich-based UBS and New York-based Goldman Sachs declined to comment. Some of the bankers interviewed for this story asked not to be identified as they weren’t authorized by their firms to speak publicly.

Sitting in front of their screens, dealers around the globe watched the franc hit 1.10 versus the euro, before surging to parity and reaching a record 0.8517 as the SNB dropped its commitment to defend the ceiling introduced in 2011. The Swiss currency jumped as much as 38 percent against the dollar while volatility climbed to the highest in more than a year.

“The move caught everyone off guard,” said David Madden, an analyst at IG Group Holdings Plc (IGG), which takes bets on financial markets under the IG Index name. “The Swiss central bank has sent the markets into a tailspin.”

As the franc spiked, investors said they found themselves unable to trade it amid a lack of price quotes.

“There was a good hour when euro-swiss was untradeable,” said Chris Morrison, London-based head of strategy at Omni Macro Fund, a hedge fund which oversees $550 million. “Clearly there was no liquidity.”

Forex.com, a currency-trading website, said it halted services briefly “until we get confirmation from our liquidity providers that we can get Swissie liquidity.” Dealing resumed at about 10:30 a.m. London time.

Spread-betters were also hit. IG Group said in a statement the SNB’s move will cost the firm as much as 30 million pounds ($46 million).

The turmoil forced top bankers to clear their diaries. At Citigroup Inc. (C), Steven Englander, global head of G-10 foreign-exchange strategy, had all his meetings canceled following today’s decision, according to a person with knowledge of the matter.

With the franc largely frozen against the euro since the SNB introduced the ceiling, the turmoil may have left some investors with losses so large they could even be forced to close, according to a trader at one bank who asked not to be identified.

Anthony Peters, a broker at Swiss Investment Corp., said firms that were selling options tied to the Swiss franc may be among today’s losers. They would have lost money as volatility surged.

“Selling puts or vol on the franc was deemed to be SNB guaranteed money for old rope,” he wrote in a note to clients today. “There will be some very red faces around as it begins to transpire who should not have been playing that game.”