"The same pattern -- a sudden surge minutes before 4 p.m. in London on the last trading day of the month, followed by a quick reversal -- occurred 31 percent of the time across 14 currency pairs over two years, according to data compiled by Bloomberg. For the most frequently traded pairs, such as euro-dollar, it happened about half the time, the data show. The recurring spikes take place at the same time financial benchmarks known as the WM/Reuters rates are set based on those trades. Now fund managers and scholars say the patterns look like an attempt by currency dealers to manipulate the rates, distorting the value of trillions of dollars of investments in funds that track global indexes. Bloomberg News reported in June that dealers shared information and used client orders to move the rates to boost trading profit. The U.K. Financial Conduct Authority is reviewing the allegations, a spokesman said. “We see enormous spikes,” said Michael DuCharme, head of foreign exchange at Seattle-based Russell Investments, which traded $420 billion of foreign currency last year for its own funds and institutional investors. “Then, shortly after 4 p.m., it just reverts back to what seems to have been the market rate. It adds to the suspicion that things aren’t right.” Authorities around the world are investigating the abuse of financial benchmarks by large banks that play a central role in setting them."