Published by Jamie JemmesonThe euro returned to four-year lows against the US dollar this morning (May 20th) as traders took profits on yesterday's late rally.In a morning of bearish trading, high-yield currencies such as the Australian and New Zealand dollars and the Brazilian real moved lower while hedge currencies such as the US dollar and the yen climbed.Writing in a note to clients, Matthew Strauss, a senior currency analyst at RBC Capital, said the euro's bounce looks like a "sucker's rally"."Technically, a bounce in the euro was long overdue with daily valuations extremely oversold, net short euro positioning also at extremes and euro 25 delta risk reversals at record levels," he commented.Meanwhile, a trader at a major Japanese bank told Reuters that mutual funds in the country were selling the currency above $1.24 in a bid to repatriate profits for the funds.However, as European markets opened the currency moved marginally higher, having earlier fallen 0.8 per cent, Bloomberg data showed.For more information on foreign exchange treasury services and risk management, visit our Corporate FX site.