When the European Central Bank, the Federal Reserve, and the Bank of Japan all announced big stimulus measures earlier this month, investors went on a buying spree. They're still buying - but they're steering clear of the biggest, most liquid currencies, known as the G4. "The USD is the second worst performer among majors and ZAR, NOK, RUB, TRL, NZD, SEK and MXN are the top seven performers," wrote Steven Englander, global head of G10 FX strategy at Citigroup, in a note to clients. "The bottom five are CAD, USD, EUR, GBP, JPY. This is less risk-off than G4 off."