The carry trade, where investors buy high-yielding major currencies and sell low-yielding ones, is having its best run in years.
Citi calculates buying the five G10 currencies with the highest rates and selling the five with the lowest would have returned just over 4% so far this year.
Low currency volatility and large interest rate gaps in developed economies are driving this trend.
Australia and Norway are hiking rates, while Japan and Switzerland keep rates low.
Morgan Stanley expects sterling to be stable against the dollar but face competition from the Australian dollar and Norwegian crown.
