Reserve Fund has doubled in size from a year ago, with more than $200 million in assets under management.

"The current slowing US economic environment with declining official short-term interest rates is positive for all Butterfield bond funds,'' said fund manager David Ware, because the fixed coupon securities in which it invests increase in price and securities offer smaller spreads.

At least $10,000 is required to invest in the fund, and the maximum average duration is 12 months.

It has returned on average 7.61 percent for one year, 5.93 percent for two years and 5.8 percent for three years.

The Liquid Reserve Fund is a short-term fund. It has received an AAf credit quality rating and an S1 volatility rating from Standard & Poor's, reflecting strong returns with a high level of safety, according to the bank.