Gilchrist resigned from Marsico Capital Management, sub-adviser of the fund’s strategy, to pursue personal opportunities and to take time out of fund management.
Henderson US Opportunities will be managed by Brandon Geisler, who has been an analyst in the Marsico team since 2006.
The fund fell by 17.6% in the year to 31 Aug, compared with a decline of 5.6% from its benchmark. Over one year, five years and since inception, the fund has underperformed its benchmark, according to Henderson Global Investors.
A spokesperson for Henderson said: "It’s understandable OBSR would want to take time to assess the new fund manager’s ability, that is prudent to do. It’s in much the same way that consultants will often take funds off their watch list if there’s a change of manager because it is an unknown context.
"But Geisler is very competent and we have every faith in him."
OBSR said it will continue to monitor the fund’s progress under the new manager.
