Siddles joined Jupiter from F&C in January having run its £101m US small companies fund for 10 years.
A spokesperson said the launch is subject to FCA approval but no issues in gaining the approval are thought likely.
She added that adding the new open-ended fund alongside Siddle’s existing US equity fund is a natural next step following his move over from F&C. The new fund will follow the same investment strategy.
Siddle’s existing fund invests in companies of between $100m and $5bn and is benchmarked against the Russell 2000 index.
