Head of retail John Ions joins the board as chief executive with immediate effect, while non-executive chairman Adrian Collins, becomes executive chairman.
Legge helped set up Liontrust in 1994 as well as being integral part of its floatation in 1999. He will remain at the firm as a consultant until August 6, 2010.
Liontrust has had a tumultuous 18 months following the resignations of star managers Jeremy Lang and William Pattisson. The firm has seen its assets dwindle and recorded a net outflow of £53m in the first quarter of 2010.
In February Liontrust announced a raft of cost-cutting measures designed to save £2.5m annually, starting from the next financial year.
Collins says: “With Nigel and the Board having begun the rebuilding of the business and the company being well positioned for the future, Nigel feels this is the right time to step down. The Board would like to thank Nigel for the energy and contribution he has made in building the company and wish him well for the future.
“In John Ions, who joined Liontrust earlier this year, we have an individual with a wealth of industry experience to lead the company and build on its strong financial position, pool of talented fund managers and range of funds to create value for investors and shareholders.”