The acquisition is expected to complete in the final quarter of this year.

The financial terms of the deal were not disclosed, but Liontrust said it will issue 9.4m new ordinary shares with GAM shareholders expected to own 12.6% of the combined firm.

The deal has been widely expected in recent weeks.

GAM is headquartered in Zurich. It employs 594 people in 14 countries and has UK investment centres in London and Cambridge.

Liontrust plans to merge the investment management businesses which will have 12 funds with assets over £1bn (7 managed by Liontrust and 5 by GAM).

The fund manager intends to rebrand all GAM funds as Liontrust as soon as possible after the completion of the acquisition.

GAM’s investment management division had CHF23.3bn (£20.9bn) in assets under management as at 31 March.

Liontrust said the deal would help broaden its fund range and asset classes, including fixed income, thematic equities and alternatives.

It added that the deal will expand the fund manager’s distribution globally. Currently 62% of GAM’s assets are sourced from Continental Europe, whereas Liontrust’s assets under management predominantly come from the UK.

John Ions, CEO of Liontrust, said: “This is a significant acquisition that accelerates the growth of Liontrust through enhancing our distribution globally, product capability and investment talent.

“Liontrust and GAM are both client centric businesses that thrive on providing solutions and first-class service. The enlarged company will provide the platform from which to deliver this to a broader client base. Liontrust and GAM will work together to provide a seamless transition for clients and enhancing the service provided in the future.”

The acquisition is not the first for Liontrust.

It bought Majedie Asset Management for £41m a year ago and said the investment team who joined from Majedie generated performance fees of £12m, out of a total of at least £17m for Liontrust as a whole. The acquisition included taking on the management of the £1.1bn Edinburgh Investment Trust.