Henderson will become vice chairman of global asset management at Ameriprise Financial, the parent company of Threadneedle. He has served as chief executive of Threadneedle since 2007 and has been with the asset manager for more than a decade.
Fleming will become Threadneedle’s chief executive after Henderson’s transition and turnover of responsibilities. The moves are subject to regulatory approval.
He joined Threadneedle in 2009 as head of distribution and is a board member of the IMA. He previously worked at JP Morgan and has held a range of regulatory and legal roles in the UK and Australia.
Both Henderson and Fleming will report to Ted Truscott, chief executive of global asset management at Ameriprise.
Truscott said: “Over the past year, Crispin has had discussions about opportunities to transition to a role that offered broader input across our global asset management businesses.
“This new role is ideally suited for him – Crispin has a deep understanding of operations and will partner across our technology and operations functions to create a strategic blueprint that will increase efficiency and operational effectiveness.”
Henderson added: “I am delighted that Campbell will lead Threadneedle and have the greatest confidence in his leadership, business acumen and deep understanding of our clients and our business.”