Guinness Peat Group founder Sir Ron Brierley is stepping down as the company's chairman after 20 years in the role.
GPG has been in turmoil in recent times. Plans to split its Australian arm into a separate business met stiff resistance, including from New Zealand director Tony Gibbs, who was later dumped.
Sir Ron leaves as chair of the company's board on Friday. Independent director Mark Johnson will succeed him.
Milford Asset Management executive director Brian Gaynor says the resignation signals a change of the guard at the investment concern which many shareholders think is long overdue.
He says GPG's board is now mostly independent directors and most investors will be happy with Mr Johnson's appointment as chair.
Sir Ron will remain on GPG's board as a non-executive director.