The SJP board has also confirmed that David Lamb, managing director of investments, will retire as a director in February. Ms Bates decision to retire was announced in May and Mr Lamb’s decision in August.
In addition to these changes, Roger Yates has been appointed as the senior independent director.
Sarah Bates stepped down from the board yesterday and Iain Cornish and Roger Yates took up their new roles from the same day.
Ms Bates joined the board in 2004 and became chair in 2014. She oversaw the transition of Andrew Croft to chief executive to replace David Bellamy in January 2018.
Ms Bates said earlier this year: "It has been a privilege to be a director of St James's Place for more than 13 years and chair of the board since 1 January 2014. Over this period, the company has delivered remarkable success, creating value for all its stakeholders.
“I am confident that Iain and Andrew, the board and the executive team will continue to deliver value to clients, partners, advisers, staff and shareholders and continue to evolve the business in the years ahead. I wish them all the best."
SJP says the recruitment of a further independent non-executive director is under way and, in the meantime, Mr Cornish has agreed to continue as interim chair of the board risk committee.