Shipbroking giant Clarksons is looking for a new chairman as Sir Bill Thomas leaves after the end of his three-year tenure.
Thomas told the board he will not seek re-election at the annual general meeting in May 2022.
He has decided now is the appropriate time to focus on other roles and activities, the London-listed group said.
Thomas has agreed to stay on until a successor has been appointed.
Peter Backhouse, Clarksons' senior independent director, will now lead an independent selection process.
The company thanked Thomas for his "significant contribution" and wished him well with his plans.
Leadership praised
Chief executive Andi Case said: "I would like to thank Bill for his leadership of the board over the last three years, during what have been unprecedented times.
"The company is in robust financial health and well placed for the next phase of its development. Bill leaves with our best wishes for the future."
Thomas said it had been a privilege to be part of Clarksons and work with many talented colleagues.
"I am pleased to leave Clarksons with a robust strategy, strong financial performance and a much-renewed board. I look forward to seeing the firm continue to go from strength to strength."
The broker has been increasing female representation on the board in recent years, with three women among the 10 directors.
Thomas was the full-time successor to Swire veteran James Hughes-Hallett when he joined in February 2019.
He brought cyber security connections as well as FTSE 250 and remuneration committee experience to the post.
Plenty to keep him busy
Thomas remains chairman of Spirent Communications, which, like Clarksons, is listed on the London Stock Exchange, and privately owned IT specialist Node4.
He also chairs the remuneration and risk committees of the Co-operative Bank, where he sits as a non-executive director on the main board.
Thomas' experience on the advisory board of cyber security specialist FireEye was also notable, given that the shipbroker became the target of a mystery hacker in 2018.
Soon after joining, the chairman had to deal with a mutiny over executive pay by Clarksons shareholders who objected to legacy contracts award to Case and financial chief Jeff Woyda.
Thomas was part of a charm offensive to bring rebels round ahead of a key vote in 2019 in which the company squeaked home with 51% in favour of the policy.
Hughes-Hallett had taken over from the retiring Bob Benton as chairman of Clarksons in January 2015.
However, he was replaced by former UK Athletics chief Ed Warner in 2018 as he recovered from illness.
