Craig Norgate has stepped down as chairman of rural services company PGG Wrightson.
The company says Mr Norgate advised it of his intention in July and the board accepted the decision on Wednesday.
Mr Norgate, who owns nearly 27.5% of PGG Wrightsons, will be replaced by existing board member, Keith Smith.
In a statement to the market, Mr Norgate said the listed status of the company meant that an independent chair is more appropriate.
Mr Norgate has been chairman of PGG Wrightson since October 2007 and will remain as a director.
Meanwhile, analysts say the focus on reducing debt at PGG Wrightson means there is likely to be a further shake-up among the board.
Mr Norgate has been an important part of PGG Wrightson's expansion, including into dairy farming in Uruguay and encouraging partnerships in the wool industry.
But the effects of the economic slowdown on farmers and the constraints imposed by a $475 million funding package negotiated with its banks means PGG Wrightson is now keenly focused on reducing costs.
With a $125 million loan repayment due by December next year, PGG Wrightson indicated that requires different leadership.
It is currently reviewing the board's composition and some analysts believe changes are on the cards.
Even Mr Smith's chairmanship may be a short one, as the company looks for directors with commercial skills to reinforce managing director Tim Miles' push to get more earnings out of its operations.