Ralph Whitworth, who'd been chairman of Hewlett-Packard for just over a year, is resigning from his job for health reasons, HP said on Tuesday.
Whitworth became interim chair last April when Ray Lane stepped down. His resignation is effective Wednesday, and HP's board will discuss a replacement at its next meeting, the company said.
Whitworth is an activist investor who holds a big financial stake in HP. He was given a seat on its board in 2011 in return for agreeing that his firm, Relational Investors, would not launch a proxy battle to take over the company.
It's another change for HP just as the company is showing signs of getting back on track. Last April, two of its directors resigned in the fallout from HP's botched acquisition of Autonomy. Since then it has looked relatively stable.
In a press release, Whitworth said HP has made "enormous progress" in getting itself back on track. "HP's shareholders can be very confident that [CEO Meg Whitman], her team and the current board will stick to the strong practices and discipline we've put in place," he said.
HP didn't give details about Whitworth's health, but news reports said he has throat cancer.
HP grew its profit last quarter thanks partly to an uptick in its PC business, but it's also slashing up to 16,000 more jobs to reduce costs.