Tim Cook, Apple’s chief operating officer, will take over as CEO of the consumer electronics giant following co-founder Steve Jobs’ resignation, apparently on health grounds.

Cook is credited with revolutionising the company’s supply chain by outsourcing manufacturing to suppliers including China’s Foxconn, and slashing the amount of inventory it holds in its warehouses. Both moves have allowed the company to improve its margins.

Before joining Apple in 1998, Cook briefly worked for PC manufacturer Compaq. That company was acquired by Hewlett-Packard in 2002, which now wants to divest itself of its PC division.  

He had previously worked for IBM, as director of fulfilment in North America. IBM sold off its PC division to Chinese manufacturer Lenovo in 2004. (Lenovo has been suggested as a potential acquirer for HP’s PC business).

Cook steps up to the top spot at a time when the PC market is in flux, in part due to the success of Apple’s smartphone and tablet PC products. Yesterday, IDC reported that China has become the world’s largest market for PCs, while earlier Gartner found that PC sales in Western Europe dropped 19% in the last year, as consumers no longer feel compelled to buy new PCs and laptops on a regular basis.

Apple published Steve Jobs’ resignation letter last night. "I have always said if there ever came a day when I could no longer meet my duties and expectations as Apple’s CEO, I would be the first to let you know," he wrote. "Unfortunately, that day has come."

Shares in the company fell 5% following the announcement of Jobs’ resignation, despite investment analysts generally endorsing Cook’s appointment as his successor. 

Jobs will become chairman of Apple’s board of directors.