(BBC News) -The chief executive of US bookstore chain Barnes & Noble, William Lynch, has resigned amid a continued drop in sales of its Nook e-books and devices.
His resignation comes just days after the firm reported that sales in the Nook business fell 34% in the fourth quarter, from a year earlier.
That saw its overall losses more than double to $118.6m (£77m) in the period.
The Nook e-reader was launched in 2009, but has failed to take on the Amazon Kindle in the growing e-books market.
"Lynch was highly instrumental in making Nook a centrepiece in Barnes & Noble's broader operational strategy," said Alan Rifkin, an analyst at Barclays.
"With this announcement, Barnes & Noble is, in our view, signalling that it is attempting to reduce its dependence upon the Nook."
The decline in sales of the Nook business has raised concerns over the future of the division and the direction that the firm may take going forward.
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The next step is Chairman Leonard Riggio deciding if he's going to bid to buy the retail division and from that they'll then decide what to do with the Nook”
John Tinker Maxim Group
While reporting its latest earnings last month, the company said that it plans to reduce losses in the segment by "limiting risks associated with manufacturing".
It said that while it will continue to develop its e-readers in-house, its tablet line will be produced and marketed with a consumer electronics manufacturer. But it did not identify the manufacturer.
Meanwhile, there have also been reports that Microsoft, which already owns 17% of Nook Media, was planning to buy the division outright.
Earlier this year, Leonard Riggio, the company's founder, chairman and largest shareholder, said he wanted to buy back the company's retail operations, but not its Nook e-reader.
Analysts said that whatever decision Mr Riggio takes about buying back the retail operations will be key to shaping the firm's future.
"The next step is Chairman Leonard Riggio deciding if he's going to bid to buy the retail division and from that they'll then decide what to do with the Nook," said John Tinker a media analyst with Maxim Group.
"Do they close it down? Do they reintegrate it back in the company? What happens to minority investors, Microsoft and Pearson?
"It all can be driven by the Chairman," he added.