Barnes & Noble Chairman Leonard Riggio wants to buy the company's stores unit, split from Nook

NEW YORK (CNNMoney) -- Barnes & Noble Chairman Leonard Riggio wants to buy the company's stores unit, and leave the company's Nook e-book business as a separate company.

Riggio, who disclosed his plans in a filing with the Securities and Exchange Commission on Monday, did not disclose a price for his planned purchase. Shares of the nation's largest book retailer soared 2.4% in premarket trading on the news.

Riggio is already the largest shareholder of Barnes & Noble, with nearly a 30% stake in the company.

The company had already been considering spinning off the Nook business as a separate company. Last April, it announced a deal with Microsoft in which the software firm bought a then 17.6% stake in Nook and publisher Pearson bought a 5% stake in Nook in December. Those deals both value the overall Nook business at more than $1.7 billion, even though Barnes & Noble stock is worth just less than $800 million.

In early January, the company reported a weak Christmas season, with sales at its retail stores falling 11% from a year earlier and sales at its Nook unit falling 12.6% to just $300 million. Earlier this month, it warned of rising losses and disappointing sales for its Nook unit during its just complete fiscal year, results of which are due to be reported Thursday.

Barnes and Noble and other traditional book retailers have struggled with competition from Amazon.com, which has its own Kindle e-book. Rival brick-and-mortar store chain Borders filed for bankruptcy two years ago and went out of business in July 2011.