Microsoft will invest $300m in Barnes & Noble's Nook e-reader, gaining a foothold in the fast-growing e-books market as the bookseller gets more firepower to compete against Amazon.com's Kindle and Apple's iPad.
The deal announced on Monday includes Microsoft taking a stake in the bookseller's college bookstore division. It also means that the two companies have settled their patent dispute.
Shares of Barnes & Noble soared nearly 70% on Monday, while Microsoft shares were nearly flat.
The agreement values the Nook and textbook businesses, which will form a new subsidiary, at $1.7 billion.
The move comes as Microsoft is looking to generate excitement around its tablet-friendly Windows 8 operating system, expected on the market around October.
"This is not a financial investment. It's a strategic investment to strengthen Windows 8 as a platform for tablets and e-reading," said BGC Partners analyst Colin Gillis.
Barnes & Noble gets a much-needed capital injection and a way to enter the digital books market outside the United States.
Microsoft will receive a 17.6% stake in the new company, temporarily called Newco. It will be run by Barnes & Noble and will maintain a relationship with the US bookstore chain's nearly 700 stores.
Barnes & Noble's Nook has found a strong following, allowing it to garner some 27% of the US e-books market in the two-and-a-half years since the device was launched. But battling Amazon's market-leading Kindle has proved expensive.
"It gives them a much larger partner with deeper pockets, it gives them increased reach," said Morningstar analyst Peter Wahlstrom. "In the last two years they've had their backs against the wall."
The companies also said on Monday that they have settled their patent litigation. Last year, Microsoft filed lawsuits for patent infringement against Barnes & Noble over the Nook in part of its assault on devices running on Google's Android system.
Nook to go global
Barnes & Noble has poured tens of millions of dollars into developing the Nook. The first version hit the market in 2009, two years after the Kindle.
The company's e-readers, tablets and electronic book sales have helped it offset a broader decline in book sales. Same-store sales of books at its brick-and-mortar stores have edged up again largely thanks to the bankruptcy last year of Borders Group.
But the Nook has been available only in the United States and the company said last year it wanted to take its digital business to new markets.
Barnes & Noble's CEO, William Lynch, told analysts on a conference call Microsoft's reach would help in that regard.
"We will have the opportunity to collaborate on developing best-in-class reading technologies for those Windows users and extend the digital bookstore to hundreds of millions of people in the US and internationally," he said.
Barnes & Noble put itself up for sale in 2010 but attracted only one firm offer, from Liberty Media which was drawn by the Nook's growth. Liberty ultimately decided to invest $204m rather than buy the company outright.
Barnes & Noble shares were up 67% at $22.85 late on Monday morning. Microsoft shares were unchanged at $31.98.