Microsoft Corporation has agreed to pay $300 million in exchange for a 17.6 percent stake in Barnes & Noble Inc.’s Nook business in a transaction that values the electronic reader at about $1.7 billion—more than its parent company’s stock market value.

Under the deal, which was announced Monday, Barnes & Noble, the largest bookseller in the United States, and Microsoft, the world’s largest software company, are entering a digital joint venture that will potentially expands the Nook’s reach to millions more customers by integrating it with the software giant’s Windows 8 operating system, according to news reports.