NEW YORK — Barnes & Noble and Microsoft are teaming up to create a new Barnes & Noble subsidiary that will house the digital and college businesses of the bookseller and include a Nook application for Windows 8.

The companies said today they are exploring separating those businesses entirely. That could mean a stock offering, sale or other deal could happen.

The partnership with Microsoft will see the Redmond, Wash., company make a $300 million investment in the subsidiary for about a 17.6 percent stake. Barnes & Noble will own about 82.4 percent of the subsidiary, which has yet to be officially named.

The possibility of a separation of the businesses has been brewing recently. In March, private investment firm G Asset Management, a Barnes & Noble shareholder, offered $460 million for a 51 percent stake in the company’s college bookstore unit, Barnes & Noble College Booksellers.

In 2009, Barnes & Noble bought the college bookstore unit from Chairman Leonard Riggio in a deal worth $596 million. The deal ended up costing Barnes & Noble $460 million after accounting for the unit’s cash on hand at the closing date.

Aside from the college business, Barnes & Noble is looking to maximize the potential of its Nook e-book readers.

The bookseller has tried to adjust to a noticeable shift in book reading habits, with e-book readers becoming increasingly popular with consumers over traditional hardcover or paperback books. But Barnes & Noble is dealing with tough competition on that end from the likes of Amazon.com’s Kindle and others.

“The formation of Newco and our relationship with Microsoft are important parts of our strategy to capitalize on the rapid growth of the Nook business and to solidify our position as a leader in the exploding market for digital content in the consumer and education segments,” Barnes & Noble CEO William Lynch said in a statement.

The companies say the subsidiary will help to speed the transition to e-reading.