Microsoft and Barnes & Noble have officially parted ways on the Nook. The digital reader turned tablet saw an investment from Microsoft in 2012 to the tune of $300 million. At the time, the cash gave Microsoft an 18% stake in Nook. In an SEC filing, Barnes & Noble acknowledges they will buy back Microsoft’s interest in Nook, with the goal making it a standalone business, and likely wholly owned by Barnes & Noble. The book retailer has previously noted they would look to spin Nook off from the company.