Bloomberg / Contributor / Getty Images  Key TakeawaysBlackstone announced Monday it was taking real estate investment trust Apartment Income REIT, known as AIR Communities, private in a $10 billion all-cash acquisition.AIR Communities shareholders will receive $39.12 per share, a nearly 25% premium over the REIT's closing price on Friday.Blackstone said it would be investing more than $400 million to upgrade AIR's communities.