Apartment Investment and Management Co. (Aimco), a Denver-based REIT, has agreed to pay $301 million to acquire a controlling interest in Oxford Properties, a division of Oxford Realty Financial Group. In the transaction, Aimco will pay $241 million in cash and $60 million in Aimco Common O.P. units and Class-A common stock. With the purchase, Aimco will acquire 166 apartment communities with 36,662 units in 18 states.