CHICAGO-Ventas Inc. has completed its $3.1 billion acquisition of Louisville, KY-based Atria Senior Living Group, and the company’s 118 seniors housing communities throughout the country. Atria, owned by funds managed by Lazard Real Estate Partners, has spun off its management business to a new firm Atria Senior Living Inc., which will continue to manage the properties.

The Ventas deal to purchase the fourth-largest assisted living property owner was announced in October. Debra Cafaro, chairwoman and CEO of Ventas, said in a statement that she is excited to join forces with Lazard and Atria. The acquisition positions the company as the largest owner of seniors living communities in the country. The company has a portfolio of more than 700 assets in 44 states and two Canadian provinces, and a pending acquisition of Nationwide Health Properties will boost the firm to more than 1,300 properties in 48 states and Canada.

John Moore, Atria’s CEO, said his firm will also manage communities for other owners and is positioned to continue to grow. “This has been a complicated process, especially the structure of the transaction and the portfolio location in high barrier-to-entry real estate markets that have complex regulatory frameworks, but I believe that our ability to work together with the Ventas team to ensure a smooth transition is a great sign of things to come. We couldn’t be more excited about what the future holds,” he said in a statement.

Atria’s management team will become owners in Ventas. Matthew Lustig, Atria’s chairman, is also expected to be appointed as a member of Ventas’ Board of Directors very soon.