Health Care REIT (HCN), the nation’s third-largest health care real estate investment trust, has agreed to acquire rival Sunrise Senior Living for nearly $845 million, yielding advisory roles for Arnold & Porter, Sidley Austin, and Wachtell, Lipton, Rosen & Katz.

The deal for Sunrise, which owns and operates more than 300 assisted living communities throughout North America and the United Kingdom, will help Toledo-based senior housing provider HCN expand its services as the baby boomer generation slides into retirement, Reuters reports. HCN’s portfolio already includes more than 900 properties it leases to senior living operators in Canada and 45 U.S. states.