HCP Inc. on Monday said that it signed an agreement to buy out a majority stake in a joint venture that owns 25 senior housing properties in several states.

HCP, a Long Beach real estate investment trust that owns or has interests in 670 properties related to health care or senior living, said it will pay about $137 million in cash and assume the partner’s share of about $650 million in Fannie Mae debt secured by the assets, which values the properties at $860 million.

The properties were acquired when HCP bought CNL Retirement Properties Inc. in 2006, and were added to a joint venture with an unnamed partner the following year. The REIT did not disclose the name of its partner. The deal is expected to close by Jan. 31.

Shares of HCP closed up 16 cents, or less than a percent, to $32.52 on the New York Stock Exchange.