American Realty Capital Properties Inc , a real estate investment trust, is in talks to buy NorthStar Realty Finance Corp in deal that could value the company at about $6.4 billion, the Financial Times reported.

The two companies are discussing an offer price of $20 per share, the FT said, citing sources familiar with the matter.

NorthStar Realty's shares rose as much as 11 percent to $17.86 in early trading on the New York Stock Exchange. (