American Realty Capital Properties has become the biggest U.S. owner of single-tenant properties in less than three years, overtaking Realty Income Corp. American Realty Capital focuses on buildings with only one tenant, such as pharmacies and restaurants. The company's shares are trading at less than their 2011 initial public offering price of $12.50. "We believe Mr. Kay will be more proactive in talking to investors and improve the company's financial transparency as he builds out his executive team," Simon Yarmak, an analyst at Stifel Nicolaus & Co., wrote in a report today. He has a hold rating on American Realty Capital. The company's shares rose 2.4% to $12.47 at 12:34 p.m. in New York. American Realty Capital raised about $70 million in the IPO, and its market value as of yesterday was almost $11 billion. The New York-based company said on its first-quarter earnings call that it planned to accelerate the CEO succession from its original plan, which was set to begin in early 2015, Yarmak said.