WebMD Health Corp (WBMD), the New York-based company behind popular health-focused websites for consumers and medical professionals, looks set to be bought by private equity firm KKR & Co (KKR).

People familiar with the matter told Reuters that an all-cash deal is expected to be announced Monday. The exact price KKR will pay for the U.S. online health publisher is not available. WebMD was valued at $2.1 billion before news of the potential deal surfaced.

Should the acquisition go ahead, WebMD’s websites, including WebMD.com, Medscape.com and MedicineNet.com, will join KKR’s Internet Brands, the new media company behind websites such as DentalPlans.com, VeinDirectory.org and AllAboutCounseling.com.

WebMD has been looking for a buyer for several months now. According to Reuters' sources, the company ran a five-month auction, during which it attracted bids from over 100 companies and private equity firms.

Weaker advertising revenues are believed to be one of the reasons why WebMD decided to sell itself. In February, the New York-based company confirmed that it would explore its options after experiencing a slowdown in demand for advertising space on its websites. It considered a similar move in 2012, but then changed its mind after business magnate Carl Icahn bought a stake in the company.

WebMD.com is most often used to look up symptoms and learn about health conditions. The company, which was founded in 1996 and went public in 2005, owns medical news and education brand Medscape and MedicineNet, a website that provides detailed information about diseases, conditions, medications and general health.

As of June, WebMD’s websites attracted nearly 72 million unique monthly users, placing it at No. 36 in comScore’s ranking of digital media properties.

Acquisition-hungry KKR acquired Internet Brands for $1.1 billion in 2014. The California-based company, which launched as CarsDirect.com in 1998, operates online media, community and e-commerce sites in vertical markets. It also develops and licenses internet software and social media applications. (See also: KKR Names Bae, Nuttall as Co-Presidents in Step Towards Succession.)

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