WebMD Health Corp (WBMD) stock surged nearly 20% midday Monday following news private equity firm KKR & Co (KKR) - Get Report will purchase the online health publisher for about $2.8 billion, Reuters reported.

WebMD stock has traded nearly 19.4 million shares so far today versus the 30-day average of 528,258 shares per day.

KKR will pay $66.50 per share, which is a 20.5% premium to WebMD's Friday closing price. The deal is expected to close in the fourth quarter.

The deal will bring WedMD's websites including WebMD.com, Medscape.com and MedicineNet.com together with KKR's Internet Brands Inc sites, DentalPlans.com and AllAboutCounseling.com.

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