Walmart has begun discussing a possible acquisition of health insurer Humana, The Wall Street Journal first reported Thursday citing people familiar with the matter. Reuters also reported the companies are discussing a partnership, but that a full acquisition is also possible.
Shares of Humana soared as much as 13 percent in after-hours trade on Thursday. Walmart shares edged slightly lower in extended trade.
The newspaper said that details of the potential deal were not immediately clear and that it's possible one may not materialize.
Walmart said in a statement to CNBC that it doesn't comment on rumors and speculation. Humana did not immediately respond to CNBC's request for comment.
As of their Thursday close, Humana had a market value of about $37 billion, according to FactSet. Shares of the insurer have surged 30 percent in the past year, while Walmart shares have jumped more than 25 percent.
The news comes amid a rush of deal chatter as insurers are under pressure to lower medical care costs.
Online retail giant Amazon has pledged to partner with J.P. Morgan and Berkshire Hathaway to tackle rising employee health-benefit costs. CNBC has also reported that Amazon has participated in exploratory talks with generic-drug makers.