CVS Health cvs is in talks to buy health insurer Aetna aet in what could be a $66 billion deal, the Wall Street Journal reported on Thursday afternoon.
The company, which operates the massive Caremark pharmacy benefits manager as well as the CVS drugstore chain, has offered more than $200 a share, according to the WSJ. The news sent Aetna shares up 12% to $180.70, showing that the markets find the news credible. CVS’ shares slipped 3%, presumably on concerns of how such a large transaction would be financed. CVS’ stock market value is about $75 billion.
A CVS spokesperson declined to comment citing company policy on market speculation, while Aetna could not immediately be reached for comment.
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The news comes eight months after Aetna, one of the largest publicly traded health insureres, scrapped a proposed merger after a U.S. federal court ruled against the deal, saying it would stifle competition in the Medicare Advantage program.
While CVS is best known for its namesake drugstores, its Caremark is the second largest PBM in the country after Express Scripts esrx and processes prescription-drug programs for big companies and health insurers, representing tens of millions of people.
CVS, which bought Caremark in 2007 for $21 billion, has made a number of deals in recent years to beef up both its retail and its PBM business, which are meant to feed business to each other. In 2015, it bought Target’s tgt pharmacy business and has hundreds of stores within the discount store. In the last few years, on CVS Health CEO Larry Merlo’s watch, the company has also bought Coram, which delivers treatments to homebound patients, for $2 billion, teamed up with Cardinal Health to create the largest U.S. generic-drug purchasing operation, Red Oak Sourcing, and in 2015, paid $12.7 billion for Omnicare, a distributor of prescription drugs to nursing homes and assisted-living facilities.
Its main rival Walgreens Boots Alliance wba has also been on a dealmaking tear, recently buying nearly 2,000 Rite Aid rad stores for $4.375 billion.