According to WSJ, Aetna (AET) approached by CVS Health Corporation (CVS)

CVS Health Corp. (CVS) is moving closer to a deal to buy Aetna Inc. (AET) for more than $66 billion in cash and stock. The deal, which could be announced by Monday, would create a health-care behemoth selling everything from drugs to insurance.

Update(s):

December 03, 2017:  CVS Health (CVS) , a company at the forefront of changing the health care landscape, and Aetna (AET), one of the nation’s leading diversified health care benefits companies, today announced the execution of a definitive merger agreement under which CVS Health will acquire all outstanding shares of Aetna for a combination of cash and stock.  Under the terms of the merger agreement, which has been unanimously approved today by the boards of directors of each company, Aetna shareholders will receive $145.00 per share in cash and 0.8378 CVS Health shares for each Aetna share.