M&A positive signal: With the U.S. Department of Justice now approving Cigna’s acquisition of Express Scripts (should be completed end of 2018), investors sitting/waiting on the CVS-Aetna deal have reason to smile:
“The Cigna decision bodes well for rivals CVS Health and Aetna, in terms of their bid to become an integrated PBM and health insurer.” 
We already know from previous media reports that things are looking good for DOJ approval of the deal and a current CNBC article sums it up nicely:
“CVS (CVS) and Aetna (AET) have expressed confidence that they will receive anti-trust clearance and close the deal by year’s end. Reuters reports that a source [familiar] with matter said a decision in their merger could come by the end of this month.” 
Arbitrage notes: There is still a positive (yet small) price gap in the CVS-AET deal. As of today, with AET at $205/sh and CVS at $78, if you factor in the deal terms, it’s about a 2.6% basic return. If they can pull it off within 3 months, that’s roughly 11% annualized.
For a contrarian view of this arbitrage play, check out this pretty good article at Investor Place from Sept. 11: