Needham analyst Kevin Caliendo upgraded CVS Health (CVS) to Buy from Hold with a $79 price target. The healthcare company closed yesterday up 3c to $69.02.

The stock's risk/reward is favorable, especially if CVS is able to consummate the reported merger with Aetna (AET), Caliendo tells investors in a research note. The analyst puts a better than 50/50 chance of Amazon (AMZN) entering the pharmacy market, and sees CVS shares trading down to 9-10 times earnings in a worst-case scenario.

His best-case scenario has Amazon putting off a decision on pharmacy and CVS buying Aetna. Caliendo thinks CVS' multiple could expand to 14 times or more under his best case.