Barclays analyst Karen Short said a potential strategic bidders for Whole Foods (WFM) can "rationally outbid" Amazon (AMZN) based on the roughly $750M in synergies she estimates for a buyer such as Kroger (KR) or Wal-Mart (WMT). For Kroger, she estimates that a 100% debt-financed bid at $50 could be about 6% accretive, and a Whole Foods bid up to $60 would still be accretive.

Source: NBCNews

For Wal-Mart, a 100% debt-financed bid at $50 could be about 2% accretive, though a could still be accretive bid up to $70 per share, she tells investors. Whole Foods was not "shopped," based on public documents, and the math indicates a superior, competing bid is "feasible," said Short, who also notes that Amazon could then outbid any other offer. Short has an Overweight rating and $48 price target on Whole Foods shares.