Amazon's path to dominance in big industries, whether it's retail or cloud computing, often involves cutting out the smaller middlemen.
The drug supply chain could be next.
Wall Street isn't on their side. McKesson, Express Scripts, Cardinal Health, CVS Health and Walgreens have lost a combined $43.5 billion in stock market value over the past year, while Amazon has picked up $95 billion in market capitalization.
All five were asked about Amazon during earnings calls or analyst meetings in the past two months. Here are some of the highlights:
CEO John Hammergren was asked at the company's investor day in June if he views Amazon as a competitor or potential customer.
"The Amazon question is one we get frequently, and it's a question you could ask about any of our businesses," he said. "We clearly understand that Amazon has great capabilities to ship product in low unit of measures."
Hammergren said McKesson customers are "supported by significant sales and distribution resources" as well as controlled substance management. Getting beyond simple things like toothpaste sales is tough in pharmaceutical distribution, and "we're very well-positioned to continue to manage," he said.
During the company's earnings call last month, CEO Timothy Wentworth was asked if Express Scripts would be willing to reimburse Amazon for home delivery drugs.
"If Amazon were looking to become an efficient provider in networks, we would welcome that opportunity," he said. "We think Amazon is a great client for us. We think they are a company that if they choose to move in a direction, we'd be interested in working with them."
Analysts at Cardinal's analyst meeting in June wanted to know if Amazon could disrupt the supply chain.
"Amazon is an incredible company," CEO George Barrett said. "We have a lot of admiration for them. What we do, which is noteworthy, is operate in an intensely regulated business where the stakes are extremely high, where a failure to comply means a huge miss."
Barrett said Amazon has been a presence for a long time, "so we've built our strategies with an awareness that they're there." He added that it's interesting to think about Amazon as a potential partner, "but there are complexities there."
Last week, CEO Larry Merlo was asked after earnings how he views Amazon as a competitor on the retail side of CVS's business.
"So listen, there's no question that Amazon is a competitor in the marketplace," he said. "They've done a great job, and you don't take anything they're doing for granted. But at the same time, I think we have a lot of capabilities and a value proposition that can compete effectively in the market."
CEO Stefano Pessina was asked on the Walgreens earnings call in July if he sees Amazon as "potential opportunity" or a "potential challenge" going forward.
"I honestly don't believe that Amazon will be interested in the near future in the next few years in this market," Pessina said. They have so many "opportunities around the world and in other categories, which are much, much simpler than health care, which is a very regulated business," he said.
Pessina acknowledged that he could be wrong, and if so, "we wouldn't exclude to partner with them." Regarding the Amazon-Whole Foods deal, Pessina said expanding into pharmacy is not the best opportunity for Amazon.
"So be relaxed, we will continue to survive in any case."
Each company has come up with its own way of reassuring shareholders, even as investors vote with their wallet. Internally, the story may be very different.
Tom Rodgers, managing director of McKesson Ventures, which invests in health-tech start-ups, described a "low-level" paranoia about Amazon and said it's influencing all companies in the drug supply chain.
The specialty drug market is where Amazon is likely to play first, according to Tom Cassels, a partner at Advisory Board Consulting. That would pit Amazon most directly against Express Scripts, Walgreens and CVS in selling medications for serious and complex conditions like multiple sclerosis, cancer and hemophilia.
A partnership route is still a possibility, said Cassels, who has closely tracked Amazon's move into health care.
"Picking a winner in specialty pharmacy and partnering with them could make more sense," he said.
In the coming months, some of the largest health IT companies might also be asked about Amazon. As CNBC reported, the company has a secret "1492" team dedicated to health-tech opportunities like telemedicine and electronic medical records.
"There is such fragmentation with digital health apps today," said Cassels. "A company that could create a platform for these apps, and digitize the patient-physician relationship in a simple, user-friendly way could be a rollup player."