PillPack's focus on making it easier for customers to order and fulfill medications is an attractive proposition for Walmart and other e-commerce companies that are looking to enhance their health care offerings. The talks come amid reports of early acquisition talks between Walmart and health insurance giant Humana, which would be a much larger deal.
The sources cautioned that the PillPack deal is not yet finalized and could still fall apart, and that Walmart has considered buying a number of start-ups. Still, the sources said discussions between the two about a sale have been happening for months.
A Walmart spokesperson told CNBC, "We are often asked to speculate on possible acquisitions and we simply don't comment on those types of questions."
Amazon also courted the company and at one point held discussions, two of the people said.
Amazon is working with Berkshire Hathaway and J.P. Morgan to bring down health costs for its own employees. It is also building a team internally to explore opportunities to disrupt the drug supply chain, which represents a $3 trillion market.
PillPack declined comment. Amazon could not be immediately reached for comment.
PillPack manages prescription medications for its customers which include those with multiple chronic conditions -- all by packaging, organizing and delivering drugs. It boasts a "full-service" pharmacy, meaning its customer service team is available 24/7.
One person close to the deal said that PillPack is committed to offering its service to customers, regardless of a buy-up.
The start-up has raised $118 million in funding from investors including CRV and Menlo Ventures, and it reached more than $100 million in revenue in 2017, the company says. In 2016 it was reported to be valued at $330 million.
Health experts say that a PillPack buy-up makes sense for Walmart, especially in light of its talks with Humana. Both companies are looking for ways to serve vulnerable seniors with one or more medical conditions.
"A PillPack-like experience for customers would be a huge differentiator for any pharmacy," said Bob Kocher, a health investor with Venrock. Kocher did not have any inside knowledge of the deal.
Kocher said it would also prove beneficial to Walmart as it looks to expand its online pharmacy business.
"Walmart is trying to offer a better e-commerce experience as a retailer, as well as on the health side with its pharmacies, and it wouldn't cost them that much to buy a company like PillPack," he added.
In 2016, PillPack hit the headlines after a contract dispute with Express Scripts, a pharmacy benefits manager, which could have lost it thousands of customers. The disagreement was patched up, in part due to pressure from PillPack's users who took to social media to defend the service. At that time, PillPack's CEO TJ Parker disclosed that Express Scripts accounts for about one-third of its revenue, making it vitally important that the relationship continue.