Amazon CEO Jeff Bezos is focused on expanding Prime membership, and to do so Amazon could follow its long-standing preference to buy rather than build new entities. The company also has some cash to spend — it is one of the five largest stocks in the S&P 500 by market capitalization and ended the first quarter with about $26 billion in cash or assets that can easily convert to cash.
Here are three categories of potential Amazon targets that have analysts speculating:
"AMZN may not be done with M&A in the grocery space," said a report Monday by Citi, citing a conversation with Supermarket News Retail Editor Jon Springer.
Potential targets include BJ's Wholesale Club, whose membership system is similar to Amazon Prime, and Sprouts, an organic grocery chain that Springer said would help Whole Foods develop its private label brand.
Amazon, BJ's and Sprouts did not immediately return CNBC requests for comment. A Whole Foods spokesperson said the firm didn't have anything to add.
Giants like Amazon can also take advantage of growth in online grocery because smaller companies can't afford such large investments, according to Springer, who also expects customer experience improvements to accelerate the growth of selling groceries online.
Overall, the Amazon-Whole Foods deal makes sense because of a likely overlap between Prime users and Whole Foods customers, Springer said, according to the Citi note. Citi has a buy rating on Amazon and a neutral rating on Whole Foods.
Separately, Wedbush Securities analysts Aaron Turner and Amir Chaudhri said in a Monday note that Amazon could acquire food delivery company Grubhub, based on similarities in its customer base with that of Whole Foods.
"An acquisition of GRUB would give AMZN a network of 50,000 restaurants, nearly 9 million active diners, and an annualized run rate of over $3 billion gross food sales. This combination of
forces would create a dominant force in restaurant delivery," the Wedbush report said, adding Amazon could also use Grubhub's delivery infrastructure for grocery delivery.
Amazon and Grubhub both told CNBC they do not comment on speculation about mergers and acquisitions.
Amazon has tried to make a name for itself in the apparel business, and buying an established brand would be a way to acquire a lifestyle category, Forte said. Warby Parker and Lululemon could also give Amazon more physical stores, he said.
None of the firms above immediately responded to CNBC requests for comment.
To be sure, all these reports are just speculation, and before moving onto other projects Amazon may take its time to integrate Whole Foods. The deal is Amazon's largest to date, 14 times larger than the e-commerce giant's purchase of video game streaming platform Twitch in 2014.
— CNBC's Matthew Belvedere, Lauren Thomas and Abigail Summerville contributed to this report.