What do former US Marines, stay-at-home moms, retirees and Chinese business veterans all have in common? You’ve probably bought something from them on Amazon.

Third-party sellers, people who sell their products through Amazon’s marketplace, come from every walk of life and increasingly make up more and more of the online giant’s sales. Amazon launched its third-party marketplace in 2000, allowing small business owners to put their products on Amazon (for a price). There are now millions of third-party sellers on the site, and third-party sales make up about 60% of Amazon’s physical product sales, Jeff Bezos told the House of Representatives in 2020.

Third-party sellers at the center of Amazon’s ecosystem––and the debate around the company’s complicated place in the world. Is Amazon exploiting these small businesses or lifting them up?

Moira Weigel, an assistant professor of communication studies at Northeastern University, says it’s not that simple.

Moira Weigel, Northeastern University assistant professor in the department of communication studies and a member of the executive committee of women’s, gender and sexuality studies. Photo by Alyssa Stone/Northeastern University

“It’s transforming what a small business is,” Weigel says.

Weigel and her graduate research assistant Zhaozhou Dai spent the last two years talking with third-party sellers across the global e-commerce market, charting Amazon’s impact on a “hidden, yet really important part of the global consumer economy.” Her report, “Amazon’s Trickle Down Monopoly,” published this week in Data & Society, is the culmination of that work.

“To be an Amazon seller does not look much like running the mom-and-pop corner store that politicians and pundits evoke when they talk about American small business,” she adds. “As several of my interviewees put it, it typically looks more like daytrading—interpreting and trying to speculate on global data flows that you experience primarily through screens.”

The impact of that shift goes beyond Amazon and its third-party sellers. Weigel says the US, China and EU place “an enormous amount of faith” in small businesses and entrepreneurs to help remedy structural inequities and create opportunities for people.

“Entrepreneurship is a state project,” Weigel says. “We have low interest rate loans, we have tax breaks, we have subsidies for small businesses. If Amazon’s market dominance is fundamentally transforming what a small business is, that is a matter of public interest.”

For third-party sellers, the advantages of selling on Amazon are clear: They gain access to the largest online marketplace in the world. All they have to do is supply their inventory––and pay Amazon to ship, store, list and advertise it. The whole enterprise is low-risk for Amazon and high-risk, high-reward for sellers.