Amazon Buy Box

Amazon's Buy Box is a feature the company displays on its website product pages to encourage shoppers to add a particular seller’s item to their cart. Between 82% to 90% of Amazon shoppers are estimated to use the Buy Box when purchasing products on Amazon.

In 2007, Amazon founder and then CEO Jeff Bezos argued that the company used 'very objective customer-centered algorithms' to automatically award the Buy Box to the lowest priced seller, provided they had the item in stock and were able to deliver it. 

Amazon Buy Box

System databank

Operator: Amazon
Developer: Amazon

Country: EU; Italy; Germany; UK; USA

Sector: Retail

Purpose: Determine seller

Technology: Machine learning
Issue: Business model; Competition/price fixing; Ethics/values

Transparency: Governance; Black box; Marketing

ProPublica investigation

In September 2016, a ProPublica investigation found that Amazon’s algorithms encourage customers to pay more than they need for popular products and give greater visibility to products that benefit the company. 

By looking at 250 items on Amazon that are purchased at a high frequency, ProPublica discovered that almost three-quarters of the time Amazon would place its own products or those from companies that pay Amazon to fulfill orders into the Buy Box, even though they weren’t always the cheapest.

EU anti-trust investigations

Italy market position abuse

In December 2021, Italy's competition authority fined Amazon USD 1.3 billion for abusing its market position by giving preferential treatment to third-party sellers that use its logistics service Fulfillment by Amazon (FBA). This included a higher higher chance of being featured in Amazon's Buy Box.

UK anti-trust investigation, lawsuit

In July 2022, the UK Competition Authority announced it is opening a formal investigation into whether Amazon has a dominant position in the market and whether it is abusing that position and distorting competition by giving an unfair advantage to its own retail business or sellers that use its services, compared to other third-party sellers on the Amazon UK Marketplace.

In October 2022, a class-action lawsuit was filed in the UK alleging that Amazon uses a 'secretive and self-favouring algorithm to ensure the Buy Box nearly always features goods sold directly by Amazon itself, or by third-party retailers who pay hefty storage and delivery fees to Amazon'.

According to Hausfeld & Co LLP partner Lesley Hannah, 'Amazon doesn’t present consumers with a fair range of choices – on the contrary, the design of the Buy Box makes it difficult for consumers to locate and purchase better or cheaper options.'

The suit, which is seeking an estimated GBP 900 million in damages to compensate tens of millions of consumers for alleged anti-competitive behaviour, is being bought by Julie Hunter, a consumer rights advocate, and is funded by LCM Finance, a global litigation funder.

US consumer protection lawsuit

A February 2024 lawsuit accused Amazon of violating US consumer protection by steering users of its website to higher-priced items commanding higher fees for the company, as opposed to the 'best prices' it promises. 


In 2016, Amazon said its Buy Box system uses a range of factors, including price, seller rating, the closest item to the customer and free delivery. The company has otherwise declined to disclose how it works.

Research, advocacy

Investigations, assessments, audits

Page info
Type: System
Published: February 2023
Last updated: February 2024