Jeff Bezos
Amazon CEO Jeff Bezos.
REUTERS/Joshua Roberts

Websites are selling fake reviews to Amazon merchants who want to boost their products’ ratings, an investigation by UK consumer-rights group Which found.

One site was selling reviews for about $18 each and said it could help Amazon sellers achieve the coveted Amazon’s Choice status within just two weeks. Another claimed to sell contact and social-media details for Amazon reviewers.

Some sites asked for free or discounted products in exchange for reviews.

These practices are against Amazon’s guidelines, which prohibits sellers from paying third parties for reviews.

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For the investigation, Which posed as an Amazon seller and registered for 10 sites selling what it classed as "review manipulation services."

AMZTigers, for example, said sellers could use its network of 62,000 global "active product testers" to increase their sales and revenue on Amazon.

When Which registered with the German site, it was told that it could buy reviews individually for 15 euros ($18.25) or purchase them in bulk, with 1,000 reviews costing 9,000 euros ($10,950).

Fake reviews like these can lift a product's rating temporarily and cause a short-term spike in sales, a study by the University of Southern California and the University of California, Los Angeles found.

AMZTigers also offered packages that include review votes. Reviews with more votes appear higher up on Amazon.

The site also told Which that it could help sellers get an Amazon's Choice endorsement in less than two weeks. The rank is determined by an algorithm that takes positive reviews into account.

Reviews in exchange for free products

Some sites also said they would provide reviews in exchange for free or discounted products, a practice known as "review incentivization." Some Amazon sellers that had made profiles on the sites even offered a small payment to potential reviewers alongside the free or discounted product, Which found.

Some of the sites had their own loyalty or reward schemes that gave reviewers access to more premium products based on how many reviews they had posted, Which found.

All the sites Which signed up to offered advice on how to write reviews, with many saying they had to be at least two sentences long. Some had a minimum word count, too.

Reviewers were also encouraged to wait a few days after receiving the product to leave a review, and some sites didn't allow the reviewers to return the products after purchase because this can affect the likelihood a product receives an Amazon's Choice endorsement.

Groups selling Amazon reviews have also popped up on social-media sites such as Facebook and Telegram. Insider spoke to some of the fake reviewers, including one who had a product refunded after deleting a negative review she had left. Another compared the fake-review phenomenon to mystery shopping.

In September, Amazon reportedly removed 20,000 product reviews after a Financial Times investigation suggested that some of the site's top UK reviewers may have profited from leaving positive ratings. 

Amazon UK's top-ranked reviewer rated products totalling £15,000 ($19,740) in August alone, including three gazebos, 10 laptops, and even dolls houses, posting a review on average every four hours, the FT found. Many of the products he reviewed were then listed for sale on an eBay account bearing his name and address, the publication added.

Which called on both e-commerce sites and authorities to take more action and regulate reviews.

Amazon told Which that it prohibits the abuse of its features by both sellers and reviewers. It suspends, bans, and takes legal action against accounts that violate these policies, it said, and it analyzes more than 10 million reviews each week.

Insider has contacted Amazon and AMZTigers for comment.

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