The CMA, Britain’s competition regulator, said it has now moved its investigation to a formal level having started looking last year at the tech giants’ systems for identifying and dealing with fake reviews.
That initial assessment raised concerns over whether Amazon and Google have been doing enough to detect fake and misleading reviews or suspicious patterns of behaviour and, if discovered, are removing offenders and imposing sanctions.
The CMA said it is also concerned that Amazon’s systems do not stop sellers lifting reviews from other sources.
Andrea Coscelli, the CMA’s Chief Executive, said: ” Our worry is that millions of online shoppers could be misled by reading fake reviews and then spending their money based on those recommendations.
“We are investigating concerns that Amazon and Google have not been doing enough to prevent or remove fake reviews to protect customers and honest businesses.”
Coscelli added that it was not clear yet if either Amazon and Google had broken the law.
Facebook, Instagram and eBay have all started removing groups and banning individuals for buying and selling fake reviews on their sites, he added.
“The CMA’s investigation into fake reviews is part of a broader programme of CMA work, which includes establishing a new pro-competition regulatory regime for digital markets, to curb the power of big tech,” the regulator added.
A spokesman for Amazon said the company devoted “significant resources to preventing fake or incentivised reviews from appearing in our store”.
“We will continue to assist the CMA with its enquiries and we note its confirmation that no findings have been made against our business.”
Google said that its policies state “reviews must be based on real experiences” and where it finds violations “we take action” including disabling user accounts.
“We look forward to continuing our work with the CMA to share more on how our industry-leading technology and review teams work to help users find relevant and useful information on Google.”
Earlier this year Which? found companies that were employing thousands of people to write reviews for £13 a time.
Which? said the CMA’s investigation must move quickly to establish if any laws had been broken.
“This should prompt Amazon and Google to finally take the necessary steps to protect users from the growing tide of fake reviews on their platforms and, if they fail to do so, the regulator must be prepared to take strong enforcement action.”
Earlier, Google said it had delayed changes to its policy on cookies in its Chrome browser after commitments to made to the CMA.
A plan to ban other people’s tracking cookies on the browser will not now be implemented until the end of 2023, the search engine giant said, a delay of around two years.
This will allow time for an informed debate around the topic, it said.
Vinay Goel, Google’s privacy engineering director added: “It’s become clear that more time is needed across the ecosystem to get this right.”
The CMA, which has also demanded it oversees the proposed changes, said it intends to accept the deal and that it comes into effect on July 11.
Third-party cookies are used by advertisers to track user activity and monitor the effectiveness of campaigns in reaching potential customers
Google plans to introduce its own new system known as Privacy Sandbox that will replace these third-party cookies.
But advertisers and regulators are concerned that this will just concentrate the market even further into Google’s hands.
The US group already has up to two-thirds of the browser market.