Amazon and Facebook owner Meta have both voluntarily committed to changes to their retail platforms to help "protect fair competition", Britain's Competition and Markets Authority (CMA) announced on Friday.
The US online giants accepted the "sets of commitments" following separate investigations by the UK regulator into "competition concerns" over their use of advertising data, the CMA said.
It opened the probe into Amazon in July 2022 amid fears the firm was abusing its dominant position as the UK's leading online retail platform by giving its own seller business "an unfair advantage" over independent competitors.
Amazon was also accused of favouring sellers that use its own warehousing and delivery services rather than rival logistics businesses, the CMA noted.
An Amazon spokesperson said in a statement that it had "engaged constructively with the CMA" during its investigation.
"We welcome this resolution which will preserve our ability to serve both our customers and the over 100,000 small and medium-sized businesses selling through our UK store," it added.
The CMA announcement follows a similar outcome within the European Union, which announced in December that Amazon had agreed to end practices deemed anti-competitive related to independent sellers' data.
The UK regulator's probe into Meta, which began in June 2021, also followed concerns it risked "having an unfair competitive advantage that could distort competition" on its Facebook Marketplace platform.
"Meta has also signed commitments, which will prevent the firm from exploiting its advertising customers' data, meaning businesses, and ultimately consumers, are protected," the CMA said.
"Going forward, competitors of Facebook Marketplace that advertise on Meta platforms can 'opt out' of their data being used to improve Facebook Marketplace."
The US behemoth has also pledged to limit how it uses ad data when developing its products, according to the regulator.
That will ensure it "cannot exploit advertising customers' data to give itself an unfair advantage when competing with products or services sold by those advertising customers".
Meta said it welcomed the CMA's decision to end its investigation following the firm's commitments to "put in place systems and controls designed to confirm and validate that advertiser data from competitors is not used in Marketplace".
It remains the subject of a similar investigation by the European Commission.(AFP)