Facebook is to end its partnerships with several large data brokers who use personal information to help advertisers target people on the social network.
The world's largest social media company has announced a series of changes to the way it operates since its involvement in a historic data scandal emerged last week, including the implementation of new privacy tools that let users delete data for good.
It has now moved to scrap relationships with Acxiom and Experian, which had been collecting data from Facebook profiles to power a tool used by advertisers to target specific people.
Graham Mudd, a product marketing director at Facebook, said: "While this is common industry practice, we believe this step, winding down over the next six months will help improve privacy on Facebook."
Acxiom shares dropped more than 10% to $25 (£17.76) following the announcement, but shares in other similar companies – including Oracle Data Cloud, TransUnion and WPP PLC – did not change dramatically.
Shares in Facebook itself remain more than 17% down since mid-March, when reports emerged that political consultancy firm Cambridge Analytica – which was hired by Donald Trump's presidential campaign team – had allegedly illegally harvested information from 50 million Facebook users.
Facebook shares were trading at $153.03 (£108.72) on Wednesday and the company has declined to comment on how its latest changes may affect advertising revenue.
Chief executive and founder Mark Zuckerberg has apologised for the mistakes the company made and said he is committed to cracking down on abuse of the Facebook platform.
He said it will continue to restrict developers' access to user information, having come under fire from politicians on both sides of the Atlantic.
A number of high-profile companies have responded to the scandal by deleting their Facebook pages, including Playboy, Tesla and Mozilla, and a Sky Data poll revealed that public trust in the company had declined.
Apple chief executive Tim Cook has also hit out at Facebook's policies, describing users' privacy as a "human right".
In an interview with Recode and MSNBC to be broadcast next week, he said: "We could make a ton of money if we monetised our customers, if our customers were our product.
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"We've elected not to do that. We're not going to traffic in your personal life. Privacy to us is a human right, a civil liberty."
And in a final swipe at his Facebook counterpart, when asked what he would do if he were in Mr Zuckerberg's position, Mr Cook said: "I wouldn't be in this situation."