The Facebook boss has apologised about the alleged misuse of data.
Mark Zuckerberg admitted to CNN that the social media site had made a mistake in trusting Cambridge Analytica.
The British company's accused of harvesting millions of people's details and using the data to predict and influence elections.
Facebook's share price has tumbled in recent days, but Mr Zuckerberg says it hasn't seen a significant number of people deleting their profiles.
