Britain's data watchdog on Tuesday said it has fined online discussion site Reddit £14.5 million ($19.5 million) over failures to protect children's personal data.
The Information Commissioner's Office said the US-based company failed to check children's ages properly and did not complete a required risk assessment for children before January 2025.
"These failures meant Reddit was using children’s data unlawfully, potentially exposing them to inappropriate and harmful content," the ICO said in a statement.
U.S.-based Reddit had launched a legal challenge to Australia's social media ban for under-16s in December, 2025.
Australia became the first to ban young teen accounts from a raft of popular apps and sites including TikTok, YouTube and Instagram.
Court filings by US-based Reddit challenged the validity of the law that "infringes the implied freedom of political communication", calling for a review by Australia's High Court.
The filing also argued that the company should be exempt from the government's list of banned platforms, on the grounds that it is an online discussion forum aimed at adults.
"Unlike other platforms included under this law, the vast majority of Redditors are adults, we don't market or target advertising to children under 18," a Reddit statement said.
"Simply put, users under 16 are not a substantial market segment for Reddit and we don't intend them to be."
Pointing to the site's age rating of "17+" on the Apple App Store, Reddit said the best way to verify age was at the app store level rather than requiring each platform to carry out checks.