Instagram has been slapped with a record fine of 405 million euros ($402 million) by Ireland’s data privacy regulator following an investigation into the social network’s handling of teenagers’ personal data, a spokesperson for the watchdog said.

Instagram plans to appeal against the fine, a spokesperson for parent company Meta Platforms Inc. said in an emailed statement.

The penalty is the second-biggest issued under the European Union’s stringent privacy rules, after Luxembourg’s regulators fined Amazon 746 million euros last year.

Meta said that while it had "engaged fully" with regulators throughout the investigation, "we disagree with how this fine was calculated and intend to appeal it."

The investigation, which started in 2020, centered on how Instagram displayed the personal details of users ages 13 to 17, including email addresses and phone numbers. The minimum age for Instagram users is 13.

The investigation began after a data scientist found that users, including those under 18, were switching to business accounts and had their contact information displayed on their profiles. Users were apparently doing it to see statistics on how many likes their posts were getting after Instagram started removing the feature from personal accounts in some countries to help with mental health.

"We adopted our final decision last Friday and it does contain a fine of 405 million euro," said the spokesperson for Ireland’s Data Protection Commissioner (DPC), the lead regulator of Meta.

Full details of the decision will be published next week, he said.

Instagram updated its settings over a year ago and has since released new features to keep teens safe and their information private, the Meta spokesperson said.

The spokesperson said Instagram disagrees with how the fine was calculated and is carefully reviewing the decision.

The DPC regulates Facebook, Apple, Google and other technology giants due to the location of their EU headquarters in Ireland. It has opened over a dozen investigations into Meta companies, including Facebook and WhatsApp.

WhatsApp was fined a record 225 million euros last year for failing to conform with EU data rules in 2018.

The Irish regulator completed a draft ruling in the Instagram investigation in December and shared it with other European Union regulators under the bloc’s "one stop shop" system of regulating large multinationals.