Asos shares slumped the most in a year after users of its shopping app received a notification indicating its systems were hacked.

The notification, widely reported on social media, appeared to refer to the British online shopping platform’s data protection officer, as well as the Snowflake online data platform.

“Dear Asos DPO and IT, we have fully compromised the Snowflake instance,” the notification said, alongside a link to a Telegram chat. “Engage with us, or we will leak it.”

A spokesperson for Asos had no immediate comment, while Snowflake didn’t immediately respond to a request for comment.

Asos had 16.4 million active customers in more than 100 markets as of the end of its 2026 fiscal year. Its stock fell as much as 13 per cent in London, the largest intraday since September 2025, before paring the drop. Snowflake shares fell as much as 3.2 per cent in premarket trading in New York.

Hacking is proliferating, aided by artificial intelligence tools and sophisticated cybercrime groups, such as ShinyHunters, that target large organisations to steal data. A number of UK businesses have been affected recently.

Marks & Spencer endured months of disruption after an attack last year forced it to pause online clothing and home orders. The retailer was one of several targeted by hackers at around the same time, including rival co-op and luxury department store Harrods.

Jaguar Land Rover was also hit by a major cyberattack last year that led to the automaker shutting down factories around the world. – Bloomberg