This “will create some anxiety around Facebook and other social media companies,” wrote Adam Crisafulli, founder of the Vital Knowledge newsletter. Snap shares tumbled as much as 30%.

Read more: Snap Tumbles as Apple Changes, Supply Chain Weigh on Ads

The warning was the latest blow for Facebook, whose shares haven’t rebounded as strongly as peers after a selloff last month amid whistleblower allegations that prompted renewed scrutiny of its services. The stock had fallen 11% from a September record, based on Thursday’s closing price.

Facebook is due to report earnings on Monday, followed by Alphabet and Twitter on Tuesday.

Snap’s report also weighed on other parts of the digital advertising ecosystem. Trade Desk Inc., which owns a platform for buying and managing ads, fell more than 5%, while peer PubMatic Inc. dropped 4%.

Pinterest Inc., which rallied this week on a report that PayPal is exploring a purchase of the company, also fell in after-hours trading, declining more than 2%.