A tweet by Kylie Jenner led to a $1.3bn (£930m) fall in the value Snap Inc, the parent company of Snapchat.
Shares (Berlin: DI6.BE - news) in the social media company plunged by 6% on Thursday - hours after the reality star asked her 24.5 million Twitter (Frankfurt: A1W6XZ - news) followers: "sooo does anyone else not open Snapchat anymore? Or is it just me..."
Jenner's comments came after Snap Inc faced a barrage of criticism over the way a new update has changed Snapchat's user interface.
More than 1.2 million people have signed a Change.org petition calling on the company to remove the update.
When Wall Street opened on Thursday, Snap Inc was trading at around $18.50 (£13.27) a share, but by 2pm it had fallen to just over $17 (£12.20) a share.
It later rallied to around $17.50 (£12.56) a share.
Snap Inc made a statement in response to the petition, saying: "We hear you, and appreciate that you took the time to let us know how you feel. We completely understand the new Snapchat has felt uncomfortable for many.
"By putting everything from your friends in one place, our goal was to make it easier to connect with the people you care about most.
"The new Friends page will adapt to you and get smarter over time, reflecting who you're most likely to be Snapping with at that moment."
Snap's chief executive and founder Evan Spiegel, who was recently awarded $638m (£458m) in stock-based awards in 2017, has also ruled out reverting to the original version.
Jenner is not the only celebrity who has taken a dim view to the update.
Snap floated in July last year at $17 a share and only recently achieved the same price having been below the level for the second half of 2017 and start of 2018.