Snap's stock market value dropped by $1.3 billion over a tweet from Kylie Jenner.
The reality TV star - who is highly influential when it comes to her fan base and trends - tweeted that she no longer uses the company's Snapchat messaging app, reaching 24.5 million followers on Twitter.
She wrote: "sooo does anyone else not open Snapchat anymore? Or is it just me... ugh this is so sad."
However, she later added: "still love you tho snap... my first love (sic)".
As reported by the BBC, the initial tweet saw Snaps' shares drop by almost 8 per cent, and they closed 6 per cent down on Wall Street before getting close to the $17 price they were listed at when the company floated on the stock market in March 2017.
One million people signed a petition demanding Snap roll back the change.
Ms Jenner's comment comes as investors are said to be worried amid competition from the Facebook-owned Instagram app, which has proven popular with celebrity users.
It comes after Snapchat boss Evan Spiegel refused to abandon the app's November image overhaul, which saw more than one million users sign a petition in protest.
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