Snapchat redesigns its app again. Stock plunges

Shares of the social media company plunged Wednesday after it changed its app again — only months after a previous redesign that ticked off users.

Snap (SNAP) stock closed down 7%, putting it more than 15% below the price when it went public last year.

Last year, Snapchat changed the app to differentiate between a user's personal friends and media superstars that a user follows. Many fans revolted. So did Wall Street.

The latest changes appear to backtrack. On the same Discover page, some users now see a test that shows Stories from their friends as well as posts from celebrities and other "influencers" that they subscribe to.

"We are always listening to our community and will continue to test updates that we hope will give Snapchatters the best possible experience on our platform," a Snapchat spokesperson told CNNMoney in response to a question about the changes.

Celebrities aren't pleased with Snap lately, either.

Kylie Jenner bashed Snapchat in February. Her tweet criticizing the redesign — she called it "so sad" — caused the stock to tank. Jenner later took a literal baby step back toward Snapchat, posting videos of her infant daughter, Stormi, to the platform.)

Related: The Kylie Jenner curse? Snapchat faces its defining moment

And just last month, Rihanna attacked the company after an ad on Snapchat made light of a 2009 incident in which Rihanna's former boyfriend Chris Brown was arrested. He later pleaded guilty to beating her during an argument.

The constant rejiggering of Snapchat has clearly annoyed lots of users, though, not just famous people. It's making investors nervous, too. And it couldn't happen at a worse time for the company.

It's still not clear that Snapchat will ever be able to be profitable enough to live up to the hype before it went public. Snapchat rallied after its last "earnings" report, but investors still worry about slow user growth.

In many respects, Snapchat's challenges are similar to those of Twitter (TWTR) — a company that never can seem to satisfy Wall Street. Twitter stock fell Wednesday even though the company reported revenue and profit that topped forecasts.

Concerns about privacy for social media users have reached new heights since the Facebook/Cambridge Analytica data scandal.

Of course, Facebook (FB) also owns Snapchat's fiercest rival, Instagram. Many investors worry that Snapchat won't ever top Instagram's user count, especially if Instagram keeps rolling out features similar to Snapchat's.

Facebook will report its latest earnings, including Instagram user numbers, after the market closes Wednesday.

— CNNMoney's Kaya Yurieff contributed to this story.