Facebook's stock suffered its worst day in six years as a public company Thursday after it reported a revenue miss and disappointing daily active user count Wednesday.

Shares lost 20 percent during trading, turning negative on the year.

Facebook had clawed its way back from bear market territory after the company's Cambridge Analytica privacy scandal and widespread reports of fake news, hate speech and foreign misinformation campaigns.

But CEO Mark Zuckerberg and the company's top executives delivered some jarring warnings to investors on the company's earnings call — forecasting weaker revenue and tightening margins.

At least three analysts downgraded the stock after the report, and many on Wall Street raised concerns about the company's policies and forecast.