https://www.cnbc.com/2018/07/25/facebook-warns-investors-of-weakening-revenue-in-second-half-of-2018.html

Facebook warned its investors of weakening revenue for the second half of the year Wednesday, sending shares plunging more than 20 percent.

The latest guidance followed a revenue miss for the company and a report of lower daily active user counts in Europe. Chief Financial Officer David Wehner said shareholders can expect "revenue growth rates to decline by high single-digit percentages from prior quarters" for the third and fourth quarter.