Golly gee, what could be the big story in the U.S. markets today?

How about the rout in Facebook (FB) shares–down 18.96% or $41.24 to $176 at the close. That $112 billion dollar drop in the market value of Facebook gives the company the record for the largest one day drop in a company’s market value. Intel (INTC) held the record previously with a $91 billion loss back in 2000.

The plunge came as the company announced a growth stumble for the second quarter. Active daily users in June were 1.47 billion versus Wall Street projections for $1.48 billion. Growth in the company’s biggest market stalled at 185 million daily users and actually fell by 1% in Europe. Total average daily users were up 11% from the second quarter of 2017. That’s not the kind of growth investors are expecting from a stock trading at more than 30 times trailing 12-month earnings.

But the killer was lowered guidance.  On Facebook’s conference call Chief Financial Officer David Wehner told analysts that revenue growth rates would decline in the third and fourth quarters. That clearly blindsided analysts. On the call you can hear the incredulity with analysts repeatedly asking how the company’s financial projections had changed to quickly. It didn’t help that the explanations seemed, well, lame. Wehner said revenue growth would decline bruise of currency headwinds (That’s new? Or unexpected?), greater investment in some kinds of content-sharing (Investments of this sort don’t normally lower revenue) and greater user control over privacy. That last tapped into fears raised by recent criticism of Facebook and the huge $5 billion fine levied against the company by the European Union that perhaps users would fight harder to protect their data, which is what gives Facebook such value to advertisers.

Facebook took down the NASDAQ Composite today by 10.01%. The Standard & Poor’s 500 was off 0.30% and the Dow Jones Industrial Average slid 0.44%.

The extent of Facebook’s continued effect on the general market depends to a large degree on what Amazon (AMZN) announces when it reports earnings after the close today.