and extending into the morning trading.

Now, for a company of that size,

that equates to roughly $123 billion of market value evaporating in just one day.

That's the biggest one-day loss of any US company in history.

It is roughly the same as the value of all of McDonald's or even greater than Goldman Sachs, Nike, or General Electric.

Now, what caused this huge slide?

Well, Facebook reported disappointing earnings on Wednesday evening.

Facebook has had a good run for a long time,

and its shares actually hit a record leading up to the earnings.

But on the call and in the numbers,

Facebook revealed that its user growth numbers are slowing in every major region.

And its revenue per user is also slowing.

Now, it's important to remember that Facebook is still a very profitable company.

It still has margins that would be the envy of almost every other company in the world.

But when people had been projecting that this growth rate would continue almost indefinitely,

this came as a very nasty surprise to investors.

And that's why they panicked yesterday evening

and pushed the shares out dramatically,

and it's extended into the morning.

Analysts and investors say that this is partially a reflection of just how extended Facebook's shares had become leading into the earnings.

And they stress that actually Facebook is still a company that is growing at a healthy clip.

And this is a healthy correction for a company.

However, this is clearly a reminder that Facebook is still under pressure on many fronts.

Its user growth is slowing.

It's facing more regulatory scrutiny after the Cambridge Analytica scandal that erupted in early March.

Until those clouds dissipate,

investors are going to be very wary of dipping back into the social media giant's stocks.