Really? They beat earnings estimates, so I would assumed the stock would have gone up, at least by a few percentage points.

I would say a 10% drop in a stock over a few hours is "plunging".

I hear plunge and I think time to by, but here are prices from last 30 days:

  286.94
  + 305.72
  - 289.66
  + 304.70
  - 294.08
  + 300.00
  - 291.21
  + 300.08
  - 280.69
  + 301.15
  - 284.45

I see numbers above the recent peak, and below the current low.