Hope Apple investors had their seat belts fastened and their trays in the upright and locked position earlier today. Because they had quite the free-fall experience for a few minutes there -- even if it was a brief and seemingly accidental one.
Slightly before 11 a.m. ET, Apple shares suddenly plunged 9.4 percent, to $542.80, before an automatic "circuit breaker" cut in and halted trading. That was a drop of $57.69 from the opening price of $600.49.