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This final note in which we're obliged to again caution investors to double check those ticker symbols before hitting the buy button.

Remember when Twitter went public and shares of a home entertainment company with the symbol TWTRQ went bananas.

It happened again today with the ticket symbol NEST, which is not the thermostat company Google spend $3.2 billion to buy.

NEST is in fact a penny stock -- a bankrupt red-light traffic camera company, in point of fact.

But at one point today, shares were up 1,900 percent to $0.10. 

Follow Kai Ryssdal at @kairyssdal