Any public company's valuation is the sum of every vested actor's belief in the stock's promise of (future) value. It definitely doesn't mean that Twitter has $

Any public company's valuation is the sum of every vested actor's belief in the stock's promise of (future) value. It definitely doesn't mean that Twitter has $11 billion in the bank. If anything happens that makes vested individuals doubt that Twitter is worth as much as it is, its value will drop, as it did right after the Q2 2016 earnings report was released.