Apple could buy every tech company not named Google(GOOG), Microsoft(MSFT), Facebook(FB), Amazon(AMZN) or Verizon(VZ).
But only Google and Microsoft are way out of Apple's reach -- it might be able to buy Amazon or Verizon in a quarter or two and Facebook in a year or so.
If Tim Cook got the buying itch, he could walk over to the headquarters of Oracle(ORCL), Intel(INTC), AT&T(T), IBM(IBM), Cisco(CSCO) or Qualcomm(QCOM) with enough cash to buy any of those companies.
