There could hardly be a starker contrast in stock market fortunes. Apple's shares have perked up last week after a strong earnings report, making it the first company to be worth US$1 trillion (S$1.4 trillion). One week earlier, Facebook's stock plummeted on a downbeat forecast, wiping nearly US$120 billion from its worth in Wall Street's eyes - the biggest one-day destruction of value ever for a US company.

The dramatic headlines were partly a reminder of the outsized impact the tech giants have on the wider investment world. Facebook's reversal reflected the kind of change in perception that often happens when high-growth companies enter a more uncertain period - it is only the company's sheer size, its stock market value is still above US$500 billion, that made the effect so startling. The bigger they come, the harder they fall.