First of all, market capitalisation is only the measure of the number of outstanding shares multiplied by the current price. You are absolutely kidding yourself if you think that all the FB shares in existence could be sold at the current NASDAQ closing price.<p>Secondly, to achieve the current $296Bn market capitalisation, investors are rating the company at <i>sixty-six</i> times 2015 earnings. That means that FB better be growing at an obscene rate for the very long term, because as we say in the market, FB is &quot;priced for perfection&quot;. Any hiccups in earnings or signs of faltering growth and investors will be just as quick to de-rate the FB price as they have been for TWTR. So it can be &quot;worth&quot; $296Bn one day and significantly less than that the next.