Many technology companies suffered setbacks but eventually weathered the dot.com bust, and most tech enterprises came through the Great Recession rather unscathed. And now, well, how about one trillion dollars? Apple’s market capitalization is equal to the entire country’s annual budget deficit. But then, more tech companies than just Apple have had remarkable valuations in today’s blustery market-capitalization bonanza. For instance, Facebook, Google (Alphabet), Netflix and Amazon delivered roughly half of all the gains achieved in the Standard & Poor’s 500-stock index this year. Together, one group, the so-called FANG (Facebook, Amazon, Netflix and Google) plus Apple (often called FAANG) has a combined market cap that exceeds in value the entire gross domestic product of England. So yes, they are doing fine – actually better than fine. But, as we wrote in the run-up to the housing-market collapse, are these stock valuations “leaning on air”?