Nearly half of tech 'unicorns' rely on tricky math to land imaginary valuations

Two business professors studied the valuations of 116 unicorns, finding that many overstated their value.
When they adjusted valuations for special protections provided to VC investors, nearly half of unicorns lost their coveted $1 billion status.
Tech "unicorns," once a rarity, have become commonplace.
Some 200 now exist around the world — with more than half coming from the US — earning an aggregate valuation of $600 billion, according to a recent study by two business profess