How does a company lose $39 billion in value in just a few weeks? This week we’re diving into all the unicorn companies that rode a wave of venture capital hype onto the rocky, unforgiving shores of the stock market. It’s not just WeWork either — Uber, Slack, Snap and plenty of other tech darlings have struggled after their splashy IPOs. Is it the exception or the rule? And what’s it say about how investors assess a company’s value? Here to help us sort through it is the New York Times’ Erin Griffith, who reports on startups and the VC world.