Now, startups' valuations begin to melt

Unicorns' rise is history and unpublicized down rounds the norm as 'gravity' takes hold

In ancient mythology, Chinese unicorns are lucky, rare creatures that appear to mark the arrival or death of a great leader, like Confucius. Today, China's tech unicorns - private companies valued at $1 billion or more - are far more commonplace and look increasingly cursed.

Four of the world's seven most valuable private companies are now Chinese, all founded in the past seven years. Didi Chuxing, the ride-hailing app, and Xiaomi, the smartphone manufacturer, for instance, both have valuations topping Airbnb and Snapchat. Five Chinese companies have valuations of at least $10 billion, and 37 are valued at $1 billion or more, according to research firm CB Insights.