"When a venture capitalist coined the concept 'unicorn club' in 2013, it referred to software start-ups valued at $1 billion or more — just 39 at that time. ... Today, Dow Jones VentureSource tracks 170 unicorns," Barron's writes in its cover story:

• "[T]he unicorns have preferred to raise funds behind closed doors. Just 32 have gone through with initial public offerings ... Large companies like Uber Technologies, Dropbox, Lyft, Spotify, and Airbnb have so far spurned the public market.
• "As the private companies become household names, they face questions about their workplace cultures, business models — and valuations.
• Why it matters: "The unicorn experience is teaching us an unexpected lesson: The public markets remain the best place to achieve long-term corporate success."
• Positive impact of scrutiny and disclosure: "For some unicorns, public disclosures leading up to the IPO have revealed underlying business issues — problems that had been hidden away."