23 startups that became unicorns in 2017, scoring valuations of $1 billion or more

Once upon a time, a startup worth $1 billion or more was considered to be a rare, almost mythical thing - a unicorn. But in the past few years, unicorns have become far more plentiful, more like horses.

A year ago, the venture capital industry looked like it was going to tighten its belt and bring valuations back to earth. But in 2017, venture investment continued to flow heavily and is on track to match or exceed dollars deployed in 2016, says PitchBook, a database that tracks such deals.

Mega deals, where investors poured giant sums into one company at a high valuation, made up less than 1% of total transactions, but, by the third quarter, PitchBook says they accounted for 22% of the total deal value.

All of that means that new unicorns were plentiful in 2017. Dozens of startups were crowned with unicorn status worldwide, including these 23 US companies, according to CB Insight's list of unicorns. (We took the valuations of these companies from Pitchbook.)

Some of them, you've likely heard of. Others may have slipped under your radar.