The 30 startups whose value ballooned the most during the 'steroid era' of funding

For the last four years, many startups have been chasing after a billion-dollar "unicorn" valuation.

Now that the $4, these richly valued companies are in the spotlight. Many will end up being worth a lot less than their last valuation. A few will surpass it.

Business Insider worked with PitchBook to rank the companies that juiced up their valuations the most since 2012.

Here are the top 30 companies who saw their valuations rise by at least $1 billion during the past 4 years, ranked by how those valuations have grown: