RANKED: The 37 hottest pre-IPO ad tech startups of 2016

The ad tech IPO market has dried up in the last 18 months. Public ad tech stocks have fallen 13% this year. But the private ad tech market is still bustling. Plenty of ad tech companies are getting snapped up by larger firms, raising VC money (although, admittedly, some of the rounds aren’t as big as they used to be), or simply steadily growing their businesses quarter-on-quarter.