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


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.

Three of the companies on last year’s ad tech startup ranking have since been acquired.

This ranking (and, yes, we were debating whether to lose the “pre-IPO” headline) looks at the hottest private ad tech companies right now.

Our data comes from CrunchBase, LinkedIn, our own reporting, that of other business publications, and the advice of a handful of ad tech industry insiders.

Our ranking takes into account: Revenues, headcount, venture funding, recent news, whispers, and reputation. Last year’s ranking was more weighted toward revenue, whereas this year’s ranking takes into account more metrics than revenue alone. (One company in the list is even pre-revenue!)

29. xAd: A mobile location specialist with triple-digit revenue growth

29. xAd: A mobile location specialist with triple-digit revenue growth

CEO: Dipanshu Sharma

Employees: 364

Estimated revenue: xAd said in May it had achieved a $250 million revenue run-rate. (That’s gross revenue, though. We couldn’t get closer to an accurate net figure.)

Total funding to date: $74 million

Comment: EMarketer’s Mobile Stat Pack 2016 report listed xAd as the “largest player in mobile location marketing” in terms of mobile and display revenue.  The company says it generated 100% revenue growth year over year in May.

The company also recently appointed former Google and Yahoo exec Shashi Seth as its chief product officer.

View the entire article on Business Insider.