RANKED: The 15 Hottest Pre-IPO Adtech Startups Right Now

AppNexus, Brian O'KelleyRobert Libetti/ Business InsiderAppNexus CEO Brian O’Kelley

The adtech business is heating up in terms of IPOs and acquisitions. Half a dozen adtech companies have staged public offerings recently, with varying levels of success.

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In the last year or so we’ve seen IPOs from Millennial Media, which raised $US130 million, Tremor Video ($75 million), YuMe ($46 million), Rocket Fuel ($116 million), Marin Software ($105 million) and Criteo ($190 million).

On top of that, the sector is ripe for buyouts: Twitter just acquired MoPub for $US350 million in stock. AOL acquired Adap.tv for $US405 million.

Rumours are circulating heavily that AppNexus, the big New York ad server which serves both buyers and sellers, will stage an IPO sometime soon. Mobile ad company Flurry has said it will eventually be required to do so.

We decided to look at some of the hotter companies subject to IPO (or at least big exit deal) rumours right now. We’re not saying all these companies will file IPOs. But we are saying they’re ripe for “liquidity events” (big financial deals) of one sort or another.

Our data comes from Crunchbase, LinkedIn, our own reporting and that of other business publications. We’ve ranked the companies by employee headcount.

Martini Media: Adtech for the 1%.

Skip Brand

CEO: Skip Brand

Estimated revenues: unknown

Employees: 30

Total venture funding: $US33 million

Comment: Martini is one of the more interesting digital advertising plays: it concentrates exclusively on publishers that serve the wealthy. The company offers full-service marketing in web display, video, mobile, and social. It has a sponsored content partnership with Forbes.

Vungle: Backed by Google and AOL.

CEO: Zain Jaffer

Estimated revenues: unknown.

Employees: 35

Total venture funding: $US8.5 million

Comment: Vungle is at the nexus of the two hottest trends in adtech right now, mobile and video: The company has an in-app mobile video platform which allows developers to display video trailers in their apps. Its backers include Google Ventures and AOL Ventures.

Drawbridge: CEO Kamakshi is the queen of cross-device targeting

Kamakshi Sivaramakrishnan

CEO: Kamakshi Sivaramakrishnan

Estimated revenues: $US20 million

Employees: 45

Total venture funding: $US20.5 million

Comment: Drawbridge is a mobile ad buying platform for cross-device targeting, the task of figuring out if the person who just searched for sushi on a mobile phone is the same person who was shopping for shoes from a laptop 2 minutes prior. This will be a big year for Drawbridge as it attempts to scale up and prove its targeting model. Clients include Expedia, Groupon, HotelTonight, Square, and Kabam. She tempted Daryl McNutt, who left an svp position at BrightRoll, to join as vp/Marketing. Drawbridge has taken total venture funding of $US20.5 million.

xAd: Google's Waze partner.

Dipanshu Sharma

CEO: Dipanshu Sharma

Estimated revenues: $US30-45 million

Employees: 70-plus

Total venture funding: $US15 million

Comment: We believe xAd is profitable. Its clients include Macy's, Home Depot (direct) and YP. xAd also gets revenue from platform partners using xAd for their long tail. More importantly, xAd recently became the exclusive third-party provider of search and display mobile ads for Waze, Google's new mobile traffic mapping app.

Kenshoo: Close to Facebook.

Yoav Izhar-Prato

CEO: Yoav Izhar-Prato

Estimated revenues: Unknown

Employees: 116

Total venture funding: $US12 million

Comment: CEO has claimed that Kenshoo handles $US25 billion in spending through its search, local marketing, and social media platforms. Kenshoo is also one of Facebook's FBX ad exchange partners. Kenshoo is probably one of Facebook's bigger ad spending clients, judging by the fact that Facebook vp/advertising and global operations David Fischer turned up at its conference recently.

Outbrain: $US1 billion valuation but no IPO in 2013.

Yaron Galai

CEO: Yaron Galai

Estimated revenues: $US130 million

Employees: 140

Total venture funding: $US64 million

Comment: This content-recommendation company has hired a CFO with IPO experience although a filing is not expected this year. The Israeli press values Outbrain at $US1 billion.

Flurry: Too big to not go public.

Simon Khalaf

CEO: Simon Khalaf

Estimated revenues: $US100 million

Employees: 150

Total venture funding: $US50.5 million

Comment: 'I consider an IPO an entrance,' CEO Simon Khalaf told us. 'We don't have a choice, our volume is too high and our scale is too big for anyone to absorb us.'

Adchemy: A quiet giant.

Murthy Nukala

CEO: Murthy Nukala

Estimated revenues: unknown

Employees: 150

Total venture funding: $US119 million

Comment: Adchemy has raised a staggering sum of money from investors. But it is one of the quietest adtech companies out there. Backers include Accenture and Microsoft. The Foster City, Calif.-based company has reportedly spent spent eight years trying to create a simple process for buying, selling, and managing keyword search campaigns.

Socialbakers: Investing in scale and growth internationally.

Jan Rezab

CEO: Jan Rezab

Estimated revenues: $US25 million

Employees: 180

Total venture funding: $US8 million

Comment: Socialbakers 'would be profitable immediately if we were not investing in scale, growth and international,' Rezab tells us. The company is growing its offices in New York and San Francisco (it's based in Prague). SB also has 1,500 clients, including Nestle, Nissan, HP and eBay.

Rubicon Project: Flirting with Yahoo?

Frank Addante

CEO: Frank Addante

Estimated revenues: unknown

Employees: 250

Total venture funding: $US51 million

Comment: Said to be profitable. Rumoured to be considered a potential Yahoo acquisition. For the last couple of years, Addante has made trips to New York to show interested parties a slide deck about Rubicon's scale and power. He doesn't need to do that, of course, because everyone in the business knows how big Rubicon's ad network is: It's ranked No.1 in overall monthly ad reach by Quantcast, ahead of Google. Rubicon is a company that, like AppNexus, might be too big to do anything other than file an IPO.

Undertone: Bespoke services for clients who want premium video inventory.

Mike Cassidy

CEO: Mike Cassidy

Estimated revenues: $US200 million

Employees: 285

Total venture funding: $US40 million

Comment: Undertone is an unusual company in adtech in that it is not concerned so much with automating the process. Rather, it has a creative, media and tech platform that allows advertisers to create one video campaign that will work across all screens. The company tells us it expects to employ 320 by the end of the year and rise to 450 next year. CEO Cassidy says Undertone has been profitable since it was bootstrapped at its founding in 2002. He doesn't rule out an IPO, but says it's 'better to be a private company today.'

OpenX: Profitable but heavily funded.

Tim Cadogan

CEO: Tim Cadogan

Estimated revenues: $US135 million

Employees: 300

Total venture funding: $US75.5 million

Comment: Positions itself as a software-as-a-service platform company that offers ad serving, real-time bidding buying, and publishers. Company says it is profitable and Cadogan tells us he declines to rule out an IPO. The company has taken so much venture funding, however, that a non-IPO exit would require a massive valuation attached to it considering the company's current revenues.

PubMatic: Made key CFO hire.

Rajeev Goel

CEO: Rajeev Goel

Estimated revenues: unknown

Employees: 380

Total venture funding: $US63 million

Comment: PubMatic offers publishers a real-time bidding media sales platform. Hired a CFO with IPO experience in late 2011, and mentioned that in a press release. Hmm.

AppNexus: $US1 billion IPO expected soon.

Brian O'Kelley

CEO: Brian O'Kelley

Estimated revenues: Greater than $US50 million.

Employees: 500

Total venture funding: $US141 million

Comment: AppNexus handles at least $US700 million in adspend a year, and probably greater than that at this point. Given the size of its employee headcount, the publicly cited revenue number of $US50 million-plus seems very low. The company is such a big handler of online ads that it may be too big to be acquired, which is why it is the subject of constant IPO rumours.

InMobi: Probably the biggest non-public mobile ad business.

Naveen Tewari

CEO: Naveen Tewari

Estimated revenues: $US372 million

Employees: 900

Total venture funding: $US220 million

Comment: InMobi now has about 900 employees, making it one of the largest mobile ad business that has not gone public. Our back-of-the-envelope maths suggests InMobi's annual revenues could be ~$372 million annually. IDC puts InMobi's U.S. revenue alone at ~$40 million. Note that the company is not likely to be profitable, based on its employee base and this revenue estimate.

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