Ad Tech Sector Sees Solid IPOs, But Threats Loom

The IPO of the Rubicon Project this week is the latest indication that public markets have warmed to the ad tech sector, a diverse group of companies that has had its ups and downs on Wall Street despite the online advertising boom. But Google and other Internet giants, which operate their own ad networks and control huge swaths of ad inventory, still pose a major competitive threat to independent ad tech firms.

Rubicon, which raised $81.3 million in its IPO and saw its stock jump 33 percent in its first day of trading Wednesday, is a so-called supply side ad tech company. It provides an automated platform for publishers to sell its inventory to a network of ad buyers. Its public offering was a successful sequel to the September IPO of Rocket Fuel and the October IPO of Criteo, both of which are so-called demand-side firms that offer tools and services to advertisers.