Real-time Ad Bidding Platform AppNexus Raises $75M In Series D Funding

Advertising technology companies are not exactly the most well-known names to the average web user, but they can certainly garner serious attention from those inside the industry — particularly investors. Case in point: AppNexus, the New York City-based company that runs a real-time bidding platform for ad networks, said today it has closed on $75 million in funding.

The round, which serves as AppNexus’ Series D, was led by Technology Crossover Ventures with the participation of Venrock and Tribeca Venture Partners. This brings the total venture capital investment in the six-year-old AppNexus to $140.5 million; the company’s other investors include Microsoft, Kodiak Venture Partners, First Round Capital, Marc Andreessen, Ben Horowitz, Ron Conway and Khosla Ventures.

These big-name backers likely see AppNexus as a good bet partly because of the pedigree of its co-founder and CEO Brian O’Kelley. Before AppNexus, the Princeton-educated O’Kelley created the first successful ad exchange platform as the CTO of Right Media, which went on to be acquired by Yahoo for a cool $850 million back in July 2007.

AppNexus says that the new funding comes after the close of a successful year. In 2012, the company says it managed some $700 million of advertising spend and nearly tripled its revenues. AppNexus’ staff now numbers more than 400 employees across nine offices worldwide.