The Trade Desk turned buying ads into something like trading stocks. Its software let agencies bid for ad space across thousands of websites, apps and video services in real time. Google and Facebook owned their own media. The Trade Desk owned none, so it pitched itself as a neutral tool that worked only for buyers. When it filed to go public in 2016, ad tech stocks had fallen out of favor after several weak offerings.

A Second Exchange Founder

Jeff Green and Dave Pickles founded The Trade Desk in Ventura, California, in 2009. Green had already started AdECN, an ad exchange that Microsoft bought. The two saw online advertising turning into a market much like stock trading. They bet that buyers would want an independent platform that worked only for them, with no conflict from selling ads. Its customers became mostly ad agencies and large brands.

Profitable, Then Connected TV

The Trade Desk priced at $18 a share in September 2016 and jumped on its first day. Unlike many ad tech peers, it was already profitable. The stock climbed for years as connected TV advertising grew. The company has stayed independent and kept its focus on serving ad buyers. It remains a public company led by Jeff Green, and its shares trade on Nasdaq.

Cover: The Stock Exchange, Joseph Pennell. Art Institute of Chicago, public domain. Chosen for a stock exchange floor (ad trading).