In what is likely the biggest funding round ever for a Ventura-based tech company, digital advertising firm The Trade Desk has raised $20 million in venture capital in a second financing round led by Hermes Growth Partners.

The Trade Desk is a technology platform that helps digital marketers structure their bids for online ad space to get the best bang for their buck out of each campaign. IA Ventures, which provided The Trade Desk with seed funding and its first formal venture capital round, also participated in the deal.

The company said the funding round will go toward international expansion in Europe, Asia Pacific, Australia and Northern Asia. In the past year, The Trade Desk has opened offices in Singapore; Sydney, Australia; and Hamburg, Germany. It has also extended its Ventura and New York offices in the United States.

“This round’s goal is to fuel uninhibited growth,” Jeff Green, CEO and founder of the company, said in a news release. “Nearly $600 billion is spent in all advertising globally each year, and right now [real-time bidding] represents only $4 billion. As budgets continue to shift into programmatic [buying], we are building a buyer’s platform that will power companies for years to come.”

Green is a co-founder of AdECN, one of the first advertising exchanges that allowed publishers to post advertising inventory for real-time bids by buyers, with auctions taking place within microseconds. Microsoft acquired AdECN in 2007, and Green later founded The Trade Desk in the Ventura Ventures Technology Center, an incubator above City Hall.

Following the funding round, Alex Kayyal of Hermes Growth Partners will join The Trade Desk’s board of directors. The company also said Chief Operating Officer Rob Perdue will join its board.