Google’s DoubleClick display ad exchange generates 188% more revenue than its rivals, according to a Google blog post.

It also said DoubleClick had tripled its transactions in the last 12 months.

Neal Mohan, Google VP of product management, told Paid Content that the recovery of display had led to “surprising” growth and the ad exchange generating 188% more revenue than rival exchanges.

According to the Google blog, the increase has been as a result of increased demand for publisher inventory fuelled by the success of AdWords and the Google display network.

“Display advertising spend among Google’s largest 1,000 advertisers increased 75% in the past year,” the blog said.” Agency trading desks and new third-party technology providers are also running more display ads through the ad exchange. And real-time bidding – which enables advertisers to tailor their bids and ads in real time to buy the ad space they value the most – continues to be a major draw, now accounting for 56% of buyers’ spend.”

Google has also added private ad slots – invite-only buying to select brands and media agencies – to its ad exchange to help publishers gain greater control over price floors.

It joins a growing number of online media companies facilitating private buying. Online media owners including IDG and Weather.com have done so through supply-side platform AdMeld as a way of cutting through third-party margins from platforms including ad exchanges.

56% of online media buying in the US is now thought to be through real time bidding, according to the blog post.