Brands will have access to 60 million people consuming digital radio, music streaming services and podcasts in Europe.
Global said it will make Dax the "single biggest audio platform across the continent, with both direct and programmatic buying options".
Oliver Deane, the commercial digital director at Global, said there has been an increase in listening and demand from clients.
He also announced that Global will set up its first international sales team, grow its digital account management team and take on a number of creatives to work on pan-European campaigns.
The creatives will report into Jo McCrostie, the creative director at Global.
The company launched Dax on June last year to give brands a single place to buy ads for more than 140 digital audio platforms including Rdio, Musicovery, audioBoom, Ministry of Sound, as well as Global’s radio brands including Capital, Heart, Radio X, Classic FM and LBC, and Bauer’s Absolute Radio network.
Mike Gordon, the chief commercial officer at Global, said: "We created Dax to give brands access to the digital audio market in one single buy. The growth we’ve experienced in just over a year has defied our expectations.
"In that period, we’ve signed up more than 140 digital audio publishers, 250 forward-thinking advertisers, grown our audience from zero to seven million and demonstrated the power of digital audio to deliver brand messages and help drive traffic to brands’ websites and apps through research among 400,000 smartphone users.
"In the US digital audio is a multi-billion dollar industry with Pandora leading the market. Our vision for Dax is to recreate the US market across Europe."