Sell-side advertising platform Magnite - which recently announced a deal with Australia's Seven Network - is set to grow with the acquisition of SpotX from RTL Group.

The definitive agreement sees Magnite pay US$1.17 billion (A$1.51 billion) in cash and stock for what is one of the world's leading platforms for CTV and video advertising. Magnite plans to finance the transaction with cash on hand, 14 million shares issued to RTL Group and committed financing from Goldman Sachs.

Together, Magnite and SpotX will become the largest independent CTV and video advertising platform in the programmatic marketplace. The combined company will add competition to the CTV advertising market according to the announcement.