Facebook has made a big push into mobile marketing with its latest ad buy.

The social network recently bought a $1.5 billion deal with adtech firm Admob, the Wall Street Times reports.

The deal with Admob is the largest mobile ad buy by a social network, and it will reportedly allow Facebook to build out its own ad inventory.

The news comes a week after the social network’s advertising arm, AdWords, purchased mobile analytics company AppNexus for $1 billion.

The ad buy with AdMob comes a few weeks after Facebook’s parent company, Facebook, announced a $10 billion acquisition of messaging app WhatsApp for $19 billion.

Facebook also recently rolled out an ad deal with Snapchat, the first of its kind.

In all, Facebook spent $3.2 billion on mobile ad buys over the past year.

Facebook has a massive ad inventory in the form of ads for products and services that advertisers want to target, including: apps and games