The combined market value of U.S. publishers EA and Activision has grown by $79 billion since 2012, largely thanks to the success of the games-as-a-service model.

A new report from DFC Intelligence broke the industry down into two segments, premium releases and games-as-a-service titles (also known as 'live games'), and found that the latter model has been fueling growth over the past six years.

The report shows that since homing in on the games-as-a-service model, EA has seen its market value leap to $33 billion from $4 billion since 2012. Activision witnessed an even bigger surge, with its value rising to $60 billion from $10 billion.

For those unfamiliar with the term, 'games-as-a-service' refers to those titles designed to be monetized beyond their initial sale -- usually though the release of purchasable extras like maps, skins, card packs, loot crates, and premium passes.

EA has a number of popular live service franchises in its portfolio, such as FIFA, Madden, NBA, Battlefield, and BioWare's upcoming online shooter Anthem.

Activision also has its fair share of successful live titles, with Destiny, Overwatch, and Call of Duty sitting next to mobile juggernauts like Candy Crush Saga and Bubble Witch Saga.

While the model has already proved lucrative for both companies, DFC claims there's still plenty of room for growth, highlighting the $1.6 billion earned by NCSoft's mobile title Lineage M -- almost as much as the $2 billion EA earned from its entire live roster last year -- as evidence of that untapped potential.