A new research report from the ad data and analysis firm Turn says advertisers are spending 500 percent more on digital media to reach Millennials than on media to reach all other consumer groups. Millennials are ages 18 through 35. There are 75 million of them in the U.S. And they have the expendable income that advertisers want. Badly.

Turn breaks it down this way: Advertisers spend four times as much on display, four times as much on social, four and a half times as much on mobile, and six times as much on video to reach Millennials versus any other group.

Turn says Millennials are “the greatest market opportunity the world has ever seen.”

The firm points out that all Millenniums are not created equal, and that the group can be divided into four distinct categories:

Struggling Aspirationals (57%) — People in this, the largest chunk of Millennials, have make less than $50,000 annually, are healthy, fit and green. They’re picky about food and spend time hunting for bargains.

Comfortable TV Watchers (8%) — The primarily Republican group likes to watch TV.

Active Affluents (17%) — These are the nest builders and the parents of kids. They’re outdoorsy, and into food and fitness. Turn believes marketers ought to be targeting this group more on mobile platforms.

Successful Homeowners (18% of millennials) — This richest class of Millenials makes $100,000 or more annually, and are likely to own homes. Turn says this crowd is reachable through video ads. “Marketers should align high-impact media with an audience that’s ready to spend.”

Hat tip: Adweek