Millions of Americans tune into the National Football League’s games because they have money riding on "fantasy" football teams they’ve created from active players—but very few affluent Americans will join them.

Nearly 60 million people participate in fantasy football leagues in the U.S. and Canada, but according to research from Spectrem’s Group, just 6 percent of Americans with more than $100,000 in assets will participate.

Fifteen percent of investors with a net worth of less than $100,000 play fantasy football, while just 3 percent of those with more than $5 million play, according to Spectrem.

In fantasy football, fans create personalized teams constructed from the full rosters of all 32 NFL teams, and then compete against each other for money or fun. Traditionally, fantasy football was an ad-hoc, social endeavor where groups of fans bought into the competition, tracked their players throughout the season and competed with each other for the pot of winnings. Fans score points based on touchdowns, field goals, and passing, rushing and defensive statistics.

In recent years, however, it has become a big business, with millions of fans using real money to enroll in online fantasy websites such as DraftKings and Fan DUel, some of which have licensing agreements with professional sports leagues and teams.

But affluent investors are largely watching from the sidelines, perhaps because of fantasy sports’ association with gambling—though fantasy sports is legal in all 50 states. 

Fantasy football appears to be a young person’s game—around 23 percent of investors under the age of 40 play fantasy football, while only 4 percent of those older than 60 do so, according to Spectrem.

Surprisingly, Spectrem's research indicates fantasy football participation is evenly split between men and women.

Online sports fantasy websites allow fans from across the country to create fantasy football groups, and sites such as DraftKings and Fan Duel allow participants to compete head-to-head on a daily basis for winnings. The traditional, season-long campaigns remain more popular, with 72 percent of participants concentrating on drafting a team they manage for months at a time, while just 17 percent selected the daily alternatives, according to Spectrem.

For its research, Spectrem surveyed 1,000 affluent investors earlier this year,