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,

The fantasy sports craze has been growing so much, and so fast, that regulators are still trying to come to grips with whether or not the activity involves gambling.

Daily fantasy football, which is expected to take in $2.6 billion in entry fees on top of $2 billion to $10 billion in ad revenues this year, was accused by some of fostering insider trading last week after revelations that employees of DraftKings were using company information to win millions in competitions on FanDuel. New York Attorney General Eric Schneiderman announced he has launched an investigation into the websites as a result of the allegations.

In the daily fantasy football schemes, fans select from the same pot of players from the 32 NFL teams, but players can be held by more than one individual contestant. Once all participants have selected their players, the organizing companies reveal how many fantasy participants have drafted each individual player.

If a participant has the same players as everyone else, their chances of winning are reduced, which means a participant selecting players that are drafted less often but still could contribute points can maximize their opportunity to win. DraftKings employees allegedly used this type of information from their own site to win big at their competitor’s site.

Last week, a DraftKings employee was revealed to have released information beneficial to fantasy football participants prior to games being played. The employee in question allegedly won $350,000 playing on Fan Duel on the same day. ESPN reported that DraftKings employees have won about $6 million on FanDuel this year alone.

According to the Sports Business Journal, 91 percent of the winnings on DraftKings and Fan Duel go to just 1.3 percent of the users. However, it is unclear what portion of that 1.3 percent are employed by the companies.