New data has shed further doubt on the long-term viability of the daily fantasy sports (DFS) industry.

Ed Miller, author of numerous books on poker strategy, and Daniel Singer, senior adviser of the McKinsey & Company Global Sports and Gaming Practice, published an article on Sports Business Journal addressing “the curse of too much skill.” Specifically, the pair voiced concerns about how a miniscule percentage of DFS players are using technological aids to capture the bulk of player winnings.

According to the authors’ stats, which Miller said were “collected by a third party from publicly available pages,” the overwhelming majority (80%) of DFS players were considered minnows, responsible for only around 8% of total DFS entry fees. Over the first half of the 2015 Major League Baseball season, these minnows spent an average of $49 in entry fees, half of which they ended up losing.

Meanwhile, just 1.3% of all DFS players accounted for 40% of fees and won 91% of player profits. The bulk of this upper echelon spent an average of $9,100 on fees, on which they realized profits of $2,400, while accounting for 23% of all fees and 77% of the profits.