The nascent sports betting industry is booming in Illinois, growing into the third-largest market in the U.S. after just two years of pandemic-disrupted operation.

But the state may soon come up empty in its efforts to add three new online-only sportsbooks to a roster already loaded with national players such as DraftKings, FanDuel and BetMGM, the increasingly dominant leaders of the online segment.

Four companies applied to the Illinois Gaming Board in December for the three online licenses, which are not tethered to casinos, racetracks or sports venues, but carry a hefty $20 million licensing fee — twice the maximum for online sportsbooks with bricks-and-mortar partnerships.