Iowa sportsbooks saw revenue fall to $3.6m in November, a decline of 36% from the previous month.
The drop of revenue occurred despite a 28% rise in handle to $59.3m.
The William Hill Sportsbook at Prairie Meadows Casino near Des Moines took $1m in revenue to lead the state.
Revenue at Prairie Meadows fell 41% month-on-month despite handle growing by nearly $3m. Online wagering accounted for 93% of the casino’s handle.
The FanDuel Sportsbook at Diamond Jo Worth Casino in Dubuque placed second with $403,000 of revenue.
Ameristar Casino in Council Bluffs came third with $343,000, down 27% from last month.
William Hill operates at Isle Casino Hotel Waterloo, which came in right behind with $326,000, a decline of 21%.
Across the state, online sports wagering accounted for 57% of all handle.
Of the 19 active sportsbooks in Iowa, only nine currently provide online sports betting. That leaves Iowa’s sports wagering market open to plenty of growth.
Bettors in The Hawkeye State won bets in November at a considerably higher rate than the prior month.
Iowa is one of many states learning that, as bettors gain experience, sportsbooks are liable to see their revenue margins shrink over time.