At BetRivers, 20% of all NFL bets have been SGPs. And half of all new users place one in their first week. Our friends at SportsHandle reported that half of FanDuel's active users who bet the NFL in 2021 have also bet an SGP.
They called it the Same Game Parlay, it became wildly popular, and every major sportsbook launched its own version (some under different names, since FanDuel is trying to trademark same game parlay).
Then magically in 2019, FanDuel began letting bettors create parlays on the same game and started marketing it like crazy. If one happens, the other is more likely, so they didn't want you to get the full multiplier a parlay offers. Many 21st-century sportsbooks stopped letting you parlay two bets from the same game, like a point spread and the over together, because those bets could be correlated.
