A significant source of anxiety arises from the risk of back taxes related to grey market betting activities that occurred before regulation in Brazil. To address this, Brazil's Secretariat of Prizes and Bets (SPA) has teamed up with the Federal Revenue Service (RFB) to ensure compliance with new tax regulations. However, this partnership has sparked concerns that both operators and players might face liability for unpaid taxes from the five-year period between the approval of initial legislation in 2018 and the full market regulation in 2023. Tax attorney Luiz Felipe Maia cautions that operators may be required to submit historical data on winnings, which could result in retroactive tax claims.