Sports wager winnings are taxable income and must be reported as such if winnings total $600 or more in a year. If that’s the case, ESPN BET will send all applicable tax forms by Jan. 31 of the tax year. If you don't receive a W-2G form but you are certain you won more than $600 that year, you are required to report those winnings. Gamblers should consult their personal accountant for all tax questions.