DraftKings’ Railbird unit filed to self-certify football combos and nine other prediction market event contracts. (Image: DraftKings/Shutterstock)In a filing with the regulator last Friday, Railbird Exchange, which DraftKings acquired last October, self-certified to offer combos – prediction market vernacular for multi-part wagers commonly known as parlays. Railbird does business as DKeX, DraftKings’ in-house prediction market exchange. Inside the Football Event ContractsJust in the nick of time for the 2026 football season, an Aug. 10 filing with the CFTC by Railbird unveiled plans for nine football event contracts. DKeX could begin offering those event contracts as soon as tomorrow, assuming the CFTC doesn’t intervene.