Office Oscar pools are merciless — you might need a perfectly guessed ballot to defeat your co-workers. You could chuck five bucks into that pot, or you could put up a dollar on a few underdogs using the online sportsbook DraftKings. Even just one correct guess could put you in the black — that is, if you live in one of the eight territories where the company’s Oscars bets are legally operating.

Regulations on online gambling have eased in the past decade, and DraftKings has steadily expanded into a handful of territories. It began taking Oscar bets ahead of the 2019 ceremony, which saw a surge of users betting on “The Favourite” helmer Yorgos Lanthimos to take best director in the last stages of the season. All those people lost money, of course; Alfonso Cuarón ended up winning for “Roma.”

Six years have passed, but the math to setting the lines has...