This article uses the context of daily fantasy sports (DFS) to analyze how companies use strategic categorization in regulatory arbitrage. Recent actions by two leaders in the DFS industry, DraftKings and FanDuel, provide an ideal context to study this issue. DraftKings and FanDuel categorized themselves differently to different audiences at different times in a manner that evaded categorization as an illegal gambling activity, only to then dominate the sports betting market after the Supreme Court's decision in Murphy v. NCAA. We examine how this type of strategic categorization, which we call “fluid categorization,” raises important questions for regulators and others concerned with regulatory arbitrage. We also explore how fluid categorization provides lessons for other businesses. While this article has broad implications for the sports gambling marketplace, it also contributes to meaningful discourse for the broader business community, as its findings are relevant to industries beyond DFS that offer gray market products and seek to fight categorical labels until there is a reclassification event.