The U.S. Senate voted Thursday to bar its members from placing bets on prediction markets, adopting the measure by unanimous consent and making it effective immediately. The resolution closes a loophole that some feared could enable lawmakers to profit from privileged information about policy outcomes.

Platforms such as Kalshi and Polymarket have surged in popularity, offering contracts that pay out on everything from election results to regulatory decisions. Lawmakers worried that insiders could trade ahead of legislative moves, prompting the Senate to act before any formal ethics rule was drafted. The move mirrors recent state efforts to curb betting on political events.

By prohibiting senators from these wagers, Congress aims to reinforce public trust and remove a potential conflict of interest that could distort market pricing. Traders may see reduced volume on political contracts, but the clear ethical line could encourage broader institutional participation. The ban takes effect today, leaving no grace period for existing positions.

Betting exchanges anticipate adjusting their compliance frameworks, requiring stricter identity verification for U.S. participants. Some analysts predict a short‑term dip in liquidity for high‑profile political contracts, but expect the sector to rebound as investors shift focus to other event categories. The Senate’s action sets a de‑facto standard for federal officials.