Congress is moving to rein in prediction markets, with lawmakers in both chambers introducing a wave of bipartisan bills this week targeting insider trading and certain types of wagers.

The push reflects growing concern on Capitol Hill that prediction markets are rapidly evolving from a niche corner of the online betting space to a high-stakes arena where traders can profit from political events, government actions, military conflicts, and even what words President Donald Trump will mention in any given speech. These markets operate with far less federal oversight than traditional, regulated industries such as gambling and the stock market.