Five Major Sports Unions Are Drawing a Line on Sports Betting

A bettor can currently place money on whether a specific NFL player gets injured during a game. Or whether a specific word, like "concussion," gets spoken during a broadcast. These aren't hypothetical scenarios cooked up to make a point. They're real prediction market contracts, and player unions across five major American sports leagues just asked the federal government to shut them down.

Unions representing the NFL, MLB, NBA, MLS and NHL formally called on the Commodity Futures Trading Commission to prohibit what they call "under bets" and "mention contracts," products they argue exist specifically to profit from something bad happening to an athlete.

What the unions are actually asking for

The language in their comment to the CFTC is blunt. Contracts based on a "negative" outcome, or ones that can be manipulated by a single individual, should be banned, the unions wrote, specifically naming bets on whether a player gets injured or penalized, and mention contracts tied to specific words being spoken during a broadcast, calling the latter "just another way of betting on a negative outcome."

The scale of the harassment behind the push

This isn't a theoretical concern dressed up as advocacy. A survey found 78 percent of surveyed MLB players said legal sports betting has changed how fans treat them or their teammates, with several players reporting death threats tied directly to lost bets. NBA players have described a similar pattern, with abusive messages tied to parlays becoming routine enough that some players expect it regardless of how they actually perform.

"The worst things you're thinking of, it's worse than that," New York Knicks guard Jalen Brunson said, describing the kind of messages players receive after a betting-driven loss.

Why prediction markets specifically worry the unions

The complaint isn't really about traditional sportsbooks, which are already state-regulated with their own responsible gambling frameworks. It's about a newer category, prediction markets like Kalshi and Polymarket, that have expanded into sports contracts under a different regulatory umbrella entirely. The unions argue this distinction is lost on the people actually placing bets. Individuals angered at losing money don't distinguish between a state-regulated wager and a prediction market contract, the unions noted. From the bettor's perspective, a bet is a bet regardless of where it was placed.

The regulatory fight this drops into

The CFTC opened a public comment period specifically asking which sports-related contracts should be prohibited as "contrary to public interest," and the unions' filing landed in the middle of well over a thousand total comments submitted during that window. Whether the commission actually acts on the request is a separate question entirely from whether the concern is legitimate.

What's clear is that the relationship between fans, bettors and athletes has shifted meaningfully since legal sports betting expanded across the country. A missed shot or a dropped pass used to just be a missed shot or a dropped pass. Increasingly, for the athlete on the receiving end, it's also a financial event in a stranger's account, and that stranger now has a direct line to tell them about it.

Where should the line sit between letting fans bet on individual player performance and protecting athletes from the harassment that comes when those bets go wrong?