John Oliver Criticizes Prediction Markets, Refuses to Pander

On Sunday’s episode of HBO’s Last Week Tonight, host John Oliver criticized prediction market platforms Kalshi and Polymarket, saying their contracts are easy to manipulate and pledging not to act to influence outcomes.

Oliver highlighted examples of trivial and potentially harmful contracts on the platforms, including wagers on whether specific words would be spoken by public figures and contracts tied to terrorism, assassination and war. He cited a third-quarter 2025 earnings call in which Coinbase CEO Brian Armstrong listed a string of crypto-related words; Oliver said that allowed many users to win bets tied to those words and made outcomes “incredibly easy for individuals to manipulate.”

The host raised concerns about Donald Trump Jr.’s advisory roles with both Kalshi and Polymarket and noted the platforms’ ties to political figures and heightened media attention. Oliver criticized the Commodity Futures Trading Commission under Chair Michael Selig for what he described as a failure to block event contracts on violent or criminal topics, saying regulators “don’t even seem to be trying” to stop those markets.

Oliver closed the segment with a direct promise to viewers, stating: “I will never do anything because someone online placed a bet on it. So you can be confident that if I ever say Bitcoin, Ethereum, blockchain, staking and Web3, it won’t be because I’m trying to move markets — it will be because I’m having a stroke.” He framed the pledge as a refusal to pander to bettors.

Prediction market activity and trading volume have grown rapidly in recent months. Some industry estimates project the sector could reach $1 trillion by 2030. State gaming regulators in several states have filed lawsuits against companies such as Kalshi, alleging illegal sports betting under state law. Legal executives, including Coinbase chief legal officer Paul Grewal, expect some disputes to reach the U.S. Supreme Court.

Financial firms and major news organizations have shown interest in the space. Executives at Charles Schwab and Citadel Securities have said they are watching developments and may consider related business moves as platforms expand the range of events users can bet on and seek broader participation.

Prediction markets let users buy and sell contracts that pay out based on the outcome of future events. Supporters say the markets can aggregate information and provide probability signals. Critics point to the risk of manipulation, regulatory uncertainty and ethical concerns when contracts are tied to violent events. Regulators, litigants and industry participants are engaged in ongoing legal and policy discussions that will determine how these markets operate in the United States.