John Oliver of ‘Last Week Tonight’ discusses prediction markets and manipulation

John Oliver, host of HBO’s “Last Week Tonight,” targeted prediction market platforms on his show’s latest weekly deep dive.

In Sunday’s airing of the show, Oliver discussed some of the trivial event contracts on platforms like Kalshi and Polymarket, including betting whether members of the Trump administration would use certain words in public addresses, to companies’ controversial partnering with news organizations. 

Specifically, the host questioned Donald Trump Jr.’s relationship with both platforms — an adviser to Kalshi and Polymarket — and how the US Commodity Futures Trading Commission (CFTC) “doesn’t even seem to be trying” to block event contracts on terrorism, assassination and war under Chair Michael Selig.

For much of the show, Oliver discussed how it is “incredibly easy for individuals to manipulate the outcomes,” citing Coinbase CEO Brian Armstrong rattling off a list of crypto-related words in his third-quarter 2025 earnings call to cause many Kalshi and Polymarket users to win their bets.

“I’m going to make you a promise tonight,” said Oliver, echoing Armstrong’s statement. “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.”

While user activity and trading volume on prediction markets have increased exponentially in recent months and are expected to reach $1 trillion by 2030, the platforms’ controversial bets and legal status in US states have raised eyebrows. Gaming authorities in several states are suing Kalshi and other companies over alleged illegal sports betting, with Coinbase chief legal officer Paul Grewal and others expecting the legal fight to end up before the US Supreme Court.

Related: Senate bill to target sports betting ban on prediction markets: WSJ

Financial giants looking to expand into prediction markets?

In addition to previously announced partnerships with media giants like CNN, CNBC, Fox News and Dow Jones, traditional financial companies including Charles Schwab and Citadel Securities recently signaled plans to consider prediction markets.

Charles Schwab CEO Rick Wurster said on a Thursday investors call that the company would “take a hard look at” prediction markets. In a separate event the same day, Citadel Securities president Jim Esposito said that the company was “absolutely keeping an eye on developments” as part of a potential move into the market.

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