John Oliver targets prediction markets manipulation risks

John Oliver criticised prediction market platforms on HBO’s Last Week Tonight, highlighting manipulation risks and weak regulatory oversight in a segment aired Sunday.

The host pointed to platforms such as Kalshi and Polymarket, noting controversial bets on political speech and their ties with major media organisations.

“I’m going to make you a promise tonight,”

Said Oliver, adding;

“I will never do anything because someone online placed a bet on it.”

Oliver also questioned Donald Trump Jr.’s advisory role with both platforms and criticised the Commodity Futures Trading Commission for failing to block contracts tied to events like war and assassination.

He argued that outcomes can be easily influenced, citing Brian Armstrong mentioning crypto terms during a 2025 earnings call, which allowed some users to win bets linked to those keywords.

Prediction markets have seen rapid growth in users and trading volumes, with projections suggesting the sector could reach $1 trillion by 2030 despite rising legal challenges across several US states.

Traditional finance firms including Charles Schwab and Citadel Securities are monitoring the sector, signalling potential institutional interest as regulatory battles intensify.