Robinhood has removed certain event contracts from its prediction market business to mitigate risks of market manipulation and insider trading. According to Robinhood UK's President Jordan Sinclair, the company is focused on preventing market abuse and has decided not to offer 'Mention Markets' contracts. These contracts allowed users to bet on specific keywords appearing in speeches or earnings calls, which are susceptible to insider control. This decision follows previous incidents where editors were penalized for insider trading related to such markets.