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Coinbase CEO Brian Armstrong has exposed a potentially serious prediction markets issue through a lighthearted side.
Armstrong closed Coinbase’s quarterly earnings call on Thursday (October 30) with a quickfire list of buzzwords: “Bitcoin, Ethereum, blockchain, staking and Web3.” Rather than being anything actionable for the company, the words were chosen based on what users of prediction market platforms Kalshi and Polymarket had bet would come up during the call.
“I was a little distracted because I was tracking the prediction market about what Coinbase will say on their next earnings call,” Armstrong said in his parting remarks, as reported by Bloomberg. “I just want to add here the words Bitcoin, Ethereum, blockchain, staking, and Web3, to make sure we get those in before the end of the call.”
While seemingly meant in jest, the quip shows how easy it would be for some people to influence what was, in this case, an $84,000 betting market. Prediction markets allow users to bet on niche categories related to any number of topics, including earning call topics and other social or business themes.
At the point where Armstrong was browsing the markets at the end of the call, many wagered terms hadn’t been said – but the CEO could then fulfil the terms of the bet by saying them in rapid succession. Odds shifted and wagers were paid out, in a move that could easily be seen as intentional.
Armstrong made it clear on social media that the line was a spontaneous decision after a link to the markets were shared on Coinbase’s internal messaging system. A Coinbase spokesperson also told Bloomberg that Armstrong’s remarks were “made in a lighthearted, offhand way, referencing online discussion around the earnings call.”
Coinbase employees cannot take part in prediction markets or any related activity involving the company according to its internal policies, the person added, meaning that neither Armstrong nor anyone else could benefit from the prediction markets pool.
lol this was fun – happened spontaneously when someone on our team dropped a link in the chat https://t.co/tQiV3B9jUj
— Brian Armstrong (@brian_armstrong) October 31, 2025
What does this mean for prediction markets?
With Kalshi already engaging with the CFTC around regulation, the offhand comment is indicative of where there’s a gap in protecting prediction markets from being abused. Coinbase’s own policy is helpful here, but down the line more official regulations could be required.
Readwrite has reached out to Kalshi and Polymarket for comment.
Featured image: TechCrunch / Wikimedia Commons, licensed under CC BY 2.0
