Published: Friday, October 31, 2025 · 5:18 PM | Updated: Friday, October 31, 2025 · 5:18 PM
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🗝️ Key Points
- He closed it out with a list: “Bitcoin, Ethereum, blockchain, staking and Web3.” Most Read from Bloomberg Those weren’t random buzzwords.
- They were part of an $84,000 betting market.
- Across prediction market platforms Kalshi and Polymarket, users had wagered on which words would be spoken during the call — part of a niche category known as mention.
Brian Armstrong
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Brian Armstrong
(Bloomberg) — When Coinbase Global Inc.’s quarterly earnings call wrapped up Thursday, its chief executive, Brian Armstrong, didn’t finish with profit guidance or statements of confidence. He closed it out with a list: “Bitcoin, Ethereum, blockchain, staking and Web3.”
Most Read from Bloomberg
Those weren’t random buzzwords. They were part of an $84,000 betting market.
Across prediction market platforms Kalshi and Polymarket, users had wagered on which words would be spoken during the call — part of a niche category known as mention markets, where the outcome isn’t tied to earnings, price moves or sports games, but to what people say in some public forum. With the final analyst question complete, several terms listed in contracts were still unsaid. Armstrong ticked them off one by one.
“I was a little distracted because I was tracking the prediction market about what Coinbase will say on their next earnings call,” he said in his parting remarks. “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.”
The exchange’s CEO had just moved a market — even if only a small one.
Mention markets are one of the more curious byproducts of the broader prediction market boom, but also one of the more controversial. Platforms like Kalshi, which is regulated by the Commodity Futures Trading Commission, and Polymarket, which is in the process of returning to the US market, let users wager on the outcomes of real-world events. That can mean elections, policy decisions, or sports — but also, increasingly, corporate rituals and even common jargon.
In total, about $84,000 had been bet on whether a Coinbase executive would say certain words — including “stablecoin,” “institution,” and “margin,” according to data from the companies’ websites. With several terms still unsaid by the final minutes, Armstrong’s insertions made those contracts pay out. Traders watching the markets saw the odds shift in real time.
After the call, Armstrong said on social media that he decided to do it spontaneously after a staff member put a link to the betting pool in Coinbase’s internal chat.
“lol this was fun,” he posted on X.
But it wasn’t just fun. It showed, in blunt fashion, how easily many prediction markets — supposedly tools for collective intelligence — can be steered by the very people they’re meant to observe.
A Coinbase spokesperson said Armstrong’s remarks were “made in a lighthearted, offhand way, referencing online discussion around the earnings call.” The company’s internal controls prohibit employees from participating in prediction markets or any related activity involving the company, the person added.
Kalshi and Polymarket declined to comment.
Under the CFTC’s core guidelines, regulated platforms aren’t supposed to list contracts that are “readily susceptible to manipulation.” Mention markets may now test the limits of that definition, though rules surrounding this new era of prediction markets are still evolving.
“I’m hopeful that we see additional guidance from the CFTC and maybe a comprehensive regulatory framework that addresses these kinds of issues as they come up,” said Andrew Kim, partner at Goodwin Procter LLP. “A core question that needs to be answered first, is there something to regulate here? Or is this a flash in the pan feature that sounds nice in theory but doesn’t work in execution and you move on to the next thing.”
For years, advocates of prediction markets have argued that they represent a cleaner, more democratic way to forecast outcomes. By letting users bet on future events, the thinking goes, the markets aggregate real information better than polls or pundits can. Yet mention markets, by design, are unusually easy to influence. They rely on public statements by a small number of people who can change the result simply by speaking.
Coinbase itself has jumped onto the prediction market bandwagon. It holds stakes in Kalshi and Polymarket, and Armstrong said during the same call that the company plans to expand into event contracts as part of its broader effort to become an “Everything Exchange” for financial products.
The online reaction to Armstrong’s remarks mixed humor and unease. The official Polymarket account on X called the move “diabolical work.”
“The way that this all blows up is if the CFTC says this is getting too ridiculous,” Chris Dierkes, head of trading at sports-focused prediction markets platform Novig, said in a video posted on X on Thursday.
Mention markets remain a niche inside a niche. Last week they represented 0.4% of activity on Kalshi, where sports made up 91%, according to publicly available data collated by the user datadashboards on Dune Analytics.
Yet they punch above their weight in quirks and disputes. Traders have sparred over what counts as a valid mention: Does an extended clip qualify? Do words inside compound words count? Kalshi’s rules say “immigrants” will satisfy a bet on “immigrant,” but “immigration” won’t. A contract for “ICE” could pay out on “ice water.”
All told, Armstrong’s words, said offhandedly and half in jest, turned a quarterly earnings ritual into a kind of mirror. What it reflected wasn’t collective wisdom, but how easily the crowd can be gamed.
(Updates Kalshi’s response in third paragraph under embedded tweet.)
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