Bitcoin bets on Kalshi and Polymarket hit a reported $2.7 billion in a week, mostly on 15-minute up-or-down contracts

Crypto event contracts on Kalshi and Polymarket reached $2.7 billion of notional volume in a single week, according to a Bloomberg newsletter dated 22 October 2026 that cites a dashboard on the data platform Dune, as relayed on 24 October by TechFlow, ChainCatcher, Bitcoin.com News and Crypto Briefing. The same reports say crypto is now the second-largest category on both prediction markets, behind sports, and that most of the bitcoin activity sits in short bets on whether the price will be higher or lower a few minutes later.

The outlets call it a record. Coindaro could not check either the word or the number. The Bloomberg newsletter sits behind a paywall, and a search on 24 October turned up no public Dune dashboard showing the figure, nor the name of whoever built it. None of the reports names the week. Every article so far repeats one upstream figure, so five headlines amount to one claim, not five confirmations. The rest of this piece works with what can be checked: how the platforms count volume, how much of their bitcoin business comes from 15-minute contracts, and where the product is blocked.

Prediction markets and bitcoin: where the $2.7 billion comes from

The chain of sourcing is short. Bloomberg’s newsletter of 22 October reported the figure and, according to TechFlow and ChainCatcher, credited Dune Analytics. Bitcoin.com News, in a piece by Shiraz Jagati published at 05:30 EDT on 24 October, linked the number to a post by the account WuBlockchain on X, which itself relays the Bloomberg item. Crypto Briefing, in an article by Estefano Gomez the same day, gave the figure without naming any data provider.

TechFlow’s summary says “last week” and nothing more precise. Counting back from a newsletter dated Thursday 22 October, the most likely window is 12 to 18 October, but that is our reading of the calendar, not a date any source gives.

Dune is a data platform where users build public dashboards from blockchain records and other feeds. Its own documentation on prediction-market data says the collection covers Polymarket trades read from the blockchain and Kalshi figures that come from the company’s public reporting, refreshed about every hour. In other words, the Polymarket half can be traced on-chain, while the Kalshi half is what Kalshi reports. Neither half has been audited by anyone outside the platforms, as far as we found.

What the $2.7 billion counts, and what it does not

The key word in the reports is “notional”. On Kalshi and Polymarket, a contract pays $1 if the event happens and nothing if it does not. A contract on “bitcoin higher in 15 minutes” might trade at 52 cents. Notional volume counts that trade at its $1 face value, not at the 52 cents that changed hands. The measure therefore says how many contracts were traded, not how much money traders put at risk.

The gap between the two can be large. In its report on Kalshi’s week of 5 to 11 October, published on 12 October, the tracker DeFi Rate put Kalshi’s total contract volume at a record $19.03 billion counted at face value, and gave a second, execution-price measure of $4.42 billion for the same week. DeFi Rate wrote that these measures have not been independently reconciled with the venue’s own series. Still, the ratio gives a sense of scale: on that week, face value was more than four times the price-based number.

Nobody has said whether the $2.7 billion counts one side of each trade or both, and nobody has said how much of it is genuine two-party trading. That second point matters on Polymarket. A Columbia University working paper, reported by Fortune in November 2025 and not peer reviewed, estimated that about 25% of Polymarket trading over three years looked like wash trading, where the same party sits on both sides of a trade. There is no such estimate for the crypto markets in the week Bloomberg measured.

The tracker itself warns against what the headline does. DeFi Rate’s Kalshi and Polymarket series use different methods and calendars, and its report says plainly that “the figures should not be added into a combined industry total.” The $2.7 billion is exactly such a combined total.

Kalshi’s share is not published, only hinted at

No source we found splits the $2.7 billion between the two platforms. Crypto Briefing writes that Kalshi’s bitcoin contracts “alone generated over $2 billion in a single week” and that they make up the bulk of the combined total, but it gives no source and no week for it. DeFi Rate’s $2.05 billion for Kalshi’s bitcoin-labelled markets from 5 to 11 October would fit that description; Crypto Briefing does not say it used it.

If both figures cover the same week and use the same measure, simple subtraction would leave Polymarket with less than about $0.7 billion. That is arithmetic from two reported numbers, not a published split, and it rests on two conditions no source confirms. It also mixes Kalshi’s bitcoin contracts with the whole crypto category. Readers should treat it as an order of magnitude at most.

On DeFi Rate’s count, the $2.05 billion was 10.78% of Kalshi’s $19.03 billion week, against $3.76 billion in markets labelled sports. About 65% of Kalshi’s volume that week was unclassified, so the sports figure is not a full count. These DeFi Rate numbers are a different measurement from the Dune figure and cover an earlier week; they should not be read as part of the $2.7 billion.

Earlier records are no help either. DeFi Rate’s 12 October report calls the $19.03 billion week a record for Kalshi across all categories. A Dune-based count for 2 to 8 March 2026 gave $2.86 billion for Kalshi and $2.50 billion for Polymarket, all categories included. We found no previously published crypto-only weekly record, so we cannot say by how much the $2.7 billion beats the last one.

For the platforms themselves, our pages on Kalshi, the CFTC-regulated prediction market and its fight with the states and on Polymarket, its two venues and its legal record explain how each one works and who can use it.

The 15-minute bitcoin contract is the engine

Crypto Briefing calls Kalshi’s 15-minute up-or-down contract on bitcoin “the standout” of a new set of short-dated products. DeFi Rate’s own numbers show how fast the format took over once Polymarket’s US exchange adopted it.

In its report on Polymarket US, updated on 17 October, DeFi Rate counted about $91.8 million in 15-minute bitcoin markets during the first full week after the 22 September launch, from 23 to 29 September. Total classified bitcoin volume on the venue went from about $625,000 the week before launch to $101.2 million, so the 15-minute markets made up about 91% of it. Daily 15-minute volume rose from $2.4 million on the first day of that week to $27.7 million on the last, and reported transactions from about 63,650 to 739,034.

Kalshi’s 15-minute bitcoin markets started much smaller, with about $226,000 in their first seven days, according to the same report. They grew into its largest crypto product. DeFi Rate counted about $8.17 billion of crypto volume on Kalshi from 1 to 28 September, “with roughly $7 billion, or 86%, coming from 15-minute markets.” Crypto went from about 2.6% of Kalshi’s volume before the 15-minute launch to 14.5% in September.

The table mixes measures on purpose, so that each one keeps its label. Only the first two rows relate to the week Bloomberg describes, and even they may not use the same method.

How a 15-minute up-or-down contract works

The idea is simple. A market opens on the question of whether bitcoin will be above or below a reference price when a 15-minute window closes. Traders buy “yes” or “no” contracts at prices between 1 cent and 99 cents. When the window ends, winning contracts pay $1 and losing ones pay nothing, and a new market opens for the next window. The settlement price comes from an outside reference: on Polymarket, crypto up-or-down markets have resolved on a Chainlink time-weighted average price since 7 August 2026.

Because a new market opens every quarter of an hour, one trader can place dozens of bets a day, and every bet adds its full face value to the notional count. That is one reason the format inflates volume so quickly, as the jump in Polymarket US transactions shows.

Bets on direction, not on bitcoin’s future

Bitcoin.com News drew the obvious conclusion from the mix of contracts: “short-dated contracts are mostly about direction, not conviction.” A trader who buys “up in 15 minutes” is not saying anything about where bitcoin will be in December. The result is closer to a coin toss with a price feed than to a forecast.

Longer-dated markets tell a different story, and a smaller one. Bitcoin.com, citing a post on X by KrownCryptoCave, reported that implied odds on the options venue Derive of bitcoin reaching $100,000 by Christmas rose from 9.7% to 12% during the week, even as US spot bitcoin ETFs lost $635.6 million in a day. Those odds come from an options market, not from Kalshi or Polymarket, and through a secondary relay.

The price itself has gone nowhere much. Bitcoin moved between about $80,000 and $84,000 over the past week, according to Bitcoin.com. It traded near $80,460 at 10:29 UTC on 24 October, down 1.51% over 24 hours and 1.30% over seven days, with the Crypto Fear and Greed Index at 51, a neutral reading. A flat market with frequent small swings is the setting in which 15-minute bets thrive: each window is close to even odds, and there is always a next one.

Why exchanges want crypto event contracts

Bloomberg frames the boom as a response to weaker spot trading, according to the accounts of its newsletter carried by Bitcoin.com and Blockonomi. Exchanges that earn less from buying and selling coins are adding prediction products. TechFlow lists Coinbase, Crypto.com, Gemini and Kraken among the firms moving into the market, through licences or partnerships with prediction platforms. Coinbase’s bitcoin and ether contracts are run by Kalshi and settle on a 60-second average from CF Benchmarks, Blockonomi reports.

There is also a legal reason, and here we are giving our own reading rather than a reported fact. The lawsuits brought by US states against Kalshi and its partners target sports contracts, which states treat as unlicensed betting. Crypto price contracts have drawn far less of that fire. For a platform that wants to grow without adding new legal fronts, bitcoin windows that reopen every 15 minutes look like the safer product. None of the platforms has said so.

Kalshi is regulated in the US by the Commodity Futures Trading Commission (CFTC), which approved a Kalshi bitcoin perpetual future on 29 May 2026. The federal licence has not stopped the states. Utah sued Kalshi and two Susquehanna firms on 19 October, arguing that the market maker acts as the house, as we reported in our story on the Utah lawsuit against Kalshi. Two federal appeals courts have since ruled against it on sports contracts: the Ninth Circuit in Nevada’s case on 28 August, and the Sixth Circuit for Ohio and Tennessee on 25 September. Kalshi has asked the full Sixth Circuit to review that panel’s decision.

Insider trading is the other pressure point. The Pentagon has barred service members from betting on military operations with nonpublic information and named both platforms, after a betting episode Bitcoin.com put at about $400,000; we covered it in our report on the Pentagon’s prediction-market rule.

France and Italy block the product the record is built on

For readers in Europe, the $2.7 billion describes markets they cannot legally use. Kalshi’s products are built for US residents, and France and Italy are among the countries listed as restricted in its member agreement, according to trackers that follow the document. Polymarket’s international site is blocked in both France and Italy as unlicensed gambling.

In France, the gambling regulator ANJ (Autorité nationale des jeux) obtained geoblocking of Polymarket’s services for French residents in November 2024. In mid-July 2026 it went further and ordered internet providers to block the site, Engadget reported on 18 July. The ANJ said Polymarket had recorded 578,751 visits from France in June, 205,057 of them from unique visitors, and called it “an illegal gambling site”. Promoting an unauthorised betting site can cost up to €100,000 in fines.

In Italy, the customs and monopolies agency ADM (Agenzia delle Dogane e dei Monopoli) ordered internet providers on 9 July 2026 to redirect polymarket.com to its warning page and added the domain to its blacklist of gambling sites on 10 July. The site became unreachable in Italy on 27 July. On 5 August the regional administrative court of Lazio (TAR Lazio) refused the urgent interim relief sought by Blockratize Inc. and Adventure One QSS Inc., the companies behind Polymarket, and set a hearing before the full bench for 25 August, Sky TG24 reported. The block stayed in place. It was the second time: the ADM had already listed Polymarket in autumn 2025 (on 22 October according to Punto Informatico, in November according to smart contract holding reserves of two or more tokens, supplied by users, that a decentralized exchange uses to execute trades automatically at a price set by a formula.">pool diverge, compared with simply holding the same tokens in a wallet. It becomes permanent when the provider withdraws.">Il Sole 24 Ore), and access returned about two months later.

Belgium, Portugal and Spain have taken their own measures against Polymarket since January 2025, and the UK’s Financial Conduct Authority was reported to be in talks with the company on 6 October 2026. The French and Italian regulators have acted against Polymarket as a gambling site as a whole, whatever the subject of each market, so a bitcoin contract is blocked as surely as a football one.

What to watch next

DeFi Rate publishes weekly reports on Kalshi and Polymarket US that label each measure, and they are the nearest thing to a checkable series. If Kalshi’s bitcoin-labelled volume for 12 to 18 October comes out near $2 billion on its face-value count, the Crypto Briefing figure will at least have a traceable match.

Two other gaps could close sooner. Kalshi and Polymarket can publish their own crypto totals for the week, and whoever built the Dune dashboard can make it public, method included. Neither had happened by 24 October.