Key Takeaways
- Kalshi recorded $19.03 billion in contract volume during Oct. 5-11, measured at payout value rather than purchase price.
- Sports and parlay-style Combos dominate recent activity, with Combos accounting for roughly 70% of volume on two major trading days.
- Different reporting methods make direct volume comparisons with Polymarket unreliable.
Kalshi recorded $19.03 billion in weekly contract volume during Oct. 5-11, highlighting how far prediction markets have expanded beyond elections and cryptocurrency forecasts.
The figure was the highest in the six-week series reviewed by data provider DeFi Rate. But it measures contracts at their payout value, rather than the amount buyers paid, a distinction that becomes especially important for low-priced, multi-outcome trades.
Sports and parlay-style “Combos” are central to the growth story.
Their popularity is also making headline volume a less straightforward measure of customer spending, fresh capital or the economic size of prediction markets.
Sports and Combos Take Center Stage
Kalshi’s recent activity has increasingly resembled the rhythm of sports calendars.
Data covering the 30 days through Oct. 6 attributed 84% of Kalshi’s notional volume to sports, including a 61% contribution from Combos. That window differs from the record week, but illustrates the platform’s broader trading mix.
Separate analysis by Bitcoin.com found Combos represented approximately 70% of notional activity on Oct. 10 and 11. Its daily estimates differed from DeFi Rate’s aggregation, underscoring the importance of identifying which dataset supports each figure.
Combos link multiple selections into one position, creating a product comparable to a sportsbook parlay.
Kalshi explains that a standard Combo pays $1 per contract if all components settle at $1. If any component settles at zero, the entire position pays nothing. Special settlement provisions can produce partial payouts.
The structure encourages inexpensive positions with high-potential payouts, especially when traders combine multiple outcomes. Those contracts can generate substantial reported notional volume even when their purchase prices are tiny.
Why $19 Billion Does Not Mean $19 Billion Spent
Kalshi counts a standard $ 1 payout contract as $1 of volume, regardless of its execution price.
In its explanation of volume methodology, the company argues that a three-cent YES purchase corresponds to 97 cents of exposure on the opposing NO side. Kalshi, therefore, considers the combined dollar the relevant measure.
For illustration, buying 100 contracts at one cent each costs $1 before fees but represents $100 in potential settlement value.
That arithmetic explains why a surge in long-shot Combos can expand face-value volume much faster than buyer expenditure. It does not, by itself, establish artificial trading or improper reporting.
DeFi Rate calculated $4.42 billion in execution-price dollar volume alongside the $19.03 billion headline. It cautioned that the supporting calculation had not been independently reconciled with a venue-certified cash-turnover series. Neither measure establishes how much new money entered accounts.
Trading volume can also count capital repeatedly as positions change hands. Deposits, outstanding exposure, and turnover answer different questions.
Bigger Headlines Require Better Comparisons
The distinction matters when comparing Kalshi with competitors.
DeFi Rate reported approximately $498.81 million in Polymarket cash-dollar volume for the same week. Its methodology explicitly separates that measure from Kalshi’s face-value contracts and Polymarket US’s venue-reported Trade Volume, warning against adding them into one industry total.
A simple comparison between those headline figures would therefore exaggerate what the data can establish about relative customer spending.
The same caution applies to growth claims. Higher notional turnover can reflect more contracts, lower-priced selections, repeated trading or changes in product mix.
For users, a cheap Combo still carries the risk that one unsuccessful selection eliminates the payout. Adding legs increases the number of conditions required for success.
Kalshi’s milestone demonstrates substantial trading activity. Assessing its commercial significance requires additional measures, including execution-price turnover, active customers, fees and outstanding positions. The $19 billion headline captures only one part of that picture.
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The information provided in this article is for informational purposes only. It is not intended to be, nor should it be construed as, financial advice. We do not make any warranties regarding the completeness, reliability, or accuracy of this information. All investments involve risk, and past performance does not guarantee future results. We recommend consulting a financial advisor before making any investment decisions.
Giuseppe Ciccomascolo began his career as an investigative journalist in Italy, where he contributed to both local and national newspapers, focusing on various financial sectors.
Upon relocating to London, he worked as an analyst for Fitch's CapitalStructure and later as a Senior Reporter for Alliance News. In 2017, Giuseppe transitioned to covering cryptocurrency-related news, producing documentaries and articles on Bitcoin and other emerging digital currencies. He also played a pivotal role in establishing the academy for a cryptocurrency exchange website. Crypto remained his primary area of interest throughout his tenure as a writer for ThirdFloor.
