2025 Market Prediction Retrospective: Total Transaction Volume Exceeds $50 Billion, Duopoly Market Share Exceeds 97.5%

Original Title: "2025 Prediction Market Review: Total Trading Volume Exceeds $50 Billion, Duopoly Market Share Exceeds 97.5%"

Original Author: Wenser, Odaily Planet Daily

As 2025 drew to a close, the prediction market track also provided its own answers.

According to PredictionIndex.xyz data, the total trading volume of the 2025 prediction market track reached $50.25 billion. Apart from Kalshi and Polymarket, the rest of the ecosystem's trading volume was $1.25 billion. According to data released by KalshiData, Kalshi's total annual nominal trading volume reached $23.8 billion, a 1108% year-on-year increase. As Polymarket and Kalshi both surpassed a valuation of over $10 billion, such achievements undoubtedly injected a strong boost into the capital market and user base. In 2026, the prediction market track will continue to be a focus of the crypto space.

The Odaily Planet Daily will summarize and briefly analyze the overall data of the 2025 prediction market in this article for readers' reference.

2025 Prediction Market Overall Scale: $50 Billion Level, Kalshi, Polymarket Market Share Exceeds 97.5%

According to PredictionIndex.xyz, a comprehensive index-based tracking of the prediction market ecosystem, covering markets, infrastructure, end-users, and new experimental projects, the final results are as follows:

- According to the platform's incomplete statistics, the overall trading volume of the 2025 prediction market was approximately $50.25 billion.

- Apart from Kalshi and Polymarket, the trading volume of the rest of the ecosystem was $1.25 billion.

- This long-tail market is key to testing and evolving new market designs, incentive measures, and concepts. Projects involved include azuroprotocol, TrendleFi, hyperstiti0ns, Limitless, MyriadMarkets, overtime, footballdotfun, xodotmarket, predictonfliq, DGbet_official, and BRKTgg.

If this data shows us the current "duopoly" situation in the prediction market, then the 2025 data from KalshiData, a platform under Kalshi, provides us with a more detailed view of the current hot racecourses' intensity.

Kalshi's 2025 Report Card: Trading Volume Reaches $23.8 Billion, Over 11x Year-on-Year Growth

On January 3, KalshiData released a statement indicating that in 2025, Kalshi saw record growth across all metrics.

In terms of nominal trading volume, the total for the year reached $23.8 billion, marking a 1108% year-on-year increase, approximately 12.1 times.

· December set a monthly record high of $6.38 billion;

· The fourth week of December set a weekly record high of $1.7 billion;

· December 21 set a daily record high of $381.7 million.

In terms of trading frequency, the total for the year reached 97 million trades, reflecting a 1680% year-on-year increase, approximately 17.8 times.

· December saw 27.67 million trades;

· The fourth week of December saw 7.6 million trades;

· December 21 saw 1.5 million trades, all setting new historical highs.

In terms of open interest, the total reached $225 million, a 169% year-on-year increase, approximately 2.7 times.

· March 9 set a daily record high of $533 million,

· The first week of March set a weekly record high of $530 million,

· February saw a monthly record high of $499.5 million.

In terms of the number of trading contracts, the total for the year reached 23.8 billion, a 1108% year-on-year increase, approximately 12.1 times.

· December saw a monthly record high of 6.38 billion contracts;

· The fourth week of December saw a weekly record high of 1.7 billion contracts;

· On December 21st, a record high of 382 million trades was set in a single day.

According to KalshiData website, since its launch on June 28, 2021, Kalshi has reached a historical total trading volume of $27,255,757,183, with a daily average trading volume of $16,619,364, and a total number of trades of 27,242,274,566.

As for Polymarket, despite its focus on the concept of an "on-chain prediction market," the transaction volume data for the year 2025 appears somewhat ambiguous, perhaps due to different statistical methodologies and discrepancies in transaction data sources.

Polymarket's 2025 Report Card: Estimated Trading Volume to be around $220-250 Billion

According to DefiLlama data, Polymarket's full-year DEX trading volume in 2025 is approximately $105 billion.

According to Dune's data dashboard, Polymarket's full-year transaction volume in 2025 is around $225 billion.

According to information from PredictionIndex.xyz website, Polymarket's cumulative historical trading volume is $232 billion.

According to a "Prediction Market Report" jointly issued by Keyrock and platforms like Dune, the total transaction volume of the prediction market in 2025 is projected to be $440 billion, with Polymarket's transaction volume estimated to be around $215 billion (Note by Odaily: In comparison, Kalshi's transaction volume is around $171 billion).

Taking into consideration the above information and the "Kalshi's annual trading volume is $238 billion" data provided by the Kalshi official platform earlier in this article, we will take a relatively middle-ground estimate and predict that Polymarket's overall trading volume in 2025 will be around $220 billion.

Prediction Market Subsector: Sports Ranks First, Political Events and Cryptocurrency Follow Closely

According to information from a "Prediction Market Report" jointly issued by Keyrock and platforms like Dune, when it comes to specific prediction market betting events,

By 2025, Kalshi continues to be sports-centric, with sports accounting for approximately 85% of nominal trading volume.

In contrast, Polymarket has demonstrated a more diversified mix —

Sports (39%), Politics (34%), and Cryptocurrency (18%) collectively drove over 90% of prediction market betting activity.

Furthermore, calculated by trading volume,

· Economic prediction event-related trading volume increased by 905% to reach $112 million;

· Technology and Science prediction event-related trading volume increased by 1637% to reach $123 million;

· Open interest betting events in Economics (grew 7x to approximately an $800 million market size) and Society & Culture (grew 6x to approximately a $700 million market size) led the way, demonstrating a growing trend of macro hedging and long-term positioning.

· Other categories (such as Culture, Society) also saw significant growth, with the overall contract open interest trading volume increasing from around $3.3 billion at the beginning of 2025 to about $13 billion, significantly increasing market depth and liquidity.

Prediction Markets also experience "Seasonality": Second Half of the Year Surge in Trading Volume

It is worth noting that as of late August 2025, data indicates that Polymarket's trading volume has remained at a market size of around $7.5 billion to $8 billion, but with the surge of various unexpected events, political events, and sports events in the second half of the year, both Polymarket and Kalshi have ushered in a "trading surge period":

In September, the combined trading volume of Kalshi and Polymarket reached $14.4 billion;

In October, the prediction market trading volume reached $87 billion, with Kalshi leading and Polymarket following;

In November, the total trading volume of Kalshi and Polymarket neared $100 billion, with Kalshi's trading volume reaching $58 billion, a 32% increase compared to the previous month; Polymarket's trading volume reached $37.4 billion, a 23.8% increase month-over-month.

In December 2025, analyst Patrick Scott published an article stating that in November 2025, the forecasted market trading volume exceeded $13 billion, more than three times the peak volume during the 2024 election. Polymarket, Kalshi, and OPINION accounted for the vast majority of the trading volume. Binary options have now been applied to areas such as political speeches, sports events, and public company financial reports, becoming a layer of probability for world events and news.

Considering Kalshi's December trading volume reaching $63.8 billion, Polymarket's trading volume is also expected to be impressive. The overall forecast market trading volume in December 2025 may reach the $13-15 billion range.

Top 5 Stars of the Prediction Market: Kalshi, Polymarket, and Others

Finally, based on current statistics from PredictionIndex.xyz, as of the time of writing, the top 5 platforms in terms of prediction market trading volume are as follows:

· Kalshi, with a historical trading volume of approximately $27.1 billion;

· Polymarket, with a historical trading volume of approximately $23.2 billion;

· Opinion, with a historical trading volume of approximately $13.1 billion (considering the platform's launch time and mechanism, there may be issues such as trading volume manipulation, so this data is based on the information provided by the data statistics platform);

· Limitless, with a historical trading volume of approximately $512 million; Azuro, with a historical trading volume of approximately $444 million.

Previously, the CEO of Kalshi had mentioned that the prediction market scale would be around $150 billion. Although the final overall trading volume in 2025 was only one-third of what was stated, considering that the prediction market track in 2024 was not fully formed, the "market scale of $150 billion" mentioned was not an empty talk. With the upcoming major events in 2026 such as the U.S. midterm elections and the World Cup, the prediction market's overall market size in 2026 may still experience a tenfold increase.

Of course, as we mentioned earlier in "Prediction Markets Are Not Easy: Less Than One in Ten May Truly Survive Until the End of the Year", popularity in the field does not mean that all projects and platforms can thrive. For ordinary players like us, considering constraints such as liquidity depth and fund allocation, it may be better to specialize in 1-3 mainstream platforms.

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