Prediction Market Volume Reaches $120.7 Billion in October, Up 64%

U.S. prediction market quantity reached $120.73 billion in October 2026, up 64.1% from $73.58 billion in September, in line with DeFi Rate’s evaluation of buying and selling exercise throughout eight exchanges.

Kalshi led with $98.15 billion, accounting for 81.3% of reported quantity, adopted by Polymarket US at $14.77 billion. Together, the 2 exchanges generated $112.92 billion, or 93.5% of the October complete.

October’s progress prolonged past the 2 market leaders. Novig and Underdog greater than doubled their month-to-month buying and selling quantity, whereas recognized combo quantity throughout 5 exchanges elevated 93.2% to at the least $79.46 billion.

The {industry}’s reported quantity elevated by $47.15 billion month over month, with Kalshi accounting for $37.30 billion of that progress.

October prediction market quantity: Key takeaways

• Total reported quantity reached $120.73 billion, growing 64.1% from September throughout eight exchanges.

• Kalshi led with $98.15 billion, including $37.30 billion and accounting for 81.3% of reported exercise.

• Polymarket US reached $14.77 billion, rising 69.8% and barely growing its share of reported quantity.

• Underdog and Novig led proportion progress, rising 174.7% and 126.1%, respectively.

• Identified combo quantity reached at the least $79.46 billion, rising 93.2% throughout 5 exchanges.

• October 25 was the busiest Sunday for Kalshi, Polymarket US, Novig and Underdog, with recognized combos accounting for a lot of the improve over different October Sundays.

October prediction market buying and selling quantity by alternate

Six of the eight exchanges in DeFi Rate’s evaluation recorded monthly trading growth. Kalshi remained the biggest by a major margin, whereas Polymarket US, Novig and Underdog grew sooner in proportion phrases.

Source: DeFi Rate evaluation of alternate buying and selling stories. The complete consists of eight exchanges with obtainable September and October figures. Underdog figures characterize its personal alternate, not trades routed to third-party venues.

Kalshi and Polymarket US accounted for practically all reported buying and selling exercise, however their mixed share declined barely as smaller exchanges grew extra shortly.

Kalshi’s share fell from 82.7% in September to 81.3% in October. Polymarket US elevated its share from 11.8% to 12.2%, whereas Novig rose from 2.0% to 2.7%. Polymarket US had already recorded a 21% weekly volume jump to $2.83 billion throughout Sept. 21–27, 2026, in line with DeFi Rate’s earlier weekly report.

Underdog additionally gained share, growing from roughly 1.0% to 1.6%.

These shares characterize the eight exchanges coated by the evaluation, slightly than the whole U.S. prediction market {industry}. Complete October totals have been unavailable for a number of further exchanges, together with CME Group, ICE Futures U.S. and DKeX/Railbird.

Kalshi provides $37.3 billion in October buying and selling quantity

Kalshi trading volume in October reached $98.15 billion, a rise of 61.3% from September’s $60.85 billion.

The alternate accounted for about 79% of the overall month-to-month quantity improve throughout the eight reporting venues.

Its largest buying and selling day was Saturday, October 24, when quantity reached $5.30 billion. Kalshi additionally generated $4.77 billion the next day, its highest-volume Sunday of the month.

Combo buying and selling represented a considerable portion of Kalshi’s October exercise. DeFi Rate recognized at the least $66.86 billion in combo quantity, in contrast with $35.49 billion in September.

That represents an 88.4% improve in recognized combo quantity, considerably sooner than Kalshi’s general month-to-month progress.

Identified combos accounted for at the least 68.1% of the alternate’s October quantity, in contrast with 58.3% in September.

Kalshi’s quantity excluding these recognized combos elevated from roughly $25.36 billion to $31.29 billion. That the rest consists of any combo contracts not captured by the verified classifications, so it can’t be handled as a completely licensed standalone quantity complete.

Polymarket US grows practically 70% to $14.77 billion

Polymarket US trading volume reached $14.77 billion in October, up 69.8% from $8.70 billion in September.

The alternate added $6.07 billion in month-to-month buying and selling exercise, the second-largest absolute improve among the many eight exchanges.

Polymarket US additionally gained share towards Kalshi, accounting for 12.2% of reported quantity in contrast with 11.8% in September.

Identified combo quantity rose from $3.91 billion to $8.60 billion, a rise of roughly 120%. Combos accounted for at the least 58.2% of the alternate’s October quantity, in contrast with 45.0% in September.

The figures present that recognized combo buying and selling expanded significantly sooner than Polymarket US’s general exercise.

October 25 was the alternate’s largest reported buying and selling day of the month, reaching $830.9 million.

Novig and Underdog greater than double month-to-month quantity

Underdog trading volume recorded the quickest proportion progress among the many eight exchanges, growing 174.7% to $1.98 billion.

Its September quantity was $721.5 million, which means the alternate added $1.26 billion throughout October.

At least $1.54 billion of Underdog’s October quantity got here from combos, representing 77.9% of its complete buying and selling exercise. That was the very best recognized combo share among the many 5 exchanges included in the combo evaluation.

Novig trading volume adopted with 126.1% progress, growing from $1.45 billion in September to $3.27 billion in October.

The alternate added $1.82 billion in month-to-month quantity, surpassing Underdog by roughly $1.29 billion.

Novig’s buying and selling exercise was practically evenly divided between combos and standalone contracts:

• Combos: $1.61 billion, representing 49.3% of October quantity.
• Standalone contracts: $1.66 billion, representing 50.7%.

Novig reported roughly 11.33 million trades in October underneath its printed trade-count methodology.

Both exchanges reached their highest-volume day of October on Sunday, October 25. Novig generated $208.7 million, whereas Underdog reached $144.6 million.

Combo buying and selling reaches at the least $79.46 billion in October

Identified combo quantity throughout Kalshi, Polymarket US, Novig, Underdog and Crypto.com/Nadex reached $79.46 billion in October, growing 93.2% from $41.13 billion in September.

The improve of roughly $38.33 billion was concentrated closely at Kalshi, which accounted for $31.37 billion of the extra recognized combo quantity.

Polymarket US contributed one other $4.69 billion in progress.

Source: DeFi Rate evaluation. Combo figures for Kalshi, Polymarket US and Underdog characterize recognized contract-family minimums. Novig and Nadex figures use their verified product classifications.

Combo quantity grew sooner than general buying and selling exercise at Kalshi, Polymarket US, Novig and Underdog.

The improve additionally modified the composition of alternate quantity. At Kalshi, recognized combos represented 68.1% of October buying and selling, up from 58.3% in September. Polymarket US’s identified combo share increased from 45.0% to 58.2%.

Novig’s combo quantity elevated roughly 160%, whereas Underdog’s recognized combo quantity rose roughly 154%.

Combos can generate considerably extra reported contract quantity than a equally priced standalone commerce as a result of a number of outcomes are mixed right into a single contract. As a end result, contract quantity shouldn’t be interpreted because the money merchants spent or the income an alternate earned.

The mixed figures set up how shortly combo buying and selling expanded in October, though the unfinished classification of some contract households prevents a definitive industry-wide standalone-versus-combo comparability.

October 25 information the very best Sunday quantity throughout 4 exchanges

October 25, was the highest-volume Sunday of the month for Kalshi, Polymarket US, Novig and Underdog.

Each alternate exceeded its common quantity for the opposite three October Sundays.

Underdog recorded the biggest proportion improve relative to its different October Sundays, adopted by Kalshi and Polymarket US.

Identified combo buying and selling accounted for a lot of the further quantity in any respect 4 exchanges.

At Polymarket US, adjustments in recognized combo exercise accounted for 99.8% of the rise above its other-Sunday common. The corresponding figures have been 89.5% at Kalshi, 84.9% at Underdog and 67.1% at Novig.

Kalshi was the one alternate among the many 4 whose highest-volume day occurred on Saturday, October 24, slightly than Sunday.

Its Saturday complete exceeded Sunday’s by $530.8 million, with $512.1 million of that distinction attributable to increased recognized combo quantity.

NFL contracts appeared among the many most-traded named markets that weekend. Kalshi recorded $45.5 million in quantity on a Kansas City versus Seattle winning-outcome contract, whereas a six-player landing combo generated $21.7 million on Sunday.

However, the obtainable contract classifications don’t set up that NFL buying and selling accounted for a lot of the October 25 quantity throughout these exchanges.

The findings present that October 25 was an unusually energetic Sunday relative to the opposite October Sundays, with combo exercise accounting for a lot of the improve.

Crypto.com and ProphetX develop as Gemini and ForecastEx decline

Crypto.com Derivatives North America, working by way of Nadex, generated $2.19 billion in October buying and selling quantity, up 40.3% from September.

Identified combo buying and selling reached $837.8 million, representing 38.3% of the alternate’s month-to-month exercise.

ProphetX additionally grew, growing 27.3% to $306.3 million.

Two exchanges moved in the other way.

Gemini Titan’s quantity declined 4.4% to $42.1 million, whereas ForecastEx fell 26.3% to $14.4 million.

Combined, the 2 declining exchanges accounted for lower than 0.05% of the October quantity coated by DeFi Rate’s evaluation.

The distinction in efficiency was substantial. While complete reported buying and selling expanded 64.1%, Novig and Underdog posted triple-digit will increase, and the smallest exchanges didn’t all take part in the broader progress.

Methodology

DeFi Rate analyzed September and October 2026 buying and selling stories masking Kalshi, Polymarket US, Novig, Crypto.com Derivatives North America/Nadex, Underdog Exchange, ProphetX, Gemini Titan and ForecastEx.

Trading quantity is offered in U.S. {dollars} underneath the $1-per-reported-contract or native-volume-unit conference. The figures measure reported quantity slightly than execution-price money exchanged. Individual exchanges could use totally different business-day reporting boundaries.

Exchange market share is calculated utilizing the eight reporting venues, excluding exchanges with out full obtainable month-to-month figures. Volume is attributed to the alternate the place the commerce occurred, avoiding double-counting of orders routed by way of third-party apps.

Combo figures for Kalshi, Polymarket US and Underdog replicate recognized contract-family minimums. Novig and Nadex figures use verified product-level classifications. Unclassified contracts aren’t routinely assigned to standalone buying and selling.