Prediction Market Combo Contracts Skewed Volume Data

Trading metrics for prediction markets like Kalshi are boosted by bundled contracts that may not represent individual cash bets.

Updated on Oct. 6, 2026 in Investing

Bold flat-color editorial illustration of stacked metallic tokens on a plinth, representing prediction market volume data. — Prediction markets are reporting inflated trading volume metrics because bundled combo contracts are counted as notional values regardless of actual cash stakes. AI Illustration. Upload story photo >

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Combo contracts now account for over 50% of the notional trading volume on platforms like Kalshi and Polymarket U.S. These figures reflect regulatory reporting requirements rather than the actual amount of cash placed by individual traders.

Why it matters

These inflated volume metrics can obscure the true level of retail financial participation in prediction markets. Because exchanges report all trades as $1 of notional volume, the popularity of these bundled, low-cost bets creates a skewed view of total market activity.

In September, combo contracts comprised 58% of Kalshi's notional volume despite accounting for under 13% of total transactions. On September 27, the average cash placed on a single contract was 47 cents, while combo contracts saw an average investment of just 9 cents.

The players

Kalshi

A U.S.-based prediction market platform where users trade event contracts.

Polymarket U.S.

A U.S.-based prediction exchange that allows users to bet on the outcomes of various events.

Commodity Futures Trading Commission

The federal agency that provides regulatory guidance for how exchanges must report trade volume.

DraftKings

A digital sports entertainment and gaming company whose stock has plunged 45% over the past year.

Flutter Entertainment

A global sports betting company whose stock has declined 70% over the past year.

The details

Prediction markets currently measure volume as $1 for every trade, regardless of the actual cash amount staked by the user. Under Commodity Futures Trading Commission guidance, platforms report notional volume, which leads to higher figures for combo contracts that bundle multiple outcomes. Traders frequently use these combos to hunt for high-payout scenarios while committing very little upfront cash.

Polymarket U.S. launched its platform in May 2026.
Combos accounted for over 50% of Kalshi volume in September 2026.
CNBC analyzed Kalshi trading data on September 27, 2026.

Money Landscape

These volume reporting standards reflect a departure from traditional exchange metrics where dollar-denominated trade volume corresponds directly to capital deployment. The current setup creates a disconnect compared to the historical transparency found in regulated equity markets.

If you are evaluating the popularity of a prediction market, remember that headline volume figures may significantly overstate real financial interest. Treat these platforms as high-risk, speculative environments rather than traditional investment vehicles, and consult a financial professional before committing funds.

The takeaway

Large volume spikes in prediction markets are often driven by low-cost, high-payout bundle bets rather than widespread capital investment. Investors should look past headline volume to evaluate the underlying transaction types when gauging market activity.