Polymarket accused of alleged double-counted volume in most public data

• Recent research shows Polymarket trades are double-counted on most public dashboards.
• The issue stems from redundant maker-taker events in smart contracts.
• According to the allegations, the actual volumes are roughly half of what dashboards report.

Polymarket, the prominent prediction market platform, is facing scrutiny after research by Storm Slivkoff suggested that the platform’s reported trading volumes may be systematically inflated across most public analytics dashboards.

The controversy has drawn attention from industry experts, data analysts, and market participants, raising questions about how trading activity is measured and reported in decentralised prediction markets.

Polymarket gives separate OrderFilled events for makers and takers

The research by Storm Slivkoff, a partner at Paradigm, which was later highlighted by Paradigm co-founder Matt Huang, has identified a technical discrepancy in Polymarket’s on-chain smart contract data.

According to Slivkoff, the platform emits separate OrderFilled events for both the maker and taker sides of each trade.

While each event is individually accurate, most public dashboards aggregate all events indiscriminately, effectively counting the same trade twice.

A simple transaction demonstrates the problem. One trade of YES tokens for $4.13 generated two identical events for the same amount, which dashboards then summed to report $8.26 in trading volume.

Slivkoff noted that this bug affects both notional volume (the number of contracts traded) and cashflow volume (the dollar value exchanged), thereby inflating every trade’s representation.

Notably, the error is unrelated to wash trading and results purely from the way Polymarket’s contracts emit data.

Polymarket refutes the volume double-counting claims

Polymarket’s internal team quickly pushed back against the allegations, asserting that the official site reports taker-side volume without double-counting, in line with standard industry practices.

The platform has emphasised that the issue primarily impacts third-party dashboards, which rely on raw event data from smart contracts without implementing corrections for redundant entries.

Notably, several major data providers, including DefiLlama, Allium Labs, and Blockworks, have confirmed they are updating their dashboards to account for the discrepancy.

Some data providers have, however, defended current methodologies, noting that more sophisticated dashboards had accounted for the distinction since 2024 but had not formally documented their approach.

Other data providers have criticised Paradigm for potential bias, as the firm holds investments in Kalshi, a competing US-based prediction market.

The broader market implications

Beyond the immediate question of reported volume, the controversy underscores broader challenges in accurately measuring activity on prediction market platforms.

Low-priced contracts can create disproportionately large notional volumes relative to actual capital at risk, making traditional volume metrics potentially misleading.

Experts have suggested that metrics such as open interest and fee revenue may offer a clearer picture of platform activity.

The timing of the revelation is also notable, coinciding with Polymarket’s plans for a full US relaunch following CFTC regulatory approval and an anticipated valuation of $12 billion to $15 billion.

The platform is also exploring an internal market-making operation that could trade against customers, raising further scrutiny and comparison to competitors like Kalshi.

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