Prediction Market Open Interest Drops as World Cup Trading Fades

TLDR:

• Prediction market open interest declined after the World Cup, while Kalshi kept about 59% and retained leadership over Polymarket.
• Polymarket market share rose from roughly 27% to 41% as capital left smaller platforms faster than it exited the two leading venues.
• Kalshi still lists 28,996 markets against Polymarket’s 8,040, showing a wider product base despite the narrowing open interest gap.
• Daily volume reached $22.38 million, with Polymarket contributing $12.48 million and Kalshi generating $9.89 million during the latest period.

Prediction market open interest declined after the World Cup ended, showing how quickly event-driven capital can leave forecasting platforms. July data places Kalshi open interest near 59% of total open positions. Polymarket market share increased to about 41%, even as open interest fell across both venues. 

The change did not come from stronger market-wide demand. Instead, capital exited smaller platforms faster, pushing more remaining exposure toward the two leaders. Kalshi still commands the larger base, but its advantage narrowed during the month. 

Prediction Market Open Interest Drops After World Cup

Prediction market open interest weakened during July as World Cup contracts settled and traders released committed capital. Kalshi felt the larger impact, reflecting its heavier concentration of event-linked positions during the tournament. Its share slipped from about 62% to 59%, a limited decline in percentage terms. However, the move reduced its lead over Polymarket at a notable moment for the sector.

Source: CryptoRank

Polymarket also recorded lower open positions during July. Even so, Polymarket market share climbed from roughly 27% to 41%. That increase mainly reflected steeper withdrawals from smaller competitors, rather than fresh capital entering Polymarket contracts. The platform therefore captured a larger portion of a shrinking pool.

The latest data shows the total open interest at $923.61 million, down 0.04% over 24 hours. Polymarket accounted for $321.54 million, falling 1.09%. Its tracked open interest moved from $352 million on July 28 to $321 million by August 2. The sequence included brief rebounds, but the broader direction stayed lower.

This pattern shows the difference between absolute growth and relative market share. A platform can lose open interest while gaining industry weight when rivals contract faster. Prediction market open interest therefore gives only part of the picture. 

Share movements reveal where traders keep capital after a major event cycle closes. Meanwhile, 37,036 listed markets represented a 0.66% daily increase. Contract creation therefore continued despite falling open positions.

Polymarket Gains Share While Kalshi Holds Market Lead

Kalshi open interest still represents the largest portion of the July comparison. Its 59% share leaves the platform firmly above Polymarket, despite the narrower gap. Kalshi also lists far more active markets. Cryptorank data shows 28,996 Kalshi markets, compared with 8,040 on Polymarket.

Trading volume tells a different story over the latest 24-hour period. Combined volume reached $22.38 million, rising 11.3%. Polymarket generated $12.48 million, while Kalshi recorded $9.89 million. That split shows Polymarket leading daily turnover despite Kalshi holding more open positions and listings.

Political and geopolitical contracts now support much of the visible activity. There are predictions tied to Iran’s leadership changes and control of Kharg Island. Another contract asks whether the United States will invade Iran before a specified deadline. That market showed $2.71 million in daily volume and $1.40 million in liquidity.

Source: CryptoRank

Prediction market open interest also helps compare retention across different event categories. These contracts differ from the concentrated sports schedule that shaped World Cup activity. They may keep capital active for longer periods, since political outcomes often carry wider timelines. However, they can also produce uneven trading bursts around breaking news and policy developments.

Prediction market open interest now reflects a more concentrated competitive field. Kalshi controls the largest share, while Polymarket has gained ground through stronger relative retention. 

Smaller platforms lost enough capital to alter the market structure without reversing the overall decline. The current balance keeps Kalshi in front. Polymarket closes the distance through volume, liquidity, and a larger share of remaining positions.

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