A look at Kalshi and Polymarket's rise; reports say Polymarket had 491K monthly active traders in December 2025, and <0.04% of addresses took 70% of profits
Context & Ripple Effects
Earlier coverage showed Kalshi reaching meaningful scale, with roughly $1B in monthly volume cited in September 2025. This report shifts the focus from top-line activity to who participates and who captures returns as the two platforms gain visibility.
The reported profit split makes Polymarket's growth story partly a market-quality story: a broad base of active traders can coexist with returns concentrated among a very small set of addresses. That distinction matters for both platforms as they compete for liquidity and credibility.
First-order effects
- Polymarket's reported 491K monthly active traders signals a sizable active user base, while the reported concentration of profits indicates that most participants are not sharing proportionally in trading gains.
- Kalshi and Polymarket face closer scrutiny not just on volume and user growth, but on whether their markets offer credible execution and outcomes to less-sophisticated participants.
Second-order effects
- A perception that a small group consistently captures most profits can raise retail acquisition and retention costs, increasing the value of transparent market rules, liquidity, and user education.
- Competitive claims based on headline activity become less decisive; each platform has an incentive to differentiate on market quality and participant trust rather than scale alone.
Third-order effects
- If concentrated returns persist, prediction markets may develop like other financial venues: broad participation at the edge, with liquidity provision and information advantages concentrated among specialized traders.
- The sector's legitimacy will increasingly rest on whether platforms can show that growing access is paired with fair, resilient market mechanics—not merely rising activity.
The trend: Prediction markets are moving from a growth narrative toward a market-structure test, where liquidity scale and participant trust must develop together.