Prediction markets reached a new record monthly volume of $28.4 billion in May according to data from Artemis. This figure exceeds the previous record of $27.1 billion set in January of this year and represents four consecutive months of higher volumes.
The font itself says more than the main number. January’s rally was fueled by the hangover of the election cycle and New Year’s positioning. May, on the other hand, had no equivalent catalyst and still outperformed him. This seems to indicate that activity on prediction market platforms is shifting from event-based spikes towards a flat floor. The idea of these markets being a place of occasional curiosity is gradually moving into a permanent space.
Calci recorded $17.3 billion in volume last month. This is a monthly record in itself for the platform and a 29% increase in volume compared to the previous month. Even more noteworthy is the fact that about 61% of the total volume came from Calcio and it processed nearly double the volume of Polymarket, which saw $8.4 billion. However, the duopoly still exists, as these two platforms accounted for nearly 90% of trading volume in May.
If we go back to last year, this split between the two largest platforms would have read in reverse. Polymarket built the category and maintained its market dominance throughout the period from 2024 until September 2025, when Calci tipped the scales. We tracked The same is reflected within crypto-themed contracts Earlier this month, Calci’s share rose vertically from February onwards.
The reason for this face is actually quite understandable. Calcio’s regulated status in the United States has helped drive its sports business, which accounts for most of its volume. Conversely, Polymarket was mired in a host of regulatory hurdles during large portions of the latest quarter. This does not mean that Polymarket’s trading volumes declined sharply month after month, but they stopped rising.
Why do four consecutive months beat a single record?
One record could just be a fluke. A sports calendar, a viral market, or one big election can spike every month and then fade away. Four months in a row is hard to get rid of. This means that the floor below the sector continues to rise even as the catalyst rotates outward.
This baseline is a signal of maturity. Prediction markets are no longer waiting for elections to matter. Newsrooms cite the odds, hedge funds watch them, and market makers like Wintermute now quote two-sided prices across the biggest venues. Plumbing is starting to look like a real derivatives market rather than a new bet.
Organization and builders are the next step
Progress is aligned with the regulatory wind. The CFTC has indicated that clearer guidance on market forecasting is coming, which favors the licensed exchange. Polymarket is playing the same game at the other end, having bought a CFTC-licensed venue to re-enter the largely shut down US market.
The build layer is the wild card. Hyperliquid ran its HIP-4 outcome contracts on the mainnet on May 2, allowing developers to deploy their own markets in addition to the exchange that already clears hundreds of billions in monthly volume. The early amount is very small, around $87.7 million, well under 1% of the sector. But it points to the next stage: markets that anyone can launch, settle on-chain, and tap into a base of 1.4 million existing traders.
For now the format is simple. Two large venues, one organized and withdrawn, sit in a sector that just posted its strongest month without anything pushing it higher.
