Everyone is watching Kalshi
But Polymarket is quietly building the bigger global setup
Latest weekly notional volume:
Kalshi: $2.22B
Polymarket US: $1.21B
Polymarket global: $1.07B
Combined Polymarket volume is already around $2.28B in one week
Now add World Cup markets, sports whales, and global attention
This is where prediction markets stop feeling niche
Polymarket traders are rushing to Kalshi after the '' MicroStrategy Sells Any Bitcoin by May 31, 2026 '' market drama. But they're missing something.
Kalshi isn't that totally different from @Polymarket
Kalshi (being centralized + CFTC-regulated) has an internal committee that can add clarifications or interpret rules.
and it sometimes feels like "changing rules after the fact" to losers which is very similar to the Polymarket complaints.
I stumbled upon a post on Reddit about Kalshi specifically a market titled '' Dartmouth vs Clarkson College Hockey Incident'' (January 2026).
Here,
– The market was set up with only two options: Dartmouth "Yes" or Clarkson Yes/No.
– A trader bet big on Dartmouth "Yes".
– Dartmouth won the game in a shootout.
– For a while after the game, Kalshi priced it as Dartmouth "Yes" winning (trader was up).
then After the market closed, Kalshi added a new rule:
“Games decided by shootout resolve as a tie according to the pre-shootout score.”
and hence turned the win into a tie which made the trader lost over $4,000.
Kalshi changed the rules after the market closed, and when the Trader checked the official PDF rules, it showed the wrong document (French Open tennis rules instead).
The Trader accused Kalshi of retroactively changing things to pay out less money.
This case is very similar to the current Polymarket drama. It shows even regulated platforms get these complaints when big bets are involved.
Kalshi more regulated than Polymarket, so they face more scrutiny, but it's not perfect.
Hope they're aware of this ?