SiaPredict DailySeptember 15, 2026
Top line
The past day was unusually quiet for prediction markets after a dense run of Supreme Court petitions, state cease-and-desist orders and product filings. New developments include a September 23 hearing date set in the New Mexico tribes' case against Kalshi and a fresh academic analysis which puts numbers on how much of the industry's edge is now concentrated among a small set of professionalized traders.
Today's top 2
- 1RegulatoryCatch-up
Federal judge sets September 23 hearing on New Mexico tribes' bid to bar Kalshi from tribal lands
U.S. District Judge Margaret Strickland scheduled a September 23 hearing in Las Cruces on the Mescalero Apache Tribe and the Pueblos of Isleta, Pojoaque and Sandia's motion for a preliminary injunction against Kalshi, alongside Kalshi's competing motion to dismiss. The tribes argue Kalshi's sports contracts let anyone 18 and older wager on tribal lands in violation of the Indian Gaming Regulatory Act and tribal compacts, and are asking the court to order geofencing around reservation boundaries.
Albuquerque JournalSia's Take
This action is the next concrete step in a tribal-sovereignty suit filed in May that has run in parallel to the state-AG and CFTC preemption fights. The myriad of different players in the overarching legal battle over prediction market regulatory oversight further complicates tracking outcomes and anticipating future compliance best practices given the number of regulatory players seeking oversight over the industry. Licensed, and license-pending, prediction market operators need to keep tabs on all of these developments in order to stay ahead of the curve when designing the future of their compliance programs.
- 2IndustryCatch-up
Study of $13.76 billion in Polymarket trades finds a small slice of accounts captures most skill-based profit
An academic working paper analyzing $13.76 billion of Polymarket trades found that roughly 3% of accounts, those showing persistent skill at moving prices toward outcomes that later occurred, captured about 27% of dollar profits. The finding lands as institutional and professionalized traders increasingly compete for the same mispricings retail users have relied on, a data point compliance and product teams can use when assessing how durable retail-trader edge is likely to remain as the category matures.
CNBC