Prediction markets are confronting a dual storyline: Kalshi has seized a dominant share of non-sports volume, while Polymarket faces new scrutiny over a cluster of accounts that won nearly every bet tied to KPMG-audited companies.
Kalshi’s brokerage-led surge. Combined non-sports prediction market volume hit $10 billion in the week ending Sept. 13, a sixth straight record, according to Artemis. Kalshi accounted for $9.6 billion; Polymarket was reduced to $344.2 million. Three months earlier the two platforms split non-sports volume roughly 50/50, and a year before Polymarket led. Kalshi's advantage stems from distribution: its contracts trade on Robinhood, Coinbase, Webull and Moomoo, placing event contracts inside funded retail brokerage accounts. About one-third of Kalshi's daily flow arrives through Robinhood alone. Product design compounds the gap: hourly contracts on the S&P 500, Nasdaq, Bitcoin and Ethereum generate rapid turnover, while longer-dated Fed contracts add persistent volume. Kalshi's CFTC-regulated US venue, acquired in July 2025 for $112 million via QCEX, provided regulatory access but did not match Kalshi's broker integrations. Combined monthly prediction market volume across all venues grew from less than $5 billion in September 2025 to about $24 billion by April 2026.
Polymarket’s KPMG-linked betting cluster. Blockchain analytics firm Bubblemaps identified 19 interconnected Polymarket accounts that won 41 of 42 bets tied to earnings of KPMG-audited companies, earning about $22,000 across 18 clients including Wells Fargo, Home Depot, DoorDash and General Mills from November 2025 into 2026. The Wall Street Journal reported the findings on Sept. 11. A separate Bitquery reconstruction grouped by positions found 21 KPMG-client markets, 19 winners and two losers, with roughly $21,519 profit; 43 of 44 positions opened before earnings filings. On non-KPMG earnings markets, the same accounts won 11 of 15 markets, broadly consistent with entry prices. KPMG said it has zero tolerance for trading on nonpublic client information and has strengthened monitoring. No charges have been announced in the wallet cluster, but federal authorities are separately investigating a KPMG employee suspected of using confidential information for earnings wagers. The cluster follows U.S. criminal cases involving a U.S. soldier accused of profiting $409,881 and a Google engineer accused of making $1.2 million on Polymarket.
The contrast underscores a regulatory challenge: Kalshi’s licensed distribution is scaling prediction markets as mainstream retail products, while Polymarket’s on-chain heritage and insider-trading controversies highlight unresolved market-integrity questions. The next test arrives around the Nov. 3 midterms and Fed decisions on Oct. 28 and Dec. 9. If Polymarket cannot narrow the distribution gap, Kalshi's 96% share may become structural.
