Traders put more than $220 million through roughly 31,000 equity-linked Polymarket contracts over the year to early September; nearly 60% of the volume concerned individual stocks. Kalshi offers about 2,500 daily markets on indexes and corporate KPIs, though not single-stock price wagers. The regulatory hinge is exact: a contract tied to one stock is generally a security-based swap, overseen by the SEC and mostly restricted to professionals. A yes/no wager on a Tesla delivery number can carry the same informational and insider-trading sensitivity while arriving through a CFTC vocabulary.
The economic novelty is less the binary payoff than the market microstructure. Twenty-four-hour event contracts can aggregate an earnings view faster than options in some moments, but they lack the surveillance, rights and cross-market controls of securities venues. If liquidity deepens, manipulation can travel in both directions: from the prediction contract into the share price, or from a share position into a thin event market. Reuters, September 28