Casino operators in two of the most mature legalized gambling markets in the U.S. are sounding the alarm about sports event contracts.

Nevada could permanently ban cigarette sales to people born after Dec. 31, 2004, to cut down on combustible tobacco use. But large casinos would be exempt.

The co-founder of U.S. prediction market platform Kalshi said the company will continue offering sports-outcome contracts across the country unless the federal Commodity Futures Trading Commission ( ...