Kalshi, Polymarket’s major rival, has heavily promoted its own efforts, including a partnership with market surveillance company Solidus Labs, as it seeks to distance itself from Polymarket and emphasize its credentials as the largest regulated platform in the US. Kalshi bans what it calls “violent markets, including war and kidnapping”—although it does allow markets on the closure of the Strait of Hormuz—saying that markets should “not incentivise harm,” while it also requires proof of identity. In contrast, Polymarket does not require most users of its international site to provide proof of identity and allows payment using anonymous cryptocurrency channels. Growing scrutiny has created a business opportunity for a wave of start-ups selling tools to help users profit by copying suspected “insiders.” “The platforms are creating new rules to try to root them out and make it clear they don’t allow that activity. That to me [ . . .…