Kalshi has flagged more than 400 suspicious trades since the start of this year, more than double the number it investigated in all of 2025, according to a Reuters report citing sources familiar with the matter. Some of those trades have been referred to the Commodity Futures Trading Commission, one source said. The surge in flagged activity arrives as Kalshi’s annualized trading volume has tripled in six months to $178 billion. Polymarket has s…