Parlays built Kalshi’s momentum. They also quietly drained retail bettors of more than $100 million in the first four months of the year. From January 1 through April 30, people betting through Kalshi’s retail app and website lost roughly $117 million placing parlay wagers, according to data compiled from Dune, an official Kalshi data partner that stores the company’s trade history for public access.  At least $35 million of that flowed directly to Kalshi in the form of estimated fees. On April 26 alone, parlay bettors dropped approximately $4.3 million in a single day. The numbers reflect a product that has grown fast and extracted steadily. Retail bettors risked around $800 million building custom multi-leg wagers during the first four months of the year.…