The savviest billionaire traders are placing their bets on budding prediction marketplaces. Thanks in part to Trumpworld connections, Kalshi is the front-runner in what could be a trillion dollar opportunity. On a frigid winter morning in 2023, discount brokerage firm billionaire Charles Schwab arrived at the SoHo offices of little known prediction market start-up Kalshi. Under his arm were several binders which seemed to be bursting at their seams. The idea that this Wall Street legend had take...