Large asset managers are required to disclose their equity holdings in quarterly Forms 13F. Investors can use those filings to track which stocks billionaires are buying. For instance, several hedge fund managers bought Palantir Technologies (PLTR 7.69%) and Upstart (UPST 1.35%) in the first quarter, as detailed below:Chris Rokos of Rokos Capital Management bought 55,809 shares of Palantir, starting a new position.Philippe Laffont of Coatue Management added 521,887 shares of Upstart, increasing his stake 15 ...