In 2012, Susquehanna International Group, the trading and investment giant cofounded by Yass, made an early investment in ByteDance, TikTok’s Chinese parent company. That stake now comprises about 15 percent of the company and is worth an estimated $40 billion. A bit under half of that holding—somewhere in the neighborhood of $18 billion—belongs to Yass personally.

Yass has an enormous financial interest in ensuring that TikTok operates legally in the United States—and that interest could increase after the House passed legislation this week seeking to compel the sale of the company to US investors under threat of an all-out ban. If that tactic works, then Yass could be well positioned to assume a larger ownership share. (Former treasury secretary Steve Mnuchin said that he wants to form a group to buy TikTok.) In the meantime, Yass has showered Republicans, right-wing PACs, and big-business groups with millions of dollars in donations.