Billions of dollars in ad revenue—and a lot of highly engaged users—would be up for grabs if the U.S. passes a ban or forces a sale of the app.

Federal prosecutors are looking into whether platforms including Facebook facilitate and profit from the illicit sale of drugs.

Steve Huffman built the social-media platform nearly two decades ago while in college. Now he’s taking it public, adding investors to the list of personalities he needs to juggle.

TikTok faces its most serious threat yet to its U.S. existence with the House passage of a bill that would ban it from operating in America or force a sale.