Using advanced computers, he went from M.I.T. professor to multibillionaire. His Medallion fund had 66 percent average annual returns for decades.

© Mark Lennihan/Associated Press

Reddit’s first earnings report as a public company showed leaps in users and advertising revenue, along with expenses related to its initial public offering.

© Natalie Keyssar for The New York Times

The market for shares of hot start-ups like SpaceX and Stripe is projected to reach a record $64 billion this year.

© Ryan Inzana

Chad Nedohin, a part-time pastor, is among the fans of Donald J. Trump who helped turn Trump Media into a meme stock with volatile prices.

© Amber Bracken for The New York Times

Andreas Bechtolsheim, the first investor in Google, has an estimated $16 billion fortune. He recently settled charges that he engaged in insider trading for a profit of $415,726.

© Thor Swift for The New York Times