Yalda Safi, a 20-year-old student in London, jumped into investing at the start of the pandemic, buying stocks including Snapchat, JustEat, Moderna and Tesla. By March, her portfolio was up 15%.

While Safi watched YouTube videos to learn the ropes, she says she has her limits: “TikTok has loads of pages with financial advice and stock recommendations. I wouldn’t ever buy those.”