SAITO MARI, a 28-year-old nurse, was frustrated. Her pay, at just ¥160,000 ($1,100) a month, was meagre; after bills, rent, shopping and a few holidays, she had little left over. So in 2020 she decided to buy some stocks. “I used to think it was too risky,” says Ms Saito, who learned about investing via books and YouTube. “But it was amazing to see my assets grow.”

Although Ms Saito’s story would be unremarkable anywhere else, it is part of a sea change in Japan. According to surveys by the Investment Trusts Association, 23% of people in their twenties invested in mutual funds last year, up from 6% in 2016. So did 29% of people in their thirties, up from 10%—a bigger rise than in any other age group. Those with exposure to the Nikkei 225, which on February 22nd passed a record high set in 1989, are reaping the rewards.