As Klarna Bank AB’s billionaire founder, Sebastian Siemiatkowski prepares to stage one of the biggest-ever European fintech company listings, a feast of capitalism, he credits an unlikely backer for his runaway success: the Swedish welfare state. In particular, the 39-year-old pinpoints a late-1990s government policy to put a computer in every home. “Computers were inaccessible for low-income families such as mine, but when the reform came into play, my mother bought us a computer the very next day,” he said. Siemiatkowski began coding on that computer when he was 16. Fast-forward more than two decades, and his payments firm Klarna is valued at