Klarna made a solid debut on the New York Stock Exchange, with shares of the Swedish buy now, pay later company rising nearly 15%, the latest in a run of high-profile initial public offerings this year. Klarna stock opened at $52 a share Wednesday, a 30% premium to the company's $40 pricing. It took roughly three-and-a-half hours for the specialists on the floor of the NYSE to manually price the first batch of trades of the company.