Sebastian Siemiatkowski

Early life & education

Siemiatkowski's parents and his eldest sister moved from their native Poland to Uppsala, Sweden in 1980. Siemiatkowski was born the year after on October 3, 1981. Siemiatkowski has said in interviews that he considers himself as a second generation immigrant, due to his Polish heritage.

He attended high school at Katedralskolan, Uppsala. He holds a master's degree from the Stockholm School of Economics.

His early influences were Richard Branson and Ingvar Kamprad, founder of IKEA. Siemiatkowski credits the Swedish digital policy of subsidizing the ownership of computers for his success because it allowed his family to acquire their first computer.

Career

Siemiatkowski started building Klarna at age 23, while on a sabbatical from the Stockholm School of Economics. He worked in sales offering accounts receivable services to small businesses, and noticed significant and regular challenges when processing with e-commerce payments. He co-founded the company with Niklas Adalberth and Victor Jacobsson in 2005. Siemiatkowski had met one of his co-founders when working at Burger King. In 2021, he was minted as a billionaire as Klarna's valuation increased to $31 billion.

In 2022, Klarna announced a round of redundancies in response to a global economic slowdown. Departing employees were asked if they wanted to join a voluntary initiative to share their availability on platforms like LinkedIn. Those who agreed to the initiative had their details shared by Klarna and also Siemiatkowski. By sharing the list, Siemiatkowski subsequently received both praise and criticism in the media.

The Swedish Financial Sector Union expressed regret to have learnt about the job cuts from the media rather than being consulted beforehand and sued the company over the layoffs. In December 2024, he stated that the company would not increase headcount because "AI can do all of the jobs that we humans do. It’s just a question of how we apply it and use it”.

Klarna listed on the New York Stock Exchange in September 2025 at a valuation of $19 billion. At the time, it was the largest IPO of the year on the NYSE.

Personal life

Siemiatkowski married Nina, a marketing executive he first met while attending the Stockholm School of Economics, in 2014. She is the founder of a digital platform to connect donors with local nonprofits and played a key role in identifying a marketing agency that created Klarna's branding. They have three children and live in Stockholm.

References

References

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4. (17 December 2021). "How Klarna’s Sebastian Siemiatkowski is making retail payments smoother". Bloomberg.
5. Larsson, Linus. (2019-11-29). "Klarnas vd Sebastian Siemiatkowski: Jag kunde inte hantera alkoholen". [[Dagens Nyheter]].
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7. Stokel-Walker, Chris. (20 June 2023). "Klarna CEO Sebastian Siemiatkowski will never play by the rule book". GQ.
8. (April 3, 2022). "Boss of buy-now, pay-later giant on his troubled childhood and expansion masterplan: 'We want Klarna to be old style bank manager". This is Money.
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11. (July 26, 2022). "IMF cuts global growth outlook, warns high inflation threatens recession". [[Euronews]].
12. (2022-06-01). "Klarna faces backlash after CEO shares names of laid-off workers on social media - CBS News".
13. (June 3, 2022). "Klarna’s CEO cops criticism for posting list of 560 redundant employees online". SmartCompany.
14. (1 June 2022). "‘Tone deaf’ or a big help? Klarna CEO sparks heated debate after posting a list of laid-off employees". Fortune.
15. "Software workers labor union sues Klarna over layoffs of 700 {{!}} Hacker News".
16. (2024-12-16). "Klarna CEO gives final verdict on AI vs human force".
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19. Levine, Joshua. (23 September 2021). "Inside Klarna CEO Sebastian Siemiatkowski’s Striking Home". [[WSJ Magazine]].
20. Rose, Hilary. (12 April 2022). "Nina Siemiatkowski: I don’t just want to be Mrs Klarna". [[The Times]].