Sebastian Siemiatkowski
Sebastian Siemiatkowski is best known as the co-founder and CEO of Klarna, the buy-now-pay-later and payments company he co-founded in Stockholm in 2005 alongside Niklas Adalberth and Victor Jacobsson. Under his leadership, Klarna grew from a small Swedish startup into one of Europe's most valuable fintech companies, at its peak reaching a valuation of approximately $45.6 billion in 2021, before a significant down-round in 2022 valued the company at around $6.7 billion. Klarna's platform enables consumers to pay for purchases in installments and gives retailers tools to offer flexible payment options, making it a significant player in e-commerce and retail marketing infrastructure. Siemiatkowski has been a vocal and often provocative voice in the technology and business world, notably making headlines for his aggressive use of AI to restructure Klarna's workforce — publicly crediting AI tools with enabling the company to reduce its headcount significantly while maintaining output. He has been an outspoken advocate for artificial intelligence in enterprise operations and a critic of what he views as bloated corporate hiring practices. Klarna filed for an IPO in the United States, signaling a major milestone in the company's trajectory. Born in Sweden to Polish immigrant parents, Siemiatkowski studied economics at the Stockholm School of Economics. His journey from working at Burger King to building one of Europe's defining fintech companies has made him a frequently cited figure in entrepreneurship and technology circles.
Last updated Oct 11, 2026 by ATDb automated enrichment
AI-drafted from public sources1 source cited
- Years in industry
- 20 years
Bio
Sebastian Siemiatkowski is best known as the co-founder and CEO of Klarna, the buy-now-pay-later and payments company he co-founded in Stockholm in 2005 alongside Niklas Adalberth and Victor Jacobsson. Under his leadership, Klarna grew from a small Swedish startup into one of Europe's most valuable fintech companies, at its peak reaching a valuation of approximately $45.6 billion in 2021, before a significant down-round in 2022 valued the company at around $6.7 billion. Klarna's platform enables consumers to pay for purchases in installments and gives retailers tools to offer flexible payment options, making it a significant player in e-commerce and retail marketing infrastructure. Siemiatkowski has been a vocal and often provocative voice in the technology and business world, notably making headlines for his aggressive use of AI to restructure Klarna's workforce — publicly crediting AI tools with enabling the company to reduce its headcount significantly while maintaining output. He has been an outspoken advocate for artificial intelligence in enterprise operations and a critic of what he views as bloated corporate hiring practices. Klarna filed for an IPO in the United States, signaling a major milestone in the company's trajectory. Born in Sweden to Polish immigrant parents, Siemiatkowski studied economics at the Stockholm School of Economics. His journey from working at Burger King to building one of Europe's defining fintech companies has made him a frequently cited figure in entrepreneurship and technology circles.
Expertise & education
Expertise
Education
- Economics, Stockholm School of Economics
Speaking topics
Recognition
Notable achievements
- Co-founded Klarna in 2005, growing it into one of Europe's most valuable fintech companies with a peak valuation of approximately $45.6 billion
- Led Klarna's expansion to over 45 countries and partnerships with hundreds of thousands of retailers globally
- Publicly credited AI tools with enabling Klarna to reduce its workforce by roughly 50% while sustaining business output
- Steered Klarna toward a US IPO filing