Sebastian Siemiatkowski – Co-Founder & CEO of Klarna

Sebastian Siemiatkowski – Co-Founder & CEO of Klarna

Sebastian Siemiatkowski is the co-founder and Chief Executive Officer of Klarna, the Swedish fintech company that helped popularize buy now, pay later (BNPL) payments and has since expanded into a broader digital banking, payments, shopping, and personal finance platform.

Siemiatkowski co-founded Klarna in Stockholm in 2005 with Niklas Adalberth and Victor Jacobsson. More than two decades later, he remains the company's CEO, making him one of Europe's longest-serving technology founders. Klarna went public on the New York Stock Exchange in September 2025 under the ticker KLAR, raising approximately $1.37 billion at an IPO valuation of about $15.1 billion.

Under Siemiatkowski's leadership, Klarna has evolved considerably beyond its original online-payment product. By the second quarter of 2026, more than 120 million consumers were using Klarna, while the company reported 1.2 million-plus merchants, $36.6 billion in quarterly gross merchandise volume (GMV), and $1.042 billion in quarterly revenue.

Today, Siemiatkowski is also one of the most outspoken technology CEOs on the business impact of artificial intelligence. Klarna has used AI extensively across customer service, product development, marketing, and internal operations, while its CEO has publicly acknowledged that the company's initial emphasis on AI-driven cost reduction went too far in some areas.

Who Is Sebastian Siemiatkowski?

Sebastian Siemiatkowski is a Swedish entrepreneur best known for co-founding Klarna and leading the company from a small Stockholm startup into a global financial technology business.

Klarna's current corporate leadership page lists Siemiatkowski as Chief Executive Officer.

His career is unusual in the technology industry because he has remained at the helm of the same company since its founding in 2005. Rather than building and selling multiple startups, Siemiatkowski spent more than 20 years expanding a single financial technology company through several major phases: online payments, BNPL, consumer shopping, digital banking, AI-powered commerce, and eventually the public markets.

Klarna's 2025 annual filing describes the company as a global commerce network serving approximately 118 million active consumers and 966,000 merchants across 26 countries at the end of 2025. The company facilitated $128 billion in GMV during 2025 and generated $3.509 billion in total revenue.

That transformation has made Siemiatkowski a significant figure in European fintech and one of the most recognizable founders associated with the BNPL industry.

Education and Early Career

Siemiatkowski studied at the Stockholm School of Economics, where he earned a Master of Science degree in Economics and Business in 2007. Klarna corporate records also list him as having been with the company since January 2005.

Before Klarna, Siemiatkowski built experience in sales and worked in several commercial roles. Klarna's own historical annual-report material describes him as having eight years of sales experience, including serving as Head of Sales at Djuice Uppsala.

One of the more frequently cited parts of his early story involves his time working at Burger King. He met future Klarna co-founder Niklas Adalberth while working there. Years later, the two would build Klarna together.

The experience also contributed to a recurring theme in Siemiatkowski's career: identifying everyday friction in commercial transactions and looking for ways technology could remove it.

How Sebastian Siemiatkowski Founded Klarna

Klarna was founded in Stockholm in 2005 by Siemiatkowski, Niklas Adalberth, and Victor Jacobsson.

The original idea emerged from problems Siemiatkowski encountered while working in sales for a factoring business. He observed that online merchants faced difficulties getting consumers to complete purchases while customers were often hesitant to pay for products before receiving them.

The founders developed a model designed to separate the payment experience from the immediate transaction between consumer and retailer. Instead of requiring customers to pay merchants upfront, Klarna could facilitate the purchase and allow consumers to pay later.

That concept eventually became one of the defining models of modern fintech: buy now, pay later.

The company initially operated as a payments business before expanding its product portfolio and becoming a bank. Siemiatkowski later described Klarna's evolution as a move from a traditional B2B payments company toward a consumer-focused financial and shopping platform.

The founding team faced skepticism in the early years, but Klarna gradually expanded across Europe and attracted institutional investors including Sequoia Capital.

Building Klarna Into a Global Fintech

One of Siemiatkowski's defining achievements as CEO has been the expansion of Klarna beyond its original payment product.

The company initially focused heavily on helping online merchants process transactions. Over time, Klarna added consumer financing, shopping discovery, payment cards, banking products, cashback, memberships, and other financial services.

The broader strategy has been to make Klarna part of the consumer's everyday financial life rather than simply a payment option presented at checkout.

That evolution can be seen in the company's current positioning. Klarna describes itself as an everyday finance network, while its products increasingly span payments, shopping, banking, and personal financial management.

In February 2026, Klarna reported that its app had surpassed 55 million monthly active users, with approximately 9 million people using it daily. The company said daily engagement had increased approximately 53% year over year.

Klarna's Growth and Scale

The scale of Klarna has changed dramatically since Siemiatkowski and his co-founders launched the company.

At the end of 2025, Klarna reported:

• Approximately 118 million active consumers

• Approximately 966,000 merchants

• Operations across 26 countries

• Approximately $128 billion in annual GMV

• $3.509 billion in annual revenue

Revenue increased 25% in 2025 compared with 2024, according to Klarna's SEC filing.

The company's momentum continued into 2026.

For the second quarter of 2026, Klarna reported:

• $36.6 billion GMV, up 18% year over year

• $1.042 billion revenue, up 27%

• $446 million transaction margin dollars, up 42%

• $91 million adjusted operating income, up 214%

• $27 million operating income

• $9 million net income

• More than 120 million active consumers

• More than 1.2 million merchants

Klarna also reported 6.5 million active users of its Klarna Card and 2 million paying membership subscribers.

These numbers illustrate how significantly Klarna has expanded beyond its original BNPL proposition.

Klarna's IPO and Public-Market Transition

After years of operating as a private company, Klarna completed its long-awaited U.S. IPO in September 2025.

The company priced its shares at $40 per share, giving Klarna an initial valuation of approximately $15.1 billion, according to Reuters. Klarna and existing shareholders raised approximately $1.37 billion through the offering.

Klarna began trading on the New York Stock Exchange under the symbol KLAR on September 10, 2025.

The IPO represented a major change for Siemiatkowski after almost two decades of running Klarna as a private company.

It also came after a significant change in the company's valuation. Klarna had reached a reported private-market valuation of approximately $46.5 billion during the 2021 fintech boom before its valuation fell sharply during the 2022 market downturn. Reuters reported that the company was valued at approximately $6.7 billion in 2022 before recovering ahead of the IPO.

For Siemiatkowski, the public listing therefore represented not simply an exit event but another stage in Klarna's long-term development.

Sebastian Siemiatkowski and AI

Artificial intelligence has become one of the defining parts of Siemiatkowski's leadership strategy.

Klarna has deployed AI across customer service, marketing, product development, internal workflows, and other areas of the business.

One of its most publicized experiments involved an AI-powered customer-service assistant. Klarna said the system was capable of handling work equivalent to hundreds of customer-service agents and significantly reducing response times.

Siemiatkowski has also been unusually direct about the organizational implications of AI.

Klarna reduced its workforce substantially through a combination of attrition, hiring restrictions, and AI-driven efficiency efforts. By 2026, Siemiatkowski was discussing a workforce of roughly 2,700–3,000 people, compared with significantly higher levels several years earlier.

However, Klarna's AI strategy has not remained purely focused on reducing headcount.

In 2025, Siemiatkowski acknowledged that the company had placed too much emphasis on cost reduction and that this could affect service quality. Reuters reported that Klarna subsequently shifted its AI strategy toward productivity, customer experience, and product development rather than treating cost reduction as the primary objective.

This makes Klarna an interesting case study in how a large technology company is attempting to integrate AI into its operating model while balancing automation with customer experience.

From BNPL to an Everyday Finance Network

The long-term strategic question surrounding Klarna is whether it can become more than a BNPL company.

Siemiatkowski has increasingly positioned Klarna as an everyday financial platform.

The company's newer products include:

• Digital banking services

• Payment cards

• Cashback

• Membership programs

• Shopping discovery

• Personal finance tools

• Mobile services

• Peer-to-peer payments

• AI-powered financial and shopping experiences

Klarna's 2026 results show the strategy beginning to move beyond occasional checkout financing. The company reported that revenue per active consumer increased 24% year over year in Q2 2026, while the Klarna Card reached 6.5 million active users.

The company has also increasingly emphasized recurring consumer engagement rather than simply transaction volume.

That distinction is important to Siemiatkowski's current strategy: Klarna wants to become a recurring destination for managing money, shopping, and payments.

Sebastian Siemiatkowski's Leadership Philosophy

Siemiatkowski's approach to leadership has generally emphasized speed, ambitious goals, experimentation, and operational efficiency.

In a 2018 Forbes interview, he described himself as a combination of a sales-oriented operator and a business economist. He also emphasized the importance of understanding what "great" looks like across different functions of a company, even when a CEO is not personally an expert in every technical discipline.

That philosophy has remained visible in Klarna's development.

The company repeatedly entered markets and product categories dominated by established financial institutions and technology companies. Instead of treating payments as a narrow infrastructure problem, Siemiatkowski pushed Klarna toward consumer branding, shopping, banking, and financial services.

His willingness to publicly discuss mistakes has also become a notable part of his leadership profile.

The company's experience with AI illustrates this particularly well. Klarna initially presented AI automation as a major efficiency opportunity, but Siemiatkowski later acknowledged that cost reduction could not be the only measure of success and that customer experience needed greater emphasis.

Challenges Facing Klarna

Leading a global fintech company at Klarna's scale brings several challenges.

Regulatory and Credit Risk

BNPL products operate within the broader consumer-credit ecosystem. Klarna therefore faces regulatory requirements and scrutiny concerning responsible lending, consumer protection, credit losses, and transparency.

As Klarna expands beyond BNPL into broader banking and financial services, managing credit risk remains a central part of the business.

Klarna reported a credit-loss provision rate of 0.52% of GMV in Q2 2026, down from 0.56% a year earlier.

Balancing AI and Human Service

Klarna's aggressive AI rollout has provided significant efficiency gains, but it has also created an important operational lesson for the company.

The shift from emphasizing AI primarily as a cost-cutting mechanism toward using it to improve products and services reflects a broader challenge facing technology companies: determining where automation creates better experiences and where human involvement remains valuable.

Competing in U.S. Financial Services

The United States has become increasingly important to Klarna's strategy.

The company is competing not only with traditional banks and credit-card networks but also with fintech companies offering overlapping payment, credit, and financial products.

Klarna's public listing in New York and its expanding U.S. operations have therefore increased the strategic importance of the American market.

Sebastian Siemiatkowski's Current Focus

As of 2026, Siemiatkowski's focus can broadly be understood through four interconnected priorities.

First, expanding Klarna's role in everyday finance. The company is attempting to move from being a checkout option toward becoming a broader financial platform.

Second, increasing consumer engagement. Klarna wants customers to use its products more frequently for spending, payments, shopping, and financial management.

Third, applying AI across the organization. AI remains central to Klarna's operating model, but the company is placing increasing emphasis on productivity, product quality, and customer experience.

Fourth, scaling in the United States. Klarna's NYSE listing and expanding American presence place the U.S. market at the center of its next phase of growth.

The company's Q2 2026 results demonstrate that this strategy is already producing substantial scale, with more than 120 million active consumers and more than 1.2 million merchants.

Sebastian Siemiatkowski's Recent Stake in Klarna

Siemiatkowski remains financially invested in the company he founded.

In August 2026, Klarna disclosed that he purchased 692,506 Klarna shares through an associated entity for approximately $9.95 million. Following the transaction, the filing reported 25,344,322 Klarna shares beneficially owned indirectly through Flat Capital AB.

The transaction came less than a year after Klarna became a publicly traded company.

Why Sebastian Siemiatkowski Matters in Fintech

Sebastian Siemiatkowski's significance in fintech comes from the length and scale of his involvement in Klarna.

He helped introduce a new approach to online payments in the mid-2000s, participated in the rise of BNPL, expanded Klarna into a global commerce network, navigated a dramatic change in private-market valuations, took the company public in the United States, and is now attempting to transform Klarna into a broader everyday financial platform.

His career also illustrates how the role of a fintech founder can change over time.

The CEO who initially focused on solving online checkout friction now runs a publicly traded financial technology company serving more than 120 million consumers and more than one million merchants.

At the same time, his experience with AI demonstrates that technological transformation is rarely linear. Klarna's journey from aggressive AI automation toward a more balanced approach offers a real-world example of how technology strategy can evolve as companies learn from implementation.

Key Facts About Sebastian Siemiatkowski

Category	Details
Full Name	Sebastian Siemiatkowski
Current Role	Co-Founder & Chief Executive Officer
Company	Klarna Group plc
Founded Klarna	2005
Co-Founders	Niklas Adalberth and Victor Jacobsson
Education	Stockholm School of Economics
Degree	M.Sc. in Economics and Business
Company Headquarters	Stockholm, Sweden
Public Listing	NYSE, ticker KLAR
IPO Date	September 2025
IPO Valuation	Approximately $15.1 billion
2025 Revenue	$3.509 billion
2025 GMV	$128 billion
2025 Active Consumers	Approximately 118 million
Q2 2026 Revenue	$1.042 billion
Q2 2026 GMV	$36.6 billion
Q2 2026 Active Consumers	120+ million
2026 Merchant Network	1.2+ million
Primary Industry	Fintech / Digital Banking / Payments

The company and financial figures above are based primarily on Klarna's SEC filings and 2026 investor disclosures, with IPO information cross-checked against Reuters reporting.

Summary

Sebastian Siemiatkowski is the co-founder and CEO of Klarna and one of the longest-serving founders in European fintech. Since launching Klarna in Stockholm in 2005, he has overseen the company's evolution from a payments startup into a global commerce and financial-services network.

His leadership has covered several major shifts in technology and finance: the rise of digital payments, the expansion of BNPL, the transformation of fintech into consumer brands, the emergence of AI-powered financial services, and the transition from private startup to publicly traded company.

Klarna's next phase under Siemiatkowski centers on becoming an everyday financial platform while using AI to improve efficiency, products, and customer experiences. With more than 120 million active consumers and 1.2 million merchants reported in Q2 2026, the company operates at a scale far beyond the original online-payments startup founded in Stockholm more than 20 years ago.