AT A GLANCE

Klarna
Sierra
2005
Founded
2023
Stockholm, Sweden
HQ
San Francisco, USA
$4.6 Billion
Total Raised
About $1.6 billion
Sebastian Siemiatkowski, Niklas Adalberth, Victor Jacobsson
Founder
Bret Taylor and Clay Bavor
Fintech
Type
AI
Public (NYSE: KLAR)
Status
Private — $15.8B valuation (May 2026)

FUNDING HISTORY

Klarna

Series A2010
$9M raised$40M val.
Series C2014
$155M raised$1.5B val.
Series D2017
$225M raised$2.5B val.
Series E2019
$460M raised$5.5B val.
Series F2021
$1.0B raised$46.0B val.
Down Round2022
$800M raised$6.7B val.
IPO2025
$1.5B raised$15.0B val.

Sierra

Seed2024
$110M raised$1.0B val.
Series A2024
$175M raised$4.5B val.
Series B2025
$350M raised$10.0B val.
Venture Round2026
$950M raised$15.8B val.

BUSINESS MODEL

Klarna

Klarna makes money from merchant fees and consumer interest. Merchants pay Klarna 3-6% of each transaction — they're willing to pay because Klarna increases conversion rates by 30%+ and average order values by 45%.

On "Pay in 4" (interest-free installments), Klarna makes money purely from merchant fees. On longer financing (6-36 months), Klarna charges consumers interest up to 25% APR.

Klarna also earns revenue from its shopping app (affiliate commissions when users discover and buy from merchants), and from its Klarna Card.

Sierra

Companies pay Sierra to run their customer service with AI agents instead of hiring rooms full of humans. The agent talks to your customers over chat.

It answers questions. It processes returns.

It updates subscriptions. Here is the clever part.

Sierra charges based on outcomes, not seats. Brands pay when the AI actually resolves a problem, not just for having the software installed.

That pricing is unusual. Most software charges a flat monthly fee no matter what.

Sierra only gets paid when the bot does the job.

HOW THEY STARTED

Klarna

Sebastian Siemiatkowski, Niklas Adalberth, and Victor Jacobsson were students at the Stockholm School of Economics. In 2005, they entered a startup competition with an idea: let people buy things online and pay later.

At the time, online shopping was still new and most people were terrified of entering their credit card details on the internet. The idea was simple — Klarna would pay the merchant immediately, and the customer would get an invoice with 14-30 days to pay.

The competition judges hated it. The idea was dismissed as financially irresponsible and the team didn't win.

But Siemiatkowski pressed on. Swedish e-commerce was growing fast and merchants were desperate for any way to reduce cart abandonment.

Klarna's "pay after delivery" model was a hit because it shifted the risk — customers could receive the product, try it on, and only pay for what they kept.

The first customers were Swedish e-commerce merchants selling fashion and home goods. Klarna handled the invoicing, fraud detection, and collections.

Merchants saw conversion rates jump because customers were more willing to buy when they didn't have to pay immediately.

Sierra

Bret Taylor had already done the impossible twice. He co-created Google Maps.

He later became co-CEO of Salesforce, chaired Twitter's board during the messy Elon Musk takeover, and became chairman of OpenAI in late 2023. Clay Bavor spent 18 years at Google, most recently running its Labs group.

The two friends left their big jobs in 2023 to build something together. They picked customer service on purpose.

It is the least glamorous corner of software. Their logic was simple.

Companies hate their support costs. Customers hate waiting on hold.

AI that actually resolves problems could fix both sides at once. They launched Sierra in February 2024 with $110 million from Sequoia and Benchmark.

HOW THEY GREW

Klarna

Klarna grew by being embedded at checkout. The strategy was to sign up the biggest online retailers and become a payment option alongside Visa and PayPal.

Once Klarna was at checkout, consumers discovered it organically. The "Pay in 4" button became ubiquitous across fashion, electronics, and home goods retailers.

The Klarna app became a growth engine beyond checkout. By building a shopping app where users could browse products, discover deals, and track deliveries, Klarna turned from a payment method into a shopping destination.

The app has 35+ million monthly active users who start their shopping journey inside Klarna before even visiting a retailer.

International expansion was aggressive. Starting in Sweden, Klarna rolled out across Europe, then into the US, UK, and Australia.

The US became the biggest growth market — American consumers were especially receptive to Pay in 4 as an alternative to credit cards. By 2023, Klarna had 34 million US users.

Sierra

Sierra went straight for big brands, not tiny startups. SoFi, Ramp, ADT, Sonos and Brex signed up early.

By 2026 it said more than 40% of the Fortune 50 were customers. The trick was trust.

Enterprises are terrified of an AI bot going rogue and insulting a customer. So Sierra built guardrails and let each company control exactly how the agent behaves.

Bret Taylor's contacts did the rest. When the chairman of OpenAI calls a Fortune 500 CEO, they pick up.

Sierra hit $100 million in annual recurring revenue in November 2025, seven quarters after launch, and $150 million by February 2026. In April 2026 it launched Ghostwriter, which builds and deploys a new agent from a plain-English description.

THE HARD PART

Klarna

The valuation collapse was humiliating. Klarna raised at a $46 billion valuation from SoftBank in 2021.

One year later, they raised a down round at $6.7 billion — an 85% haircut. It was the most dramatic valuation drop in fintech history.

Employee stock options were underwater. Siemiatkowski had to lay off 10% of the workforce.

The entire BNPL category went from hot to radioactive in months.

Credit losses are the existential risk. Klarna is lending money to consumers who want to buy things they can't afford to pay for right now.

When the economy slows, defaults rise. Klarna's credit losses ran to roughly $600 million in 2022.

The company had to tighten underwriting significantly and pull back from riskier markets. The tension between growth (approve more loans) and profitability (reject risky borrowers) defines every quarter.

The IPO in 2025 was a comeback story but with caveats. Klarna went public at $15 billion — a major recovery from the $6.7 billion trough but still less than a third of its 2021 peak.

The company finally turned profitable by slashing costs with AI (replacing hundreds of customer service agents with AI chatbots) and tightening credit standards. But investors remain cautious about the BNPL model's long-term sustainability.

Sierra

Everyone is building AI customer service agents right now. Decagon has raised at a multi-billion valuation.

Salesforce, ServiceNow and Intercom all shipped their own agents. Sierra is not the cheap option.

It sells premium AI to giant companies that move slowly. The bigger risk sits underneath the product.

Sierra does not make its own AI models. It rents them from providers like OpenAI and Anthropic.

If those model makers decide to compete directly, Sierra's edge gets thin fast, and its co-founder chairing one of them only makes that question louder. A $15.8 billion valuation on roughly $150 million in revenue leaves almost no room for a stumble.

THE PRODUCTS

Klarna

Pay in 4 is the signature product — split any purchase into four interest-free payments over six weeks. Pay in 30 lets customers receive the product first and pay within 30 days.

Financing offers longer-term payment plans with interest for larger purchases. The Klarna App is a shopping destination — browse deals, track orders, manage payments, and earn cashback.

The Klarna Card is a physical Visa card that lets users Pay in 4 anywhere. Klarna Creator is a platform for influencers to earn commissions sharing products.

Klarna AI is their customer service chatbot that handles two-thirds of support queries.

Sierra

The core product is the Sierra AI agent. It is a branded customer service bot that companies deploy on their website, app, and phone lines.

It handles the boring stuff. Order tracking.

Refunds. Password resets.

Account changes. Sierra also built its own tools to test and monitor these agents so they do not make things up.

In 2024 the company added a voice version that talks to customers on the phone. In April 2026 it added Ghostwriter, a tool that builds and deploys a new agent from a plain-English description.

The whole pitch is one AI agent that carries your brand's name and never sleeps.

WHO BACKED THEM

Klarna

Sequoia Capital, SoftBank, Silver Lake, GIC, Atomico, Commonwealth Bank of Australia, Heartland

Sierra

Sequoia Capital and Benchmark wrote the first checks at launch in February 2024, $110 million between them. Greenoaks Capital then led both the $175 million round in 2024 and the $350 million round in September 2025.

In May 2026 Tiger Global and Google's GV led a $950 million round at a $15.8 billion valuation, with Benchmark, Sequoia and Greenoaks back in. That takes total funding to about $1.6 billion.

That is partly the product and partly Bret Taylor. Investors bet on founders who have already built billion-dollar things.

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