Nubank

OpenAI

Nubank

Nubank makes money from credit card interchange fees (1-3% of every transaction), interest on credit card balances and personal loans, and net interest income from deposits (lending out customer deposits at higher rates than it pays in savings interest). The company also earns fees from insurance products and investment marketplace commissions.

The key insight is that by being digital-only with no branches, Nubank's cost to serve a customer is roughly 85% lower than traditional Brazilian banks.

OpenAI

OpenAI makes money primarily through API access and subscriptions. The API charges developers per token (roughly per word) for using GPT models in their applications.

ChatGPT Plus costs $20/month for individual users, ChatGPT Team is $25-30/user/month, and ChatGPT Enterprise is custom-priced. Microsoft pays OpenAI licensing fees and also resells OpenAI models through Azure OpenAI Service.

OpenAI's annualised revenue ran past $13 billion during 2025 and kept climbing from there, which is the kind of growth curve that normally only exists in a pitch deck.

Nubank

David Vélez grew up in Colombia, studied at Stanford Business School, and worked at Sequoia Capital in Silicon Valley. In 2012, Sequoia sent him to Brazil to find investment opportunities.

What he found instead was the worst banking experience he'd ever encountered.

Brazilian banks were controlled by five massive institutions that charged outrageous fees — annual credit card fees of $200+, account maintenance fees, fees on fees. Customer service was a nightmare.

Branches required hours of waiting. The banks had zero incentive to improve because they had a captive market of 200 million people and no competition.

Vélez saw the opportunity and left Sequoia to start Nubank in 2013 with Cristina Junqueira (a former Itaú banker) and Edward Wible (a Princeton engineer). Their first product was a purple credit card — no annual fee, managed entirely through a beautiful app, with transparent billing and real-time notifications.

In a country where banks treated customers like an inconvenience, Nubank treated them like human beings.

OpenAI

OpenAI was founded in December 2015 as a nonprofit AI research lab. The founding donors — including Elon Musk, Sam Altman, Peter Thiel, Reid Hoffman, and Jessica Livingston — pledged $1 billion with a mission to build artificial general intelligence (AGI) that would benefit all of humanity.

The idea was that AI was too important and too dangerous to leave in the hands of Google alone.

Sam Altman became chairman while Greg Brockman (former CTO of Stripe) became president. Ilya Sutskever, one of the most respected AI researchers alive, left Google Brain to become chief scientist.

The early team was stacked with world-class researchers who published their work openly — hence "Open" AI.

But AI research turned out to be staggeringly expensive. Training large models required millions of dollars in compute.

In 2019, OpenAI created a "capped-profit" subsidiary — investors could earn up to 100x their money, but profits beyond that would flow to the nonprofit. Microsoft invested $1 billion.

The mission was still to save humanity. The method now involved making a lot of money first.

Nubank

Nubank grew through word of mouth in a country where everyone hated their bank. The product was so much better than the alternative that customers became evangelists.

The invite-only launch created exclusivity and a waitlist that hit millions. People would beg friends for an invite code because getting a Nubank card felt like escaping prison.

The cost advantage was structural. Traditional Brazilian banks operated thousands of branches with tens of thousands of employees.

Nubank had an app and a customer service team. This let Nubank offer free products that banks charged hundreds of dollars for.

The unit economics were unbeatable — when your competitor has 4,000 branches and you have zero, you can afford to be generous.

Geographic expansion into Mexico and Colombia replicated the playbook. Both countries had the same banking problem — concentrated, fee-heavy, customer-hostile banks.

Nubank launched in Mexico in 2019 and Colombia in 2020. Mexico alone already has over 8 million Nubank customers.

OpenAI

ChatGPT's launch in November 2022 was the growth strategy — it just wasn't planned that way. The team expected a modest research preview.

Instead, ChatGPT hit 1 million users in 5 days and 100 million monthly active users in 2 months, making it the fastest-growing consumer application in history. The product went viral because it felt like magic — for the first time, anyone could have a natural conversation with a machine that seemed to understand them.

The Microsoft partnership provided distribution at massive scale. Microsoft integrated OpenAI models into Bing, Office 365 (Copilot), GitHub (Copilot), and Azure.

Overnight, hundreds of millions of Microsoft users had access to OpenAI technology. Microsoft's $13 billion investment was the largest AI bet in history and gave OpenAI nearly unlimited compute.

The API created an ecosystem. Thousands of startups built products on top of OpenAI's models — from customer service bots to coding assistants to content generators.

Each API customer locked themselves into OpenAI's ecosystem, creating switching costs and recurring revenue.

Nubank

The IPO timing was terrible. Nubank went public on the NYSE in December 2021 at a $41 billion valuation.

The stock immediately crashed as the global tech sell-off hit and rising interest rates in Brazil increased the cost of capital. The stock fell from $12 to under $4 by mid-2022.

Vélez had to spend a year convincing investors that a Brazilian digital bank was worth owning during a global risk-off environment.

Credit risk in Latin America is inherently higher. Brazil has volatile inflation, currency risk, and a large unbanked population with limited credit history.

Nubank's loan book grew rapidly, and delinquency rates spiked in 2022 as Brazil's economy slowed. Managing credit risk at scale in emerging markets is fundamentally harder than in developed economies.

Nubank has since tightened underwriting and delinquency has improved, but it remains the biggest operational risk.

Regulatory complexity across three countries is a constant headache. Brazil, Mexico, and Colombia each have different banking regulations, consumer protection laws, and compliance requirements.

Navigating three regulatory environments simultaneously while growing at speed requires significant legal and compliance investment.

OpenAI

The board crisis of November 2023 nearly destroyed the company. The nonprofit board fired Sam Altman as CEO on a Friday, citing a loss of confidence.

Within 48 hours, 95% of employees threatened to quit and follow Altman to Microsoft. By Tuesday, Altman was reinstated and the board was restructured.

The incident exposed the fundamental tension between OpenAI's nonprofit governance and its for-profit ambitions — a tension it finally addressed in late 2025 by restructuring the business as a public benefit corporation sitting under the original nonprofit.

The cost of training frontier models is eye-watering. Each new GPT generation costs hundreds of millions to train.

OpenAI is reportedly spending over $7 billion annually on compute. The company is burning through cash faster than almost any startup in history, which is why it keeps raising at higher and higher valuations.

If revenue growth slows before costs stabilize, the math gets ugly.

Safety concerns are not going away. Multiple prominent researchers have left OpenAI over disagreements about the pace of development versus safety research.

Ilya Sutskever, the chief scientist who was central to the board's decision to fire Altman, left in 2024 to start a safety-focused AI lab. The public debate about whether OpenAI is moving too fast — and whether its safety commitments are genuine — grows louder with every capability improvement.

Nubank

Nu Credit Card is the flagship — a no-annual-fee Mastercard managed entirely through the app. NuConta is the digital bank account with free transfers and bill payments.

Nu Invest is the investment platform offering stocks, ETFs, and fixed income. Personal Loans are offered based on credit behavior within the app.

Nu Life Insurance and other insurance products are distributed through the app. Ultraviolet is the premium tier with higher limits, airport lounges, and additional perks.

NuPay is the payments solution for merchants.

OpenAI

ChatGPT is the consumer chatbot — the product that made AI mainstream overnight. The flagship GPT models are multimodal, handling text, images, and audio in one system.

The OpenAI API lets developers integrate GPT into any application. DALL-E generates images from text descriptions.

Whisper transcribes and translates audio. Sora generates videos from text prompts.

GPT Store lets users create and share custom GPT agents. ChatGPT Enterprise gives businesses a private, secure version of ChatGPT with admin controls and no data training.

Nubank

Sequoia Capital, Tiger Global, DST Global, Tencent, Berkshire Hathaway, SoftBank, Dragoneer

OpenAI

Microsoft ($13B), Thrive Capital, Khosla Ventures, Sequoia Capital, Founders Fund, Tiger Global, SoftBank, a16z