Stephen Vafier (@svafier) profile picture

wringing the humanity out of stocks

Joined June 2009
Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)Photo by Stephen Vafier (@svafier)
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“To love anything good, at any cost, is a bargain.” -Jayber Crow | RIP Wendell Berry
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David Vélez is the founder of Nubank, a bank with 140 million customers and a market capitalization of $60 billion. When he started the business in 2013, no one thought it would work, not even his investors. He has faced down regulators, oligopolies, and corruption to build Latin America's largest digital bank. Now he is bringing Nubank to the United States, where he faces his biggest challenge yet. @gabi_imarques, who grew up four miles from Nubank's headquarters in Brazil, spent time with @velez_david in São Paulo, where the business started, and in Miami, its latest beachhead. She profiles a man who is no stranger to a fight, having grown up in Medellín, Colombia, when the city was at war with Pablo Escobar. Six-year-old Vélez would pull on layers of sweaters before stepping outside, hoping, as a child might, that the extra padding would cushion any bullets. colossus.com/article/david-v…
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Replying to @Restructuring__
You are totally wrong. I’ve had even worst slides. Thank god I change my mind frequently!
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Leadership
No company has meant more to me professionally than MongoDB. I spent more than 11 years as CEO, and even after stepping down last year, I never really left. Serving on the board kept me close to our people, our customers and the business, and only strengthened my conviction in MongoDB’s future. Today, I’m returning as interim CEO. I’m grateful for the trust of our board and our team, and I’m ready to get to work. I also return with a different perspective. As a Partner and Senior Advisor at Sequoia Capital, I have a front-row seat to the founders, technologies and companies shaping the AI era. I see firsthand how AI is not only changing how software is built and businesses operate, but expanding technology’s role from helping people manage work to increasingly helping perform the work itself. I look forward to bringing those insights back to MongoDB as we help our customers capitalize on what may be the most consequential platform shift of our generation. And we’re getting started immediately. Tomorrow at 11 AM ET, we’ll host Investor Day and share our long-term strategy, market opportunity and the product innovation driving MongoDB forward. On Wednesday, our sold-out .local NYC event will bring together developers and business leaders focused on putting AI into production and moving from generating answers to taking action at scale. We’ll have exciting announcements at both events. What has always made MongoDB special is the ambition of our people, the importance of what our customers build with our technology, and the size of the opportunity ahead. I’m proud to lead this team again. There is a lot to do, and I couldn’t be more excited to get back to work. mongodb.com/company/newsroom…
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Kyoto, Japan.
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Through play, toward wisdom.
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Dialectic continues to be a criminally underrated podcast.
Dialectic 56: Miles Grimshaw @milesgrimshaw is an investor at @ThriveCapital. He has spent his life hunting change: from "adventure racing" to finding and working with the world's most ambitious companies. His favorite part: getting to go back down the mountain and begin again. I talked to Miles about playing infinite games, seeing greatness up close, and the biggest change he's seen so far: After a career of software investing, all of the underlying assumptions for venture-backed software startups are in question. What moats will persist? Is software over? We also discuss: - Impatient patience: flying to Ottawa for dinner with @Sirupsen and waiting a year to invest in @turbopuffer - Two fundamental questions: "what is it?" and "who cares?" - Software's barbell future: Benioff building "sales city" and "the champagne region of Palantir" - Founder Vision: "you go where you look" and what @mntruell saw for @cursor_ai - Getting up to speed as a generalist: "I don't know" and "I'll figure it out" - Intuition for great: committing to SpaceX laser engineers (@meshoptical) in 48 hours, with no domain expertise - Humility and conviction: leaving Thrive after a ~decade for Benchmark, and coming back Timestamps: (0:00) Opening Highlights (1:37) Intro: Miles Grimshaw (4:30) Infinite Games, Adventure Racing, and Starting Anew, Over and Over (11:01) Staying Hungry: Proactive Hunting and the Turbopuffer Story (17:35) Impatiently Patient: Courtship, Cursor, Recruiting, and Joining the Team (25:33) Loving Change: London to America, the Himalayas, and Learning New Sports (31:36) The Genetics of Companies: "What Is It?" and "Who Cares?" (38:08) House Cats & Tigers: Where Is the Founder Looking? (47:00) Confidence in Uncertainty and Customers That Pull You Into the Future (54:25) What Remains for Software: Moats, Cities, Wall-Clock Time, and the Barbell of Scale & Luxury (1:04:54) Craft, Trust, and Why Software Isn't Over (1:11:13) Intuition: Gradient Descent and Seeing Greatness Up Close (1:18:07) "I Don't Know" and "I'll Figure It Out" (1:22:12) Commitments, Not Bets: Closing People and Board Work (1:29:06) Joining Thrive, Being a Punk, and Music Studios over Jury Trials (1:36:18) Leaving for Benchmark and Returning to Thrive (1:43:18) Dream Bigger: Lessons from Josh, Teaching Agency to Kids, and Going the Distance @DialecticPod 56: Miles Grimshaw - Back Down the Mountain - is out now below and on all platforms.
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We are releasing the world's first case study of self improving products at Amplitude. A lot of companies have talked about it but none have shown any examples. We have the holy grail of this space and can show it! We've been running our self improving product engine, Wave, on top of Amplitude for the last few months. It's made lots of changes to our website and product based on analytics, session replay, and many other data sources. These have resulted in MASSIVE improvements in metrics on the order of 50% to 3x, not incremental ones. These include: - Personalized suggestion cards on a homepage led to a +160% increase in usage - Improved doc search accuracy from 92% to 97% by setting a 3 character minimum - Reducing setup checklist from five next steps to one guided first step, projected to improve onboarding completion from ~6% to ~9%. - Adding a CTA to each blog post leading to 45 extra signups a week We're slowly rolling Wave out to a few customers and will be sharing examples from them soon. Check it out here and sign up if you're interested in entering the closed beta:
(1/6) i'm the pm on Wave at @Amplitude, our agent for self-improving products. for the past few months we've had it running on our own product. it finds problems, ships fixes, and measures whether they worked. here are some highlights:
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Dolly Parton understood that becoming yourself is an act of creation.
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Not dead yet! Always wonderful to see reaccelerating growth.
Fireworks and Baseten are the two largest inference clouds and I think of them as *an* index for open-source AI adoption. Also first time seeing SpaceXAI on the list of “fastest growing” IIRC. SambaNova!  Will wonders never cease.
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If you’re curious and love to learn, there has never been a better time to be alive.
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Replying to @StableBread
Over 18.5 years, I’ve sold less than 5% of my total holdings. I’m not sure of many who’ve held more for longer. Regarding the stock price, the story isn’t over.
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"more code" ≠ "better product"
Today we're introducing Wave. A proactive product agent that helps teams build self-improving products. Every product team runs the same loop. Build, ship, use, learn. AI has made building and shipping extraordinarily fast. Understanding usage and learning still happen by hand. Wave runs the whole loop: - Analyzes your Amplitude data for signals across analytics, feedback, session replays, error logs, agent traces, and experiment results - Surfaces opportunities in the form of full product specs that you or your agents can approve and ship - Tracks the experiments and outcomes of what you've built so you can start the loop over again Your product learns what works and gets smarter every cycle: amplitude.com/wave
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We're now regularly shipping new features again with @statsig It's amazing to see how excited customers are by the product!
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Replying to @thebeautyofsaas
Holy moly. Haven’t seen that in a long time. This was how I got a taste for sharing stuff. That list of 50k people or so built up from reading books obsessively for ten years was what made the podcast launch possible. 571 of those people listened to episode one. Years of book emails to get 571 listeners haha.
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Jefferies hosted a call today with David and Lago following the $nu announcement. My most important takeaways from their notes: • Lago initiated the transition in late 2025 for personal reasons, with no link to performance, strategy, or any disagreement with management or the Board. • Lago will stay on as a strategic advisor, continuing to support leadership and key projects, including ongoing involvement in internal initiatives. • Importantly, Lago remains a significant shareholder, and alignment with the company remains strong. • Organizational evolution underway: i) Separation of global vs. local CFO roles, ii) ongoing hiring of local finance leadership (e.g. Brazil, Mexico) to meet regulatory and operational needs • Management framed broader C-suite changes (~4–5 out of 18 roles in the past 12–18 months) as necessary to support the next phase of growth, particularly as the company scales internationally, with recent changes already contributing to improved execution and growth acceleration (e.g. 1Q performance). • On recent concerns around credit losses and delinquency in Brazil, management reiterated no change vs. Q1 messaging and remains comfortable with current trends. • Management explicitly clarified that CFO transition is unrelated to Brazil credit performance, with CLA levels viewed as healthy and recent trends driven by seasonality and ongoing growth. • Expansion strategy remains disciplined: ~10% of resources allocated to new bets (e.g. US expansion), and strict guardrails to manage risk in new geographies • More broadly, resource allocation follows a structured framework: ~70% core markets (Brazil/Mexico), ~20% adjacencies (e.g. Colombia), ~10% new initiatives. Lago – Personal Remarks & Transition: • Described the past 7 years as his best professional experience, expressing pride in what has been built. • Decision driven by a desire to rebalance after an intense period and pursue entrepreneurial opportunities, while maintaining alignment with Nubank. • Will remain a large shareholder and strategic advisor, with no intention to compete with the business. Q&A Highlights: • CFO Brazil search: ongoing for several weeks; expected to take a few months, with confidence in finding a strong candidate. • Management reiterated that leadership transitions are part of scaling a high-growth, global platform, and comparable companies have undergone similar evolution.
Been getting a bunch of DMs asking for my thoughts on Lago’s departure from $NU, so I figured I’d share them here. In a vacuum, Lago’s departure is a loss. He’s well-liked and respected internally and by investors alike. He helped take the company public and did an exceptional job articulating and synthesizing Nu’s financial position, operating performance, and long-term strategy. He’ll be missed. If you zoom out, though, the timing of this announcement is undeniably poor. As investors who closely follow the stock know, Nu is already being heavily scrutinized for its U.S. expansion ambitions. At the same time, concerns around Brazilian credit remain front and center, especially after the Q1 credit loss allowance surprise. Lago’s departure directly amplifies both concerns. First, the hiring of a Canadian-American executive who will be based in the U.S. rather than Brazil reinforces the perception that management is doubling down on U.S. expansion—a topic that was already a sensitive point for investors. Second, the more skeptical investor may interpret Lago’s departure as a key executive leaving just ahead of a major credit expansion cycle in Brazil. Fair or not, some will inevitably wonder whether he sees risks to the model that others don’t. Given that backdrop, I’m not surprised the market has treated the news as a negative surprise. The stock market has a funny way of turning momentum into narrative, and narrative into paranoia. What’s the other side of the argument? Nu is clearly gearing up for international expansion, and the asymmetry of the bets it’s making is substantial. Colombia and Mexico already operate with independent finance organizations. Brazil soon will as well. Rob’s appointment appears designed to consolidate and oversee that broader global structure as the company positions itself for its next phase of growth. The opportunity is enormous. If the U.S. strategy works, the U.S. alone could eventually represent another Nu-sized business. If it doesn’t, the downside from these investments appears relatively contained given the scale of the existing franchise. The market’s concern is that management becomes too enamored with global expansion and loses focus on its core markets. With Revolut and others preparing for a similar battle, that concern is understandable. This stock has never been for the faint of heart, and building a meaningful U.S. business could easily take 3–5 years, if Mexico is any guide. But when the downside appears limited and the upside remains significant, it may be worth sticking around.
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@vinaygo is looking to develop Agent Analytics with a few companies. Please let him know if you want to use it and you can get one of the best engineers at Amplitude working directly with you to build what you want!
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This means the world. Credit to @tylercowen for the idea that stuck with me before I became a principal: the highest-return thing a teacher can do is raise a student’s expectations of themselves. We built Alpha School around that exact idea.
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