Visual summary of operating lessons from Dan Sundheim.

Lessons from Dan Sundheim

Dan Sundheim founded D1 Capital Partners, which researches and invests in both public and private companies. In direct interviews, he discusses a multi-year approach to business analysis, portfolio risk, private-market access and the economics of emerging technologies. — Cheeky Pint Interview.

Part 1: Investment Philosophy

  1. Assess the product and business: D1 studies whether a company sells a good product and can turn customer demand into an enduring business, rather than relying on market excitement alone. — Cheeky Pint Interview.
  2. Recognize the limits of size: Sundheim says returns in his short-selling strategy become harder to sustain as fund size grows, which is why capacity matters when scaling a firm. — Cheeky Pint Interview.
  3. Study the business beneath the narrative: His stated process is bottom-up research into business models, company prospects and management, without trading on short-term technical signals. — Cheeky Pint Interview.
  4. Invest on a multi-year horizon: D1 applies a three-to-five-year horizon to both public and private positions, even though public holdings can be sold more readily. — Cheeky Pint Interview.
  5. Read broadly to develop judgment: Sundheim advises aspiring investors to read stock pitches relentlessly and follow how the ideas play out; that was central to his own learning on Value Investors Club. — Cheeky Pint Interview.
  6. Adapt the talent model as you grow: Sundheim says D1 generally recruits analysts from private equity for their accounting and modeling skills, then invests years in teaching its stock-picking approach. — Cheeky Pint Interview.

Part 2: Crossover Investing

  1. Use comparable diligence in both markets: D1 says it applies the same fundamental due-diligence process to public and private companies, while recognizing private shares are much harder to exit. — Cheeky Pint Interview.
  2. Let private exposure inform public views: Sundheim says proximity to leading private AI companies helps D1 understand potential suppliers, beneficiaries and disrupted public businesses. — Invest Like the Best Interview.
  3. Seek access to exceptional private companies: He argues private investing is competitive in a different way: even when investors agree a company is excellent, its founders can choose which investors to admit. — Invest Like the Best Interview.
  4. Judge private valuations case by case: Sundheim says late-stage private valuations vary with the cycle and can be reasonable or expensive depending on the growth and business model actually underwritten. — Invest Like the Best Interview.
  5. Question the benefits of going public: Sundheim says he would hesitate to take a company like Stripe public because he regards aspects of today's public markets as problematic for management. — Cheeky Pint Interview.
  6. Connect private innovation to public analysis: D1's public/private overlap has increased as private AI advances affect the outlook for public suppliers, cloud providers and software companies. — Invest Like the Best Interview.
  7. Treat private shares as hard to sell: He calls private investing a one-way door: secondary sales can be slow, require company information rights and send an unwelcome signal to management. — Cheeky Pint Interview.
  8. Reassess late-stage opportunities by cycle: Sundheim sees current late-stage private opportunities in unusually large, innovative businesses, but stresses that relative attractiveness changes with market cycles. — Invest Like the Best Interview.

Part 3: Fundamental Research and Valuation

  1. Do the accounting work yourself: His Orthodontic Centers of America case began with hours spent reconciling filings, models and unit-level economics; he concluded the reported numbers did not add up. — Invest Like the Best Interview.
  2. Study cost advantage in context: Sundheim credits SpaceX's reusable rockets with materially lowering launch costs and making its launch business unusually strong; he does not claim every industry has one inevitable winner. — Cheeky Pint Interview.
  3. Value durable cash flows: He explains that the market multiple assigned to a company changes as investors gain confidence that its future cash flows will persist. — Cheeky Pint Interview.
  4. Develop pattern recognition: After more than two decades assessing companies, Sundheim says repeated exposure helps him recognize business-model and valuation patterns, while acknowledging it remains an art. — Cheeky Pint Interview.
  5. Assess management execution: In his Rolls-Royce example, strong technology had been undermined by poor management and contracts; a new CEO's operational changes altered the investment case. — Cheeky Pint Interview.
  6. Compare upside and downside: Sundheim describes position selection as a risk-reward calculation: a large potential gain is not enough if the corresponding downside would make the whole portfolio fragile. — Cheeky Pint Interview.
  7. Look for a reinforcing moat: He argues Netflix's large upfront content investment and global distribution created a flywheel that made its economics stronger over time. — Cheeky Pint Interview.
  8. Stay within your analytical edge: Sundheim says he avoids macro bets because their outcome can depend on a binary timing call; he prefers company-level positions where time can compound value. — Cheeky Pint Interview.
  9. Underwrite a turnaround's evidence: In Rolls-Royce, Sundheim looked for operating progress under new management rather than relying solely on a projected improvement plan. — Cheeky Pint Interview.

Part 4: Risk, Resilience, and The GameStop Squeeze

  1. Understand the GameStop stress test: Sundheim calls the 2021 short squeeze a harrowing period for D1; he says positions moved violently without a fundamental change and exposed a weakness in his risk framework. — Cheeky Pint Interview.
  2. Separate thesis risk from position risk: He says his fundamental short theses could be right while his position sizing was wrong, a distinction he drew explicitly after GameStop. — Cheeky Pint Interview.
  3. Size risk before a squeeze: His revised approach sizes individual shorts small enough that a sudden retail-driven spike need not force a cover at the worst moment. — Cheeky Pint Interview.
  4. Diversify single-name shorts: After pausing shorts, D1 resumed them with smaller, more diversified positions; Sundheim says that reduced squeeze exposure without necessarily sacrificing short alpha. — Cheeky Pint Interview.
  5. Protect the ability to hold a thesis: Sundheim's risk-management rule is to choose position sizes that let the fund withstand a technical surge instead of being forced out before the fundamental view can play out. — Cheeky Pint Interview.
  6. Recognize retail-driven short squeezes: He describes the 2021 episode as a technical shock in which heavily shorted prices rose rapidly despite little underlying business change. — Cheeky Pint Interview.

Part 5: Artificial Intelligence and Tech Investing

  1. Treat scaling laws as an underwriting question: Sundheim says the core investment question for frontier models is whether future capability gains will justify the rapidly rising capital spent on training and compute. — Invest Like the Best Interview.
  2. Price the capital burden of frontier AI: He describes frontier-model development as unusually capital intensive, with large up-front compute commitments and uncertain returns on each additional round of spending. — Invest Like the Best Interview.
  3. Examine where AI economics accrue: Sundheim distinguishes model providers, hyperscalers and applications; he argues model APIs have shown more differentiation and pricing power than some early investors expected. — Invest Like the Best Interview.
  4. Allow for multiple frontier winners: He resisted treating Anthropic as merely a second-place clone of OpenAI because it was too early to know the ranking and he saw distinct strengths in its leadership and product. — Invest Like the Best Interview.
  5. Expect software business models to adapt: Sundheim expects AI to pressure traditional software economics, but says strong distribution and systems of record may adapt rather than simply disappear. — Invest Like the Best Interview.
  6. Value SpaceX's launch economics: He argues reusable rockets lowered the cost of launch dramatically, strengthened SpaceX's core business and created options for new services in orbit. — Cheeky Pint Interview.
  7. Treat compute spending as a real constraint: For AI infrastructure, Sundheim focuses on the scale of GPU and power investment and the uncertainty of returns on that capital, not a guaranteed path from more compute to profit. — Invest Like the Best Interview.
  8. Engage founders on business-model choices: Sundheim describes discussing monetization with AI founders, including his view that OpenAI could have introduced advertising earlier. — Invest Like the Best Interview.
  9. Distinguish valuation from the narrative: He says a compelling technology still requires a view on growth, margins and ultimate returns on invested capital; attractive narratives do not settle the price question. — Invest Like the Best Interview.
  10. Look for economy-wide uses of AI: His investment interest in large language models rests partly on their potential to improve many kinds of work and consumer activity, while he stresses the capital returns are uncertain. — Invest Like the Best Interview.

Part 6: Private Markets and Venture Strategy

  1. Earn access by being useful to founders: Sundheim says private founders choose their investors, making access a distinct investment challenge; he also describes a founder group chat as useful to both founders and D1. — Invest Like the Best Interview.
  2. Let exceptional holdings compound: His SpaceX discussion illustrates how a large private holding can become increasingly consequential as the underlying business scales; that outcome was not guaranteed at entry. — Cheeky Pint Interview.
  3. Match deep-tech claims to capital needs: The SpaceX/Rivian comparison shows how very large engineering and manufacturing investments can produce radically different outcomes; capital intensity is part of the thesis. — Invest Like the Best Interview.
  4. Avoid selling the strongest holdings reflexively: Sundheim says private investments can benefit from illiquidity because a manager cannot easily sell a great company too early—the mistake he made with Netflix in public markets. — Cheeky Pint Interview.

Part 7: Lessons from Value Investors Club and Viking Global

  1. Learn by publishing a researched thesis: Early in his career, Sundheim posted anonymous investment cases on Value Investors Club; his Orthodontic Centers case became a calling card for hedge-fund interviews. — Invest Like the Best Interview.
  2. Reconcile the accounting details: In his Orthodontic Centers analysis, Sundheim says the filings and unit economics failed to reconcile; he suspected expenses were being capitalized improperly. — Invest Like the Best Interview.
  3. Read other investors' work: Sundheim credits the habit of reading many Value Investors Club pitches, then observing the outcomes, as a practical way to learn investing. — Cheeky Pint Interview.
  4. Use mentorship to broaden coverage: At Viking, he learned from Tom Purcell but moved beyond banks into healthcare, industrials and technology to grow his investment responsibilities. — Invest Like the Best Interview.
  5. Train for the firm's actual process: D1 often hires analytically trained private-equity professionals rather than lateral public-equity portfolio managers, because its own stock-picking habits take years to learn. — Cheeky Pint Interview.
  6. Do not sell a good thesis too early: Sundheim says his Netflix thesis was broadly right but he failed to hold the shares long enough to capture its compounding; he treats that as a painful public-market error. — Cheeky Pint Interview.
  7. Recognize organizational concentration: By 2016, Sundheim says he managed more than half of Viking's capital and understood why that concentration was not ideal for the firm or its investors. — Invest Like the Best Interview.

Part 8: The Psychology of Markets

  1. Notice what repeated habits reveal: Sundheim says he often wakes near the European open around 3 a.m. without an alarm after many years in the market; he does not recommend the habit as a universal edge. — Cheeky Pint Interview.
  2. Understand contrarian holding risk: Netflix was an unpopular pitch in 2018 because it consumed cash; Sundheim says his analysis of the content flywheel was right but he exited too soon. — Cheeky Pint Interview.
  3. Combine conviction with risk humility: After GameStop, Sundheim held that the shorts' fundamentals could still be sound while admitting his portfolio sizing had been wrong. — Cheeky Pint Interview.
  4. Read the filings beneath market noise: His Orthodontic Centers work illustrates a preference for reconciling financial statements and unit economics instead of accepting a company's surface story. — Invest Like the Best Interview.
  5. Notice where younger talent prefers to work: Sundheim told Bloomberg that D1 is co-headquartered in New York and Miami, and that about 75% of its younger talent preferred New York at the time of the interview. — Bloomberg Wealth Interview.
  6. Give compounding time to work: He prefers owning strong businesses through temporary earnings misses because, unlike many macro bets, growth in their underlying value can make time an ally. — Cheeky Pint Interview.