Practical rules and heuristics, stated so they can be used tomorrow.
A compelling story is a claim to test, and the test for a technology is watching it work.
Venture and growth diligence, and any investment where the case rests on a founder's account of something that cannot yet be seen.
From The Inventor: Out for Blood in Silicon Valley · 2019
Returns on a rolled futures position include the roll, so the shape of the curve matters as much as where spot goes.
Any question on commodity exposure, futures-based products or the difference between spot and investable returns.
From The Little Book of Commodity Investing · John Stephenson
Results come from a few outcomes, so the job is to survive long enough to be there when they arrive.
Position sizing, venture portfolio construction, and any moment of frustration that most of your effort seems to produce nothing.
From The Psychology of Money · Morgan Housel
Separate a bad year into your errors and the market's mood, name the errors specifically, and say whether the method changes.
Reviewing your own record, reading any manager's bad year, and the interview question about a mistake.
From Giverny Capital's 2025 annual letter, on a year of underperformance · François Rochon
Start from an observation you can make and others cannot, then do the work to see whether the market already knows.
Stock idea generation and the stock pitch question in any buy-side interview.
From One Up on Wall Street · Peter Lynch
Before estimating, ask what number is anchoring you and what the base rate is for cases like this.
Valuation, deal pricing, forecasting, and the behavioural finance questions in hedge fund and asset management interviews.
From Thinking, Fast and Slow · Daniel Kahneman
Ask what period a model was fitted to, and whether that period contained the event you are worried about.
Any risk model, stress test or structured product that reports a probability of loss.
From Berkshire Hathaway's 2008 letter to shareholders · Warren Buffett
Duration beats brilliance in compounding; arrange your life and portfolio so you are never forced to stop.
Thinking about personal finance, about a long career, or about why survival matters more than any single year's return.
From Becoming Warren Buffett · 2017
Before weighing advice, work out how the adviser is paid and what that pays them to say.
Evaluating any product, fund or recommendation, and in interviews about asset management economics.
From Where Are the Customers' Yachts? · Fred Schwed Jr.
Profit is not cash, and growth widens the gap; model the cash a business needs to grow before admiring its sales.
Any three-statement question, any growth company's cash flow, and any founder conversation about runway.
From Shoe Dog · Phil Knight
Judge a network by whether its first small market is dense and self-sustaining, not by the size of the market it aims at.
Early-stage diligence, growth strategy questions, and any marketplace that reports total users rather than density.
From The Cold Start Problem · Andrew Chen
Lead with something useful to the other person; a request with nothing attached is ignored by anyone worth reaching.
Cold outreach, coffee chats, and off-cycle recruiting where there is no process to carry you.
From Never Eat Alone · Keith Ferrazzi
Whoever can take a position must not be the person who confirms it. Separate the hands, and the rest of the controls become possible.
Risk, operations and compliance questions, and any time a process lets one person both act and verify.
From Rogue Trader · 1999
A track record with no bad months is a question, not a credential.
Due diligence on any manager, strategy or product that reports steady positive returns.
From Madoff: The Monster of Wall Street · 2023
Protecting a secret and refusing to demonstrate a result are different things; a company that cannot tell them apart may have no result.
Technology diligence, and any situation where access to evidence is being refused on grounds of confidentiality.
From Bad Blood · John Carreyrou
Measure what changed for the customer, not what was shipped; a team given an outcome behaves differently from one given a list.
Product interviews at large companies, metrics questions, and any discussion of how a team should be judged.
From Escaping the Build Trap · Melissa Perri
Find the subproblem and the recurrence first; the implementation is mechanical once the structure is clear.
Coding interviews, and any problem whose difficulty is in the decomposition.
From 5 Simple Steps for Solving Dynamic Programming Problems · Reducible
Being distinctive is not a state but a cost paid continuously; stop paying it and the drift to typical begins.
Questions about culture, moats that depend on behaviour rather than assets, and personal career choices.
From Amazon's 2020 letter to shareowners, Jeff Bezos's last as chief executive · Jeff Bezos
When every option is bad, the cost is in the delay; choose the least bad one and move.
Assessing a management team under stress, and any interview question about a difficult decision you made.
From The Hard Thing About Hard Things · Ben Horowitz
The common factor among people who last is not how they pick trades but how they limit what a wrong one costs.
Sales and trading, hedge fund and any markets interview that asks how you would manage a position.
From Market Wizards · Jack D. Schwager