Topic
Behavior
18 articles
How long do you have to hold stocks to not lose money? We ran every window since 1928.
Over 98 years, no 20-year holding period in the S&P 500 lost money in nominal terms. But adjust for inflation and 11% of 10-year periods lost purchasing power — with the worst down 34%. The usual answer is right for the wrong reason.
Does trading more often hurt your returns? 66,465 households say yes.
The definitive study tracked every trade in 66,465 brokerage accounts for six years. The most active traders earned 11.4% a year while the market returned 17.9% — and the average household turned over 75% of its portfolio annually to underperform by 1.5 points.
Does rebalancing improve returns? We tested 98 years — it cost 1.1 points a year.
A 60/40 portfolio rebalanced annually since 1928 grew to $257,108. The identical portfolio left alone grew to $697,640. Rebalancing lost money — and it is still the right thing to do, for a reason that has nothing to do with returns.
What is the average stock market return? We ran 98 years of data — the answer is 10%, 6.8%, or neither.
We computed it from the raw annual series: 11.86% arithmetic, 10.02% compounded, 6.79% after inflation. And in 98 years, only four landed anywhere near the average — which is the finding that actually matters for planning.
Why most day traders lose money — what 3.7 billion trades actually show
The definitive study tracked every trade on the Taiwan Stock Exchange for 15 years. Around 1% of day traders were predictably profitable after costs, and 93% had quit within five years. Here's the mechanism behind those numbers.
What percentage of fund managers beat the index? The 15-year number is brutal.
Over 15 years, 89.5% of active large-cap US funds failed to beat the S&P 500. Professionals with research teams and Bloomberg terminals lose this bet nine times in ten — which should change how you think about your own stock picking.
How long do bear markets last? Why every source gives you a different number.
You'll see "9.6 months," "13 months," and "4.5 years" quoted as the answer. All three are defensible. The disagreement is the useful part, because it tells you which number applies to your situation.
Do investors really underperform their own funds? The famous number is disputed.
Morningstar says bad timing costs investors 1.2 percentage points a year — about 15% of their funds' returns. A 2026 paper in the Financial Analysts Journal says that figure is largely a statistical artifact. Both matter.
We gave five AI models $100,000 each. One never placed a single trade.
Claude, GPT, Gemini, Grok, and Llama each run a live paper portfolio with real prices and public reasoning. After ten weeks the spread between best and worst is 16.45 points — and the most interesting result isn't the winner.
Do stop-losses actually work? What they protect and what they cost
A stop-loss is a good tool wearing a misleading name. It caps a trade, not a risk — and for long-term investors it usually sells the exact thing they should be holding.
What to do when the market drops — a checklist for the actual moment
Everyone knows the advice. Almost nobody can execute it at 3pm on a red day. Here's what to do instead of deciding, in the order to do it.
When should you sell a stock? The four honest reasons
Almost everyone has a buying process and no selling process. That asymmetry is where most of the damage happens — here are the only four reasons to sell that survive scrutiny.
Seven investing mistakes beginners make (and what each one really costs)
Not the usual list. These are the seven errors that show up over and over when you grade thousands of real decisions — ordered by how much damage they actually do.
Dollar-cost averaging vs lump sum — the honest answer
Lump sum wins more often on the math. Dollar-cost averaging wins more often in practice. Both statements are true, and the gap between them is the whole point.
The psychology of panic selling — why smart people sell at the bottom
Panic selling isn't a knowledge problem. Everyone knows not to sell low. Here's what's actually happening in the moment, and the only defenses that survive contact with a real decline.
Time in the market vs timing the market — what the phrase actually means
"Time in the market beats timing the market" is repeated so often it has stopped meaning anything. Here's the real mechanism behind it, and the one case where it's misleading advice.
The one lesson every market crash teaches — and why most people fail it
Every crash in modern history eventually recovered. The people who got hurt weren't wrong about the market — they were wrong about themselves.
What if you'd invested in Nvidia at the start of the AI boom?
The 2023 AI boom is the trade everyone claims they'd have made. Hindsight makes it obvious. Living through it was anything but.
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