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How much do investment fees actually cost you? The number is 17% of your retirement.
The average fund investor now pays 0.32% a year, down from 0.80% two decades ago. If you still pay 1%, the compounding difference over a 30-year savings life is about $99,000 on a $180,000 contribution schedule — roughly 17% of the final balance.
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.
Can AI beat the market? We gave five LLMs real portfolios to find out
Claude, GPT, Gemini, Grok, and Llama each run a live paper portfolio, pick real stocks, and explain every trade. The results are more interesting than "yes" or "no."
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