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Data

6 articles

· 6 min

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.

· 5 min

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.

· 6 min

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.

· 6 min

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.

· 9 min

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.

· 4 min

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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