Fraud and its warning signs, leverage, illiquidity, concentration, story-driven buying, and a recurring mistake library worth learning from other people's losses.
The mistakes that show up again and again
Lessons
Fraud, and the tells that give it away — Most investment fraud does not look exotic. It arrives through someone you already trust, offers returns that are only slightly too good, and fails a small number of checks that take an afternoon. (12 min)
Leverage: the same asset, a different outcome — Borrowing to invest does not change what you own. It changes how far the asset can fall before the decision is taken out of your hands. (11 min)
Illiquidity: when you cannot get out — A price you cannot transact at is a quote, not a value. The losses here come from needing money at a moment when the asset will not give it back. (9 min)
Concentration: one thing going wrong — Concentration is how fortunes are made and it is how they are lost, and the two facts are the same fact viewed at different times. (10 min)
Buying the story — A good narrative is not evidence, and it is the most reliable way to end up paying a price that only works if the story is much better than it says. (8 min)
The mistake library — Losses are cheaper to learn from when they are someone else's. This is the practice of keeping a written record of both kinds so the same error cannot arrive twice wearing a different name. (13 min)