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S&P 500612.44+0.36%Nasdaq 100559.12+0.70%Dow 30448.76-0.19%Russell 2000232.05+0.54%ASML921.40+1.24%TSMC214.68+1.15%Costco904.22-0.35%MercadoLibre2,140.50+1.34%Berkshire486.90+0.21%Novo Nordisk88.34-1.58%S&P 500612.44+0.36%Nasdaq 100559.12+0.70%Dow 30448.76-0.19%Russell 2000232.05+0.54%ASML921.40+1.24%TSMC214.68+1.15%Costco904.22-0.35%MercadoLibre2,140.50+1.34%Berkshire486.90+0.21%Novo Nordisk88.34-1.58%
Issue 47Oct 26, 2026 · 2 min · From the desk

The cost of chasing

Why the most expensive decision in a bull market is the trade you make because you are bored.

Good morning. Three of the six notes on our watchlist moved more than eight percent last week. We bought none of them. That is the subject of today's letter.

There is a particular kind of pressure that builds in a strong market. It is not greed exactly. It is the feeling that everyone else is participating in something and you are reading a filing. The remedy most people reach for is a small, impulsive purchase in the thing that has already moved — and that is the most expensive transaction in investing, because it costs you both money and the discipline that produced the money.

A rule we actually follow

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BehaviourPortfolio construction