RuleOne

← Learn · Module: Understand the business

345 · How and Why to Know When You're Right

2021-12-01 · 37 minUnderstandLoveReduce basis

In one sentence: Phil and Danielle walk down the checklist pyramid on a live (unnamed) candidate: a quick gut-level pass on Munger's four, a week of work on Ackman's eight, and a strict test of simplicity, then explain why you buy a quarter of the position first so a falling price is something to welcome.

Key ideas

How it maps to RuleOne

Buffett, Munger and Graham links

Words to know

Try this

Open /stocks/ and pick one company from your watch list. Write the Munger four in one line each without opening the price. Then draft a three-tranche plan (first at your margin-of-safety price, the next two at 20% lower) and enter the plan in /holdings/ notes.

Check yourself

  1. Why must you not buy your whole position at the first margin-of-safety price?
    AnswerThe event that cut the price may still be running, and with no view of the bottom you could use all your cash before it falls further.
  2. What is the first thing the Ackman eight tests?
    AnswerWhether the business is simple and predictable enough to fall within your circle of competence.
  3. If a company you passed on doubles, was passing a mistake?
    AnswerNot necessarily. Price movement alone doesn't tell you if your analysis was right.

Short quotes

"Just because something goes up doesn't mean it was a mistake to not buy it." (Phil, ~21:45, auto-transcribed)

patiencechecklist logisticsmunger fourackman eightcircle of competencetoo hard pilesimplicitytranche buyingoptions to reduce basisconfirmation bias

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AI study notes from an automatic transcript. Names and figures may be misheard, and quotes are short excerpts for study. Not investment advice.