Put Bill Ackman's rule through your numbers
One rule JMM has located in a dated source, rebuilt as a working calculator, and taken a position on.
- Sources located
- Pershing Square Holdings, Ltd.
- Source years
- 2026
- JMM verdicts
- depends on you
Not every rule here survives its own arithmetic
JMM does not grade this rule as a set. The verdict on activist concentration model is where the position turns critical: Concentration is not a strategy. It is a multiplier on whether you were right.
Each page separates three things people usually run together: what the source states, what JMM's model adds to make it computable, and where the rule itself breaks. The last one is not the calculator's limitations list. It is the failure of the idea, which is the part the person who published the rule has no reason to write down.