Given at USC Marshall School of Business

  • facts are not enough, you need models which is the structure facts hang off.
  • you need many models, otherwise you'll see everything through the narrow lense of a single pattern
  • models are effective ways to understand aspects of complex systems
    • therefore models should come from a variety of disciplines, to capture more aspects of the whole interconnected complexity
  • a minority of models will carry the majority of weight. 80/20 rule.

learn the fundamental ideas in each major discipline, always prefer the explanation that uses more fundamental ideas –> use the checklist style for these fundamental ideas


use a big bag of multidisciplinary tricks, mastered to fluency, applied to all complex problems in life

  • This talk discusses models and their application in investing
  • math
    • permutations
    • combinations
    • basic probability as discovered by Fermat/Pascal are highly applicable to the real world
  • Engineering models and hard science are the most reliable
    • quality control
    • breakpoint controls
    • backup system
    • critical mass
  • bell curve from statistics
  • cost benefit analysis
  • biology and physiology models are the next most useful
  • psychology models
    • the brain has shortcuts which can be manipulated, don't fall victim
  • think of an economy as an ecosystem. Similar rules apply from nature to a competitive market economy
    • specialization, for example

advantages of scale

  • surface area vs volume
  • special access to expensive opportunities
  • efficiencies with volumne
  • social proof
  • cascading one-winner take all industries
  • chain store effect – advantage of scale with small units for experiment and local specialization

disadvantages of scale

  • big, fat, dumb, unmotivated, corrupt beucrocracy

  • Avoid natural antipathy towards information that runs counter to your current belief. Learn to destroy your own favorite ideas/beliefs.
  • copy what's working for others
  • management matters - but, on balance, good business is safer to bet on than merely good management

why do some industries lose margin from fierce competition and others leave a margin for owners?

  • brand identity
  • competitive tendencies of the players
  • airlines vs cereals example

  • efficiency gains don't always benefit owners. Increase efficiency in a low margin business will still flow mostly to the end customer
  • rapid tech development result in sometimes unpredictable competitive destruction
  • stock market behaves like a pari-mutuel system at racetrack. Intelligent, intentional bets should out perform the average, plus the house take a %
  • Bet big when a golden opportunity arrives; otherwise, don't. It's that simple
  • Investment managers are in the business of selling their product to people; not primarily buying stock
  • Ben Graham's Mr. Market concept

In the long run, it's hard for a stock to outperform the underlying business

  • get in early
  • find great businesses w/ great managers
  • avoid taxes by buying and selling


Buying great companies can get overdone at times. It always needs to be bought at a good price.


3 Rules for work

  1. Never sell something you wouldn't buy
  2. Never work for whom you don't respect and admire
  3. Work only with people you enjoy