Guru Speak: Buffett Partnership Letters (1957 to1970) - Key Takeaways and Learnings - Part V

In continuation of reading the Buffet Partnership Letters, here is the 5th part in the series. You can read the previous posts here:
Part I
Part II
Part III  

Part IV

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Last year in commenting on the inability of the overwhelming majority of investment managers to achieve performance superior to that of pure chance, I ascribed it primarily to the product of: "(1) group decisions - my perhaps jaundiced view is that it is close to impossible for outstanding investment management to come from a group of any size with all parties really participating in decisions; (2) a desire to conform to the policies and (to an extent) the portfolios of other large well-regarded organizations; (3) an institutional framework whereby average is "safe" and the personal rewards for independent action are in no way commensurate with the general risk attached to such action; (4) an adherence to certain diversification practices which are irrational; and finally and importantly, (5) inertia.”

We diversify substantially less than most investment operations. We might invest up to 40% of our net worth in a single security under conditions coupling an extremely high probability that our facts and reasoning are correct with a very low probability that anything could drastically change the underlying value of the investment."

We have to work extremely hard to find just a very few attractive investment situations. Among the few we do find, the expectations vary substantially. The question always is, “How much do I put in number one (ranked by expectation of relative performance) and how much do I put in number eight?" This depends to a great degree on the wideness of the spread between the mathematical expectation of number one versus number eight.” It also depends upon the probability that number one could turn in a really poor relative performance.

If good performance of the fund is even a minor objective, any portfolio encompassing one hundred stocks (whether the manager is handling one thousand dollars or one billion dollars) is not being operated logically. The addition of the one hundredth stock simply can't reduce the potential variance in portfolio performance sufficiently to compensate for the negative effect its inclusion has on the overall portfolio expectation. Anyone owning such numbers of securities after presumably studying their investment merit (and I don't care how prestigious their labels) is following what I call the Noah School of Investing - two of everything. Such investors should be piloting arks.