In simple terms: Buffett could become the largest holder at an attractive price, but the company name was withheld. The late-1958 'better special situation' is included in the Buffett Partnership special-situations record with an evidence grade of A- - directly described, but anonymous.
What Buffett saw
Buffett said he found a late-1958 special situation in which he could become the largest holder at an attractive price, and sold the Commonwealth Trust block to fund it.
The sentence is tantalising because it reveals a real portfolio decision: Buffett sold a position he still liked in order to fund an opportunity he believed was better. But the letter stops there and never names the company.
How the situation was meant to work
Event-driven and control investing can recycle capital faster than ordinary long-term ownership. The payoff is not merely an individual return; it is the ability to move money from a good idea into a better idea when the expected value and duration justify it.
Sanborn Map fits the chronology and later became large, but the letter never identifies it as this opportunity. The capital and return therefore remain unknown as a separate case.
The timeline, capital and risk
Capital disclosed: Large enough to motivate the sale of the 12% Commonwealth Trust block; exact capital undisclosed.
Time frame: Late 1958 onward.
Sanborn Map fits the chronology, but a plausible link is not proof. Combining the two would make a satisfying story at the cost of turning a disclosed anonymous position into a falsely named one.
What happened
Outcome: Unknown as a separately identifiable investment.
What the return means - and the lasting lesson
Return record: Unknown.
Opportunity cost belongs in special-situations research. A good investment can be sold because another opportunity offers a superior expected return, but the historical record should not merge two cases without evidence.
This guide is educational information, not a recommendation, investment advice or a substitute for reading the underlying disclosure.