In simple terms: A hedge was used to remove general market risk so the profit depended chiefly on the corporate action spread. Unnamed hedged workout is included in the Buffett Partnership special-situations record with an evidence grade of A- - directly quantified, but anonymous.

What Buffett saw

The January 1963 letter records roughly $340,000 of securities sold short and says most were connected to one late-year work-out. Buffett says the hedge eliminated general market risk rather than expressing a bearish view.

That one sentence gives a rare window into the plumbing of early merger arbitrage. Buffett appears to have paired a long claim on the event with an offsetting short, so a broad market move would matter less than the completion of the corporate action itself.

How the situation was meant to work

A paired position can protect an investor when both sides move with the market. The hoped-for profit is the spread between the security bought and the security sold short, not a prediction that either company will rise or fall on its own.

The identity and exact structure remain undisclosed, so it would be wrong to invent a target or acquirer. What is known is the few-month duration and the greater-than-10% gross profit.

The timeline, capital and risk

Capital disclosed: Associated with roughly $340,000 of short securities; the long capital is not disclosed.

Time frame: Late 1962, over a few months.

A hedge removes one kind of risk but can leave others untouched. If the deal breaks, the exchange ratio changes or the short is not a true offset, the position can behave very differently from the tidy spread imagined at entry.

What happened

Outcome: Completed profitably; Buffett withheld the company and transaction structure.

What the return means - and the lasting lesson

Return record: More than 10% gross over a few months, explicitly not annualised.

A hedge can change the risk you own, but it cannot eliminate deal failure, basis risk or an incorrect understanding of the transaction terms.

This guide is educational information, not a recommendation, investment advice or a substitute for reading the underlying disclosure.