In simple terms: An insurer's float could become a recurring source of investable capital, changing a control purchase into a compounding platform. National Indemnity and National Fire & Marine is included in the Buffett Partnership special-situations record with an evidence grade of A - named in the letters; purchase amount supplied by later Berkshire disclosures.

What Buffett saw

Berkshire acquired National Indemnity and National Fire & Marine in 1967. Unlike an asset-separation case, the attraction was the ability of a sound insurer to collect premiums before claims were paid.

Insurance changed the meaning of 'control' for Buffett. The asset was not simply a balance sheet to shrink or a business to sell. It was a source of float: premiums received now and claims paid later, leaving investable funds in between when underwriting was sound.

How the situation was meant to work

The combined $8.6 million purchase brought both operating earnings and access to investable float. By 1968 Buffett described National Indemnity and Associated as earning about 20% on capital employed, and later Berkshire figures show the insurance operation scaling without issuing new Berkshire shares for the growth.

Later Berkshire disclosures put the combined price at about $8.6 million. Buffett later highlighted the two insurance businesses as high-return controlled operations rather than candidates for sale.

The timeline, capital and risk

Capital disclosed: About $8.6 million combined purchase price in later Berkshire disclosures.

Time frame: Purchased March 1967 and retained permanently.

Float is not free cash. Poor underwriting can turn it into an expensive liability, and the Partnership letters do not report an exit because Berkshire intended to keep the insurers. This is a compounding case, not a closed workout return.

What happened

Outcome: It became the foundation of Berkshire's insurance and float model.

What the return means - and the lasting lesson

Return record: No realised exit; operating value compounded inside Berkshire.

The most valuable control purchase may be one that is never liquidated. Float can continuously create new capital to allocate, provided underwriting remains disciplined.

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