Why Warren Buffett Loves Insurance – The Business Model Behind Berkshire’s Engine
If you read Berkshire Hathaway’s shareholder letters, one theme appears again and again: insurance is the engine of the whole empire. Warren Buffett has called it the most important business they own – not because it’s flashy, but because of how its economics work.
The key concept is “float.” Property‑casualty insurers collect premiums today and pay claims later, sometimes decades later. The money sitting in between – premiums received but not yet paid out – is float. Buffett’s insight was simple but powerful: if you can write insurance at breakeven or better, you are effectively being paid to invest other people’s money.
Property‑casualty insurers receive premiums upfront and pay claims later… This collect‑now, pay‑later model leaves P/C companies holding large sums – money we call ‘float’ – that will eventually go to others.
Warren Buffet
To think of float as strictly a liability is incorrect; it should instead be viewed as a revolving fund.
Warren Buffet
Berkshire’s float reached around $170 billion in 2024, and historically they have earned attractive returns on that capital while also generating underwriting profits. In other words, the insurance operations both make money themselves and supply a huge, low‑cost pool of investment capital to deploy into stocks, bonds, and whole businesses.
Buffett often contrasts this with a typical fund manager. A fund has to raise money from clients and charge fees; an insurer with disciplined underwriting gets capital “loaned” to it via float and may even earn a profit for holding it. When interest rates are reasonable and underwriting is conservative, float becomes an enormous structural advantage.
That’s why Buffett loves insurance: it’s a repeatable, cash‑generating business that, when run prudently, creates a self‑funding compounding machine. The flywheel is simple – collect premiums up front, invest the float wisely, and keep underwriting standards tight – but over decades it has powered one of the greatest compounding stories in history.
