Insurance FloatWide moat

Float is the secret sauce of the whole enterprise, and understanding it is the key to understanding why Berkshire is not merely a good holding company but a great one. When Berkshire's insurers write a policy, they collect the premium up front and pay any claim only later — sometimes years later — and in the meantime that money sits in Berkshire's hands to be invested. Across the whole insurance operation this adds up to a vast, low-cost, and growing pool of capital that does not belong to Berkshire but is Berkshire's to put to work, and the returns it earns on that pool flow to the shareholders.

The magic of it is that, if the underwriting is run at even a modest profit — if the insurers collect at least as much in premiums as they eventually pay in claims and expenses — then the float is not merely cheap capital but essentially free leverage. Berkshire gets to invest billions of dollars it did not have to borrow and does not have to repay on any fixed schedule, and it keeps the investment returns. Ordinary companies must choose between using their own money or borrowing at a cost; Berkshire, through float, gets to invest money that costs it less than nothing.

Wielding float well, however, demands an underwriting discipline that most insurers conspicuously lack — the willingness to write less business, and to watch rivals take the volume, when prices turn foolish. The temptation in insurance is always to chase premium by underpricing risk, which grows the float in the short run and then destroys it in the long run when the claims come due. Berkshire's insistence on pricing risk sanely, even at the cost of shrinking when the market is irrational, is what keeps its float a blessing rather than the curse it has proven to be for so many others.

The pool has grown steadily larger over the decades, which compounds the advantage in a way that is easy to underappreciate. A larger float means more capital to invest, and a float that reliably grows means the investable base expands year after year without Berkshire having to raise a dollar from shareholders or lenders. It is a source of permanent, expanding capital that renews itself through the ordinary operation of the insurance business.

Finally, the sheer size and strength of Berkshire's balance sheet lets it write catastrophe insurance that few others dare to touch — the enormous, lumpy risks that would bankrupt a smaller insurer if they went wrong. Because Berkshire can absorb a very bad year that would destroy a competitor, it can charge handsomely for taking on risks no one else will, and it can be greedy for such business precisely when a disaster has made everyone else afraid. The float, the discipline, the growth, and the capacity to bear what others cannot all reinforce one another into an advantage that has powered the whole enterprise for half a century — the float stood at $177.5 billion at the end of June 2026.¹