Growing PoolNarrow moat

Berkshire Hathaway (BRK.B) — moat facet

$177.5 billion of float that compounded larger for decades — scale as the by-product of patience.

A float that merely persisted would be valuable; a float that grows is a compounding marvel. Over the decades Berkshire's float has swelled from millions to $177.5 billion by June 2026¹, and every increase enlarges the base of investable capital without Berkshire raising a cent from shareholders or lenders. The insurance business, simply by operating, manufactures more investable money each year — a self-funding source of permanent capital most companies can only dream of.

The pool more than doubled in twelve years, the last few billion at a time.

The growth has come from a mix of organic expansion, above all at GEICO, and the acquisition of insurers like General Re² and the National Indemnity operations. Each addition widened the pool and diversified the risks feeding it. Because much of the money is long-tailed — some of it, in reinsurance and workers'-compensation lines, will not be paid out for many years — it behaves almost like permanent equity that Berkshire gets to invest as it pleases.

The honest limit is that float cannot grow forever at will. It expands only as fast as Berkshire can write profitable insurance, and at today's scale meaningful growth requires enormous volumes of sensibly priced risk, which do not always exist. In soft markets the pool may stall or even shrink as discipline forces the insurers to write less. So the growth is real and immensely valuable, but it is a function of underwriting opportunity, not a dial management can simply turn.

Moat trajectory: Holding steady

Holding steady, and increasingly hard to grow. The float is enormous and long-tailed, a permanent block of investable capital — but at this scale meaningful growth requires vast volumes of profitably-priced risk that soft markets don't offer, and GEICO faces sharper competition than it once did. So the pool holds at a high level rather than compounding as it did in leaner decades. That is no weakness: a flat, profitable float still throws off free leverage on a huge base. Stable, with growth that comes in fits.

The number that tests this moat

Reported

Float growth over a decade

$177.5B at June 2026, from $91B at end-2016

The pool nearly doubled in ten years, partly by acquisition (MLMIC 2018, Alleghany 2022). Organic growth now runs about $1B a half-year, which is the realistic pace.

Source: Berkshire Form 10-Q, quarter ended 30 June 2026; Form 10-K FY2016 ↗

⚠ Threats to the moat

⚠ THREAT 01

The Pool Can Stall or Shrink

Float grows only when there's profitable risk worth writing.

References

ReportedOver the decades Berkshire's float has swelled from millions to $177.5 billion by June 2026, and every increase enlarges the base of investable capital without Berkshire raising a cent from shareholders or lenders.
Berkshire Hathaway Form 10-Q, quarter ended 30 June 2026 - after-tax earnings (underwriting $1,731M vs $1,992M, insurance investment income $3,059M vs $3,367M, BNSF $1,558M vs $1,466M, BHE $891M vs $702M, manufacturing, service and retailing $4,470M vs $3,601M, investment gains $12,684M, net earnings $25,667M); GEICO pre-tax underwriting $994M vs $1,821M, combined ratio 91.2% vs 83.5%; Reinsurance $913M vs $650M; float $177.5B; insurance and other cash and Treasury Bills net $359.2B; consolidated cash $35,096M + $324,905M + $5,513M; equity securities $323.8B; H1 purchases of equities $39.4B and sales $27.8B; acquisitions of businesses net of cash $9.7B; $4.8B of treasury stock acquired in H1, most in Q2; OxyChem about $9.4B on 2 January; Taylor Morrison agreed 31 May at $72.50 a share, about $6.8B, closed 24 July; notes payable of insurance and other $43.3B; shareholders' equity $747.9B; BNSF revenue $6,601M vs $5,769M, fuel $1,173M vs $698M; BHE revenue $6,735M vs $6,418M; investment income down 9.1% on lower interest rates — Q2 2026 · publ. August 2026 · source ↗
ReportedThe growth has come from a mix of organic expansion, above all at GEICO, and the acquisition of insurers like General Re and the National Indemnity operations.
Berkshire shareholder letters / 10-K — insurance float grown from millions to well over $100B (GEICO organic growth; General Re, Alleghany acquisitions) — 1967-2026 · publ. Annual letters · source ↗

Sources

Generated September 23, 2026