Underwriting DisciplineWide moat

Berkshire Hathaway (BRK.B) — moat facet

The willingness to write less when prices turn foolish is the whole trick.

Underwriting discipline is the price of admission for using float safely, and it is far rarer than it sounds. The temptation in insurance is permanent and seductive: write more policies, cut the price, grow the float, and book the premium now — while the claims that will prove the pricing foolish arrive only years later, often on someone else's watch. Most insurers succumb, chasing volume in soft markets and discovering their mistake when it is too late. Berkshire built its culture on the opposite instinct.

Pre-tax underwriting result, all insurance ($B)$2.1B2016-$3.2B2017$2.0B2018$0.4B2019$0.8B2020$0.9B2021-$0.1B2022$6.9B2023$11.4B2024$9.5B2025Forms 10-K FY2018, FY2020, FY2022, FY2025
Two losing years in ten, one of them by less than $100 million.

The discipline expresses itself as a willingness to shrink. When prices turn irrational, Berkshire's insurers write less, let rivals take the unprofitable volume, and wait — sometimes for years — until pricing turns sane again. That patience costs market share and invites the impatient to ask why the float isn't growing, but it is exactly what keeps the float profitable. An underwriting profit means the leverage is free; an underwriting loss means the float carried a cost after all.

The vulnerability is that this discipline is cultural, not structural — it lives in the judgment and temperament of the people running the insurers, above all Ajit Jain, and in a headquarters that never pressures them to chase premium. A future culture that prized growth over profit could swell the float impressively for a while and destroy it spectacularly later. Discipline is the thin, essential thread on which the whole float advantage — grown from $114 billion in 2017 to $177.5 billion, with an underwriting loss in only two of the years since, 2017 and 2022123 — hangs.

Moat trajectory: Holding steady

Holding steady. The willingness to write less when prices turn foolish is the thread the whole float advantage hangs on, and it has held across generations of Berkshire underwriters. It neither widens nor narrows so much as it must be continually re-earned — and the coming test is whether the discipline embodied in Ajit Jain survives his eventual departure as cleanly as it has survived every soft market so far. For now the culture holds firmly, keeping this a durable, stable pillar.

The number that tests this moat
Reported
Insurance underwriting earnings after tax, latest quarter
$1,731M in Q2 2026, from $1,992M

GEICO's combined ratio rose to 91.2% from 83.5% while reinsurance earned more. Two more quarters of GEICO decline would mean the auto-pricing cycle has turned.

Source: Berkshire Form 10-Q, quarter ended 30 June 2026 ↗
⚠ Threats to the moat
⚠ THREAT 01
Discipline Erodes After Its Keepers
Shrinking on purpose is a temperament, not a rule — and temperaments retire.
References
  1. ReportedDiscipline is the thin, essential thread on which the whole float advantage — grown from $114 billion in 2017 to $177.5 billion, with an underwriting loss in only two of the years since, 2017 and 2022 — hangs.
    Berkshire Hathaway Form 10-K, FY2018 - float $123 billion (2018) and $114 billion (2017); pre-tax underwriting by unit 2016-2018 (Reinsurance Group -$3,648M in 2017, total -$3,239M); insurance and other cash about $109 billion — FY2016-FY2018 · publ. February 2019 · source ↗
  2. ReportedDiscipline is the thin, essential thread on which the whole float advantage — grown from $114 billion in 2017 to $177.5 billion, with an underwriting loss in only two of the years since, 2017 and 2022 — hangs.
    Berkshire Hathaway Form 10-K, FY2022 - float $164 billion (2022) and $147 billion (2021); after-tax earnings by line 2020-2022 (insurance investment income $6,484M in 2022); pre-tax underwriting -$98M in 2022; Reinsurance Group -$930M (2021) and +$1,389M (2022); $7.9 billion of share repurchases in 2022; insurance and other cash $125.0 billion; about 383,000 employees; Alleghany acquired for about $11.5 billion; acquisitions of businesses net of cash $456M (2021) and $10,594M (2022) — FY2020-FY2022 · publ. February 2023 · source ↗
  3. ReportedDiscipline is the thin, essential thread on which the whole float advantage — grown from $114 billion in 2017 to $177.5 billion, with an underwriting loss in only two of the years since, 2017 and 2022 — hangs.
    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 ↗
Sources
Generated September 23, 2026