BRK-B: slightly undervalued.
Figures as of the 2026-09-22 close.
Book value at 1.63x, the multiple a 12.1% return on equity justifies, blended with earnings, values the shares at $562.02; the price of $503.49 is 10% below that value. The value is recomputed every night after the US close, from the company's own filings with the SEC and the day's closing price.
We call it the buy zone when the price is at least 20% below our estimate of intrinsic value. BRK-B trades at $503.49 against a value of $562.02, a margin of safety of +10.4%: it is not in the buy zone. A margin of safety is room for our estimate to be wrong, not a forecast.
At $449.61 or lower, which is 20% below our estimate of $562.02. That is 11% under today's price of $503.49, if our estimate does not change. It will: it moves with every annual report.