BRK's Active-Cap-to-Investor-Cap ratio — both are cost-basis caps, so it is structurally flat (~0.5–0.7 across every cycle, it does NOT spike at tops) and is therefore NOT a valuation oscillator. Used here only as a data-integrity check (aviv_ratio = active_cap ÷ investor_cap must reconcile); the displayed valuation oscillator is Cointime MVRV instead.