Say, I have a view on the potential dislocation between On-shore and Off-shore currency markets. To take advantage of that I buy one and sell the other. Apart from other risks, one that I am particularly interested in is basis risk between the official settlement rate On-shore (usually set by Central Bank), and some sort of a consensus rate on where the corresponding NDF would settle Off-shore.In the case of Argentina - USDARS - for example, it is more or less clear:On-shore is Bloomberg code ARORREX Index <GO> (set by Banco Central de la Republica)Off-shore is Bloomberg code EMTAARS Index <GO> (set by Emerging Markets Traders Association)This last one is actually used as a reference settlement rate in all USD ARS NDF contracts. So the difference between the two is my basis risk (well, one definition of basis risk).Is it a lot less clear in the case of USDCNY . On-shore is Bloomberg code CNYMUSD Index <GO> (set by China Foreign Exchange Trading System - a body under People's Bank of China - PBOC). This rate is also known as the "Central Parity Rate", which is the weighted average of prices given by market makers. This is a closing quote - mid-point.But I am not clear at all on the Off-shore part. The USDCNY NDF contracts refer to CNY SAEC (CNY01) Rate "which is published at approximately 5:00 p.m. Beijing time on the Valuation Date". Which is actually Reuters equivalent quote of the same exact Central Parity Rate shown above.Official statements indicate that PBOC allows the rate to rise or fall 0.5 percent from its mid-point each day. Perhaps that is my basis risk?