The value of CBNIs in the possession of a traveller and denominated in a currency other than HKD (e.g. foreign currency) would be calculated in accordance with the opening indicative counter exchange selling rate published by the Hong Kong Association of Banks ("HKAB") on the day when the traveller arrives or is about to depart. If HKAB does not publish such rate on the day, or the time when the traveller arrives or is about to depart is before the publication time of such rate, the value of the CBNIs would be calculated according to the most recent rate HKAB published before the day. For example, if a traveller arrives in Hong Kong on 29 July 2018 (which is a Sunday on which HKAB normally does not publish exchange rates), reference should be made to the rate published on 28 July 2018. Historical rates are available at HKAB"s website.
If no opening indicative counter exchange selling rate is published by HKAB for a particular currency, the value of the CBNIs would be determined by reference to the United Nations Operational Rates of Exchange ("UN rate") being effective for the currency concerned on the day when the traveller arrives or is about to depart. The value of the CBNIs in HKD can be obtained by converting the nominal value of the CBNIs first to USD and then HKD using the UN rate.
In making a written declaration, the value of CBNIs should be stated in the currency in which the CBNIs are denominated. No conversion to HKD is necessary. For example, in declaring USD20,000, the value should be stated as "USD 20,000".
If you are not sure about the prevailing exchange rate adopted for a currency at the time of arrival or departure, you should approach a Customs officer for assistance.