Can I trade in a warrant or CBBC on the expiry date?

No, the expiry day of a warrant or CBBC is not the same as the last trading day. Investors can only trade a warrant or CBBC on or before the last trading day:

(a) For a warrant, there should be 3 settlement days between the last trading day and the expiry day. For example, if a warrant expires on Friday, 23 June, the last day of trading will be Monday, 19 June (assuming the 3 days between 19 and 23 June are settlement days. In general, half trading day will not count as settlement day. For details, please refer to HKEX announcement.); and

(b) For a CBBC, the last trading day falls on the trading day immediately before its expiry date, subject to the occurrence of a mandatory call event following which the CBBC is terminated early and the trading of that CBBC ceases immediately.

You may read further "How and when are warrants and CBBCs settled?"