Securities under trading restriction on the HOSE (Even Lot Trading only) are traded using the Periodic Call Auction (PCA) mechanism.
Order placement rules during PCA sessions:
* Permitted trading periods: the opening call auction, multiple 15-minute PCA sessions throughout the day, and the closing call auction.
* Cancellation or modification of orders is not allowed during the last 5 minutes of the PCA session. 
* Only Limit Orders (LO) are allowed during PCA sessions.
* Unmatched orders from previous PCA sessions may continue to wait for execution in the next PCA session. 
* The matching results are received at the end of each 15-minute PCA session.