Phu Hung Securities (PHS) would like to update investors on the expected changes in trading regulations as the Ho Chi Minh Stock Exchange (HoSE) implements its new information technology system.
According to the announcement from HoSE, certain trading regulations will be adjusted once the new system goes live. Investors are advised to review these changes carefully to trade effectively.
1. ATO/ATC Orders in Periodic Matching Sessions
Under the new IT system, ATO (At The Open) and ATC (At The Close) orders will no longer take priority over limit orders entered earlier during the matching process (currently, they do). ATO/ATC orders will be displayed at their indicative prices, similar to limit orders, instead of being marked as "ATO" or "ATC" as they are now.
According to the new display principle:
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If only unmatched ATO/ATC orders remain, the displayed price will be the indicative match price. If no indicative price is available, the displayed price will be the last traded price or the reference price.
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For remaining unmatched limit orders, the indicative buy price for ATO/ATC buy orders will be the highest bid plus one tick (capped at the ceiling price). The indicative sell price for ATO/ATC sell orders will be the lowest ask minus one tick (floored at the floor price).
2. Modification and Cancellation of Limit Orders
Investors will be allowed to modify the price or volume of unfilled limit orders (LO) or the unexecuted portion of such orders during continuous matching sessions. Modifications follow these rules:
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Reducing the order volume will not affect the order's priority.
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Increasing the order volume or modifying the price will reset the order's priority.
3. Negotiated Transactions
Under the new system, investors will not be able to modify or cancel executed negotiated transactions (currently, they may do so by canceling and re-entering the order).
4. Trading by Foreign Investors
For matched orders involving stocks and closed-end fund certificates, the foreign ownership limit (“foreign room”) will decrease once the buy order by a foreign investor is entered into the system (currently, it decreases upon transaction completion).
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If the foreign investor cancels the buy order, the foreign room will be restored accordingly.
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If the order volume is reduced, the foreign room will increase by the reduced volume.
For negotiated transactions, the foreign room will decrease once a foreign buy order is entered (currently, it decreases upon completion). If such an order is canceled, the room will increase immediately upon cancellation.
5. Odd-Lot Transactions
Odd-lot transactions will be allowed through periodic matching, continuous matching, and negotiated transactions (currently limited to continuous matching and negotiated transactions).
6. Trading of Securities under Restricted Status
Securities under trading restrictions will be traded throughout the day via periodic matching, including:
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Opening price determination session,
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15-minute periodic matching sessions,
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Closing price determination session.
(Currently, these securities are traded only in the afternoon session via matching and negotiated transactions.)
7. Display of Top 3 Bid/Ask Prices
During periodic matching sessions, the top 3 bid and ask prices displayed will be the remaining indicative prices after matching (currently, all order prices in the order book are shown).
HoSE encourages investors to consult the official Listing and Trading Regulations issued by the Vietnam Stock Exchange to ensure compliance when trading on HoSE.
