General Trading Regulations

The trading hours of the Vietnamese stock market are from Monday to Friday, excluding holidays as stipulated by the Labor Code. The detailed trading hours are as follows:

Securities matching transaction period:

• The trading hours for odd-lot securities, closed-end fund certificates, ETF certificates, and covered warrants are from 9:00 AM to 11:30 AM and from 1:00 PM to 2:30 PM.

Trading hours for matched orders:

Derivatives Trading Time::

Limit Order

• • A Limit Order (LO) is a buy or sell order for securities at a specified price or better. For sell orders, it is at the specified price or higher, and for buy orders, it is at the specified price or lower.
  • LO orders can be entered into the trading system during continuous order matching sessions and periodic order matching sessions.
  • A Limit Order remains valid from the time it is entered into the trading system until the end of the periodic closing order matching session or until the order is canceled.

Market order

A Market Order is an order to buy securities at the lowest available selling price or to sell securities at the highest available buying price on the market. Market orders can only be entered into the trading system during continuous order matching sessions. The types of market orders include:

• Market Order (MP): This is an order to buy securities at the lowest available selling price or to sell securities at the highest available buying price on the market. A market order will be canceled immediately after entry into the trading system if there are no matching counter-orders.
• Market-to-Limit Order (MTL): If not fully executed, the remaining portion of the order is converted into a Limit Order (LO). For a buy order, the remaining portion is converted to an LO with a price one tick higher than the last executed price or at the ceiling price if the last executed price is the ceiling price. For a sell order, the remaining portion is converted to an LO with a price one tick lower than the last executed price or at the floor price if the last executed price is the floor price. MTL orders, once converted into LO orders, are subject to the regulations on modification and cancellation applicable to LO orders.
• Match-or-Kill Market Order (MOK): This is an order that must be fully executed; otherwise, it will be canceled immediately after entry into the trading system. 
• Match-and-Kill Market Order (MAK): This is an order that can be fully or partially executed. Any unfilled portion of the order will be canceled immediately after the matching process.

At the Opening Order (ATO) trade

The ATO order is an order to trade at the opening price, applicable only on the HOSE exchange. ATO orders are prioritized over limit orders during the matching process. The principles for determining the order price are as follows:

• If there are only ATO orders in the order book:
  • Reference Price: If the order book contains only ATO buy orders, ATO sell orders, or if the total buy volume equals the total sell volume.
  • Higher than Reference Price: The price is set at one tick higher than the reference price if the total buy volume exceeds the total sell volume.
  • Lower than Reference Price: The price is set at one tick lower than the reference price if the total sell volume exceeds the total buy volume.If this price is lower than the floor price, the system records the price as the floor price.
• If there are limit orders in the order book:
  • Price for ATO Buy Orders: The price is the highest among the following three values: The highest buy price plus one tick (if this exceeds the ceiling price, it is recorded as the ceiling price); The highest sell price of the counterparty; The reference price.
  • Price for ATO Sell Orders: The price is the lowest among the following three values: The lowest sell price minus one tick (if this is below the floor price, it is recorded as the floor price); The lowest buy price of the counterparty; The reference price.

ATO orders are entered into the trading system during the periodic order matching session to determine the opening price; Any unexecuted or partially executed ATO orders are automatically canceled after the opening price is determined.

At the Closing Price (ATC) trade

The ATC order is an order to trade at the closing price, applicable on both the HOSE and HNX exchanges. ATC orders are prioritized over limit orders during the matching process. The principles for determining the order price are as follows:

• If there are only ATC orders in the order book:
  • Last Executed Price or Reference Price: The price is the last executed price, or the reference price if there is no last executed price, in cases where the order book contains only ATC buy orders, ATC sell orders, or if the total buy volume equals the total sell volume.
  • Higher than Last Executed Price: The price is set at one tick higher than the last executed price if the total buy volume exceeds the total sell volume. If this price exceeds the ceiling price, the system records it as the ceiling price.
  • Lower than Last Executed Price: The price is set at one tick lower than the last executed price if the total sell volume exceeds the total buy volume. If this price is lower than the floor price, the system records it as the floor price.
• If there are limit orders in the order book:
  • Price for ATC Buy Orders: The price is the highest among the following three values: The highest buy price plus one tick (if this exceeds the ceiling price, it is recorded as the ceiling price); The highest sell price of the counterparty; The last executed price or the reference price if there is no last executed price.
  • Price for ATC Sell Orders: The price is the lowest among the following three values: The lowest sell price minus one tick (if this is below the floor price, it is recorded as the floor price); The lowest buy price of the counterparty; The last executed price or the reference price if there is no last executed price.
  • ATC orders are entered into the trading system during the periodic order matching session to determine the closing price; Any unexecuted or partially executed ATC orders are automatically canceled after the closing price is determined.

Post-Market Matching Order (PLO)

• The PLO order is a buy or sell order for securities at the closing price, placed after the periodic closing order matching session has ended. PLO orders are currently only allowed on the HNX exchange during the time frame of 2:45 PM to 3:00 PM.
• PLO orders can only be entered into the system during the post-market trading session, a PLO order is matched immediately upon entry into the system if there is a corresponding counter-order available, the execution price is the closing price of the trading day. If the closing price cannot be determined, the PLO order will not be accepted into the system.
• At the end of the post-market trading session, any unmatched PLO orders or the unfilled portion of partially matched orders will be automatically canceled.

Periodic Order Matching

• Periodic order matching is a trading method where the system matches buy and sell orders for securities at a specific point in time.
• Principles for Determining the Matching Price: 
  • The matching price is the price at which the largest trading volume can be executed, ensuring that all buy orders with prices higher than the selected price and all sell orders with prices lower than the selected price are fully executed.
  • If multiple prices satisfy condition (a), the selected price is the one at which all orders on one side are fully executed, while orders on the opposite side are fully or partially executed.
  • If multiple prices still satisfy condition (b), the selected price is the one that matches or is closest to the last executed price under the order matching method.
  • If no price satisfies condition (b), the selected price is the one that satisfies condition (a) and matches or is closest to the last executed price under the order matching method.

Continuous Order Matching

• Continuous order matching is a trading method in which the system matches buy and sell orders for securities immediately as they are entered into the trading system.
• Principle for Determining the Matching Price: The execution price is the price of the counter-order already pending in the order book.

Put-through order matching is a trading method where the buyer and seller negotiate the terms of the transaction directly with each other and then notify the securities company to record the transaction result in the trading system. Alternatively, the buyer or seller can work through a securities company to find a counterparty for the negotiated transaction.

HOSE (Ho Chi Minh Stock Exchange)

• ATO/ATC Orders: Investors are not allowed to modify or cancel orders (including orders transferred from the prior continuous order matching session).
• Continuous Matching Orders: Investors can modify or cancel orders if the order or its remaining unexecuted portion has not been executed. This applies to both unexecuted orders or portions of orders from prior periodic or continuous order matching sessions.
• Put-through Orders (Negotiated): 
  • Orders can only be modified or canceled if they have not been confirmed.
  • If a representative from a securities company enters the order incorrectly, modification is only allowed with approval from HOSE and the related investor.

HNX (Hanoi Stock Exchange)

• ATC: Modifying or canceling LO and ATC orders is not allowed (including LO orders transferred from the continuous matching session).
• Continuous Matching Orders: Limit Orders (LO) can be modified (price or quantity) or canceled during the trading session. Priority after modification:
  • If the quantity is reduced, the order’s priority remains unchanged.
  • If the quantity is increased and/or the price is modified, the order’s priority is reset from the time the modification is entered into the trading system.
• PLO: Modifying or canceling PLO orders is not allowed.
• Put-through Orders: 
  • Orders can only be modified or canceled if they have not been confirmed.
  • If a representative from a securities company enters the order incorrectly, modification is only allowed with approval from HNX and the related investor.

UPCOM

• Continuous Matching Orders: Modifying (price or quantity) and canceling orders is only allowed for unmatched orders. Priority after modification:
  • If the quantity is reduced, the order’s priority remains unchanged.
  • If the quantity is increased or the price is modified, the order’s priority is reset from the time the modification is entered into the trading system.
• Put-through Orders: Put-through transactions already executed on the UPCOM trading system cannot be canceled.