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Trading Procedure

Trading Units, Tick sizes, and Price Limits

Trading Units, Tick sizes,
and Price Limits
Trading Units, Tick sizes, and Price Limits
Trading Units

Generally, each trading unit, called a "board lot," contains 100 units of each security; however, for a security priced at 500 baht or more per unit for 6 consecutive months, one board lot is equivalent to 50 units.

Though, One Board Lot of Depository Receipts shall be equal to one unit of Depository Receipts.

Tick sizes

Minimum price movements, as prescribed by the SET for securities trading, vary according to each market price level as follows

Market Price Level (THB)Tick sizes (THB)
(effective since March 30, 2009)
Less than 20.01
2 up to less than 50.02
5 up to less than 100.05
10 up to less than 250.10
25 up to less than 1000.25
100 up to less than 2000.50
200 up to less than 4001.00
400 up2.00

The above Tick sizess do not apply to trading of unit trusts and ETFs, whose Tick sizes is THB 0.01

Floor & Ceiling Limits

The upper and lower price limit set for securities traded on SET are as below

Securities typeCeiling & Floor
First day of Trading*Other Trading days

- Shares
 - Investment Units
 - Foreign ETF Units
 - REIT Units
 - Depositary Receipts

  • Not exceeding 3 times the IPO price and will not be less than Baht 0.01.
  • Not exceeding 30% of the closing price of the Securities on the preceding Trading day and will not be less than Baht 0.01.

 - Securities Held by Foreign Nationals

  • Not exceeding 3 times the IPO price and will not be less than Baht 0.01.
  • Not exceeding 60% of the closing price of the Local Securities on the preceding Trading day and will not be less than Baht 0.01

- Transferable Subscription Rights
 - Warrants
 - Derivative Warrants :Local underlying asset
 - Derivative Warrants Convertible Securities issued by Foreign Listed Companies to shareholders in Thailand, in proportion to shares held by each shareholder

  • Change from the closing price on the preceding Trading day, not exceeding 1 time the closing price of the Underlying Asset on the preceding Trading day, multiplied by a Conversion Ratio and will not be less than Baht 0.01.
  • Change from the closing price on the preceding Trading day, not exceeding 30% of the closing price of the Underlying Asset on the preceding Trading day, multiplied by a Conversion Ratio and will not be less than Baht 0.01.

 - Derivative Warrants: Foreign underlying asset

  • Not exceeding 20 times the IPO price and will not be less than Baht 0.01
  • Not exceeding 20 times of the closing price of the Securities on the preceding Trading day and will not be less than Baht 0.01

*The ceiling and floor prices limit criteria will be valid until trading of the securities occur.

The Exchange may change the ceiling or floor price of Securities in any of the following events

  • Such security is not traded for more than 15 consecutive business days;
  • Once the Trading of such security starts on the first Trading day using the new par value; or
  • The Exchange is of the opinion that there is a circumstance which may cause a price of any security to be significantly changed; or that the application of change of ceiling or floor may not be possible under actual conditions.