The Stock Exchange of Thailand (SET) is the national stock exchange of Thailand. It is located in Bangkok. The indices of the stock exchange are SET Index, SET50 Index & SET100 Index.

History
Legislation establishing "The Securities Exchange of Thailand" (SET) was formally enacted in 1974 and the SET began trading on April 30, 1975. On January 1, 1991 "The Securities Exchange of Thailand" officially changed its name to "The Stock Exchange of Thailand" (SET).
As defined in the SEA (1992), the SET's primary roles are: To serve as a center for the trading of listed securities, and to provide the essential systems needed to facilitate securities trading; To undertake any business relating to the Securities Exchange, such as a clearing house, securities depository center, securities registrar, or similar activities; To undertake any other business approved by the SEC.

Roles

The Stock Exchange of Thailand is a juristic entity set up under the Securities Exchange of Thailand Act, B.E. 2517 (1974). Operations started on April 30, 1975.
Its mandate is to be a market or center for the trading of listed securities, and promoter of financial planning, as well as provide related services connected to such activities, without distributing any profits to members.
Encourage the general public to become shareholders in a variety of local industries.
It operates under the legal framework laid down in the Securities and Exchange Act, B.E. 2535 (1992).
Its main operations include securities listing, supervision of listed companies and information disclosure, trading, market surveillance and member supervision, information dissemination and investor education. Operations

Trading
This section describes the SET's trading facilities, details on trading rules, and information on Internet trading.
Fully Computerized Trading System
The SET has operated fully computerized trading since April 1991, through the "Automated System for the Stock Exchange of Thailand", or ASSET, which enables trading to be efficient, equitable and fluid. In this trading system, two principal methods of trading are available: Automatic Order Matching (AOM) and Put-Through transactions (PT).
Two Trading Methods
1 Automatic Order Matching (AOM) Trading
AOM trading performs the order matching process according to price, then time, priority, without human intervention. After brokerage houses electronically send buy or sell orders from their offices to the SET mainframe computer, the ASSET system queues the orders and arranges them according to a price-then-time priority. This means orders are first grouped according to price, with the best price taking precedence. Then, within each price group, orders are arranged according to time. In terms of the matching process, there are two methods: continuous order matching and call market method. Continuous Order Matching procedures operate during the regular trading sessions. The ASSET continuously matches the first buy and sell orders in the queue, and at the same time, confirms each executed transaction via the member's (broker's) terminal.
The Call market matching is utilized in calculating the opening and closing prices of a security at the opening and closing of the trading hours. This method allows brokers to enter their orders to be queued for matching at a specified time at a single price that generates the greatest trading volumes for that particular stock. Automatic Order Matching (AOM) Trading
2 Put Through (PT) Trading
The ASSET also allows brokers to advertise their buy or sell interests by announcing bid or offer prices. Members may then deal directly with each other, either on behalf of their clients or for themselves. Prices may be adjusted during the negotiation; hence, the effective executed price may not be the same as that advertised and may not follow the price spread rules. After concluding negotiations, dealers must send details of the result(s) to the ASSET for recording purposes.

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

Trading Units
Floor & Ceiling Limits
On 1 December 1997, the SET introduced new floor and ceiling price limits for trading. The former limits allowed stock prices to fluctuate within a range of 10 per cent, while the current limits allow prices of a stock to fluctuate within a range of 30 per cent of the previous closing price on the main board. However, if the market price is less than 1 baht, stock prices may fluctuate within a range of 100 per cent of the previous closing price. Ceiling and floor limits apply to each trading board utilizing the AOM system, with the exception of the foreign board.
Circuit Breaker
Together with the introduction of the floor and ceiling trading limits, the SET also implemented a circuit breaker system to ease any unusual volatility in the market that may cause investor panic.
The circuit breaker functions as follows:
First stage: If the SET index falls by 10% from the previous day's close, all trading in listed securities will be halted for 30 minutes.
Second stage: If the SET index falls by 20% from the previous day's close (i.e., another 10%), trading in all listed securities will be halted for one hour.
If the trading time left in a session is less than 30 minutes, or one hour (as the case may be) after the circuit breaker comes into effect, trading will be halted until the closing time of that session, and the trading will then resume in the next session.

Price Regulations
In addition to the SET Index, which is calculated from the prices of all common stocks on the main board, The SET also provides industry group indices and sectoral indices. Both these types of indices are calculated from the prices of the common stocks which share the same fundamentals which characterize each particular industry group and sector, respectively.
The index calculation methodology is identical to that of the SET Index which is a market capitalization weighted index. The Industry Group and Sectoral index calculations are adjusted in line with the same factors that influence the calculation of the SET Index. These influencing factors include the shifting of a stock from one sector to another sector or the shifting of a stock from a sector in one industry group to a sector in another industry group. In addition, the base date of the Industry Group Indices is on December 31, 2003, which was when the Industry Group Indices were established and set at 100 points.
There are 8 Industry Group Indices and 25 Sectoral Indices

Agro & Food Industry

1. Agribusiness
   Food and Beverage
   Consumer Products
   
   
   
   1. Fashion
      Home & Office Products
      Personal Products & Pharmaceuticals
      Financials
      
      
      
      1. Banking
         Finance and Securities
         Insurance
         Industrials
         
         
         
         1. Automotive
            Industrial Materials & Machinery
            Packaging
            Paper & Printing Materials
            Petrochemicals & Chemicals
            Property & Construction
            
            
            
            1. Construction Materials
               Property Development
               Resources
               
               
               
               1. Energy & Utilities
                  Mining
                  Services
                  
                  
                  
                  1. Commerce
                     Health Care Services
                     Media & Publishing
                     Professional Services
                     Tourism & Leisure
                     Transportation & Logistics
                     Technology
                     
                     
                     
                     1. Electronic Components
                        Information & Communication Technology Largest Public Companies
                        
                        Market for Alternative Investment (MAI)
                        Thai non-voting depository receipts (NVDR)