The selection of stocks is a four-steps approach:

• Step 1:  Belgian All Shares (BAS) index eligible stocks selection.
  The first step consists of excluding low liquid Domestic stocks by eliminating stocks with a free float equal to or lower than 5%.
• Step 2:  Belgian Continuous Index eligible stocks selection.
  Out of the BAS sample, all Belgian stocks traded continuously on the regulated market.
• Step 3:  BEL 20 index eligible stocks selection.
  Minimum 10 and maximum 20 most liquid Domestic stocks out of the largest free float adapted market capitalizations.
• Step 4:  BEL Mid and BEL Small index eligible stocks selection:
  BEL Mid index includes all Domestic companies with a free float market capitalization higher than 50,000 times the BEL 20 index level but not included in the BEL 20 index.
  BEL Small index includes all Domestic companies with a free float market capitalization > than 5,000 times but < 50,000 times the BEL 20 index level.
  

• Belgian All Shares Index (BAS) – price + return index
  Base value 1,000 at 01/01/1980
  
  This index includes all Domestic stocks traded on the regulated market with the exception of all companies with a free float of < or = to 5%.  This index is the benchmark for the Belgian companies.
  
  
• Belgian Continuous Index – return index
  Base value 1,000 at 01/01/1980
  
  This index includes all Belgian shares traded continuously on the regulated market. The components are weighted on their total market capitalization.  Minimum free float is 5 %.
  
  
• BEL 20 Index – price + return index
  Base value 1,000 at 31/12/1990
  
  Minimum 10 and maximum 20 components taken from the most liquid stocks listed on the regulated market. The free-float market capitalization has to be 500,000 times the BEL 20 index level.
  2 return indices are calculated.
  The BEL 20 return private index where the net dividend is added to the index basket and the BEL 20 return institutional index takes the gross dividend into account.
  
  
• BEL Mid index – price + return index
  Base value 2631,03at 31/12/2004
  
  The BEL Mid index consists of the next largest capitalizations following the maximum biggest that make up the BEL 20 Index (horse tailing). 
  As such the components of the BEL Mid index also have a free float market capitalization higher than 50,000 times  the BEL 20 index level with a minimum annual free float velocity of 10 %. The weight of individual stocks is capped at 10%.
  
  
• BEL Small index – price + return index
  Base value 4999,83 at 31/12/2004
  
  This index is made up of stocks whose free float market capitalization is in between the level of the BEL 20 index level multiplied by 5,000 and 50,000. Free float velocity is to be at least 10% and the weight of each stock is capped at 10 %.
  

The Index Steering Committee (ISC) supervises the Euronext Brussels indices.
The ISC is tasked with managing the index samples and making sure the indices are reliable and representative. 

The ISC comprises following members :

• Hugo Clemeur
• Roland Gillet
• Betty Pestiaux
  

This committee meets two times a year.  Its decisions on rule adjustments are disclosed in press releases published after Committee meetings.  However, the decisions do not effect for at least 2 months.
The ISC may convene an extraordinary meeting if circumstances so require, notably in the case of exceptional events affecting component stocks.

Review procedures depend on the type of index.  Euronext uses two index types:

• tradable index : BEL 20 Index
• benchmark indices: BAS, Belgian Continuous, BEL Mid and BEL Small

Tradable indices are reviewed annually, with component stocks examined in terms of eligibility and selection criteria. Benchmark indices are reviewed quarterly with stocks deleted from the indices following corporate actions are replaced by the compiler at its quarterly meetings.

*Change relatively to the current methodology