Roughly speaking, the selection is made as follows: To start with, 20 companies are selected on the basis of on-exchange trading during the past 12 months and ranked according to market value after adjusting for free-float. The 15 companies with the highest free-float adjusted market cap are selected for the index, provided they fulfil the criterion that the difference between the most favourable bid-ask prices at the end of the day is no more than 1.5% on average. If they fail to fulfil this requirement, companies ranked lower on the list of these 20 leading companies can replace them if the average bid-ask spreads of the latter are below 1.5%. For a more detailed discussion of the methodology applied, see the ICEX website (www.icex.is) under Quotes and Markets / Share Indices / About Indices.
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