The ISE has a free-float based methodology for calculating its ISEQ® indices. A free-float weighted ISEQ® methodology ensures that investors are not at a disadvantage when trying to match the constituent weighting of a stock where a significant portion of an issuers shares are not available for active trading in the market.

Free-float collection and publication

The ISEQ®20 index has been free-float based since its inception in March 2005. In June 2007all ISEQ® indices adopted the same process of free-float collation and calculation. 

• Free-float information is received directly from ISEQ constituent companies as well as from third party sources.
• Free-float figures calculation dates are the last trading day of February, May, August and November.
• Free-float adjustments are applied on the third Friday of the last month in each calendar quarterly; i.e. March, June, September and December. This quarterly adjustment procedure is known as “Chaining”.
• Free-float adjustments are made available to the market in advance of each Chaining date.