11. Earnings per share

Denominator for earnings and diluted earnings per share calculations

Equity awards under the ICG Performance Share Plan are treated initially as contingently issued shares because any shares which may in future be issued are contingent on the satisfaction of performance conditions set at the date of grant, in addition to the passage of time. Where the performance conditions have been met at the end of the performance period and the awards remain unexercised, they are no longer treated as contingently issuable and are treated as issued shares from the end of the performance period and included in the weighted average number of ordinary shares for the purpose of basic earnings per share.

Those contingently issuable shares for which the performance period has not yet expired, are included in the weighted average number of ordinary shares for the purposes of diluted earnings per share unless the performance conditions governing their exercisability have not been met at the reporting date.

A total of 664,484 (2021: 3,646,828) unvested share options outstanding at the reporting date have been excluded from the weighted average number of ordinary shares for the purposes of diluted earnings per share as they were either antidilutive or had not met the performance conditions governing their exercisability.

The earnings used in both the adjusted basic and adjusted diluted earnings per share are adjusted to take into account the net interest on defined benefit obligations and the effect of non-trading items after tax. The calculation of the basic and diluted earnings per share attributable to ordinary equity holders of the parent is based on the following data: