2.3 Loss per share

Basic loss per share is calculated by dividing the loss attributable to equity holders of the parent by the weighted average number of ordinary shares in issue during the period, excluding ordinary shares held pursuant to the Group's JSOS and accounted for as treasury shares.

Diluted loss per share is calculated by adjusting the weighted average number of ordinary shares outstanding to assume conversion of all dilutive potential shares. The Company has two categories of potentially dilutive shares, namely share options and shares held pursuant to the JSOS.

The calculation for the prior period basic and diluted loss per share reflects the conversion of the ordinary shares and preference shares from Ocado Limited to Ocado Group plc on a 1:100 basis on 9 February 2010.

There was no difference in the weighted average number of shares used for the calculation of basic and diluted loss per share as the effect of all potentially dilutive shares outstanding was anti-dilutive.

Basic and diluted loss per share has been calculated as follows:

52 weeks
ended
27 November
2011
'000
52 weeks
ended
28 November
2010
'000
Issued shares at the beginning of the period 520,959 400,051
Effect of share options exercised in the period 619 927
Effect of treasury shares disposed of in the period 105
Effect of shares issued in the period 41,237
Weighted average number of shares at the end of the period 521,683 442,215

£'000 £'000
Loss attributable to the owners of the parent (503) (7,211)



pence pence
Basic and diluted loss per share (0.10) (1.63)

The only transactions involving ordinary shares or potential ordinary shares between the reporting date and the date of these financial statements were the exercise of 340,000 share options.