28 Earnings per share

Basic and diluted earnings per share are calculated in accordance with IAS 33 as follows:

    2017 2016 2015
Profit attributable to the owners of the parent (net profit (loss)) millions of € 3,461 2,675 3,254
Adjustment millions of €
Adjusted basic/diluted net
profit (loss)
millions of € 3,461 2,675 3,254
Number of ordinary shares issued millions 4,722 4,645 4,574
Treasury share millions (19) (20) (21)
Adjusted weighted average number of ordinary shares outstanding (basic/diluted) millions 4,703 4,625 4,553
Basic/diluted earnings  per share € 0.74 0.58 0.71

The calculation of basic earnings per share is based on the time-weighted number of all ordinary shares outstanding. Furthermore, the weighted ­average number of ordinary shares outstanding is determined by deducting the weighted average number of treasury shares held by Deutsche Telekom AG. There are currently no diluting shares.