The DKK 5.6bn ($1bn) programme was announced earlier this month and will be carried out over 12 months.
The first phase begins on 1 September and runs to 30 November.
The owner will spend up to $400m on a maximum of 50,000 A shares and 200,000 B shares.
Lead manager Nordea will act independently to the company in acquiring the stock.
The company currently holds just 108,865 B shares, equal to 0.5%