Bookmaker PaddyPower Betfair (PPB) has started returning £500 million (US$667.4 million) to shareholders via a stock buyback as it seeks to reduce the company’s share capital.

PPB plans to implement the share buyback program in tranches that will run over the next 12 to 18 months, the company said in a statement. The maximum number of ordinary shares to be repurchased under the share buyback program will reach 12,692,692.

For the first tranche, PPB intends to give back £200 million ($267 million) in the next three months, subject to market conditions. The Dublin-based wagering firm said ordinary shares may be repurchased on both the London Stock Exchange and the Irish Stock Exchange, trading as Euronext Dublin.

PPB has tapped international investment bank Goldman Sachs Group Inc. to repurchase the shares on its behalf.