US private equity firm Blackstone Group and UK buyout firm BC Partners are thought to be among those contending in the €500m ($653m) auction of a stake in a German media company owned by UK buyout firms Candover and Cinven in what would be the largest private equity deal in Europe this year.

The two firms were among contestants tabling offers to inject funds into Springer Science + Business Media, according to a source close to the bidding. It is thought several media specialists are thought to have also submitted first round bids.