BERLIN (AP) — Media group Bertelsmann AG says it is acquiring the 25.1-percent stake in German publisher Gruner + Jahr that it didn’t already own for an undisclosed sum.

Bertelsmann said Monday that the acquisition will take effect Nov. 1. Gruner + Jahr’s publications include news weekly Stern, celebrity magazine Gala and German, French and Dutch editions of National Geographic magazine.

Bertelsmann CEO Thomas Rabe described the full acquisition of Gruner + Jahr as “a strategic milestone in strengthening our core.”

The company will pay for the minority stake held until now by Jahr Holding in cash. Both sides agreed not to disclose the price.

Privately held Bertelsmann also owns European broadcaster RTL Group and a 53-percent stake in book publisher Penguin Random House.

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