BERLIN (AP) — Global investment firm KKR is set to take a stake in Germany's Axel Springer, the publisher of the mass-circulation Bild daily, in what is described as a strategic partnership.

Springer said Wednesday that a holding company owned by KKR-advised funds will launch a cash offer for Springer's outstanding shares valuing the firm at some 6.8 billion euros ($7.7 billion).

It wasn't immediately clear how large KKR's stake will ultimately be. Friede Springer, the widow of Bild founder Axel Springer, controls 42.6% of the shares. CEO Matthias Doepfner owns 2.8%. Both will keep their stakes. Other Springer family members hold 9.8% of the shares.

Doepfner said the deal will enable Springer to pursue growth opportunities by providing additional finance and "relieving the mere focus on short-term financial targets."