MSD Capital built up a stake of just over 10 percent in GfK, potentially throwing into doubt KKR's plans to take over the German company together with GfK Verein.

KKR said in a statement late on Friday it has agreed to acquire around 3.7 million shares, equivalent to a 10.07 percent stake in GfK from three shareholders. The three shareholders are funds managed by MSD Capital and MSD Partners. MSD Capital is the private investment firm that manages the capital of Michael Dell and his family.

KKR will pay around 50 million euros (43.19 million pounds) for a portion of the shares, while around 6.89 percent of the shares will be exchanged for a stake in the investment vehicle through which KKR is investing in GFK, according to the statement.

The deal means KKR and GfK Verein have together passed the 75 percent threshold they needed for the 43.50 euro per share offer for GfK to succeed.

The takeover values the German company at about 1.69 billion euros.

($1 = 0.9416 euros)

(This version of the story has been corrected throughout to show deal agreed by fund managed on behalf of Dell, not by Dell himself)

(Reporting by Alexander Huebner; Writing by Victoria Bryan; Editing by Alexander Smith)