KKR & Co LP announced that William Sonneborn would resign from his positions in KKR to pursue a new challenge. William Sonneborn heads KKR's equity investment and corporate credit business units. Sonneborn is also the chief executive of KFN, KKR's publicly traded specialty finance unit.

KKR conveyed disappointment with Sonneborn's sudden decision but still acknowledged all his contributions to the company. A KKR spokeswoman did not provide details on what the executive's new challenge would be but mentioned he would be serving as a senior adviser to KKR even after resigning.

"If I'm true to my word on doing everything I can to maximize shareholder value, it's an optimal time for me to make a change. Orson Welles once said: 'If you want a happy ending, you need to know when to end your story,'" Sonneborn explained to a conference call with experts on 23 July, Tuesday.

Effective 24 July, Wednesday, the 43-year-old executive will be succeeded by Craig Farr, 41. Farr currently serves as KKR's capital markets global head and origination business. He is expected to retain the position.

"Bill's calm leadership, long-term focus and commitment to protecting shareholder value not only navigated KFN through the crisis but to its current position of stability and strength," Farr said on the same conference.