VR Equitypartner, a Frankfurt investment company, agreed to acquire a minority stake in Bookwire, a digital publishing marketplace. Financial terms were not disclosed. "For e-books and audio books, there is no way around Bookwire. The company is excellently positioned in its niche market and we look forward to supporting it in the development of this leading position in the future," Christian Futterlieb, VR Equitypartner Managing Director.