The spin-out of research and development (R&D) activities from established companies has increased during recent years. The reasons for realising corporate spin-outs, especially regarding the involvement of financial investors, were investigated based on 30 European case studies within the chemical and pharmaceutical industry. The reasons can be categorised into two groups: an investment and a divestment rationale. Whereas the chemical industry uses both rationales, there are only divestment cases in the pharmaceutical industry. The investment cases within the chemical industry show that R&D spin-outs can make an important contribution towards the flexibilisation and performance improvement of a company's internal R&D. The divestment cases show that R&D spin-outs can be a suitable possibility to continue promising R&D activities. The survival rate of the analysed spin-outs is high and numerous new jobs have been created in the past years, especially in pharmaceutical spin-outs.