[en] In the last decade the world-wide research expenditures of the major oil companies have dropped. This is remarkable since their investments in fixed assets remained stable. This study reveals that the level of fixed investments particularly depend on their financial strength, while R and D mainly relates to competitors' research and common expectations. The decline in R and D is initiated by common expectations. In the mature oil industry, companies foresee diminishing research potential within the current technology. This is also confirmed by the declining number of patent applications. The high risks of research on renewable energy may lead to wait and see behaviour instead of new research initiatives. Actually, oil companies have hardly applied for patents on renewable energy. The R and D decline is intensified by a dwindling R and D-race, which is due to a large overlap in research topics. The companies protect their research results because they largely compete on their unique technologies which embody their research results. The research overlap appears from patents: the oil companies apply for patents in exactly the same patent classes. 19 refs