The relation of expenditure on research and development (R&D) to economic output (R&D intensity) is often considered as an indicator of the economic and technological capability of an economy. In this context, Austria is one of the few developed countries with a significant increase in both R&D expenditure and intensity over the last 20 years. The theoretical basis for this work is literature on innovation and R&D as well as current studies on the development at national and international level. Technical innovation and R&D generally influence firm growth positively and are one of the most important drivers for economic growth and the long-term prosperity of an economy. This work examines the growth of the R&D expenditure of the Austrian business enterprise sector based on data from the F&E Erhebung of 2002 and 2013. In a first step, the R&D performing companies are divided into groups on the basis of firm size, technology or knowledge intensity as well as relative and absolute R&D expenditure. The development is then analyzed in these groups. In a second step, we identify companies that perform R&D over a longer period of time and analyze their growth and mobility. The role of structural change is examined by a shift-share analysis, which decomposes the change in R&D intensity into a structural, interaction, and diffusion effect. Our results show that the increase in R&D expenditure mainly comes from large, R&D-intensive companies and that it is due to an intensification of R&D across all sectors. We found only low mobility among the R&D performing companies in the considered period: there are almost no small companies that have risen to large, research-intensive actors.