This paper combines horizontal and vertical innovations to generate an endogenous growth model allowing for structural change as an endogenous phenomenon. Older technologies are continuously replaced by newer ones due to creative destruction, and new technologies appear as a result of horizontal innovations and due to the consumers' preference for variety. We assume fixed operational costs for the manufacturing sector and an endogenously defined patent price for every new technology. Every industry is profitable only for a limited period of time, making the effective time of existence of the technology endogenous and finite. We find that in such an economy endogenous structural change is the source of ongoing economic growth. Furthermore, the range of existing sectors as well as growth rates stays constant as long as the technologies are symmetric.

In the modern world, the main assets are immaterial ideas. Such assets are much more easily stolen than traditional factors such as physical capital and land. In this paper, we investigate the long-run growth effects of intellectual misappropriation at the R&D level. We adopt a generalized framework with both vertical and horizontal innovation. Inspired by recent evidence and by the patent law, we assume that only vertical innovations can be spied, because they are less easily patented than horizontal innovations. The main results are: (1) despite growing population, the fraction of labor engaged in spying activities tends to be constant; (2) in economies in which the R&D process is more vulnerable to ideas theft, growth rates are lower but product differentiation will be more intense; (3) intellectual misappropriation neutralizes the positive growth effect of R&D subsidies but not their positive level effects.