The disequilibrium of the job market is far from being only critical in terms of oversupply. Over-demand of gifted, well educated employees can produce serious anomalies as well. Firms, universities or governmental organizations are facing great challenges, when attempting to fill the openings or newly created positions with talented co-workers. Talent shortage is especially distressing in the healthcare industry, in the education, in the IT sector and in the business service sector, even in those sectors, which determine the future competitiveness of countries. The concept of talent is redefined by the author, in order to make it usable for economic analysis. Namely the employers always buy talent in "packages" together with the employees' accumulated knowledge, so it can be describe in statistics just together. An extension of the talent shortage concept, the author introduced the quality talent shortage, which endanger even in those sectors, where otherwise surplus of manpower exists. The main goal of the paper is searching for the reasons of the global talent shortage and systematize the quite diverse explanations, appearing in the literature separately. The author looked for deeper determination behind the several concrete factors caused over-demand of talent. Her main finding is, that most reasons of talent over-demand closely connected with the trends of technological development, whilst the insufficient talent supply can be explained basically by social factors, resulted from the social system. The author formulates the conclusions, that in many countries the ever shrinking sources of talent make it necessary to discover and to consciously exploit new, so far insufficiently exploited sources of talent (women, elderly people, socially disadvantaged groups, minorities etc.).