The lack of a register-based sampling frame on high-worth individuals in many countries challenged previous attempts to sample high-worth individuals in voluntary scientific surveys. As a result, these individuals are typically under-represented in population surveys. In a novel research design, we draw on register data on the shareholding structures of companies as a sampling frame. Our design builds on the empirical regularity that high-worth individuals are likely to hold at least part of their assets in the form of shareholdings. Based on data from over 270 million companies worldwide, we identify individuals who are both German residents and registered shareholders of companies. These shareholders will form the sampling population for a large scale survey (N=2000) with the standard SOEP questionnaire including its wealth module, starting by the end of 2018. The project is funded by the German Federal Ministry of Labour and Social Affairs.
In a feasibility study, we interviewed 124 households. Our analysis shows that register data on shareholding structures correctly identifies the individuals’ rank in the wealth distribution, that the quality of personal information, particularly the residential address, is sufficiently high for subsequent interviewing, and that the approach can fill a major data and research gap in the study of high-worth individuals and the top-end of the wealth distribution.