Teoria dochodu rynkowego a konstrukcja niemieckiego podatku dochodowego od osób fizycznych

The theory of market income (Markteinkommenstheorie), developed in 1970s by H.G. Ruppe, has generated widespread interest among German tax-law theorists and, partially, in courts’ case law. Its fundamental assertion is that only income derived from one’s intentional, legitimate engagement in market transactions may be subject to taxation. Thus, occasional income (other than derived from one’s regular occupation, e.g. from one’s hobby) as well as inheritance and donations are excluded from taxability. Evaluating the impact of the income on one’s ability to incur income tax constitutes an essential factor in the analysis.