Abstract
The aim of this paper is to present an analysis of the relationship between concentration of the banking sector and banks' markups on offered loans. The markup is understood as the difference between the rate offered by banks and the reference rate fixed by the Monetary Policy Council. The period between 2009 and 2013 was analyzed. Monthly data from the Polish banking sector were considered. This paper also consists of the literature review, which focuses on the mortgage market. The methodology used for the analysis is based mainly on simple linear regression techniques. It is found that such methods are not sufficient to give conclusive answers. Therefore additional future research is proposed.