Determinants of Net Interest Margins. Are Banks equally affeced by Negative Interest Policy Rates?

Seminar paper from the year 2019 in the subject Business economics - Banking, Stock Exchanges, Insurance, Accounting, grade: 1,0, University of Frankfurt (Main), course: Inspecting the European Banking Sector, language: English, abstract: In the novel monetary environment of negative interest policy rates (NIPR) in the Euro area, it is questionable whether the existing findings on determinants of Net Interest Margins (NIM) still hold. This paper analyzes differences in the development of NIM across business models represented by a set of three indicators prior to and after the introduction of NIPR. The strategies are based on a binary categorization between high and low levels of the business indicators using a median, 67-33 and 80-20 percentile cut-off rule. I use a difference in differences (DiD) estimation approach, even though NIPR impact all banks' NIM. Thus, the obtained estimates do not measure the impact of NIPR itself, but the DiD between strategies. I mostly find positive albeit insignificant effects on banks with low asset held for trading, high deposit and customer loan ratios. In contrast, the DiD coefficient for banks with high deposit-based financing using an 80-20 cut-off is -14 bp, which proves to be a highly significant and economically relevant. These findings support the notion that multiple channels are affecting banks' NIM.