Geopolitical risk and oil tanker freight rates: Clean–dirty asymmetries and route-level evidence

This paper examines how geopolitical risk is transmitted to maritime oil transportation costs across crude-oil and petroleum-product markets. Using monthly data from January 2005 to December 2024 and a vector autoregressive (VAR) framework, we analyse the Baltic Dirty Tanker Index (BDTI), the Baltic Clean Tanker Index (BCTI), and major individual tanker routes. Both aggregate indices exhibit positive responses to geopolitical risk shocks. Under the recursive identification scheme, dirty tanker freight rates respond upon impact, whereas the clean tanker response builds more gradually. Their estimated peaks are similar and their confidence bands overlap; the analysis does not establish a statistically significant difference in response magnitude or persistence. Route-level point estimates vary across corridors, with Basra–Fos and Mumbai–Chiba recording the largest peaks within their respective route groups. These rankings are descriptive and are not formal tests of differences between routes. The findings inform maritime transport policy, energy security, and risk management while highlighting the importance of route-specific analysis.