Our first aim in this paper is to introduce a futures-based model able of capturing the main features displayed by Crude Oil futures and options contracts, such as the Samuelson volatility effect and the volatility smile. We calculate the joint characteristic function of two futures contracts in the model in analytic form and use it to price calendar spread options. In an empirical application we show that the model, in contrast to simpler nested models, can be successfully calibrated to market prices of vanilla and calendar spread options. Our second aim is to use this model to analyze the dependence structure of Crude Oil futures contracts. To this end, we propose analytical expressions giving the copula and copula density directly in terms of the joint characteristic function. These tools allow us to perform an in-depth analysis for pairs of futures, and we observe a phenomenon we call the Samuelson correlation effect.

This study investigates the impact of the harmonization of tax transfer pricing across jurisdictions on multinational companies’ reporting and tax authorities’ auditing strategies. Applying a game-theoretical approach, we assess how enhancing standards consistency and global tax transparency influences tax avoidance and double taxation, producer and consumer surplus, and countries’ tax revenue. Although increasing transparency is generally perceived to discourage tax avoidance, we show that this effect vanishes when standards are inconsistent. We demonstrate that high global tax transparency and consistent standards maximize global social welfare. However, from the perspective of multinational companies or individual countries, the optimal mix of consistency and transparency may differ. These findings highlight why transfer pricing harmonization is difficult and how single-player incentives undermine the envisioned benefits of tax harmonization. This study offers valuable insights for policymakers who aim to curb tax avoidance and mitigate the risk of double taxation.