Digital Services Taxes (DSTs) and the OECD/G20 BEPS reforms are central pillars of current efforts to tax multinational digital platforms, yet their joint effects remain poorly understood. We develop a model of a platform that sells hardware to consumers and advertising to firms, with the two...

This paper shows that the OECD inclusive framework of Pillar Two fails to implement the claimed 15% minimum corporate tax for all subsidiaries of multinational corporations that are not shell companies. The reason is that the Substance-based Income Exclusion of Pillar Two allows to tax-deduct...