Following the OECD’s BEPS report on Action 5, countries with preferential tax regimes are adjusting the criteria that need to be met in order for their regimes to meet the so-called modified nexus approach. This article explores those aspects of existing regimes which led the OECD to conclude that the preferential tax regimes of its members amount to harmful tax practices. It also considers which features various countries propose to change to ensure that their preferential tax regimes are acceptable to the OECD.