It is well known that multinational enterprises take advantage of corporate tax systems worldwide to avoid taxation. Transfer pricing is one common method used for profit-shifting, as intra-firm transactions are shielded from the market mechanism. Numerous guidelines and regulations have been implemented to tackle such profit-shifting, but challenges remain. This column theoretically explores how one such regulation, the ‘arm’s length principle’, affects the licensing strategies of multinationals in the presence of a tax haven. It shows that the mere existence of this principle may lead to further profit-shifting and may worsen the welfare of high-tax countries.