After describing the size of corporate tax losses and the policy issues related to their tax treatment, this report identifies three key risk areas in relation to use of losses for tax purposes: corporate reorganisations, financial instruments and non-arm's length transfer pricing. The report summarises aggressive tax planning schemes encountered by revenue bodies in participating countries, together with their detection and response strategies. These schemes aim for instance at shifting profits or losses to related or unrelated parties, circumventing restrictions on the use of losses, creating artificial losses and obtaining the dual/multiple deduction of the same loss. The report ends with certain conclusions and reccomendations for revenue bodies and government officials.