Corporate losses raise compliance risks if aggressive tax planning is used as a means of increasing or accelerating tax relief in ways not intended by the legislator, or to generate artificial losses. This report describes the size of loss carry-forwards, the rules applicable in relation to losses, and identifies the following risk areas: corporate reorganisations, financial instruments and non-arm’s length transfer pricing. After having summarised aggressive tax planning schemes on losses, as well as country detection and response strategies, it offers a number of conclusions and recommendation for tax administration and tax policy officials.