The Windfall tax or windfall profits tax in Mongolia was a taxation on the profits made by mining companies operating in Mongolia. It was implemented in 2006 and was the highest windfall profits tax in the world. It was a tax on unsmelted copper and gold concentrate that was produced in Mongolia. The tax was repealed in 2009 and phased out over two years. Repealing the 68% tax law was considered essential to enable foreign mining companies to invest in mineral resources development of Mongolia.