The MicroSectors U.S. Big Oil Index -3X Inverse Leveraged ETN (ticker: NRGD) is a mutual fund that seeks to provide investors with a -3x leveraged inverse exposure to the performance of the U.S. Big Oil industry. This means that for every 1% decrease in the index, the fund aims to provide a 3% increase in returns. The fund is designed for investors who are looking to profit from a decline in the U.S. Big Oil sector.