ProShares UltraShort Dow 30-2X Shares 

DXD is designed to deliver -2x daily performance of the 30 US large-caps in the DJIA, weighted by price. As with any fund tracking the popular but dated DJIA, it's important to remember that it's not tracking a particularly robust representation of the larger US equity market. This is inverted, geared exposure to an index with arbitrary sector biases and antiquated weighting. Anyone holding DXD for longer than a day will be exposed to the path dependency. This dynamic is especially acute in funds that overlay leverage on inverse exposure as DXD does. Longer term investors must manage their exposure on a daily basis or use it as it was intended to be used: as a short-term trading tool. The expense ratio for DXD matters less than the total all in trading costs.