ProShares UltraShort Bloomberg Natural Gas(AMEX:KOLD)

KOLD provides two times the inverse exposure to the performance of a futures contract on natural gas for one day. The fund is therefore designed to be used as a tactical trading tool, to be held for no longer than one day. Investors using it as a buy-and-hold investment will be subject to the effects of compounding, which can and often will cause the fund to drift from its promised -2x exposure over longer holding periods. The fund's index weights contracts by both by liquidity (2/3) and US dollar-weighted production (1/3). It follows a pre-determined roll schedule, which rolls the expiring contracts into contracts that are about two months out. Investors should take note its trading costs rather than its holding costs, given its short-term nature.