These fall into four general categories, agricultural, which includes livestock and "softs"; energy resources; industrial materials; and precious metals.
Using a combination of options, futures, and swaps some firms have designed ETFs capable of tracking approximately −1x, 2x, −2x, 3x and −3x the daily returns of an index.
These funds are structured in a sophisticated way, and due to their extreme volatility they may not be appropriate vehicles for the casual investor.
[citation needed] On August 18, 2009 the U.S. Securities and Exchange Commission issued a warning to investors that leveraged exchange-traded funds could lead to big losses even if the market index or benchmark they track shows a gain.
The most common ones use fixed strategies, which can be described with terms like "aggressive" or "conservative", denoting more in stocks and more in bonds, respectively.