ProShares

As with almost any other industry, financial products have brands. Burger King is known for burgers. KFC is known for chicken. Taco Bell is known for causing you to make a beeline for the toilet at 3 am.

ProShares represents a particular brand of ETF, or exchange-traded fund. It offers many plain vanilla ETFs, i.e. the kind you'd find at most other firms that provide these investment vehicles. But the company has a specialty. It's known for its leverage (or inverse) funds. You can get burgers at Burger King, Wendy's, or McDonald's, but you can only get a Big Mac at Mickey D's. You can get vanilla ETFs anywhere, but if you want a leveraged or inverse one...ProShares is for you.

Most ETFs track a particular index or industry. Buy an ETF based on a particular biotech index. The index rises 10%. Your ETF rise 10%. Leveraged ETFs come with a multiplier. Buy a 2x leveraged ETF, and a 10% rise in the index equals a 20% rise in your position.

Meanwhile, an inverse fund goes the opposite direction of the index in question. A 10% increase in the index means a 10% drop in the ETF. Or vice versa. It allows you to bet against particular industries, i.e. make a short without the hassle of buying options or actually putting a short sale in place.