Exchange-traded funds offer a convenient way to invest in sectors or niches that interest you. If you're drawn to mid-cap stocks because they're somewhat proven and yet tend to still have plenty of room for further growth, the Guggenheim S&P Midcap 400 Pure Growth ETF
The basics
ETFs often sport lower expense ratios than their mutual fund cousins. The mid-cap ETF's expense ratio -- its annual fee -- is a relatively low 0.35%.
This ETF has performed rather well in its somewhat young life, handily outperforming the S&P 500 over the past three and five years, on average -- and so far this year, as well. As with most investments, of course, we can't expect outstanding performances in every quarter or year. Investors with conviction need to wait for their holdings to deliver.
What's in it?
Plenty of mid-cap growers had strong performances over the past year. Regeneron Pharmaceuticals
Monster Beverage
Data integration specialist Informatica
Other companies didn't do as well last year, but could see their fortunes change in the coming years. Green Mountain Coffee Roasters
The big picture
A well-chosen ETF can grant you instant diversification across any industry or group of companies -- and make investing in and profiting from it that much easier.
Learn about the 5 ETFs That Could Soar in 2012. And if you're looking for some great investments beyond ETFs, consider these 12 Dividend Stocks for 2012.