Exchange-traded funds offer a convenient way to invest in sectors or niches that interest you. If you'd like to add some mid-cap stocks to your portfolio because they're big enough to have proven themselves to some degree and yet small enough to still have lots of room to grow, the Guggenheim S&P MidCap 400 Equal Weight ETF
It's noteworthy, too, that the index weights its holdings equally, instead of letting the higher market-cap companies dominate it, as many other indexes do. (The famous S&P 500 index, for example, is market-cap-weighted.)
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 0.41%. The fund is very small, too, so if you're thinking of buying, beware of occasionally large spreads between its bid and ask prices. Consider using a limit order if you want to buy in.
At roughly one year of age, this ETF is far too young to have its performance assessed. And 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.
With a low turnover rate of 7%, this fund isn't frantically and frequently rejiggering its holdings, as many funds do.
What's in it?
Plenty of mid-cap companies had strong performances over the past year. Omega Healthcare Investors
Other companies didn't do as well last year, but could see their fortunes change in the coming years. Oil and gas specialist Quicksilver Resources
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.
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Longtime Fool contributor Selena Maranjian, whom you can follow on Twitter, holds no position in any company mentioned. Click here to see her holdings and a short bio. The Motley Fool owns shares of Tempur-Pedic International. The Motley Fool has a disclosure policy.