Exchange-traded funds offer a convenient way to invest in sectors or niches that interest you. If you'd like to add a bunch of mid-cap companies to your portfolio because they're more proven than small caps and have more room to grow than most large caps, the Vanguard Mid-Cap ETF
The basics
ETFs often sport lower expense ratios than their mutual fund cousins. The Vanguard ETF's expense ratio -- its annual fee -- is an ultra-low 0.10%. (Vanguard is known for low fees.)
This ETF has performed rather well, beating the S&P 500 over the past three years and inching ahead of it over the past five. 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 22%, 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. Alexion Pharmaceuticals
A fertilizer company with a lot going for it, CF Industries
Seagate Technology
Other companies didn't do as well last year, but could see their fortunes change in the coming years. Memory giant SanDisk
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.
The best mid-cap stocks become massive large-cap companies, enriching shareholders along the way. Get introduced to several such contenders in our special report: "3 American Companies Set to Dominate the World." The report's free today, but it won't be for long -- so click quick.