What does your ETF own? It's easy to find out

— -- A: When it comes to sausage, it's often best not to ask what's inside. But it's a different story with exchange-traded funds.

Exchange-traded funds, or ETFs, are baskets of stocks designed to mirror the performance of a market sector, an industry or an index. It's critical to know what an ETF owns so you can be sure you know what you're investing in.

There are several sources for the information you're asking for, but a great place to start is ETFconnect.com. Just enter the ticker symbols of the ETFs, PPA for PowerShares Aerospace & Defense Portfolio and ITA for iShares DJ US Aerospace & Defense index.

On the right-hand side of the screen, you'll see a link for Sector and Holdings Summary. That will list the top ten holdings in the fund. You will also see a pie chart showing the industries the ETF is invested in.

If you'd like more than just the top 10 holdings, scroll to the top of the page and click on Fund Sponsor Website on the right-hand side of the page under the Third Party Links & Reports heading. That will take you to the ETF sponsor's website, where you can view the full prospectus for the ETF. The prospectus contains all the vital data needed by investors, including a complete list of holdings.

Matt Krantz is a financial markets reporter at USA TODAY and author of Investing Online for Dummies. He answers a different reader question every weekday in his Ask Matt column at money.usatoday.com. To submit a question, e-mail Matt at mkrantz@usatoday.com. Click here to see previous Ask Matt columns.