What to look for in your fund investments, beyond low fees

Fees are the first thing that investors should consider when looking at a fund investment, and the financial industry has been tripping over itself to cut expenses ever lower. But expenses are hardly the only thing to consider.

Here are some other points:

What index does the fund compare itself against?

Two index funds with similar names and similar expenses should be similar, right? Not if they are tracking different indexes.

Todd Rosenbluth, head of mutual fund and ETF research at CFRA Research, points to two that invest in stocks from developing economies as an example. Vanguard's FTSE Emerging Markets ETF and the iShares Core MSCI Emerging Markets ETF charge an identical amount in fees: $14 annually of every $10,000 invested.

But their performance has not been identical. In 2014, Vanguard's ETF was virtually flat, while the iShares ETF lost 3.4 percent.

One reason for the difference: all those curved-edge mobile phones people are using. The iShares fund counts Samsung Electronics as its biggest investment, part of the nearly 15 percent of its portfolio that it allocates to South Korean companies. The Vanguard fund, meanwhile, has no South Korean stocks.

Fidelity's Total Bond fund and American Funds' Bond Fund of America are both among the biggest fixed-income funds, and both focus on intermediate-term bonds with similar maturities. Both are actively managed funds.

But investors who invest in the Fidelity fund should be willing to potentially take on more risk than those in the American Funds offering. That's because the Fidelity fund can put up to 20 percent of its investments in junk bonds, which offer some of the highest yields but are issued by companies with weak credit ratings. The American Funds offering, meanwhile, typically caps its potential investment in junk bonds at 10 percent.

How popular is the ETF?

Besides price, investors should check to see how actively traded an ETF is. Ones that are small and trade infrequently can have wide gaps in price between what sellers and buyers are offering.

Funds that are larger in terms of assets are also less likely to be in danger of shutting down. ETFs are wildly popular, and more are opening every day, but many also close when their popularity wanes. BlackRock's iShares, for example, shut ones that focused on foreign inflation-linked bonds and on Latin American stocks last year, among others.