It is never too late to invest in mutual funds for retirement. As such, if you plan to invest in some of the best funds, the Zacks Mutual Fund Rank can provide you with valuable guidance.

How can you tell a good mutual fund from a bad one? It's pretty basic: if the fund is diversified, has low fees, and shows strong performance, it's a keeper. Of course, there's a wide range, but using the Zacks Mutual Fund Rank, we've found three mutual funds that would be great additions to any long-term retirement investors' portfolios.

Here are the funds that have achieved the Zacks Mutual Fund Rank #1 (Strong Buy) and have low fees.

AB Lg Cap Growth A (APGAX): 0.84% expense ratio and 0.48% management fee. APGAX is a part of the Large Cap Growth mutual fund category, which invest in many large U.S. companies that are expected to grow much faster compared to other large-cap stocks. With annual returns of 12.75% over the last five years, this fund is a winner.

First Eagle Gold Fund I (FEGIX): 0.92% expense ratio and 0.75% management fee. Sector - Precious Metal funds like FEGIX normally invest in stocks focused on the mining and production of precious metals such as gold, silver, platinum, and palladium. With yearly returns of 12.05% over the last five years, FEGIX is an effectively diversified fund with a long reputation of solidly positive performance.

Fidelity Select Brokerage and Investment Management (FSLBX): 0.74% expense ratio and 0.53% management fee. Sector - Finance funds offer a stable, diversified approach to investing that focuses on the financial industry, an infamously large, complex, and heavily-regulated space. The fund is mainly invested in equities, has a long reputation of salutary performance, and has yearly returns of 12.28% over the last five years.

These examples highlight the fact that there are some astonishingly good mutual funds out there. If your advisor has you in the good ones, bravo! If not, you may need to have a talk.

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