Investing in mutual funds for retirement is never too late. And the Zacks Mutual Fund Rank can be an excellent tool for investors looking to invest in the best funds.

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 investors' portfolios.

Let's break down some of the mutual funds with the top Zacks Mutual Fund Rank and the lowest fees.

If you are looking to diversify your portfolio, consider Columbia Seligman Global Technology A (SHGTX). SHGTX is part of the Sector - Tech mutual fund category that invests in technology and lets investors own a stake in a notoriously volatile sector, but with a much more diversified approach. This fund is a winner, boasting an expense ratio of 1.25%, management fee of 0.91%, and a five-year annualized return track record of 23.02%.

Fidelity Advisor Stock Select Allocation Cap Z (FZAPX): 0.46% expense ratio and 0.41% management fee. FZAPX is a Large Cap Growth mutual fund, and these funds invest in many large U.S. firms that are projected to grow at a faster rate than their large-cap peers. With yearly returns of 12.19% over the last five years, FZAPX is an effectively diversified fund with a long reputation of solidly positive performance.

Causeway Global Value Institutional (CGVIX Quick QuoteCGVIX - Free Report) : 0.85% expense ratio and 0.8% management fee. CGVIX is a Global - Equity mutual fund investing in bigger markets like the U.S., Europe, and Japan; these kinds of funds aren't limited by geography. With a five-year annual return of 12.69%, this fund is a well-diversified fund with a long track record of success.

There you have it. If your financial advisor had you put your money into any of our top-ranked funds, then they've got you covered. If not, you may need to talk.