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 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 T. Rowe Price Tax-Efficient Equity (PREFX). PREFX 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. This fund is a winner, boasting an expense ratio of 0.82%, management fee of 0.63%, and a five-year annualized return track record of 12.36%.

Causeway Global Value Institutional (CGVIX) is a stand out amongst its peers. 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 five-year annualized performance of 14.91%, expense ratio of 0.85% and management fee of 0.8%, this diversified fund is an attractive buy with a strong history of performance.

American Century Global Gold A (ACGGX Quick QuoteACGGX - Free Report) : 0.91% expense ratio and 0.65% management fee. ACGGX is a Sector - Precious Metal mutual fund, typically investing in companies that are involved in the mining and production of precious metals like gold, silver, platinum, and palladium. With a five-year annual return of 20.27%, 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.