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 retirement investors' portfolios.

Let's learn about some of Zacks' highest ranked mutual funds with low fees you may want to consider.

GMO U.S. Equity Allocation Fund ClIII

(GMUEX): 0.49% expense ratio and 0.46% management fee. GMUEX is a Large Cap Growth option; these mutual funds purchase stakes in numerous large U.S. companies that are expected to develop and grow at a faster rate than other large-cap stocks. With annual returns of 15.29% over the last five years, this fund is a winner.

MFS International Growth A

(MGRAX) is a stand out amongst its peers. MGRAX is a Non US - Equity option, focusing their investments acoss emerging and developed markets, and can often extend across cap levels too. With five-year annualized performance of 10.4%, expense ratio of 1.05% and management fee of 0.67%, this diversified fund is an attractive buy with a strong history of performance.

American Funds Investor Company of America R3

(RICCX) is an attractive large-cap allocation. RICCX is part of the Large Cap Blend section, and these mutual funds most often invest in firms with a market capitalization of $10 billion or more. By investing in bigger companies, these funds offer more stability, and are often well-suited for investors with a "buy and hold" mindset. RICCX has an expense ratio of 0.91%, management fee of 0.23%, and annual returns of 15.36% over the past 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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This article originally published on Zacks Investment Research (zacks.com).

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