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.

JPMorgan Large Cap Growth R2 (JLGZX): 1.19% expense ratio and 0.45% management fee. JLGZX 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. JLGZX has achieved five-year annual returns of an astounding 10.98%.

Victory Pioneer Global Equity A (GLOSX Quick QuoteGLOSX - Free Report) . Expense ratio: 1.11%. Management fee: 0.65%. GLOSX is a Global - Equity mutual fund. These funds invest in large markets like the U.S., Europe, and Japan, and operate with very few geographical limitations This fund has managed to produce a robust 14.78% over the last five years.

MFS Blended Research Core Equity R4 (MUEUX). Expense ratio: 0.49%. Management fee: 0.25%. Five year annual return: 13.46%. MUEUX 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.

We hope that your investment advisor (if you use one) has you invested in one or all of the top-ranked mutual funds we've reviewed. But if that isn't the case, it might be time to have a conversation or reconsider this vitally important relationship.