There is never a wrong time to invest in mutual funds for retirement. So, if you're still looking for the best mutual funds, the Zacks Mutual Fund Rank can be a great guide.

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

Fidelity Advisor Semiconductors A (FELAX Quick QuoteFELAX - Free Report) has a 1% expense ratio and 0.53% management fee. FELAX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. With yearly returns of 25.16% over the last five years, this fund clearly wins.

Voya Growth & Income Portfolio S (ISVGX Quick QuoteISVGX - Free Report) : 0.92% expense ratio and 0.6% management fee. ISVGX 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. With yearly returns of 10.46% over the last five years, ISVGX is an effectively diversified fund with a long reputation of solidly positive performance.

Ivy Large Cap Growth R (WLGRX Quick QuoteWLGRX - Free Report) . Expense ratio: 1.23%. Management fee: 0.61%. Five year annual return: 11.55%. WLGRX 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.

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.