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.

The best way to shortlist great mutual funds is to ensure solid performance, diversification, and low fees. Some are better than others, but utilizing the Zacks Mutual Fund Rank, we have identified three mutual funds that could be solid additions to one's retirement portfolio.

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

If you are looking to diversify your portfolio, consider Fidelity Convertible Securities (FCVSX Quick QuoteFCVSX - Free Report) . FCVSX is a Convertible Bonds mutual fund, and these funds are unique in the fixed income world; these securities have components of both fixed income and equity, making them hybrid securities. This fund is a winner, boasting an expense ratio of 0.73%, management fee of 0.51%, and a five-year annualized return track record of 10.69%.

Hood River Small Cap Growth Institutional (HRSMX Quick QuoteHRSMX - Free Report) : 1.06% expense ratio and 0.9% management fee. HRSMX is a Small Cap Growth mutual fund building their portfolio around stocks with market caps under $2 billion and large growth opportunities. With yearly returns of 11.19% over the last five years, HRSMX is an effectively diversified fund with a long reputation of solidly positive performance.

MFS Mass Investors Growth Stock R6 (MIGNX Quick QuoteMIGNX - Free Report) is an attractive large-cap allocation. MIGNX 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. MIGNX has an expense ratio of 0.37%, management fee of 0.33%, and annual returns of 11.94% over the past five years.

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.