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.

Fidelity Select Insurance (FSPCX Quick QuoteFSPCX - Free Report) : 0.8% expense ratio and 0.53% management fee. Sector - Finance funds offer a stable, diversified approach to investing that focuses on the financial industry, an infamously large, complex, and heavily-regulated space. FSPCX has achieved five-year annual returns of an astounding 15.35%.

MFS Growth Fund R3 (MFEHX Quick QuoteMFEHX - Free Report) is a stand out amongst its peers. MFEHX 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 five-year annualized performance of 15.71%, expense ratio of 0.85% and management fee of 0.49%, this diversified fund is an attractive buy with a strong history of performance.

BlackRock Balanced Capital I (MACPX Quick QuoteMACPX - Free Report) . Expense ratio: 0.54%. Management fee: 0.42%. Five year annual return: 10.16%. MACPX is an Allocation Balanced mutual fund. Allocation Balanced funds look to invest across asset types, like stocks, bonds, and cash, and including precious metals or commodities is not unusual; these funds are mostly categorized by their respective asset allocation.

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.