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.

The easiest, most reliable way to judge a mutual fund's quality over time is by analyzing its performance, diversification, and fees. The Zacks Mutual Fund Rank, which covers over 19,000 mutual funds, has helped us identify three outstanding options that are perfect for any long-term investors' portfolios that is retirement-focused.

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

Nuveen Core Equity Premier (TRPGX): 0.55% expense ratio and 0.39% management fee. TRPGX 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. TRPGX has achieved five-year annual returns of an astounding 13.62%.

Janus Henderson Global Tech N (JATNX) is a stand out amongst its peers. JATNX is a Sector - Tech mutual fund, allowing investors to own a stake in a notoriously volatile sector with a much more diversified approach. With five-year annualized performance of 13.66%, expense ratio of 0.69% and management fee of 0.64%, this diversified fund is an attractive buy with a strong history of performance.

Davis New York Venture Fund Y (DNVYX Quick QuoteDNVYX - Free Report) is an attractive large-cap allocation. DNVYX is a Global - Equity mutual fund, which invests their assets in large markets, leveraging the global economy. DNVYX has an expense ratio of 0.67%, management fee of 0.54%, and annual returns of 12.09% over the past five years.

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.