Fund Evaluator:

American Century High-Yield Muni Y Overview

American Century High-Yield Muni Y (AYMYX) is an actively managed Municipal Bond High Yield Muni fund. American Century Investments launched the fund in 2017.

The investment seeks high current income that is exempt from federal income tax; capital appreciation is a secondary consideration. The fund invests in municipal and other debt securities with an emphasis on high-yield securities. Under normal market conditions, the portfolio managers invest at least 80% of the fund's net assets in municipal securities with interest payments exempt from federal income tax. Some of these investments in municipal securities are not necessarily exempt from the federal alternative minimum tax.

About American Century High-Yield Muni Y (AYMYX)

There are 2 members of the management team with an average tenure of 14.59 years: Alan Kruss (2012), Joseph Gotelli (2012). Management tenure is more important for actively managed funds than passive index funds.

The fund has 3 primary benchmarks: S&P National AMT Free Muni TR USD index with a weighting of 100%, S&P Municipal Bond High Yield TR index with a weighting of 50% and S&P Municipal Bond IG TR USD index with a weighting of 50%. American Century High-Yield Muni Y has 419 securities in its portfolio. The top 10 holdings constitute 8.8% of the fund’s assets. The fund meets the SEC requirement of being classified as a diversified fund. The fund is not considered to have an ESG focus with its investment selection and management.

American Century High-Yield Muni Y is part of the Fixed Income global asset class and is within the Municipal Bond fund group. American Century High-Yield Muni Y has 2.7% of its portfolio invested in foreign issues. The overall assets allocated to domestic stock is 0.0%. There is 0.0% allocated to foreign stock, and 0.0% is allocated to preferred stocks. The bond allocation as a percentage of total assets is 99.8% (97.1% domestic bond, 2.7% foreign bond and 0.0% convertible bond). American Century High-Yield Muni Y has 0.2% of the portfolio in cash.

Assets Under Management

The fund has $94 million in total assets, which is below the $803 million average for the High Yield Muni category. Normally, lower assets under management translates to higher average expense ratios, and greater total assets are desired. However, for some investment categories, such as small-cap investing, it may be difficult for the manager to fully employ the desired active strategy if assets grow too large or too quickly.

AYMYX Performance and Fees

The expense ratio measures how much of a fund’s assets are used for administrative expenses and operating expenses, including adviser fees and fees for the transfer agent and custodial services. The American Century High-Yield Muni Y expense ratio is below average compared to funds in the High Yield Muni category. American Century High-Yield Muni Y has an expense ratio of 0.37%, which is 62% lower than its category average, making the fund expense ratio grade a A. While it is difficult to predict returns, it is known that high annual expense ratios reduce your rate of return, and excessive fees are difficult to overcome. Active management normally comes with higher expense ratios than passive index management. Certain investment categories such as small company and foreign also normally have higher expense ratios. It is best to compare fund expense ratios against the category averages for meaningful assessments.

High portfolio turnover can translate to higher expenses and lower aftertax returns. American Century High-Yield Muni Y has a portfolio turnover rate of 49%, indicating that holds its assets around 0.0 years. By way of comparison, the average portfolio turnover is 51% for the High Yield Muni category.

Recently, in the month of July 2026, American Century High-Yield Muni Y returned -1.8%, which earned it a grade of B, as the High Yield Muni category had an average return of -1.8%. The letter grades of A, B, C, D and F are based upon relative rankings within the investment category. A grade of A, for example, would indicate that the return is in the highest 20% for that time period compared to all funds in that category.

American Century High-Yield Muni Y has a trailing yield of 4.62%, which is above the 4.46% category average. The fund normally distributes its income monthly.

It’s natural to seek the best-performing investments, but you must consider the relationship between risk and return and the impact of costs and taxes on your realized returns.

American Century High-Yield Muni Y Grades

Year to date, the fund has returned 1.7%, 0.2 percentage points better than the category, which translates into a grade of C. The fund has returned 7.4% over the past year (grade of C), 4.5% over the past three years (grade of B) and 0.5% per year over the past five years (grade of B) and 2.8% per year over the past 10 years (grade of B).

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