Fund Evaluator:
MM S&P 500® Index I (MMIZX)
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Best Performing in Large Blend Over the Last Year
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Fund Details
MM S&P 500® Index I Overview
MM S&P 500® Index I (MMIZX) is a passively managed U.S. Equity Large Blend fund. MassMutual launched the fund in 2011.
The investment seeks to provide investment results that correspond to the total return performance of publicly traded common stocks in the aggregate as represented by the S&P 500® Index. The fund invests at least 80% of its net assets (plus the amount of any borrowings for investment purposes) in the equity securities of companies included within the S&P 500® Index. It invests in the equity securities of companies included in the index in weightings that approximate the relative composition of the securities contained in the index, and in S&P 500 Index futures contracts.
About MM S&P 500® Index I (MMIZX)
There are 2 members of the management team with an average tenure of 1.22 years: Jennifer Hsui (2025), Peter Sietsema (2025). Management tenure is more important for actively managed funds than passive index funds.
The fund has 1 primary benchmark: S&P 500 (TR) (1970) index with a weighting of 100%. MM S&P 500® Index I has 507 securities in its portfolio. The top 10 holdings constitute 36.2% 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.
MM S&P 500® Index I is part of the Equity global asset class and is within the U.S. Equity fund group. MM S&P 500® Index I has 0.5% of its portfolio invested in foreign issues. The overall assets allocated to domestic stock is 99.2%. There is 0.5% allocated to foreign stock, and 0.0% is allocated to preferred stocks. The bond allocation as a percentage of total assets is 0.0% (0.0% domestic bond, 0.0% foreign bond and 0.0% convertible bond). MM S&P 500® Index I has 0.3% of the portfolio in cash.
Assets Under Management
The fund has $541 million in total assets, which is below the $6 billion average for the Large Blend 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.
MMIZX 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 MM S&P 500® Index I expense ratio is low compared to funds in the Large Blend category. MM S&P 500® Index I has an expense ratio of 0.14%, which is 83% 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. MM S&P 500® Index I has a portfolio turnover rate of 5%, indicating that holds its assets around 0.2 years. By way of comparison, the average portfolio turnover is 48% for the Large Blend category.
Recently, in the month of July 2026, MM S&P 500® Index I returned -0.1%, which earned it a grade of C, as the Large Blend category had an average return of 0.4%. 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.
MM S&P 500® Index I has a trailing yield of 0.98%, which is above the 0.56% category average. The fund normally distributes its income annually and its capital gains annually.
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.
MM S&P 500® Index I Grades
Year to date, the fund has returned 10.0%, 0.7 percentage points better than the category, which translates into a grade of B. The fund has returned 19.4% over the past year (grade of B), 19.1% over the past three years (grade of B) and 12.7% per year over the past five years (grade of B) and 14.9% per year over the past 10 years (grade of A).
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MMIZX Trailing NAV Total Returns Data as of 7/31/26
| Last Month |
Last Quarter |
Ann'l. 1Yr |
Ann'l. 3Yr |
Ann'l. 5Yr |
Ann'l. 10Yr |
|
| MMIZX Return (NAV) | -0.1% | 4.2% | 19.4% | 19.1% | 12.7% | 14.9% |
| MMIZX Grade | C | C | B | B | B | A |
| +/- Category | -0.5% | 0.1% | 1.9% | 1.8% | 1.6% | 1.3% |
| Large Blend Avg | 0.4% | 4.1% | 17.5% | 17.3% | 11.1% | 13.7% |
| MMIZX Tax Cost Ratio | na | na | 3.7% | 3.9% | 4.1% | 3.8% |
MMIZX Annual NAV Total ReturnsData as of 7/31/26
| 2026 | 2025 | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | |
| MMIZX Return (NAV) | 10.0% | 17.7% | 24.7% | 26.2% | -18.2% | 28.6% | 18.3% | 31.4% | -4.6% | 21.7% | 11.8% |
| MMIZX Grade | B | B | B | B | C | B | C | B | B | B | B |
| +/- Category | 0.7% | 1.8% | 2.7% | 2.5% | -0.9% | 2.1% | 0.8% | 1.5% | 1.3% | 0.4% | 1.6% |
| Large Blend Avg | 9.3% | 15.8% | 22.1% | 23.7% | -17.3% | 26.5% | 17.5% | 29.8% | -5.9% | 21.3% | 10.2% |
| Risk Measures | |
| Standard Deviation: | 13.1% |
| Total Risk Index: | 1.06 - Above Average |
| Category Risk Index: | 0.99 - Average |
| Category Risk Grade: | C (44% Rank) |
| Beta: | 1.00 |
| R-Squared: | 100% |
| Leveraged Fund: | No |
| Inverse Fund: | No |
| Portfolio Characteristics | |
| Equity Investment Style: | Large-Cap Blend |
| Bond Investment Style: | na |
| Yield: | 1.0% |
| Dividend Distribution: | Annually |
| Cap Gains Distribution: | Annually |
| Total Assets: | $2208 Mil |
| Fund Total Assets: | $ 542 Mil |
| Share Class Type: | Inst |
| Portfolio Turnover: | 5% |
Management Team
| Number of Managers: 2 | |||
| Longest Tenure: 1.3 years | |||
| Average Tenure: 1.2 years | |||
| Managers (Year): Hsui Jennifer (2025), Sietsema Peter (2025) | |||
Portfolio Composition (as of 6/30/26)
| # of Holdings: | 507 |
| % in Top 10 Holdings: | 36.2% |
| Fund is Non-Diversified: | No |
| % in Foreign Issues: | 0.5% |
Portfolio Allocation |
|
| Domestic Stock: | 99.2% |
| Foreign Stock: | 0.5% |
| Preferred Stock: | 0.0% |
| Domestic Bond: | 0.0% |
| Foreign Bond: | 0.0% |
| Convertible Bond: | 0.0% |
| Other: | 0.0% |
| Cash: | 0.3% |
Purchase Information
| Fund Family: | MassMutual |
| Phone Number: | 888-309-3539 |
| Website: | www.massmutual.com |
| Status: | Open |
| Inception Date: | December 7, 2011 |
| Min. Initial Purchase: | $ 0 |
| Min. Initial IRA Purchase: | $ 0 |
| True No-Load: | Yes |
| Front Load Maximum: | 0.00% |
| Deferred Charge Maximum: | 0.00% |
| Redemption Charge Maximum: | 0.00% |
| 12b-1 Fee: | na |
Expenses and Fees | |
| Expense Ratio (%): | 0.14% ( Rating : Low ) |
| Category Average Expense Ratio (%): | 0.81% |
| Share Class: | MM S&P 500® Index Svc |
| Min. Subsequent Purchase: | $ 0 |
| Min. Subsequent IRA Purchase: | $ 0 |
