Summary Prospectus     May 1, 2023

INVESTMENT OBJECTIVE

This Fund seeks growth of capital over the long-term.

FEES AND EXPENSES OF THE FUND

This table describes the fees and expenses that you may pay if you buy, hold, and sell shares of the Fund. The expenses in the table do not reflect deductions at the separate account level or contract level for any charges that may be incurred under a variable life insurance or variable annuity contract. If these charges were reflected, the fees and expenses in the table would be higher.

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

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(1)

The expenses in the above table reflect a written agreement by MML Advisers to waive 0.05% of its management fees through April 30, 2024. This agreement can only be terminated by mutual consent of the Board of Trustees on behalf of the Fund and MML Advisers.

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Example

This example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. It assumes that you invest $10,000 in each share class of the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The example also assumes that your investment earns

a 5% return each year and that the Fund’s operating expenses are exactly as described in the preceding table. If separate account or variable life insurance or variable annuity contract expenses were included, overall expenses would be higher. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

Portfolio Turnover

The Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 335% of the average value of its portfolio.

INVESTMENTS, RISKS, AND PERFORMANCE​

Principal Investment Strategies

The Fund invests primarily in common stocks of large- and medium-capitalization U.S. companies. The Fund’s subadviser, Invesco Advisers, Inc., and sub-subadviser, Invesco Capital Management LLC (together with Invesco Advisers, Inc., “Invesco”), invest the Fund’s assets using an indexing strategy. Under normal circumstances, 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 Russell 1000® Invesco Dynamic Multifactor

Index*(the “Index”). As of February 28, 2023, the market capitalization range of companies included in the Index was between $496 million and $36.41 billion.

FTSE Russell (the “Index Provider”) compiles and maintains the Index, which is an index of U.S. equity securities designed to reflect a dynamic combination of “factor investing” strategies that, in the view of the Index Provider, have historically outperformed other factors during various parts of the economic cycle. The Index’s universe of investable stocks is taken from the Russell 1000 Index (the “Russell 1000” or “Parent Index”), which measures the performance of the 1,000 largest-capitalization companies in the United States.

A factor is a stock characteristic that is associated with a security’s risk and return profile (e.g., high quality, high momentum, or low volatility). The Index’s rules-based framework seeks to identify equity securities that tend to exhibit various investment factors to a greater extent than the overall market, depending on the overall economic environment. The Index emphasizes investments that exhibit the following factors: low volatility, momentum, quality, size, and value. At any given time, depending on the current stage of the economic cycle of the overall market, the Index will target different subsets (that is, two or three) of those five factors (referred to as “factor configurations”). The Index is designed to utilize factor configurations that, in the view of the Index Provider, have historically outperformed other factors in certain stages of the economic cycle. The specific factor configurations used by the Index will change depending on which of the following four stages of the economic cycle currently is prevalent: recovery, expansion,

slowdown, and contraction. These four stages are defined as follows:

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Recovery: when growth is below trend but accelerating.

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Expansion: when growth is above trend and accelerating.

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Slowdown: when growth is above trend but decelerating.

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Contraction: when growth is below trend and decelerating.

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Invesco Indexing LLC (“Invesco Indexing”) identifies which stage of the economic cycle it currently believes the market to be in by evaluating leading economic and market sentiment indicators (such as manufacturing business surveys, labor market conditions, monetary conditions, and consumer sentiment surveys). Each month, Invesco Indexing provides information to the Index Provider in the form of a data signal (the “Signal”) on the current stage of the economic cycle, and the Index Provider uses that information to determine the appropriate factor configuration for the Index during that month. Each of the four stages is correlated to a specific, predetermined factor configuration.

To determine which securities within the Parent Index are eligible for inclusion in the Index in a given factor configuration, each constituent in the Parent Index is assigned a multi-factor score based on the extent to which the security exhibits a factor relative to the other constituents in the Parent Index. The multi-factor score is the product of the security’s individual factor scores, each of which is calculated based on certain aspects of the issuer, as set forth below.

Value. A company’s value factor score is based on an equally-weighted composite of cash flow yield, earnings yield, and sales to price ratio, calculated based on the company’s total market capitalization and information reported in the company’s most recent annual financial statement as of the last business day of the prior month.

Momentum. A company’s momentum factor score is based on historical total return over the 11 months ending on the last business day of the prior month.

Quality. A company’s quality factor score is based on a composite of three measures of profitability (return on assets, change in asset turnover, and accruals) and a single measure of leverage, calculated as the ratio of operating

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cash flow to total debt based on information reported in the company’s most recent annual financial statement.

Low Volatility. A company’s volatility factor score is based on the standard deviation of weekly total returns to a company’s stock price over the trailing five years ending on the last business day of the prior month.

Size. A company’s size factor score is based on total market capitalization as of the last business day of the prior month.

An initial weight for each security is determined from the product of the security’s multi-factor score and its weight in the Parent Index. The Index’s methodology will exclude securities from the Index if their relevant factor characteristics fall below certain relative thresholds, as set forth in the methodology rules of the Index, or if their adjusted weights fall below a certain de minimis amount. Finally, a maximum security weight limit is applied to ensure no security weight exceeds a fixed level.

The Index is sponsored by the Index Provider, which is unaffiliated with the Fund, Invesco Indexing, or Invesco. However, since Invesco Indexing provides the Index Provider with monthly data relating to the stage of the economic cycle, Invesco Indexing may also be deemed a creator and sponsor of the Index. Invesco Indexing is affiliated with Invesco.

The Index is rebalanced and reweighted at the beginning of the month when the Signal for the Index changes, which may be as frequently as monthly. The Fund is rebalanced and reweighted in accordance with the Index, meaning that it will buy and sell securities in response to changes in the Index.

Although the Fund generally will invest in substantially all of the securities comprising the Index in proportion to their weightings in the Index, under various circumstances it may not be possible or practicable to purchase all of those securities in those same weightings. In those circumstances, the Fund may hold cash or purchase a sample of the securities in the Index. When it relies on a “sampling” methodology, Invesco uses quantitative analysis to select securities from the Index universe to obtain a representative sample of securities that has, overall, investment characteristics similar to the Index in terms of key risk factors, performance attributes, and other characteristics such as industry weightings, market

capitalization, return variability, earnings valuation, yield, and other financial characteristics of securities. When employing a sampling methodology, Invesco bases the number of the holdings in the Fund on a number of factors, including asset size of the Fund, and generally expects the Fund to hold fewer than the total number of securities in the Index. However, Invesco reserves the right to invest in as many securities as it believes necessary to achieve the Fund’s investment objective. The Fund may use futures contracts, a type of derivative, to seek performance that corresponds to the Index and/or to manage cash flows. Use of futures contracts by the Fund may create investment leverage.

The Index, and therefore the Fund, may at times have significant exposure to one or more industries or sectors.

Changes in the Index, or use of the sampling methodology described above, may result in active and frequent trading by the Fund and as a result the Fund may have a relatively high portfolio turnover rate.

Principal Risks

The following are the Principal Risks of the Fund. The value of your investment in the Fund could go down as well as up. You can lose money by investing in the Fund. References in this section to the Fund’s subadviser may include any sub-subadvisers as applicable. Certain risks relating to instruments and strategies used in the management of the Fund are placed first. The significance of any specific risk to an investment in the Fund will vary over time, depending on the composition of the Fund’s portfolio, market conditions, and other factors. You should read all of the risk information presented below carefully, because any one or more of these risks may result in losses to the Fund.

Equity Securities Risk Although stocks may have the potential to outperform other asset classes over the long term, their prices tend to fluctuate more dramatically over the shorter term. These movements may result from factors affecting individual companies, or from broader influences like changes in interest rates, market conditions, or investor confidence, or announcements of economic, political, or financial information.

Indexing Risk The Fund’s performance may not track the performance of the index due to a number of factors, including fees and expenses of the Fund, the Fund’s cash positions, and

differences between securities held by the Fund and the securities comprising the index which may result from legal restrictions, costs, or liquidity constraints, especially during times when a sampling methodology is used.

Large Company Risk Large-capitalization stocks as a group could fall out of favor with the market, causing the Fund’s investments in large-capitalization stocks to underperform investments that focus on small- or medium-capitalization stocks. Larger, more established companies may be slow to respond to challenges and may grow more slowly than smaller companies.

Small and Mid-Cap Company Risk Market risk and liquidity risk are particularly pronounced for securities of small and medium-sized companies, which may trade less frequently and in smaller volumes than more widely-held securities, and may fluctuate in price more than other securities. Their shares can be less liquid than those of larger companies, especially during market declines. Small and medium-sized companies may have limited product lines, markets, or financial resources and may be dependent on a limited management group; they may have been recently organized and have little or no track record of success.

Momentum Investing Risk The momentum style of investing is subject to the risk that the securities in which the Fund invests may be more volatile than the market as a whole, or that the returns on securities that previously have exhibited price momentum are less than returns on securities associated with other styles of investing. Momentum can turn quickly, and stocks that previously have exhibited high momentum may not experience continued positive momentum, and they may experience rapid and substantial declines in value. In addition, there may be periods when the momentum style of investing is out of favor, and the investment performance of the Fund may suffer compared to the returns from other styles of investing.

Cash Position Risk If the Fund holds a significant portion of its assets in cash or cash equivalents, its investment returns may be adversely affected and the Fund may not achieve its investment objective.

Derivatives Risk Derivatives can be highly volatile and involve risks different from, and potentially greater than, direct investments, including risks of imperfect correlation between the value of

derivatives and underlying assets, counterparty default, potential losses that partially or completely offset gains, and illiquidity. Derivatives can create investment leverage. Losses from derivatives can be substantially greater than the derivatives’ original cost and can sometimes be unlimited. If the value of a derivative does not correlate well with the particular market or asset class the derivative is designed to provide exposure to, the derivative may not have the effect or benefit anticipated. Derivatives can also reduce the opportunity for gains or result in losses by offsetting positive returns in other investments. Many derivatives are traded in the over-the-counter market and not on exchanges.

Frequent Trading/Portfolio Turnover Risk Portfolio turnover generally involves some expense to the Fund. The trading costs associated with portfolio turnover may adversely affect the Fund’s performance.

Management Risk The Fund relies on the manager’s investment analysis and its selection of investments to achieve its investment objective. There can be no assurance that the Fund will achieve the intended results and the Fund may incur significant losses.

Market Risk The value of the Fund’s portfolio securities may decline, at times sharply and unpredictably, as a result of unfavorable market-induced changes affecting particular industries, sectors, or issuers. Stock and bond markets can decline significantly in response to issuer, market, economic, industry, political, regulatory, geopolitical, public health, and other conditions, as well as investor perceptions of these conditions. The Fund is subject to risks affecting issuers, such as management performance, financial leverage, industry problems, and reduced demand for goods or services.

Passive Management Risk With an indexing strategy, there is no attempt to seek returns in excess of a benchmark index, to use defensive strategies, or to reduce the effects of any long-term poor investment performance. Therefore, the Fund would not necessarily buy or sell a security unless that security is added to, or removed from, the index, even if that security generally is underperforming.

Sector Risk The Fund may allocate more of its assets to particular industries or to particular economic, market, or industry sectors than to others. This could increase the volatility of the

Fund’s portfolio, and the Fund’s performance may be more susceptible to developments affecting issuers in those industries or sectors than if the Fund invested more broadly.

Valuation Risk The Fund is subject to the risk of mispricing or improper valuation of its investments, in particular to the extent that its securities are fair valued.

Value Company Risk The value investment approach entails the risk that the market will not recognize a security’s intrinsic value for a long time, or that a stock the investment adviser or subadviser judges to be undervalued may actually be appropriately priced.

Performance Information

The following bar chart and table provide some indication of the risks of investing in the Fund. The bar chart shows changes in the Fund’s performance from year to year for Class II shares. The table shows how the Fund’s average annual returns for 1 and 5 years, and since inception, compare with those of a broad measure of market performance and an additional index that provides a style-specific comparison for the Fund’s returns (Russell 1000 Invesco Dynamic Multifactor Index). The Fund’s investment strategy changed on November 23, 2020. The performance results shown below would not necessarily have been achieved had the Fund’s current investment strategy been in effect for the entire period for which performance results are presented. Performance shown does not reflect the fees and expenses deducted under the variable life insurance or variable annuity contract through which you invest in the Fund. If these amounts were reflected, returns would be less than those shown. Past performance is not necessarily an indication of how the Fund will perform in the future.

Annual Performance

Class II Shares

Average Annual Total Returns

(for the periods ended December 31, 2022)

MANAGEMENT

Investment Adviser: MML Investment Advisers, LLC (“MML Advisers”)

Subadviser(s): Invesco Advisers, Inc. (“Invesco Advisers”)

Sub-subadviser(s): Invesco Capital Management LLC (“ICM”)

Portfolio Manager(s):

Pratik Doshi, CFA  is a Portfolio Manager at ICM. He has managed the Fund since November 2020.

Peter Hubbard  is Head of Equities and Director of Portfolio Management at ICM. He has managed the Fund since November 2020.

Michael Jeanette  is a Senior Portfolio Manager at ICM. He has managed the Fund since November 2020.

Tony Seisser is a Portfolio Manager at ICM. He has managed the Fund since November 2020.

PURCHASE AND SALE OF FUND SHARES

Shares of the Fund are generally available to separate investment accounts of variable life insurance and variable annuity contracts offered by companies such as MassMutual. An investor should consult the company issuing the investor’s variable life insurance or variable annuity contract to determine how to make redemptions.

TAX INFORMATION

Dividends and capital gain distributions are paid to the insurance company separate accounts. Variable life insurance and variable annuity

contract owners should refer to the variable life insurance or variable annuity product prospectus or consult with their own tax adviser for information regarding the tax consequences of their investment.

PAYMENTS TO INSURANCE COMPANIES AND THEIR AFFILIATES

The Fund is not sold directly to the general public but instead is offered as an underlying investment option for variable insurance contracts. The Fund and its related companies may make payments to the sponsoring insurance company (or its

affiliates) or other intermediary for distribution and/or other services. These payments may be a factor that the insurance company considers in including the Fund as an underlying investment option in the variable insurance contract or may create a conflict of interest by influencing the insurance company or other intermediary to recommend the variable insurance contract over another investment. The prospectus (or other offering document) for your variable insurance contract may contain additional information about these payments.