# EDGAR Filing Document

**Accession Number:** 0000742212
**File Stem:** 0001193125-26-180866
**Filing Date:** 2026-4
**Character Count:** 24823
**Document Hash:** 6253513b8a4b4978f779677377a0a381
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-26-180866.hdr.sgml**: 20260427

**ACCESSION NUMBER**: 0001193125-26-180866

**CONFORMED SUBMISSION TYPE**: 497K

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260427

**DATE AS OF CHANGE**: 20260427

**EFFECTIVENESS DATE**: 20260427

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** NORTHWESTERN MUTUAL SERIES FUND INC
- **CENTRAL INDEX KEY:** 0000742212

**ORGANIZATION NAME:**
- **EIN:** 391603401
- **STATE OF INCORPORATION:** MD
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 497K
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-89971
- **FILM NUMBER:** 26898570

**BUSINESS ADDRESS:**
- **STREET 1:** 720 E WISCONSIN AVE
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53202
- **BUSINESS PHONE:** 4142992508

**MAIL ADDRESS:**
- **STREET 1:** 720 EAST WISCONSIN AVE
- **CITY:** MILWAUKEE
- **STATE:** WI
- **ZIP:** 53202

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** NORTHWESTERN MUTUAL VARIABLE LIFE SERIES FUND INC
- **DATE OF NAME CHANGE:** 19940830

## Series and Classes Contracts Data

### International Equity Portfolio (Series ID: S000000052)

| Class ID   | Class Name                     | Ticker Symbol   |
|:---|:---|:---|
| C000000087 | International Equity Portfolio |  |

**International Equity Portfolio**

**SUMMARY PROSPECTUS**

**MAY 1, 2026**

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <br>Before you invest, you may want to review the Portfolio's prospectus, which contains more information about the Portfolio and its risks. You can find the Portfolio's prospectus, reports to shareholders, and other information about the Portfolio online at www.nmseriesfund.com. You can also get this information at no cost by calling (866) 910-1232 or by sending an e-mail request to sfprospectus@northwesternmutual.com. The current prospectus and statement of additional information, each dated May 1, 2026, along with the Portfolio's most recent annual report dated December 31, 2025, are incorporated by reference into this Summary Prospectus. The Portfolio's statement of additional information and annual report may be obtained, free of charge, in the same manner as the prospectus.

The Securities and Exchange Commission has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

**INVESTMENT OBJECTIVE**

The investment objective of the Portfolio is long-term growth of capital and income.

**FEES AND EXPENSES OF THE PORTFOLIO**

The table below describes the fees and expenses that you may pay when you buy, hold, and sell interests in a separate account that invests in shares of the Portfolio as a result of your purchase of a variable annuity contract or variable life insurance policy. The fees and expenses shown in the table and Example do not reflect fees and expenses separately charged by variable annuity contracts or variable life insurance policies. If the fees and expenses separately charged by variable annuity contracts and variable life insurance policies were included, the fees and expenses shown in the table and the Example would be higher.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

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| | |
|:---|:---|
| &nbsp;&nbsp; ***Shareholder Fees***<br> (fees paid directly from your investment)<br>| N/A |

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&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

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| | |
|:---|:---|
| &nbsp;&nbsp; ***Annual Portfolio Operating Expenses***<br> (expenses that you pay each year as a percentage <br> of the value of your investment)<br>|  |
| Management Fee | 0.65% |
| Distribution and Service (12b-1) Fees |  |
| Other Expenses | 0.03% |
| Total Annual Portfolio Operating Expenses | 0.68% |
| Fee Waiver<sup>(1)</sup> <br>| 0.00% |
| &nbsp;&nbsp; Total Annual Portfolio Operating Expenses After <br> Fee Waiver<sup>(1)</sup> <br>| 0.68% |

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<sup>(1)</sup>

The Portfolio's investment adviser has contractually agreed to waive a portion of its management fee. This contractual agreement will continue through at least April 30, 2027 and may not be terminated prior to that date without action by the Board of Directors.

***Example***

This Example is intended to help you compare the cost of investing in the Portfolio with the cost of investing in other mutual funds. The Example assumes that you invest $10,000 in the Portfolio for the time periods indicated and then redeem or hold all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year and that the Portfolio's operating expenses remain the same. The Example reflects adjustments made to the Portfolio's operating expenses due to the fee waiver agreement with the investment adviser for the first year only. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

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| | | | |
|:---|:---|:---|:---|
| **1 Year** | **3 Years** | **5 Years** | **10 Years** |
| $69 | $218 | $379 | $847 |

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***Portfolio Turnover***

The Portfolio pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover may indicate higher transaction costs. These costs, which are not reflected in Annual Portfolio Operating Expenses or in the Example, affect the Portfolio's performance. During the most recent fiscal year, the Portfolio's portfolio turnover rate was 16% of the average value of its portfolio.

**PRINCIPAL INVESTMENT STRATEGIES**

Normally, the Portfolio invests at least 80% of net assets (plus any borrowings for investment purposes) in equity securities. The Portfolio will primarily hold equity securities of issuers from at least three different countries (not including the U.S.). The Portfolio's equity investments may include common stocks, depositary receipts evidencing ownership of common stocks, certain preferred stocks, and securities that carry the right to buy common stocks (e.g., rights and warrants). The Portfolio may purchase securities in any country, including those with developed markets and emerging markets and is not required to allocate its investments in set percentages in particular countries, except that the Portfolio's investments in emerging markets countries normally will be limited to 30% of its net assets. From time to time, the Portfolio may have significant investments in one or more countries, a geographic region, or in particular sectors. The Portfolio may enter into currency forward contracts in order to hedge direct or indirect foreign currency exposure. The adviser may hedge currency risk using "proxy" currencies (i.e., currencies that are correlated with, but not the same as the currency of the instrument being hedged).

The Portfolio typically invests in well-established companies of medium-to-large capitalization based on standards of the applicable

**NMSF-SP1Northwestern Mutual Series Fund, Inc.**

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**International Equity Portfolio – Summary**

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market. The Portfolio typically invests in companies that, in the adviser's opinion, appear to be temporarily undervalued but have a favorable outlook for long- term growth. The Portfolio's adviser also focuses on the underlying financial condition and prospects of individual companies, including future earnings, cash flow, and dividends. Various other factors, including financial strength, economic condition, competitive advantage, quality of the business franchise, financially material environmental, social, and governance ("ESG") issues, along with the reputation, experience, and competence of a company's management are weighed against valuation in selecting individual securities. The adviser also considers the economic and political stability of the country where the issuer is located and the protections provided to shareholders.

The adviser may consider selling an equity security when it believes the price of the security reflects more optimistic expectations about the company's prospects than the adviser's expectations, when its assessment of the company's long-term fundamentals grows negative, or when the adviser identifies a more attractive investment opportunity.

**PRINCIPAL RISKS**

Portfolio shares will rise and fall in value and there is a risk you could lose money by investing in the Portfolio. There can be no assurance that the Portfolio will achieve its objective. The main risks of investing in this Portfolio are identified below.

• **Active Management Risk –** The adviser's investment strategies and techniques may not perform as expected which could cause the Portfolio to underperform other mutual funds or lose money.

• **ADR Risk –** ADRs are receipts representing ownership of shares of a foreign issuer held by a U.S. bank or similar financial institution that entitle the holder to dividends and capital gains on the underlying foreign shares. ADRs are alternatives to directly purchasing the underlying foreign securities in their national markets and currencies. They, and other similar depositary receipts, are subject to many of the risks associated with direct investments in foreign securities, such as currency risk, political and economic risk and market risk, because their values depend on the performance of the non-dollar denominated underlying foreign securities. The Portfolio is also subject to fees and the credit risk of the financial institution holding the ADRs or other depositary receipts. ADRs may be "sponsored," meaning that they are implemented by a financial institution in collaboration with the issuing foreign company, or "unsponsored," meaning that the financial institution created the instrument without the sponsorship or direct involvement of the foreign company. Differing registration requirements apply to each type of ADR. ADRs may transact on exchanges or on over-the-counter markets ("OTC"). Conducting transactions in OTC markets may result in higher costs, a lack of pricing transparency and lower liquidity when compared with exchange-based transactions. Risks associated with different ADR types will vary, based upon differences in registration, reporting and disclosure requirements that apply to such ADRs and the characteristics of the market in which transactions for the particular ADR are conducted.

• **Derivatives Risk –** The value of a derivative generally depends upon, or is derived from, an underlying asset, reference rate or index. The Portfolio's use of derivatives involves risks different from, or possibly greater than, the risks associated with investing directly in securities or other traditional investments. Investments in derivatives may not have the intended effects and may result in losses for the Portfolio that may not otherwise have occurred or missed opportunities for the Portfolio. Certain derivatives involve leverage, which could cause the Portfolio to lose more than the principal amount invested. The derivatives could involve management, credit, interest rate, liquidity and market risks, and the risks of misplacing or improper valuation. Changes in the value of the derivative may not correlate as intended with the underlying asset, rate or index. In addition, the Portfolio could sustain a loss in the event the counterparty to a derivatives transaction fails to make the required payments or otherwise comply with the terms of the contract. The Portfolio's purchase of forwards contracts may involve risks related to imperfect correlation between the prices of such instruments and the price of the underlying asset, as well as leverage, liquidity and volatility risks. In addition, the purchase of forwards also involves counterparty credit risk as well as heightened market risk.

• **Emerging Markets Risk –** Investing in emerging market securities increases foreign investing risk, and may subject the Portfolio to more rapid and extreme changes in the value of its holdings compared with investments made in U.S. securities or in foreign, developed countries. Investments in emerging markets may be subject to political, economic, legal, market, and currency risks. Emerging market securities trade in smaller markets which may experience significant price and market volatility, fluctuations in currency values, interest rates and commodity prices, higher transaction costs, and the increased likelihood of the occurrence of trading difficulties, such as delays in executing, clearing and settling Portfolio transactions or in receiving payment of dividends. Special risks associated with investments in emerging market issuers may include a lack of publicly available information, a lack of uniform disclosure, accounting, financial reporting, and recordkeeping standards, and more limited investor protection provisions when compared with developed economies. Emerging market risks also may include unpredictable and changing political, economic and tax policies, the imposition of capital controls and/or foreign investment limitations by a country, nationalization of businesses, and the imposition of sanctions or restrictions in certain investments by other countries, such as the United States.

• **Equity Securities Risk –** The value of equity securities, such as common stocks, could decline if the financial condition of the companies the Portfolio is invested in declines or if overall market and economic conditions deteriorate. Equity securities generally have greater price volatility than fixed income securities.

• **ESG Risk –** Incorporating the consideration of ESG factors in the investment process may affect the Portfolio's exposure to certain issuers or industries and may not work as intended. The Portfolio may underperform other funds that do not consider ESG factors or that use different ESG factors to evaluate a security. Information used to evaluate ESG factors may not be readily available, complete, or accurate, and may vary across providers and issuers, as ESG factors are not uniformly defined or

**NMSF-SP2Northwestern Mutual Series Fund, Inc. Prospectus**

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**International Equity Portfolio – Summary**

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assessed. There is no guarantee that evaluating ESG considerations for individual securities will positively contribute to the Portfolio's performance results.

• **Foreign Currency Risk –** The risk that foreign (non-U.S. dollar) currency denominated securities may be adversely affected by decreases in foreign currency values relative to the U.S. dollar. Investments in securities subject to foreign currency risk may have more rapid and extreme changes in value or more losses than investments in U.S. dollar denominated securities.

• **Foreign Investing Risk –** Investing in foreign securities may subject the Portfolio to more rapid and extreme changes in value or more losses than a fund that invests exclusively in U.S. securities. This risk is due to potentially smaller markets, differing reporting, accounting and auditing standards, and nationalization, expropriation or confiscatory taxation, currency blockage, political and economic conditions, or diplomatic developments. Foreign securities may be less liquid, more volatile, and harder to value than U.S. securities.

• **Geographic Focus Risk** – The Portfolio's performance could be more volatile than that of a more geographically diversified fund and could be significantly impacted as a result of the Portfolio investing a relatively large percentage of its assets in issuers located in a single country, a small number of countries, or a particular geographic region. Also, the Portfolio's performance may be more closely tied to the market, currency, economic, political, or regulatory conditions in those countries or that region.

• **Investment Style Risk –** A portfolio managed using a value style of investing, such as the Portfolio, may underperform when the market does not favor the particular style used by the Portfolio. Different investment styles tend to shift in and out of favor, depending on market conditions and investor sentiment.

• **Large Cap Company Risk –** Investing in large cap stocks could cause the Portfolio to underperform in markets favoring faster growing companies. Large cap stocks tend to be more mature with fewer opportunities to grow and may not have the same growth potential as stocks with smaller capitalizations.

• **Liquidity Risk –** Markets for foreign securities, in particular emerging markets securities, may be less liquid than markets for larger cap stocks and domestic securities, and therefore may be difficult to purchase or sell at an advantageous time or price, if at all. These risks may be magnified during periods of economic turmoil or in an extended economic downturn.

• **Market Risk –** The risk that the market price of securities owned by the Portfolio may go up or down, sometimes rapidly or unpredictably. The value of a security may decline due to changes in general market conditions, economic trends or events that are not specifically related to the issuer of the security, or factors that affect a particular issuer or issuers, exchange, country, group of countries, region, market, industry, group of industries, sector or asset class. Global economies and financial markets are increasingly interconnected, which magnifies the potential that conditions in one country or region might adversely impact issuers in, or foreign exchange rates with, a different country or region. Geopolitical and other events, including war, terrorism, economic uncertainty, trade disputes, tariffs, public health crises (such as epidemics and pandemics), and related events have led, and in the future may lead, to increased market volatility, which may disrupt U.S. and world economies and markets and may have significant adverse direct or indirect effects on the Portfolio and its investments.

• **Mid Cap Company Risk –** Investing in mid cap stocks may cause greater risk of loss and price fluctuation than investing in stocks of larger cap companies due to a more limited track record, narrower product markets, more limited resources and less liquid trading markets. These stocks may be more volatile and more difficult to buy and sell than stocks with larger capitalizations.

• **Sector Focus Risk –** To the extent the Portfolio invests a relatively high percentage of its assets in a particular sector, it will have greater exposure to the risks associated with that sector, including the risk that the securities of companies within the sector will underperform due to adverse economic conditions, regulatory or legislative changes, or increased competition affecting the sector. To the extent the Portfolio is underweight in other sectors, the Portfolio risks missing out on advances in those sectors.

• **Underlying Portfolio Risk –** The Portfolio may serve as an investment option, or "Underlying Portfolio," for other portfolios of Northwestern Mutual Series Fund, Inc. that are managed as "fund of funds." As a result, from time to time, the Portfolio may experience relatively large investments or redemptions from those other portfolios and could be required to invest cash or sell securities at a time when it is not advantageous to do so.

• **Warrants Investing Risk –** Investments in warrants may be more volatile than the underlying common stock and may cause the Portfolio increased risk of loss if the warrants cannot be exercised prudently by the expiration date or if the warrants lack a liquid secondary market for resale. Warrants can provide exposure to an underlying stock for a portion of the price of direct ownership of shares of that stock. As a result, most warrants have some degree of leverage, which can vary depending on the type of warrant. This means that small changes in the value of the underlying stock results in larger changes in the value of the warrant. This can magnify gains when stock prices rise, but it can also magnify losses when stock prices fall.

**PERFORMANCE**

The following bar chart illustrates the risks of investing in the Portfolio by showing how the performance of the Portfolio has varied from year to year. The table to the right of the bar chart shows the Portfolio's average annual total return over certain time periods and compares the Portfolio's returns with those of an index that has characteristics relevant to the Portfolio's investment strategy (Strategy Index). The table also shows the Portfolio's returns against an index that represents the overall securities market (Broad-Based Index), which the Portfolio has added to comply with new regulatory requirements. Prior to November 1, 2021, the

**NMSF-SP3Northwestern Mutual Series Fund, Inc. Prospectus**

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**International Equity Portfolio – Summary**

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Portfolio was managed by a different sub-adviser. Performance shown may have been different if the current strategy, and the current sub-adviser, had been in place during the periods shown. Returns are based on past results and are not an indication of future performance. Neither the bar chart nor the table reflects the fees and expenses separately charged by the variable annuity contract or variable life insurance policy separate account that invests in the Portfolio and returns would be lower if those fees and expenses were reflected.

![](g933420ie.jpg)

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| | | |
|:---|:---|:---|
|  | Quarter/Year | Return |
| Best Quarter | 4th quarter, 2022 | 15.79% |
| Worst Quarter | 1st quarter, 2020 | -24.42% |

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**Average Annual Total Return** <br> **(for periods ended December 31, 2025)** 

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| | | | | |
|:---|:---|:---|:---|:---|
|  |  | 1 Yr | 5 Yr | 10 Yr |
| Portfolio: | International Equity Portfolio | 38.35% | 10.31% | 6.65% |
| Strategy Index: | MSCI<sup>®</sup> All Country World <br> (ex-US) Value Index (Net)<br> (reflects no deduction for fees, <br> expenses or taxes)<br>| 39.50% | 11.87% | 8.74% |
| Broad-Based <br> Index:<br>| MSCI<sup>®</sup> All Country World <br> (ex-US) Index (Net)<br> (reflects no deduction for fees, <br> expenses or taxes)<br>| 32.39% | 7.91% | 8.41% |

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**PORTFOLIO MANAGEMENT**

**Investment Adviser:** Mason Street Advisors, LLC <br> **Sub-Adviser:** Dodge & Cox <br> **Portfolio Managers:** The Portfolio is managed by Dodge & Cox's International Equity Investment Committee ("IEIC"), whose members are jointly and primarily responsible for the management of the Portfolio. The IEIC consists of the following members: <br>*Roger G. Kuo,* CFA, Chief Executive Officer, President, Director, and Research Analyst, joined Dodge & Cox in 1998 and has been an IEIC member since 2006 and has managed the Portfolio since 2021. <br>*Englebert T. Bangayan,* CFA, Vice President and Research Analyst, joined Dodge & Cox in 2002 and has been an IEIC member since 2015 and has managed of the Portfolio since 2021. <br>*Sophie Chen,* CFA, Vice President and Research Analyst, joined Dodge & Cox in 2012 and has been an IEIC member since 2024 and has managed the Portfolio since 2024. <br>*David C. Hoeft CFA,* Chair, Senior Vice President, Director, Chief Investment Officer, joined Dodge & Cox in 1993 and has been an IEIC member since 2025 and has managed the Portfolio since 2025. <br>*Raymond J. Mertens,* CFA, Senior Vice President and Director, and Research Analyst, joined Dodge & Cox in 2003 and has been an IEIC member since 2018 and has managed the Portfolio since 2021. <br>*Paritosh Somani,* CFA, Vice President and Research Analyst, joined Dodge & Cox in 2007 and has been an IEIC member since 2021 and has managed the Portfolio since 2021.

**TAX INFORMATION**

Shares of the Portfolio are offered only for funding variable annuity contracts and variable life insurance policies offered by The Northwestern Mutual Life Insurance Company through separate accounts. Insurance company separate accounts generally do not pay tax on dividends or capital gain distributions. Investors in variable annuity contracts and variable life insurance policies should refer to the prospectuses for the variable products for a discussion of the tax considerations that affect the insurance company and its separate accounts and the tax consequences to investors of owning such products.

**COMPENSATION TO BROKER-DEALERS AND OTHER FINANCIAL INTERMEDIARIES**

Neither the Portfolio nor any related companies pay compensation to broker-dealers or other financial intermediaries for the sale of Portfolio shares or related services. Investors in variable annuity contracts and variable life insurance policies should refer to the prospectuses for the variable products for important information about compensation paid to financial intermediaries for sales of variable annuity contracts and variable life insurance policies.

**NMSF-SP4Northwestern Mutual Series Fund, Inc. Prospectus**

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