MASON STREET ADVISORS, LLC

720 East Wisconsin Avenue

Milwaukee, WI 53202

February 26, 2026

Paul A. Mikelson, President

Northwestern Mutual Series Fund, Inc.

720 East Wisconsin Avenue

Milwaukee, Wisconsin 53202

Re: | Agreement to Waive Mason Street Advisors, LLC Investment Advisory Fees Relating to Certain Portfolios of Northwestern Mutual Series Fund, Inc.

Dear Mr. Mikelson:

This letter constitutes an agreement between Mason Street Advisors, LLC (“MSA”) and Northwestern Mutual Series Fund, Inc. (“Series Fund”) regarding the investment advisory fee for each of the Series Fund portfolios set forth below (each, a “Portfolio”). MSA agrees to waive, from May 1, 2026 through April 30, 2027 (unless renewed by the parties hereto), its investment advisory fee applicable to each Portfolio such that the investment advisory fee is as follows:

Growth Stock Portfolio

Assets |  | Fee |  |
Up to $50 million |  | 0.60%
$50 million - $100 million |  | 0.50%
$100 million - $1 billion |  | 0.40%
Excess over $1 billion |  | 0.38%

Focused Appreciation Portfolio

Assets |  | Fee |  |
Up to $100 million |  | 0.62%
$100 million - $1 billion |  | 0.57%
Excess over $1 billion |  | 0.54%

Large Cap Core Stock Portfolio

Assets |  | Fee |  |
Up to $50 million |  | 0.60%
$50 million - $100 million |  | 0.50%
$100 million - $500 million |  | 0.40%
Excess over $500 million |  | 0.37%

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Large Cap Blend Portfolio

Assets |  | Fee |  |
Up to $150 million |  | 0.65%
$150 million - $300 million |  | 0.55%
$300 million - $500 million |  | 0.55%
Excess over $500 million |  | 0.52%

Index 500 Stock Portfolio

Assets |  | Fee |  |
Up to $2 billion |  | 0.20%
Excess over $2 billion |  | 0.18%

Large Company Value Portfolio

Assets |  | Fee |  |
Up to $100 million |  | 0.67%
$100 million - $250 million |  | 0.62%
$250 million - $500 million |  | 0.59%
Excess over $500 million |  | 0.57%

Domestic Equity Portfolio

Assets |  | Fee |  |
Up to $100 million |  | 0.65%
$100 million - $250 million |  | 0.55%
$250 million - $500 million |  | 0.50%
$500 million - $1 billion |  | 0.43%
Excess over $1 billion |  | 0.41%

Equity Income Portfolio

Assets |  | Fee |  |
Up to $500 million |  | 0.56%
$500 million - $1.5 billion |  | 0.53%
Excess over $1.5 billion |  | 0.52%

Mid Cap Growth Stock Portfolio

Assets |  | Fee |  |
Up to $50 million |  | 0.80%
$50 million - $100 million |  | 0.65%
$100 million - $1 billion |  | 0.50%
Excess over $1 billion |  | 0.49%

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Index 400 Stock Portfolio

Assets |  | Fee |  |
Up to $500 million |  | 0.25%
Excess over $500 million |  | 0.20%

Mid Cap Value Portfolio

Assets |  | Fee |  |
Up to $150 million |  | 0.78%
$150 million - $500 million |  | 0.66%
Excess over $500 million |  | 0.63%

Small Cap Value Portfolio

Assets |  | Fee |  |
Up to $500 million |  | 0.85%
Excess over $500 million |  | 0.80%

International Growth

Assets |  | Fee |  |
Up to $100 million |  | 0.75%
$100 million - $250 million |  | 0.65%
$250 million - $1 billion |  | 0.55%
Excess over $1 billion |  | 0.54%

Research International Core

Assets |  | Fee |  |
Up to $1.5 billion |  | 0.54%
Excess over $1.5 billion |  | 0.52%

International Equity Portfolio

Assets |  | Fee |  |
Up to $50 million |  | 0.85%
$50 million - $2 billion |  | 0.65%
Excess over $2 billion |  | 0.63%

Emerging Markets Equity Portfolio

Assets |  | Fee |  |
Up to $250 million |  | 0.84%
$250 million - $500 million |  | 0.76%
Excess over $500 million |  | 0.68%

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Government Money Market Portfolio

Assets |  | Fee |  |
Up to $500 million |  | 0.30%
$500 million - $1 billion |  | 0.29%
Excess over $1 billion |  | 0.28%

Short-Term Bond Portfolio

Assets |  | Fee |  |
Up to $100 million |  | 0.35%
$100 million - $250 million |  | 0.33%
$250 million - $500 million |  | 0.30%
Excess over $500 million |  | 0.28%

Select Bond Portfolio

Assets |  | Fee |  |
Up to $2 billion |  | 0.30%
Excess over $2 billion |  | 0.28%

Long-Term U.S. Government Bond Portfolio

Assets |  | Fee |  |
Up to $100 million |  | 0.555%
$100 million - $250 million |  | 0.515%
$250 million - $500 million |  | 0.495%
Excess over $500 million |  | 0.445%

Inflation Managed Portfolio

Assets |  | Fee |  |
Up to $100 million |  | 0.42%
$100 million - $250 million |  | 0.40%
Excess over $250 million |  | 0.38%

High Yield Bond Portfolio

Assets |  | Fee |  |
Up to $50 million |  | 0.60%
$50 million - $100 million |  | 0.50%
$100 million - $1.0 billion |  | 0.40%
Excess over $1.0 billion |  | 0.30%

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Multi-Sector Bond Portfolio

Assets |  | Fee |  |
Up to $100 million |  | 0.73%
$100 million - $250 million |  | 0.72%
$250 million - $500 million |  | 0.69%
Excess over $500 million |  | 0.64%

Active/Passive Balanced Portfolio (“Balanced Portfolio” until 6/30/2025)

All assets |  | 0.10%

Active/Passive Moderate Portfolio (“Asset Allocation Portfolio” until 6/30/2025)

All assets |  | 0.10%

Active/Passive Conservative Portfolio

All assets |  | 0.10%

Active/Passive Aggressive Portfolio

All assets |  | 0.10%

Active/Passive Very Aggressive Portfolio

All assets |  | 0.10%

This letter supplants and supersedes any prior agreements between the parties relating to the same investment advisory fee matters addressed herein.

Very truly yours,
MASON STREET ADVISORS, LLC
By: |  | /s/ Brent G. Schutte

Name: |  | Brent G. Schutte
Title: |  | Vice President, Chief Investment Officer

Agreed to and accepted:

NORTHWESTERN MUTUAL SERIES FUND, INC.

By: |  | /s/ Paul A. Mikelson

Name: |  | Paul A. Mikelson
Title: |  | President

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