Document


American Century Mutual Funds, Inc. Statement of Additional Information Supplement
Supplement dated August 1, 2026 n Statement of Additional Information dated March 1, 2026

The following replaces the entries for Growth Fund and Ultra Fund in the management fee table under Investment Advisor on pages 39-41 of the Statement of Additional Information:


Fund	Class	Percentage of Strategy Assets
Growth	Investor, A, C, and R	0.830% of the first $25 billion 0.800% over $25 billion
	I and R5	0.630% of the first $25 billion 0.600% over $25 billion
	Y, R6 and G	0.480% of the first $25 billion 0.450% over $25 billion
Ultra	Investor, A, C and R	0.920% of the first $15 billion 0.880% of the next $10 billion 0.800% over $25 billion
	I and R5	0.720% of the first $15 billion 0.680% of the next $10 billion 0.600% over $25 billion
	Y, R6 and G	0.570% of the first $15 billion 0.530% of the next $10 billion 0.450% over $25 billion

Joseph Reiland, CFA, Vice President and Senior Portfolio Manager, has announced his plans to retire. As a result, he no longer serves as a portfolio manager for the Balanced Fund, Growth Fund, and Large Cap Equity Fund effective July 31, 2026.

Justin Brown, CFA, Vice President and Portfolio Manager, no longer serves as portfolio manager for the Balanced Fund, Growth Fund, and Large Cap Equity Fund effective July 31, 2026.

Accounts Managed

Registered Investment

Companies (e.g., American Century Investments funds and American Century Investments- subadvised funds)

Other Pooled Investment Vehicles (e.g., commingled

trusts and 529 education savings plans)

Other Accounts (e.g., separate accounts and

corporate accounts

including incubation

strategies and

corporate money)

Scott Marolf1

Number of Accounts

Assets

$18.7 billion2

$582.0 million

$658.7 million

The following entries are added for DJ Cross, Radu Gabudean, Vidya Rajappa, Richard Weiss, and Scott Wilson in the Accounts Managed table on pages 42-43 of the Statement of Additional Information:

Accounts Managed

Registered Investment

Companies (e.g., American Century Investments funds and American Century Investments- subadvised funds)

Other Pooled Investment Vehicles (e.g., commingled

trusts and 529 education savings plans)

Other Accounts (e.g., separate accounts and

corporate accounts

including incubation

strategies and

corporate money)

DJ Cross1

Number of Accounts

Assets

$18.7 billion2

$582.0 million

$658.7 million

Radu Gabudean1

Number of Accounts

Assets

$18.1 billion3

$8.8 billion

$283.0 million

Vidya Rajappa1

Number of Accounts

Assets

$18.1 billion3

$8.8 billion

$283.0 million

Richard Weiss1

Number of Accounts

Assets

$18.1 billion3

$8.8 billion

$283.0 million

Scott Wilson1

Number of Accounts

Assets

$17.9 billion3

$8.8 billion

$283.0 million

Ranges: A – none; B – $1-$10,000; C – $10,001-$50,000; D – $50,001-$100,000; E – $100,001-$500,000; F – $500,001-$1,000,000; G – More than $1,000,000.

The following entries for DJ Cross, Radu Gabudean, Vidya Rajappa, Richard Weiss, and Scott Wilson are added in the Ownership of Securities table on page 46 of the Statement of Additional Information:


Ownership of Securities
			Aggregate Dollar Range of Securities in Fund
Balanced
Radu Gabudean1			A
Vidya Rajappa1			A
Richard Weiss1			A
Scott Wilson1			A
Growth
DJ Cross1			F
Large Cap Equity
DJ Cross1			B

Ranges: A – none; B – $1-$10,000; C – $10,001-$50,000; D – $50,001-$100,000; E – $100,001-$500,000; F – $500,001-$1,000,000; G – More than $1,000,000.