# EDGAR Filing Document

**Accession Number:** 0000100334
**File Stem:** 0000100334-25-000077
**Filing Date:** 2025-7
**Character Count:** 21529
**Document Hash:** a30fbee58a4ae67c081f9e7e0bb450f5
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000100334-25-000077.hdr.sgml**: 20250731

**ACCESSION NUMBER**: 0000100334-25-000077

**CONFORMED SUBMISSION TYPE**: 497

**PUBLIC DOCUMENT COUNT**: 20

**FILED AS OF DATE**: 20250731

**DATE AS OF CHANGE**: 20250731

**EFFECTIVENESS DATE**: 20250731

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** AMERICAN CENTURY MUTUAL FUNDS, INC.
- **CENTRAL INDEX KEY:** 0000100334

**ORGANIZATION NAME:**
- **EIN:** 446006315
- **STATE OF INCORPORATION:** MD
- **FISCAL YEAR END:** 1031

**FILING VALUES:**
- **FORM TYPE:** 497
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 002-14213
- **FILM NUMBER:** 251170015

**BUSINESS ADDRESS:**
- **STREET 1:** 4500 MAIN STREET
- **CITY:** KANSAS CITY
- **STATE:** MO
- **ZIP:** 64111
- **BUSINESS PHONE:** 816-531-5575

**MAIL ADDRESS:**
- **STREET 1:** 4500 MAIN STREET
- **CITY:** KANSAS CITY
- **STATE:** MO
- **ZIP:** 64111

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AMERICAN CENTURY MUTUAL FUNDS INC
- **DATE OF NAME CHANGE:** 19970107

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** TWENTIETH CENTURY INVESTORS INC
- **DATE OF NAME CHANGE:** 19920703

## Series and Classes Contracts Data

### SELECT FUND (Series ID: S000006194)

---

|  |  |  |
|:---|:---|:---|
| Class Name     | Ticker Symbol | Class ID   |
| INVESTOR CLASS | TWCIX         | C000017053 |
| A CLASS        | TWCAX         | C000017054 |
| I CLASS        | TWSIX         | C000017055 |
| C CLASS        | ACSLX         | C000017058 |
| R CLASS        | ASERX         | C000017059 |
| R6 CLASS       | ASDEX         | C000131597 |
| R5 CLASS       | ASLGX         | C000189737 |
| Y CLASS        | ASLWX         | C000189738 |
| G Class        | ASLDX         | C000247666 |

---

### ULTRA FUND (Series ID: S000006195)

---

|  |  |  |
|:---|:---|:---|
| Class Name     | Ticker Symbol | Class ID   |
| INVESTOR CLASS | TWCUX         | C000017060 |
| A CLASS        | TWUAX         | C000017061 |
| I CLASS        | TWUIX         | C000017062 |
| C CLASS        | TWCCX         | C000017063 |
| R CLASS        | AULRX         | C000017064 |
| R6 CLASS       | AULDX         | C000131598 |
| R5 CLASS       | AULGX         | C000189739 |
| Y CLASS        | AULYX         | C000189740 |
| G Class        | AULNX         | C000214991 |

---

### GROWTH FUND (Series ID: S000006205)

---

|  |  |  |
|:---|:---|:---|
| Class Name     | Ticker Symbol | Class ID   |
| INVESTOR CLASS | TWCGX         | C000017101 |
| A CLASS        | TCRAX         | C000017102 |
| I CLASS        | TWGIX         | C000017103 |
| R CLASS        | AGWRX         | C000017105 |
| C CLASS        | TWRCX         | C000088050 |
| R6 CLASS       | AGRDX         | C000131599 |
| R5 CLASS       | AGWUX         | C000189743 |
| Y CLASS        | AGYWX         | C000189744 |
| G Class        | ACIHX         | C000236113 |

---

## Series and Classes Contracts Data

### SELECT FUND (Series ID: S000006194)

| Class ID   | Class Name     | Ticker Symbol   |
|:---|:---|:---|
| C000017053 | INVESTOR CLASS | TWCIX           |
| C000017054 | A CLASS        | TWCAX           |
| C000017055 | I CLASS        | TWSIX           |
| C000017058 | C CLASS        | ACSLX           |
| C000017059 | R CLASS        | ASERX           |
| C000131597 | R6 CLASS       | ASDEX           |
| C000189737 | R5 CLASS       | ASLGX           |
| C000189738 | Y CLASS        | ASLWX           |
| C000247666 | G Class        | ASLDX           |

### ULTRA FUND (Series ID: S000006195)

| Class ID   | Class Name     | Ticker Symbol   |
|:---|:---|:---|
| C000017060 | INVESTOR CLASS | TWCUX           |
| C000017061 | A CLASS        | TWUAX           |
| C000017062 | I CLASS        | TWUIX           |
| C000017063 | C CLASS        | TWCCX           |
| C000017064 | R CLASS        | AULRX           |
| C000131598 | R6 CLASS       | AULDX           |
| C000189739 | R5 CLASS       | AULGX           |
| C000189740 | Y CLASS        | AULYX           |
| C000214991 | G Class        | AULNX           |

### GROWTH FUND (Series ID: S000006205)

| Class ID   | Class Name     | Ticker Symbol   |
|:---|:---|:---|
| C000017101 | INVESTOR CLASS | TWCGX           |
| C000017102 | A CLASS        | TCRAX           |
| C000017103 | I CLASS        | TWGIX           |
| C000017105 | R CLASS        | AGWRX           |
| C000088050 | C CLASS        | TWRCX           |
| C000131599 | R6 CLASS       | AGRDX           |
| C000189743 | R5 CLASS       | AGWUX           |
| C000189744 | Y CLASS        | AGYWX           |
| C000236113 | G Class        | ACIHX           |

?xml version='1.0' encoding='ASCII'? ck0000100334-20250731

---

| | |
|:---|:---|
| American Century Mutual Funds, Inc.<br>**Prospectus Supplement**<br>**Growth Fund** | ![newaci_logoblk.jpg](ck0000100334-20250731_g1.jpg) |
| Supplement dated August 1, 2025 ■ Prospectus dated March 1, 2025 | Supplement dated August 1, 2025 ■ Prospectus dated March 1, 2025 |

---

*The following replaces the* Fees and Expenses *tables on page 2 of the prospectus:*

---

| | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | |
|  | *Investor* | *I* | *Y* | *A* | *C* | *R* | *R5* | *R6* | *G* |
| Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) |  |  |  | 5.75% |  |  |  |  |  |
| Maximum Deferred Sales Charge (Load) (as a percentage of the lower of the original offering price or redemption proceeds when redeemed within one year of purchase) |  |  |  | None¹ | 1.00% |  |  |  |  |
| Maximum Annual Account Maintenance Fee (waived for unmatured Giftrust accounts, if eligible investments total at least $25,000 or shareholder has elected electronic delivery) | $25 |  |  |  |  |  |  |  |  |

---

---

| | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | |
|  | *Investor* | *I* | *Y* | *A* | *C* | *R* | *R5* | *R6* | *G* |
| Management Fee | 0.96% | 0.76% | 0.61% | 0.96% | 0.96% | 0.96% | 0.76% | 0.61% | 0.61% |
| Distribution and Service (12b-1) Fees |  |  |  | 0.25% | 1.00% | 0.50% |  |  |  |
| Other Expenses | 0.01% | 0.01% | 0.01% | 0.01% | 0.01% | 0.01% | 0.01% | 0.01% | 0.01% |
| Total Annual Fund Operating Expenses | 0.97% | 0.77% | 0.62% | 1.22% | 1.97% | 1.47% | 0.77% | 0.62% | 0.62% |
| Fee Waiver<sup>2</sup> | 0.13% | 0.13% | 0.13% | 0.13% | 0.13% | 0.13% | 0.13% | 0.13% | 0.61%³ |
| Total Annual Fund Operating Expenses After Fee Waiver | 0.84% | 0.64% | 0.49% | 1.09% | 1.84% | 1.34% | 0.64% | 0.49% | 0.01% |

---

<sup>1&nbsp;&nbsp;&nbsp;&nbsp;</sup>*Purchases of $1 million or more may be subject to a contingent deferred sales charge of 1.00% if the shares are redeemed within one year of the date of the purchase.*

<sup>2&nbsp;&nbsp;&nbsp;&nbsp;</sup>*The advisor has agreed to waive a portion of the fund's management fee such that the management fee does not exceed 0.832% for Investor, A, C and R Classes, 0.632% for I and R5 Classes, and 0.482% for Y and R6 Classes. The advisor expects this waiver arrangement to continue until July 31, 2026 and cannot terminate it prior to such date without the approval of the Board of Directors.*

<sup>3&nbsp;&nbsp;&nbsp;&nbsp;</sup>*The advisor has agreed to waive the G Class's management fee in its entirety. The advisor expects this fee waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Directors.*

------

*The following replaces the* Example *section on pages 2 and 3 of the prospectus:*

The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods and that you earn a 5% return each year. The example also assumes that the fund's operating expenses remain the same except, that it reflects the rate and duration of any fee waivers noted in the table above. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | *1 year* | *3 years* | *5 years* | *10 years* |
| Investor Class | $86 | $297 | $524 | $1178 |
| I Class | $66 | $233 | $416 | $942 |
| Y Class | $50 | $186 | $333 | $762 |
| A Class | $680 | $928 | $1196 | $1956 |
| C Class | $187 | $607 | $1051 | $2089 |
| R Class | $137 | $453 | $791 | $1745 |
| R5 Class | $66 | $233 | $416 | $942 |
| R6 Class | $50 | $186 | $333 | $762 |
| G Class | $1 | $3 | $6 | $13 |

---

©2025 American Century Proprietary Holdings, Inc. All rights reserved.CL-SPL-98756 2508

------

---

| | |
|:---|:---|
| American Century Mutual Funds, Inc.<br>**Prospectus Supplement**<br>**Select Fund** | ![newaci_logoblk.jpg](ck0000100334-20250731_g1.jpg) |
| Supplement dated August 1, 2025 ■ Prospectus dated March 1, 2025 | Supplement dated August 1, 2025 ■ Prospectus dated March 1, 2025 |

---

*The following replaces the* Fees and Expenses *tables on page 2 of the prospectus:*

---

| | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | |
|  | *Investor* | *I* | *Y* | *A* | *C* | *R* | *R5* | *R6* | *G* |
| Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) |  |  |  | 5.75% |  |  |  |  |  |
| Maximum Deferred Sales Charge (Load) (as a percentage of the lower of the original offering price or redemption proceeds when redeemed within one year of purchase) |  |  |  | None¹ | 1.00% |  |  |  |  |
| Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $25,000 or shareholder has elected electronic delivery) | $25 |  |  |  |  |  |  |  |  |

---

---

| | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | |
|  | *Investor* | *I* | *Y* | *A* | *C* | *R* | *R5* | *R6* | *G* |
| Management Fee | 0.98% | 0.78% | 0.63% | 0.98% | 0.98% | 0.98% | 0.78% | 0.63% | 0.63% |
| Distribution and Service (12b-1) Fees |  |  |  | 0.25% | 1.00% | 0.50% |  |  |  |
| Other Expenses | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% |
| Total Annual Fund Operating Expenses | 0.98% | 0.78% | 0.63% | 1.23% | 1.98% | 1.48% | 0.78% | 0.63% | 0.63% |
| Fee Waiver<sup>2</sup> | 0.08% | 0.08% | 0.08% | 0.08% | 0.08% | 0.08% | 0.08% | 0.08% | 0.63%³ |
| Total Annual Fund Operating Expenses After Fee Waiver | 0.90% | 0.70% | 0.55% | 1.15% | 1.90% | 1.40% | 0.70% | 0.55% | 0.00% |

---

<sup>1&nbsp;&nbsp;&nbsp;&nbsp;</sup>*Purchases of $1 million or more may be subject to a contingent deferred sales charge of 1.00% if the shares are redeemed within one year of the date of the purchase.*

<sup>2&nbsp;&nbsp;&nbsp;&nbsp;</sup>*The advisor has agreed to waive a portion of the fund's management fee such that the management fee does not exceed 0.900% for Investor, A, C and R Classes, 0.700% for I and R5 Classes, and 0.550% for Y and R6 Classes. The advisor expects this waiver arrangement to continue until July 31, 2026 and cannot terminate it prior to such date without the approval of the Board of Directors.*

<sup>3&nbsp;&nbsp;&nbsp;&nbsp;</sup>*The advisor has agreed to waive the G Class's management fee in its entirety. The advisor expects this fee waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Directors.* 

------

*The following replaces the* Example *section on page 3 of the prospectus:*

The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods and that you earn a 5% return each year. The example also assumes that the fund's operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | *1 year* | *3 years* | *5 years* | *10 years* |
| Investor Class | $92 | $305 | $535 | $1194 |
| I Class | $72 | $242 | $426 | $959 |
| Y Class | $56 | $194 | $344 | $779 |
| A Class | $686 | $936 | $1205 | $1971 |
| C Class | $193 | $615 | $1061 | $2104 |
| R Class | $143 | $461 | $801 | $1760 |
| R5 Class | $72 | $242 | $426 | $959 |
| R6 Class | $56 | $194 | $344 | $779 |
| G Class | $0 | $0 | $0 | $0 |

---

©2025 American Century Proprietary Holdings, Inc. All rights reserved.CL-SPL-98757 2508

------

---

| | |
|:---|:---|
| American Century Mutual Funds, Inc.<br>**Prospectus Supplement**<br>**Ultra Fund** | ![newaci_logoblk.jpg](ck0000100334-20250731_g1.jpg) |
| Supplement dated August 1, 2025 ■ Prospectus dated March 1, 2025 | Supplement dated August 1, 2025 ■ Prospectus dated March 1, 2025 |

---

*The following replaces the* Fees and Expenses *tables on page 2 of the prospectus:*

---

| | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | **Shareholder Fees** (fees paid directly from your investment) | |
|  | *Investor* | *I* | *Y* | *A* | *C* | *R* | *R5* | *R6* | *G* |
| Maximum Sales Charge (Load) Imposed on Purchases (as a percentage of offering price) |  |  |  | 5.75% |  |  |  |  |  |
| Maximum Deferred Sales Charge (Load) (as a percentage of the lower of the original offering price or redemption proceeds when redeemed within one year of purchase) |  |  |  | None¹ | 1.00% |  |  |  |  |
| Maximum Annual Account Maintenance Fee (waived if eligible investments total at least $25,000 or shareholder has elected electronic delivery) | $25 |  |  |  |  |  |  |  |  |

---

---

| | | | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|:---|:---|
| **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | **Annual Fund Operating Expenses** (expenses that you pay each year as a percentage of the value of your investment) | |
|  | *Investor* | *I* | *Y* | *A* | *C* | *R* | *R5* | *R6* | *G* |
| Management Fee | 0.92% | 0.72% | 0.57% | 0.92% | 0.92% | 0.92% | 0.72% | 0.57% | 0.57% |
| Distribution and Service (12b-1) Fees |  |  |  | 0.25% | 1.00% | 0.50% |  |  |  |
| Other Expenses | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% | 0.00% |
| Total Annual Fund Operating Expenses | 0.92% | 0.72% | 0.57% | 1.17% | 1.92% | 1.42% | 0.72% | 0.57% | 0.57% |
| Fee Waiver<sup>2</sup>  | 0.05% | 0.05% | 0.05% | 0.05% | 0.05% | 0.05% | 0.05% | 0.05% | 0.57%³ |
| Total Annual Fund Operating Expenses After Fee Waiver | 0.87% | 0.67% | 0.52% | 1.12% | 1.87% | 1.37% | 0.67% | 0.52% | 0.00% |

---

<sup>1&nbsp;&nbsp;&nbsp;&nbsp;</sup>*Purchases of $1 million or more may be subject to a contingent deferred sales charge of 1.00% if the shares are redeemed within one year of the date of the purchase.*

<sup>2&nbsp;&nbsp;&nbsp;&nbsp;</sup>*The advisor has agreed to waive a portion of the fund's management fee such that the management fee does not exceed 0.865% for Investor, A, C and R Classes, 0.665% for I and R5 Classes, and 0.515% for Y and R6 Classes. The advisor expects this waiver arrangement to continue until July 31, 2026 and cannot terminate it prior to such date without the approval of the Board of Directors.*

<sup>3&nbsp;&nbsp;&nbsp;&nbsp;</sup>*The advisor has agreed to waive the G Class's management fee in its entirety. The advisor expects this waiver to remain in effect permanently and cannot terminate it without the approval of the Board of Directors.* 

------

*The following replaces the* Example *section on pages 2 and 3 of the prospectus:*

The example below is intended to help you compare the costs of investing in the fund with the costs of investing in other mutual funds. The example assumes that you invest $10,000 in the fund for the time periods indicated and then redeem all of your shares at the end of those periods and that you earn a 5% return each year. The example also assumes that the fund's operating expenses remain the same, except that it reflects the rate and duration of any fee waivers noted in the table above. Although your actual costs may be higher or lower, based on these assumptions your costs would be:

---

| | | | | |
|:---|:---|:---|:---|:---|
|  | *1 year* | *3 years* | *5 years* | *10 years* |
| Investor Class | $89 | $289 | $505 | $1127 |
| I Class | $69 | $226 | $396 | $890 |
| Y Class | $53 | $178 | $314 | $709 |
| A Class | $683 | $921 | $1178 | $1909 |
| C Class | $190 | $599 | $1033 | $2042 |
| R Class | $140 | $445 | $772 | $1697 |
| R5 Class | $69 | $226 | $396 | $890 |
| R6 Class | $53 | $178 | $314 | $709 |
| G Class | $0 | $0 | $0 | $0 |

---

©2025 American Century Proprietary Holdings, Inc. All rights reserved.CL-SPL-98758 2508