# EDGAR Filing Document

**Accession Number:** 0002127306
**File Stem:** 0001104659-26-040979
**Filing Date:** 2026-4
**Character Count:** 41687
**Document Hash:** 420cbd4242344e690d486c09439536ce
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-26-040979.hdr.sgml**: 20260408

**ACCESSION NUMBER**: 0001104659-26-040979

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D

**PUBLIC DOCUMENT COUNT**: 3

**FILED AS OF DATE**: 20260408

**DATE AS OF CHANGE**: 20260408

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Blue Bird Corp
- **CENTRAL INDEX KEY:** 0001589526
- **STANDARD INDUSTRIAL CLASSIFICATION:** TRUCK & BUS BODIES [3713]
- **ORGANIZATION NAME:** 04 Manufacturing
- **EIN:** 463891989
- **FISCAL YEAR END:** 1003

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-87838
- **FILM NUMBER:** 26848833

**BUSINESS ADDRESS:**
- **STREET 1:** 3920 ARKWRIGHT ROAD
- **STREET 2:** SUITE 200
- **CITY:** MACON
- **STATE:** GA
- **ZIP:** 31210
- **BUSINESS PHONE:** 478-822-2801

**MAIL ADDRESS:**
- **STREET 1:** 3920 ARKWRIGHT ROAD
- **STREET 2:** SUITE 200
- **CITY:** MACON
- **STATE:** GA
- **ZIP:** 31210

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Hennessy Capital Acquisition Corp.
- **DATE OF NAME CHANGE:** 20131017
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Groupe Autobus Girardin Ltee
- **CENTRAL INDEX KEY:** 0002127306

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** Z4
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D

**BUSINESS ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** 4000 GIRARDIN
- **CITY:** DRUMMONDVILLE
- **PROVINCE COUNTRY:** A8
- **ZIP:** J2E 0A1
- **BUSINESS PHONE:** 888-697-3222

**MAIL ADDRESS:**
- **ADDRESS IS A NON US LOCATION:** YES
- **STREET 1:** 4000 GIRARDIN
- **CITY:** DRUMMONDVILLE
- **PROVINCE COUNTRY:** A8
- **ZIP:** J2E 0A1

## Ex-1

**Exhibit 1**

**JOINT FILING AGREEMENT**

**Pursuant to Rule 13d-1(k)**

The undersigned acknowledge and agree that the foregoing statement on Schedule 13D is filed on behalf of each of the undersigned and that all subsequent amendments to this statement on Schedule 13D shall be filed on behalf of each of the undersigned without the necessity of filing additional joint filing agreements. The undersigned acknowledge that each shall be responsible for the timely filing of such amendments, and for the completeness and accuracy of the information concerning him or it contained herein and therein, but shall not be responsible for the completeness and accuracy of the information concerning the others, except to the extent that he or it knows or has reason to believe that such information is inaccurate.

Dated: April 8, 2026

---

| | |
|:---|:---|
| **GROUPE AUTOBUS GIRARDIN LTÉE** | **GROUPE AUTOBUS GIRARDIN LTÉE** |
| By: | /s/ Steve Girardin |
|  | Steve Girardin, Authorized Signatory |
| **STEVE GIRARDIN** | **STEVE GIRARDIN** |
| By: | /s/ Steve Girardin |
|  | Steve Girardin |
| **DAVE GIRARDIN** | **DAVE GIRARDIN** |
| By: | /s/ Steve Girardin |
|  | Steve Girardin, Attorney-in-Fact for Dave Girardin |
| **ANDRÉ GIRARDIN** | **ANDRÉ GIRARDIN** |
| By: | /s/ Steve Girardin |
|  | Steve Girardin, Attorney-in-Fact for André Girardin |

---

## Ex-5

**Exhibit 5**

**Power of Attorney**

Know all by these presents, that the undersigned hereby makes, constitutes and appoints each of Dave Girardin and Maxime Chamberland, or either of them acting singly, and with full power of substitution and re-substitution, the undersigned's true and lawful attorney-in-fact (each of such persons and their substitutes being referred to herein as the "Attorney-in-Fact"), with full power to act for the undersigned and in the undersigned's name, place and stead, in any and all capacities, to:

&nbsp;&nbsp;&nbsp;&nbsp;1. Prepare, execute, and submit to the Securities and Exchange Commission ("SEC") a Form ID, for any filings relating to Groupe Autobus Girardin Ltée (the "Company"), including amendments thereto, and any other documents necessary or appropriate to obtain codes and passwords enabling the undersigned to make electronic filings with the SEC of reports required or considered by the Attorney-in-Fact to be advisable under Section 13 or Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or any rule or regulation of the SEC;

&nbsp;&nbsp;&nbsp;&nbsp;2. Prepare, execute and submit to the SEC, the Company, and/or any national securities exchange on which the Company's securities are listed any and all reports (including any amendments thereto) the undersigned is required to file with the SEC, or which the Attorney-in-Fact considers it advisable to file with the SEC, under Section 13 or Section 16 of the Exchange Act or any rule or regulation thereunder, or under Rule 144 under the Securities Act of 1933 ("Rule 144"), with respect to the any security of the Company, including Forms 3, 4 and 5, Schedules 13D and 13G, and Forms 144; and

&nbsp;&nbsp;&nbsp;&nbsp;3. Obtain, as the undersigned's representative and on the undersigned's behalf, information regarding transactions in the Company's equity securities from any third party, including the Company and any brokers, dealers, employee benefit plan administrators and trustees, and the undersigned hereby authorizes any such third party to release any such information to the Attorney-in-Fact.

The undersigned acknowledges that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a) This Power of Attorney authorizes, but does not require, the Attorney-in-Fact to act in his or her discretion on information provided to such Attorney-in-Fact without independent verification of such information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b) Any documents prepared or executed by the Attorney-in-Fact on behalf of the undersigned pursuant to this Power of Attorney will be in such form and will contain such information as the Attorney-in-Fact, in his or her discretion, deems necessary or desirable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c) Neither the Company nor the Attorney-in-Fact assumes any liability for the undersigned's responsibility to comply with the requirements of Section 13 or Section 16 of the Exchange Act or Rule 144, any liability of the undersigned for any failure to comply with such requirements, or any liability of the undersigned for disgorgement of profits under Section 16(b) of the Exchange Act; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d) This Power of Attorney does not relieve the undersigned from responsibility for compliance with the undersigned's obligations under Section 13 or Section 16 of the Exchange Act, including, without limitation, the reporting requirements under Section 13 or Section 16 of the Exchange Act.

The undersigned hereby grants to the Attorney-in-Fact full power and authority to do and perform each and every act and thing requisite, necessary or advisable to be done in connection with the foregoing, as fully, to all intents and purposes, as the undersigned might or could do in person, hereby ratifying and confirming all that the Attorney-in-Fact, or his or her substitute or substitutes, shall lawfully do or cause to be done by authority of this Power of Attorney.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 4 or 5 or Schedules 13D or 13G or Forms 144 with respect to the undersigned's holdings of and transactions in securities of the Company, unless earlier revoked by the undersigned in a signed writing delivered to the Attorney-in-Fact. This Power of Attorney revokes all previous powers of attorney with respect to the subject matter of this Power of Attorney.

IN WITNESS WHEREOF, the undersigned has executed this Power of Attorney as of April 8, 2026.

---

| |
|:---|
| /s/ Steve Girardin |
| Steve Girardin |

---

**Power of Attorney**

Know all by these presents, that the undersigned hereby makes, constitutes and appoints each of Steve Girardin, Dave Girardin and Maxime Chamberland, or either of them acting singly, and with full power of substitution and re-substitution, the undersigned's true and lawful attorney-in-fact (each of such persons and their substitutes being referred to herein as the "Attorney-in-Fact"), with full power to act for the undersigned and in the undersigned's name, place and stead, in any and all capacities, to:

&nbsp;&nbsp;&nbsp;&nbsp;1. Prepare, execute, and submit to the Securities and Exchange Commission ("SEC") a Form ID, for any filings relating to Groupe Autobus Girardin Ltée (the "Company"), including amendments thereto, and any other documents necessary or appropriate to obtain codes and passwords enabling the undersigned to make electronic filings with the SEC of reports required or considered by the Attorney-in-Fact to be advisable under Section 13 or Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or any rule or regulation of the SEC;

&nbsp;&nbsp;&nbsp;&nbsp;2. Prepare, execute and submit to the SEC, the Company, and/or any national securities exchange on which the Company's securities are listed any and all reports (including any amendments thereto) the undersigned is required to file with the SEC, or which the Attorney-in-Fact considers it advisable to file with the SEC, under Section 13 or Section 16 of the Exchange Act or any rule or regulation thereunder, or under Rule 144 under the Securities Act of 1933 ("Rule 144"), with respect to the any security of the Company, including Forms 3, 4 and 5, Schedules 13D and 13G, and Forms 144; and

&nbsp;&nbsp;&nbsp;&nbsp;3. Obtain, as the undersigned's representative and on the undersigned's behalf, information regarding transactions in the Company's equity securities from any third party, including the Company and any brokers, dealers, employee benefit plan administrators and trustees, and the undersigned hereby authorizes any such third party to release any such information to the Attorney-in-Fact.

The undersigned acknowledges that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a) This Power of Attorney authorizes, but does not require, the Attorney-in-Fact to act in his or her discretion on information provided to such Attorney-in-Fact without independent verification of such information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b) Any documents prepared or executed by the Attorney-in-Fact on behalf of the undersigned pursuant to this Power of Attorney will be in such form and will contain such information as the Attorney-in-Fact, in his or her discretion, deems necessary or desirable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c) Neither the Company nor the Attorney-in-Fact assumes any liability for the undersigned's responsibility to comply with the requirements of Section 13 or Section 16 of the Exchange Act or Rule 144, any liability of the undersigned for any failure to comply with such requirements, or any liability of the undersigned for disgorgement of profits under Section 16(b) of the Exchange Act; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d) This Power of Attorney does not relieve the undersigned from responsibility for compliance with the undersigned's obligations under Section 13 or Section 16 of the Exchange Act, including, without limitation, the reporting requirements under Section 13 or Section 16 of the Exchange Act.

The undersigned hereby grants to the Attorney-in-Fact full power and authority to do and perform each and every act and thing requisite, necessary or advisable to be done in connection with the foregoing, as fully, to all intents and purposes, as the undersigned might or could do in person, hereby ratifying and confirming all that the Attorney-in-Fact, or his or her substitute or substitutes, shall lawfully do or cause to be done by authority of this Power of Attorney.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 4 or 5 or Schedules 13D or 13G or Forms 144 with respect to the undersigned's holdings of and transactions in securities of the Company, unless earlier revoked by the undersigned in a signed writing delivered to the Attorney-in-Fact. This Power of Attorney revokes all previous powers of attorney with respect to the subject matter of this Power of Attorney.

IN WITNESS WHEREOF, the undersigned has executed this Power of Attorney as of April 8, 2026.

---

| |
|:---|
| /s/ André Girardin |
| André Girardin |

---

**Power of Attorney**

Know all by these presents, that the undersigned hereby makes, constitutes and appoints each of Steve Girardin and Maxime Chamberland, or either of them acting singly, and with full power of substitution and re-substitution, the undersigned's true and lawful attorney-in-fact (each of such persons and their substitutes being referred to herein as the "Attorney-in-Fact"), with full power to act for the undersigned and in the undersigned's name, place and stead, in any and all capacities, to:

&nbsp;&nbsp;&nbsp;&nbsp;1. Prepare, execute, and submit to the Securities and Exchange Commission ("SEC") a Form ID, for any filings relating to Groupe Autobus Girardin Ltée (the "Company"), including amendments thereto, and any other documents necessary or appropriate to obtain codes and passwords enabling the undersigned to make electronic filings with the SEC of reports required or considered by the Attorney-in-Fact to be advisable under Section 13 or Section 16 of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), or any rule or regulation of the SEC;

&nbsp;&nbsp;&nbsp;&nbsp;2. Prepare, execute and submit to the SEC, the Company, and/or any national securities exchange on which the Company's securities are listed any and all reports (including any amendments thereto) the undersigned is required to file with the SEC, or which the Attorney-in-Fact considers it advisable to file with the SEC, under Section 13 or Section 16 of the Exchange Act or any rule or regulation thereunder, or under Rule 144 under the Securities Act of 1933 ("Rule 144"), with respect to the any security of the Company, including Forms 3, 4 and 5, Schedules 13D and 13G, and Forms 144; and

&nbsp;&nbsp;&nbsp;&nbsp;3. Obtain, as the undersigned's representative and on the undersigned's behalf, information regarding transactions in the Company's equity securities from any third party, including the Company and any brokers, dealers, employee benefit plan administrators and trustees, and the undersigned hereby authorizes any such third party to release any such information to the Attorney-in-Fact.

The undersigned acknowledges that:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;a) This Power of Attorney authorizes, but does not require, the Attorney-in-Fact to act in his or her discretion on information provided to such Attorney-in-Fact without independent verification of such information;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;b) Any documents prepared or executed by the Attorney-in-Fact on behalf of the undersigned pursuant to this Power of Attorney will be in such form and will contain such information as the Attorney-in-Fact, in his or her discretion, deems necessary or desirable;

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;c) Neither the Company nor the Attorney-in-Fact assumes any liability for the undersigned's responsibility to comply with the requirements of Section 13 or Section 16 of the Exchange Act or Rule 144, any liability of the undersigned for any failure to comply with such requirements, or any liability of the undersigned for disgorgement of profits under Section 16(b) of the Exchange Act; and

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;d) This Power of Attorney does not relieve the undersigned from responsibility for compliance with the undersigned's obligations under Section 13 or Section 16 of the Exchange Act, including, without limitation, the reporting requirements under Section 13 or Section 16 of the Exchange Act.

The undersigned hereby grants to the Attorney-in-Fact full power and authority to do and perform each and every act and thing requisite, necessary or advisable to be done in connection with the foregoing, as fully, to all intents and purposes, as the undersigned might or could do in person, hereby ratifying and confirming all that the Attorney-in-Fact, or his or her substitute or substitutes, shall lawfully do or cause to be done by authority of this Power of Attorney.

This Power of Attorney shall remain in full force and effect until the undersigned is no longer required to file Forms 4 or 5 or Schedules 13D or 13G or Forms 144 with respect to the undersigned's holdings of and transactions in securities of the Company, unless earlier revoked by the undersigned in a signed writing delivered to the Attorney-in-Fact. This Power of Attorney revokes all previous powers of attorney with respect to the subject matter of this Power of Attorney.

IN WITNESS WHEREOF, the undersigned has executed this Power of Attorney as of April 8, 2026.

---

| |
|:---|
| /s/ Dave Girardin |
| Dave Girardin |

---

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**Blue Bird Corp**

*(Name of Issuer)*

**Common Stock, $0.0001 par value**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Groupe Autobus Girardin Ltee**<br>4000 Girardin Street<br>Drummondville<br>Quebec A8 J2E 0A1<br>888-697-3222

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**04/01/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Groupe Autobus Girardin Ltee** | Name of reporting person<br>**Groupe Autobus Girardin Ltee** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**QUEBEC** | Citizenship or place of organization<br>**QUEBEC** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**2702180.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**2702180.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2702180.00** | Aggregate amount beneficially owned by each reporting person<br>**2702180.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**7.88%** | Percent of class represented by amount in Row (11)<br>**7.88%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** (1) Represents shares of common stock, par value $0.0001 per share (the "common stock"), of Blue Bird Corporation (the "Issuer") issuable upon the exchange of Class A non-voting exchangeable common shares (the "Exchangeable Shares") of MB Exchangeco Inc., a newly formed subsidiary of the Issuer existing under the law of the Province of Ontario ("MB ExchangeCo"). The Exchangeable Shares are exchangeable at any time at the option of the holder on a one-to-one basis into shares of common stock of the Issuer.

(2) Based on (i) 31,591,902 shares of common stock outstanding as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on February 4, 2026 and (ii) 2,702,180 shares of common stock issuable upon exchange of the Exchangeable Shares held by the Reporting Person.

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Steve Girardin** | Name of reporting person<br>**Steve Girardin** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**QUEBEC** | Citizenship or place of organization<br>**QUEBEC** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**625825.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**625825.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**625825.00** | Aggregate amount beneficially owned by each reporting person<br>**625825.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**1.94%** | Percent of class represented by amount in Row (11)<br>**1.94%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** (1) Represents shares of common stock of the Issuer issuable upon the exchange of Exchangeable Shares of MB ExchangeCo. The Exchangeable Shares are exchangeable at any time at the option of the holder on a one-to-one basis into shares of common stock of the Issuer. The Reporting Person holds 23.16% of the holding company of Groupe Autobus Girardin Ltee ("GAG").

(2) Based on (i) 31,591,902 shares of common stock outstanding as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on February 4, 2026 and (ii) 625,825 shares of common stock issuable upon exchange of the Exchangeable Shares held by the Reporting Person.

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Andre Girardin** | Name of reporting person<br>**Andre Girardin** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**QUEBEC** | Citizenship or place of organization<br>**QUEBEC** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**1450530.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**1450530.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**1450530.00** | Aggregate amount beneficially owned by each reporting person<br>**1450530.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**4.39%** | Percent of class represented by amount in Row (11)<br>**4.39%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** (1) Represents shares of common stock of the Issuer issuable upon the exchange of Exchangeable Shares of MB ExchangeCo. The Exchangeable Shares are exchangeable at any time at the option of the holder on a one-to-one basis into shares of common stock of the Issuer. The Reporting Person holds 53.68% of the holding company of GAG.

(2) Based on (i) 31,591,902 shares of common stock outstanding as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on February 4, 2026 and (ii) 1,450,530 shares of common stock issuable upon exchange of the Exchangeable Shares held by the Reporting Person.

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Dave Girardin** | Name of reporting person<br>**Dave Girardin** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**QUEBEC** | Citizenship or place of organization<br>**QUEBEC** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**625825.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**625825.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**625825.00** | Aggregate amount beneficially owned by each reporting person<br>**625825.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**1.94%** | Percent of class represented by amount in Row (11)<br>**1.94%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** (1) Represents shares of common stock of the Issuer issuable upon the exchange of Exchangeable Shares of MB ExchangeCo. The Exchangeable Shares are exchangeable at any time at the option of the holder on a one-to-one basis into shares of common stock of the Issuer. The Reporting Person holds 23.16% of the holding company of GAG.

(2) Based on (i) 31,591,902 shares of common stock outstanding as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on February 4, 2026 and (ii) 625,825 shares of Common Stock issuable upon exchange of the Exchangeable Shares held by the Reporting Person.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock, $0.0001 par value

**(b) Name of Issuer:**
Blue Bird Corp

**(c) Address of Issuer's Principal Executive Offices:**
3920 ARKWRIGHT ROAD, SUITE 200, Macon, GA, 31210

**Item 4. Purpose of Transaction**

Share Purchase Agreement

On February 15, 2026, the Issuer and its wholly owned subsidiary, Blue Bird Body Company, a Georgia corporation (collectively, "Blue Bird"), MB Callco Inc., an Ontario corporation ("MB Callco") and MB Exchangeco Inc., an Ontario corporation ("MB ExchangeCo") entered into a Share Purchase Agreement (the "Purchase Agreement"), with the AG 2014 Trust ("AG Trust"), the SG One 2014 Trust ("SG Trust"), and the DG One 2014 Trust ("DG Trust" and collectively with AG Trust and SG Trust, the "Trusts"), GAG, Girardin Minibus JV 2 Inc., a corporation existing under the laws of the Province of Quebec (the "MB US Seller" and together with the Trusts and GAG, the "Sellers" and each, a "Seller"), to acquire 100% of the issued and outstanding equity securities of Girardin Minibus JV Inc., a corporation existing under the laws of the Province of Quebec ("MB Canada Target") and 100% of the issued and outstanding equity securities of Girardin Minibus JV 2 USA Inc., a Delaware corporation ("MB US Target", together with MB Canada Target, the "Micro Bird Targets" and each, a "Target"). Each of the Micro Bird Targets owns fifty percent of the outstanding shares of Micro Bird Holdings, Inc. ("Micro Bird Canada") and Micro Bird USA Holding LLC ("Micro Bird US"), respectively.

The closing of the transactions contemplated by the Purchase Agreement occurred on April 1, 2026 (the "Closing Date"). The aggregate purchase price was $201,787,194 (the "Purchase Price").
Under the terms of the Purchase Agreement, the Purchase Price was paid as follows: (i) 30% of the Purchase Price was paid as cash at closing and (ii) 70% of the Purchase Price was paid through the issuance at closing of a combination of (a) 2,702,180 non-voting exchangeable shares (the "Exchangeable Shares") in the capital of MB ExchangeCo, which are exchangeable at the option of the holder on a one-to-one basis into shares of Issuer common stock, and (b) one share of preferred stock of the Issuer with voting rights equivalent to Issuer common stock equal to the number of Exchangeable Shares outstanding at any time (the "Special Voting Preferred Stock"). The Exchangeable Shares and one share of Special Voting Preferred Stock of the Issuer were issued to GAG on the Closing Date. The issuance of Exchangeable Shares was intended to minimize certain adverse Canadian tax consequences for certain of the Sellers.

The Exchangeable Shares are not transferable without the Issuer's consent. In addition, the Exchangeable Shares and any shares of Issuer common stock issued upon the exchange of the Exchangeable Shares will be subject to a contractual lock-up as follows: no transfers of the shares may occur until October 1, 2026, six months following the Closing Date. Thereafter, (i) 17.9% of the shares will be released from lock-up on October 1, 2026, (ii) an additional 17.9% of the shares will be released from lock-up on April 1, 2027, (iii) an additional 17.9% of the shares will be released from lock-up on October 1, 2027, (iv) an additional 27.8% of the shares will be released from lock-up on April 1, 2028, and (v) the remaining shares will be released from lock-up on April 1, 2029.

The issuance of the Exchangeable Shares was not registered under the Securities Act of 1933, as amended, or any U.S. state securities laws, in reliance on an exemption from such registration requirements. The Issuer has agreed to file with the U.S. Securities and Exchange Commission a registration statement covering the resale of the Issuer common stock issued upon the exchange of the Exchangeable Shares, use commercially reasonable efforts to cause the registration statement to become effective prior to the expiration of the contractual restrictions described above, and to generally cause the registration statement to remain effective while the Exchangeable Shares remain outstanding.

The Exchangeable Shares issued by MB ExchangeCo have no rights with respect to MB ExchangeCo, other than the right to exchange such Exchangeable Shares for shares of Issuer common stock. This right requires MB ExchangeCo to redeem Exchangeable Shares upon the request of the holder for a redemption price equal to one share of Issuer common stock for each Exchangeable Share redeemed, plus any unpaid dividends.

The Reporting Persons have filed the Purchase Agreement as Exhibit 2 to this Schedule 13D, which is incorporated herein by reference. The description of the Purchase Agreement set forth above does not purport to be complete and is qualified in its entirety by reference to the provisions of the Purchase Agreement.

Arrangements Relating to the Exchangeable Shares

As a condition of the closing of the acquisition of the Micro Bird Targets, the Issuer entered into an Exchange and Support Agreement (the "Support Agreement") with GAG, MB ExchangeCo, and MB Callco. Pursuant to the terms of the Support Agreement, the holders of the Exchangeable Shares must be provided economic benefits to the same extent as holders of Issuer common stock in the event of any dividend or other distribution, change, or adjustment relating to Issuer common stock (such as a stock split, stock dividend, reclassification or reorganization). Additionally, the Support Agreement contains certain covenants of the Issuer while the Exchangeable Shares are outstanding, including: (i) not to declare or pay any dividends on its common stock unless MB ExchangeCo simultaneously declares an equivalent dividend for the Exchangeable Shares, (ii) advising MB ExchangeCo in advance of any dividend declaration by the Issuer, (iii) taking all actions reasonably necessary to enable MB ExchangeCo to pay and otherwise perform its obligations with respect to the issued and outstanding Exchangeable Shares, (iv) providing the holders of Exchangeable Shares with voting rights equivalent to the holders of Issuer common stock through the issuance of the share of the Special Preferred Voting Stock, and (v) reserving for issuance and keeping available from its authorized common stock such number of shares as may be equal to: (a) the number of Exchangeable Shares issued and outstanding from time to time; and (b) the number of Exchangeable Shares issuable upon the exercise of all rights, if any, to acquire Exchangeable Shares from time to time.

The Reporting Persons have filed the form of Support Agreement as Exhibit 3 to this Schedule 13D, which is incorporated herein by reference. The description of the Support Agreement set forth above does not purport to be complete and is qualified in its entirety by reference to the provisions of the Support Agreement.

Board Election Agreement

As a condition of the closing of the acquisition of the Micro Bird Targets, the Issuer and GAG also entered into a Board Election Agreement providing for the election of Steve Girardin to the Board of Directors of the Issuer as a Class III director, effective as of the closing, with a term expiring at the annual stockholder meeting in 2029, and under certain circumstances if Steve Girardin leaves the board prior to such annual meeting, providing for the election of Dave Girardin as his replacement through the 2029 annual meeting. Pursuant to the Board Election Agreement, GAG agrees, during such time as Steve Girardin or Dave Girardin is serving on the Board, to vote all securities of the Issuer held by GAG and its affiliates in accordance with the Board's recommendations. The Board Election Agreement will terminate on the earlier of (i) immediately prior to the 2029 annual stockholder meeting and (ii) 90 days after such time as neither Steve Girardin nor Dave Girardin is serving on the Board. During such time as Steve Girardin or Dave Girardin is serving on the Board, in such capacity, such individual may have influence over the corporate activities of the Issuer, including activities which may relate to items described in subparagraphs (a) through (j) of Item 4 of Schedule 13D.

The Reporting Persons have filed the form of Board Election Agreement as Exhibit 4 to this Schedule 13D, which is incorporated herein by reference. The description of the Board Election Agreement set forth above does not purport to be complete and is qualified in its entirety by reference to the provisions of the Board Election Agreement.

General

The Reporting Persons acquired the Exchangeable Shares and the right to exchange such shares at their option on a one-to-one basis into shares of Issuer common stock for investment purposes, and such purposes were made in the Reporting Persons' ordinary course of business. In pursuing such investment purposes, the Reporting Persons may further purchase, hold, vote, trade, dispose or otherwise deal in the common stock at times, and in such manner (including pursuant to hedging transactions), as they deem advisable to benefit from changes in market prices of the common stock, changes in the Issuer's operations, business strategy or prospects, or from a sale or merger of the Issuer. To evaluate such alternatives, the Reporting Persons routinely will monitor the Issuer's operations, prospects, business development, management, competitive and strategic matters, capital structure, and prevailing market conditions, as well as alternative investment opportunities, liquidity requirements of the Reporting Persons and other investment considerations. Consistent with their investment research methods and evaluation criteria, the Reporting Persons may discuss such matters with management or directors of the Issuer, other shareholders, industry analysts, existing or potential strategic partners or competitors, investment and financing professionals, sources of credit and other investors. Such factors and discussions may materially affect, and result in, the Reporting Persons' modifying their ownership of the common stock, exchanging information with the Issuer pursuant to appropriate confidentiality or similar agreements, proposing changes in the Issuer's operations, governance or capitalization, or in proposing one or more of the other actions described in paragraphs (a) through (j) of Item 4 of Schedule 13D. The Reporting Persons reserve the right to formulate other plans and/or make other proposals, and take such actions with respect to their investment in the Issuer, including any or all of the actions set forth in paragraphs (a) through (j) of Item 4 of Schedule 13D, or acquire additional shares of common stock or dispose of all shares of common stock beneficially owned by them, in public market or privately negotiated transactions. The Reporting Persons may at any time reconsider and change their plans or proposals relating to the foregoing. Any actions described above by the Reporting Persons would be subject to the contractual transfer restrictions applicable to the Exchangeable Shares and shares of Issuer common stock obtain in exchange therefor and applicable securities law.

**Item 5. Interest in Securities of the Issuer**

**(a)**
The information set forth on rows 11 and 13 of the cover page of this Schedule 13D is incorporated by reference.

**(b)**
The information set forth in rows 7 through 10 of the cover page to this Schedule 13D is incorporated by reference.

**(c)**
Except as set forth in Item 4 hereof, the Reporting Persons have not effected any transactions in the common stock in the sixty days preceding the date of this Schedule 13D.

**Item 6. Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer.**

The Reporting Persons are parties to an agreement with respect to the joint filing of this Schedule 13D and any amendments hereto. A copy of such agreement is attached as Exhibit 1 to this Schedule 13D and is incorporated by reference herein.

The information in Item 4 of this Schedule 13D is incorporated by reference herein.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Groupe Autobus Girardin Ltee

**Signature:** /s/ Steve Girardin

**Name/Title:** Authorized Signatory

**Date:** 04/08/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Steve Girardin

**Signature:** /s/ Steve Girardin

**Name/Title:** Steve Girardin

**Date:** 04/08/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Andre Girardin

**Signature:** /s/ Steve Girardin

**Name/Title:** Attorney-in-Fact for Andre Girardin

**Date:** 04/08/2026

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Dave Girardin

**Signature:** /s/ Steve Girardin

**Name/Title:** Attorney-in-Fact for Dave Girardin

**Date:** 04/08/2026