# EDGAR Filing Document

**Accession Number:** 0001297184
**File Stem:** 0001104659-23-034573
**Filing Date:** 2023-3
**Character Count:** 9837
**Document Hash:** 20c9e41464c53d973aa8093719fc32df
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-23-034573.hdr.sgml**: 20230320

**ACCESSION NUMBER**: 0001104659-23-034573

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20230316

**FILED AS OF DATE**: 20230320

**DATE AS OF CHANGE**: 20230320

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Luo Mary Z.
- **CENTRAL INDEX KEY:** 0001611156

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-36509
- **FILM NUMBER:** 23747586

**MAIL ADDRESS:**
- **STREET 1:** 11570 6TH STREET
- **CITY:** RANCHO CUCAMONGA
- **STATE:** CA
- **ZIP:** 91730
**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Zhang Jack Y.
- **CENTRAL INDEX KEY:** 0001611157

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-36509
- **FILM NUMBER:** 23747587

**MAIL ADDRESS:**
- **STREET 1:** 11570 6TH STREET
- **CITY:** RANCHO CUCAMONGA
- **STATE:** CA
- **ZIP:** 91730
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Amphastar Pharmaceuticals, Inc.
- **CENTRAL INDEX KEY:** 0001297184
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **IRS NUMBER:** 330702205
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 11570 SIXTH STREET
- **CITY:** RANCHO CUCAMONGA
- **STATE:** CA
- **ZIP:** 91730
- **BUSINESS PHONE:** 909-980-9484

**MAIL ADDRESS:**
- **STREET 1:** 11570 SIXTH STREET
- **CITY:** RANCHO CUCAMONGA
- **STATE:** CA
- **ZIP:** 91730

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

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Zhang Jack Y.<br><sub>(Last) (First) (Middle)</sub><br>C/O AMPHASTAR PHARMACEUTICALS, INC.<br>11570 6TH STREET<br><sub>(Street)</sub><br>RANCHO CUCAMONGA,, CA 91730<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-03-16 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_CEO & Chief Scientific Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Amphastar Pharmaceuticals, Inc. [ AMPH ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Luo Mary Z.<br><sub>(Last) (First) (Middle)</sub><br>C/O AMPHASTAR PHARMACEUTICALS, INC.<br>11570 6TH STREET<br><sub>(Street)</sub><br>RANCHO CUCAMONGA,, CA 91730<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2023-03-16 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[X] Director [X] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_COO,Chief Scientist & Chairman_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Amphastar Pharmaceuticals, Inc. [ AMPH ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[ ] Form filed by One Reporting Person<br>[X] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2023-03-16 |  | G |  | 57365 | D | $0.00 | 0 | I | See footnote<sup>(1)</sup> |
| Common Stock | 2023-03-16 |  | G |  | 57365 | D | $0.00 | 0 | I | See footnote<sup>(2)</sup> |
| Common Stock | 2023-03-16 |  | F |  | 25241<sup>(3)</sup> | D | $37.60 | 2094486<sup>(4)</sup> | D |  |
| Common Stock | 2023-03-16 |  | F |  | 9998<sup>(3)</sup> | D | $37.60 | 1462654<sup>(5)</sup> | I | See footnote<sup>(6)</sup> |
| Common Stock | 2023-03-17 |  | F |  | 15768<sup>(3)</sup> | D | $36.29 | 2078718 | D |  |
| Common Stock | 2023-03-17 |  | F |  | 7052<sup>(3)</sup> | D | $36.29 | 1455602 | I | See footnote<sup>(6)</sup> |
| Common Stock |  |  |  |  |  |  |  | 6827679 | I | See footnote<sup>(7)</sup> |
| Common Stock |  |  |  |  |  |  |  | 5000 | I | See footnote<sup>(8)</sup> |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

---

### Footnotes:

(1) The shares are held of record by The Jack Y. Zhang 2020 GRAT dated February 7, 2020, Jack Y. Zhang trustee (the "Zhang GRAT"). On February 7, 2020, Dr. Zhang contributed 353,797 shares of directly held Issuer common stock to the Zhang GRAT for the benefit of himself and his three adult children (the "Distributees"). Pursuant to the terms of the Zhang GRAT, upon termination of the Zhang GRAT, 57,365 of the shares were distributed to Distributees. The remaining 296,431 shares representing annuity payments under the Zhang GRAT were previously distributed to Dr. Zhang and continue to be reported in this Form 4 as directly owned by Dr. Zhang.

(2) The shares are held of record by The Mary Z. Luo 2020 GRAT dated February 7, 2020, Mary Z. Luo trustee (the "Luo GRAT"). On February 7, 2020, Dr. Luo contributed 353,797 shares of directly held Issuer common stock to the Luo GRAT for the benefit of herself and her three adult children (the "Distributees"). Pursuant to the terms of the Luo GRAT, upon termination of the Luo GRAT, 57,365 of the shares were distributed to Distributees. The remaining 296,431 shares representing annuity payments under the Luo GRAT were previously distributed to Dr. Luo and continue to be reported in this Form 4 as directly owned by Dr. Luo.

(3) The reported shares were withheld to satisfy the reporting person's tax liability in connection with the vesting of restricted stock units, or RSUs.

(4) Excludes 57,365 shares previously reported as held directly by Dr. Zhang as described in footnote (1) above.

(5) Excludes 57,365 shares previously reported as held directly by Dr. Luo as described in footnote (2) above.

(6) The securities are held of record by Dr. Luo. The reporting persons are husband and wife.

(7) The shares are held of record by Applied Physics & Chemistry Laboratories, Inc., of which the reporting persons and The Bill Luobei Zhang 2004 Irrevocable Trust are the sole owners.

(8) The shares are held of record in an account for the benefit of the reporting persons' son. The reporting persons disclaim beneficial ownership of these shares, and the inclusion of these shares in this report should not be deemed an admission of beneficial ownership of any such shares for purposes of Section 16, or for any other purpose.

**Signature:** /s/ Eva Wen, by power of attorney for Jack Y. Zhang  
**Date:** 2023-03-20

**Signature:** /s/ Eva Wen, by power of attorney for Mary Z. Luo  
**Date:** 2023-03-20

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**