SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Zhang Jack Y. (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET (Street) RANCHO CUCAMONGA CA 91730 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol Amphastar Pharmaceuticals, Inc. [ AMPH ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner X Officer (give title below) Other (specify below) CEO & Chief Scientific Officer
	3. Date of Earliest Transaction (Month/Day/Year) 02/05/2021
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	02/05/2021		S(1)		15,507	D	$18.9412(2)	6,932,372	I	See footnote(3)
Common Stock	02/08/2021		S(1)		13,452	D	$18.8856(4)	6,918,920	I	See footnote(3)
Common Stock	02/09/2021		S(1)		11,927	D	$18.9298(5)	6,906,993	I	See footnote(3)
Common Stock								2,246,988	D
Common Stock								1,449,961	I	See footnote(6)
Common Stock								5,000	I	See footnote(7)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

1. Name and Address of Reporting Person* Zhang Jack Y. (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET (Street) RANCHO CUCAMONGA CA 91730 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner X Officer (give title below) Other (specify below) CEO & Chief Scientific Officer

1. Name and Address of Reporting Person* Luo Mary Z. (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET (Street) RANCHO CUCAMONGA CA 91730 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner X Officer (give title below) Other (specify below) COO, Chief Scientist & Chairma

1. Name and Address of Reporting Person* Applied Physics & Chemistry Laboratories, Inc. (Last) (First) (Middle) C/O AMPHASTAR PHARMACEUTICALS, INC. 11570 6TH STREET (Street) RANCHO CUCAMONGA CA 91730 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. The sales reported in this Form 4 was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on June 12, 2020.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.735 to $19.15, inclusive. The reporting person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in footnotes (2), (4) and (5).

3. 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 (the "BLZ Trust") are the sole owners.

4. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.68 to $19.15, inclusive.

5. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $18.79 to $19.09, inclusive.

6. The securities are held of record by Mary Z. Luo. The reporting persons are husband and wife.

7. 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.

	/s/ William J. Peters, by power of attorney for Jack Y. Zhang	02/09/2021
	/s/ William J. Peters, by power of attorney for Mary Z. Luo	02/09/2021
	/s/ William J. Peters, by power of attorney for Jack Y. Zhang, principal and owner of Applied Physics & Chemistry Laboratories, Inc.	02/09/2021
	** Signature of Reporting Person	Date
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