[Form 4] APPLIED OPTOELECTRONICS, INC. Insider Trading Activity

Rhea-AI Filing Summary

Applied Optoelectronics (AAOI) officer Hung‑Lun (Fred) Chang reported share surrenders to cover taxes upon RSU vesting. On 10/22/2025, he surrendered 1,705, 2,676, 614, and 774 shares (Code F) at $33.4 per share to satisfy withholding tied to RSU awards granted on June 27, 2022; June 26, 2023; April 29, 2024; and April 11, 2025. Following these transactions, he directly beneficially owns 250,557 shares. These are administrative tax-withholding events, not open‑market sales.

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

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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^*

Chang Hung-Lun (Fred)

(Last) (First) (Middle)

C/O APPLIED OPTOELECTRONICS, INC.

13139 JESS PIRTLE BLVD.

(Street)

SUGAR LAND TX 77478

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
APPLIED OPTOELECTRONICS, INC. [ AAOI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	*** See Remarks

3. Date of Earliest Transaction (Month/Day/Year)
10/22/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	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, $.001 par value	10/22/2025		F		1,705(1)	D	$33.4	254,621	D
Common Stock, $.001 par value	10/22/2025		F		2,676(2)	D	$33.4	251,945	D
Common Stock, $.001 par value	10/22/2025		F		614(3)	D	$33.4	251,331	D
Common Stock, $.001 par value	10/22/2025		F		774(4)	D	$33.4	250,557	D

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

Explanation of Responses:

1. Reflects shares surrendered to the Issuer to satisfy tax-withholding obligations upon the vesting of restricted stock unit award granted on June 27, 2022.

2. Reflects shares surrendered to the Issuer to satisfy tax-withholding obligations upon the vesting of restricted stock unit award granted on June 26, 2023.

3. Reflects shares surrendered to the Issuer to satisfy tax-withholding obligations upon the vesting of restricted stock unit award granted on April 29, 2024.

4. Reflects shares surrendered to the Issuer to satisfy tax-withholding obligations upon the vesting of restricted stock unit award granted on April 11, 2025.

Remarks:

*** Senior Vice President and North America General Manager.

	/s/ David C. Kuo, attorney in fact for Hung-Lun (Fred) Chang	10/24/2025
	** Signature of Reporting Person	Date
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.

FAQ

What did AAOI insider Hung‑Lun (Fred) Chang report on Form 4?

He reported share surrenders to satisfy tax‑withholding obligations upon the vesting of multiple RSU awards on 10/22/2025.

How many AAOI shares were surrendered for taxes?

A total of 5,769 shares, across transactions of 1,705; 2,676; 614; and 774 shares.

At what price were the AAOI tax-withholding shares valued?

The withholding transactions were recorded at $33.4 per share (Code F).

What is the insider’s remaining AAOI share ownership?

Following the reported transactions, he directly beneficially owns 250,557 shares.

What was the purpose of these AAOI transactions?

They were to cover taxes due at RSU vesting; they are not open‑market sales.

Which RSU grants were involved in AAOI’s Form 4?

Awards granted on June 27, 2022; June 26, 2023; April 29, 2024; and April 11, 2025.

What is the insider’s role at AAOI?

Senior Vice President and North America General Manager.