IMOS (IMOS) EVP Teng-Yueh Tsai discloses direct and indirect share holdings

Rhea-AI Filing Summary

CHIPMOS TECHNOLOGIES INC Executive Vice President Teng-Yueh Tsai filed an initial ownership report on the company’s common stock. The filing shows direct ownership of 272,572 common shares and indirect ownership of 820,000 common shares held through Yung Hsiang Investment Co., Ltd., where Tsai serves as representative and director.

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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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1. Name and Address of Reporting Person^*

Tsai Teng-Yueh

(Last) (First) (Middle)

C/O NO 1 R&D ROAD 1

HSINCHU SCIENCE PARK

(Street)

HSINCHU F5 300092

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
03/13/2026

3. Issuer Name and Ticker or Trading Symbol
CHIPMOS TECHNOLOGIES INC [ IMOS ]

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Executive Vice President

5. 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 Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)
Common Stock	272,572	D
Common Stock	820,000	I	Yung Hsiang Investment Co., Ltd.(1)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Teng-Yueh Tsai serves as the representative and director of Yung Hsiang Investment Co., Ltd.

Remarks:

Exhibit List: Exhibit 24 - Power of Attorney

	/s/ Hsiu-Ling Teng, attorney-in-fact	03/13/2026
	** 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 5 (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.
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FAQ

What does the Form 3 filed by IMOS executive Teng-Yueh Tsai show?

The Form 3 shows Teng-Yueh Tsai’s initial ownership in CHIPMOS TECHNOLOGIES INC common stock. It reports both directly held shares and additional shares held indirectly through an affiliated entity, giving investors a baseline view of this executive’s equity stake at the reporting date.

How many IMOS shares does Teng-Yueh Tsai hold directly and indirectly?

The filing reports 272,572 IMOS common shares held directly and 820,000 IMOS common shares held indirectly. The indirect stake is held through Yung Hsiang Investment Co., Ltd., providing a combined picture of Tsai’s economic exposure to CHIPMOS TECHNOLOGIES INC equity.

What is Yung Hsiang Investment Co., Ltd.’s role in IMOS share ownership?

Yung Hsiang Investment Co., Ltd. holds 820,000 IMOS common shares indirectly attributable to Teng-Yueh Tsai. A footnote explains that Tsai serves as the representative and director of this company, clarifying the relationship behind the reported indirect ownership position in the filing.

Does the IMOS Form 3 show any recent stock transactions by Teng-Yueh Tsai?

The Form 3 functions as an initial ownership statement and does not report any specific buy or sell transactions. It instead lists the number of common shares beneficially owned directly and indirectly as of the reporting date, establishing Tsai’s starting ownership position in IMOS stock.

Why is Teng-Yueh Tsai required to file a Form 3 for IMOS?

As an Executive Vice President of CHIPMOS TECHNOLOGIES INC, Teng-Yueh Tsai is considered an insider under U.S. securities rules. Insiders must file Form 3 to disclose their initial beneficial ownership in company securities when they become subject to reporting obligations.