ChipMOS (NASDAQ: IMOS) VP Su Yu-Chiao reports direct and indirect stakes

Rhea-AI Filing Summary

CHIPMOS TECHNOLOGIES INC vice president and director Yu-Chiao Su filed an initial ownership report on the company’s common stock. The filing shows direct ownership of 346,101 shares and indirect ownership of 830,000 shares held through Tsai Fu Investment Co., Ltd., where Su 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^*

Su Yu-Chiao

(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)

X	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	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	346,101	D
Common Stock	830,000	I	Tsai Fu 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. Yu-Chiao Su serves as the representative and director of Tsai Fu 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).
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FAQ

What does the IMOS Form 3 filing by Yu-Chiao Su report?

The Form 3 filing reports Yu-Chiao Su’s initial ownership in CHIPMOS common stock, including both directly held shares and shares held indirectly through Tsai Fu Investment Co., Ltd., where Su serves as representative and director.

How many IMOS shares does Yu-Chiao Su hold directly according to the Form 3?

The filing shows Yu-Chiao Su directly holds 346,101 shares of CHIPMOS common stock. This reflects Su’s personal stake recorded as direct ownership, separate from any additional shares held through related entities or investment companies.

What indirect IMOS ownership is disclosed for Yu-Chiao Su?

The Form 3 discloses indirect ownership of 830,000 shares of CHIPMOS common stock held through Tsai Fu Investment Co., Ltd. Yu-Chiao Su serves as the representative and director of this company, which holds the shares on an indirect basis.

Were any IMOS share purchases or sales reported in Yu-Chiao Su’s Form 3?

No purchases or sales are reported. The Form 3 consists of two holding entries that simply state direct and indirect ownership levels, without identifying any buy or sell transactions or changes in position on the reported date.

Who is Tsai Fu Investment Co., Ltd. in relation to IMOS insider Yu-Chiao Su?

Tsai Fu Investment Co., Ltd. is the entity through which 830,000 CHIPMOS shares are held indirectly. A footnote explains that Yu-Chiao Su serves as the representative and director of Tsai Fu Investment Co., Ltd., linking Su to those indirect holdings.