UMC (UMC) director Shiu Kuang-Si submits initial Form 3 insider report

Rhea-AI Filing Summary

UNITED MICROELECTRONICS CORP director Shiu Kuang-Si has filed an initial insider ownership report on Form 3. This filing establishes his status as a director and provides the starting point for tracking any future insider transactions or changes in his holdings in the company’s securities.

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Accepted by SEC EDGAR 03/18/2026 - 06:12 AM Learn about SEC filing dates

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^*

Shiu Kuang-Si

(Last) (First) (Middle)

8F, NO.68, SEC. 1, NEIHU RD.,

(Street)

TAIPEI TAIWAN 11493

(City) (State) (Zip)

TAIWAN, PROVINCE OF CHINA

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
03/18/2026

3. Issuer Name and Ticker or Trading Symbol
UNITED MICROELECTRONICS CORP [ UMC ]

3a. Foreign Trading Symbol
[2,303]

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

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

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

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)

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:

Remarks:

Exhibit 24 Power of Attorney.

No securities are beneficially owned.

	/s/Chitung Liu, attorney-in-fact	03/18/2026
	** 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.
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.
* Form 3: SEC 1473 (03-26)

FAQ

What does the UMC Form 3 filed by Shiu Kuang-Si show?

The Form 3 for UNITED MICROELECTRONICS CORP (UMC) records Shiu Kuang-Si as a company director. It serves as his initial insider ownership report and baseline for any future Form 4 or Form 5 filings.

Who is the reporting person on the UMC Form 3 filing?

The reporting person is Shiu Kuang-Si, listed as a director of UNITED MICROELECTRONICS CORP. As a director, he is considered an insider and must report his beneficial ownership in company securities to regulators.

Does the UMC Form 3 include any insider transactions?

This Form 3 lists no insider transactions in the transaction detail section. It functions primarily as an initial ownership and status report rather than a record of buying, selling, or exercising company securities.

Why is a Form 3 important for UMC insiders like Shiu Kuang-Si?

Form 3 is the starting disclosure for insiders at UNITED MICROELECTRONICS CORP. It creates a baseline from which regulators and investors can compare later Forms 4 and 5 that report subsequent trades or changes in beneficial ownership.

Is Shiu Kuang-Si a 10% owner of UNITED MICROELECTRONICS CORP?

In this Form 3, Shiu Kuang-Si is identified as a director and not flagged as a 10% owner. His reporting status is therefore tied to his board role rather than to holding a large percentage of UMC’s outstanding shares.