[Form 3] UNITED MICROELECTRONICS CORP Initial Statement of Beneficial Ownership

Rhea-AI Filing Summary

UNITED MICROELECTRONICS CORP executive Liao Ching Yu, General Counsel & VP, filed an initial Form 3 reporting current ownership in the company’s common shares. The filing shows direct holdings of 732,480 common shares.

The position includes 700,800 shares of Restricted Stock Awards (RSA), with a specified number of these RSAs scheduled to vest annually on December 5 from 2026 through 2029. This Form 3 records existing beneficial ownership and does not report any recent share purchases or sales.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider LIAO CHING YU

Role General Counsel & VP

Type	Security	Shares	Price	Value
holding	Common Shares	--	--	--

Holdings After Transaction: Common Shares — 732,480 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

Total common shares held: 732,480 shares Restricted Stock Awards: 700,800 shares RSA vesting period start: December 5, 2026 +1 more

4 metrics

Total common shares held 732,480 shares Direct beneficial ownership reported on Form 3

Restricted Stock Awards 700,800 shares Portion of holdings classified as RSAs

RSA vesting period start December 5, 2026 First annual vesting date for RSAs

RSA vesting period end December 5, 2029 Final annual vesting date for RSAs

Key Terms

Restricted Stock Award (RSA), Common Shares, Form 3, General Counsel & VP

4 terms

Restricted Stock Award (RSA) financial

"Includes 700,800 shares of Restricted Stock Award (RSA) and a specified number of shares subject to the RSA will vest annually"

Common Shares financial

"security_title": "Common Shares""

Common shares are the basic units of ownership in a company that give holders a claim on profits and a right to vote on key matters, like electing the board. Think of them as membership cards in a club: they let you share in successes and losses, but in a bankruptcy or liquidation they are paid after creditors and preferred shareholders, so their value can swing more and matters for assessing risk and potential return.

Form 3 regulatory

"INSIDER FILING DATA (Form 3)"

Form 3 is the initial public filing that officers, directors and large shareholders must submit to report their ownership of a company’s securities when they become insiders. It acts like an opening inventory sheet that gives investors a starting point to see who holds significant stakes and to spot later trades or potential conflicts of interest, helping assess insider confidence and transparency.

General Counsel & VP other

"officer_title": "General Counsel & VP""

Understanding Insider Trading Forms →

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^*

LIAO CHING YU

(Last) (First) (Middle)

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

(Street)

TAIPEI TAIWAN 11493

(City) (State) (Zip)

TAIWAN

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
04/29/2026

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

3a. Foreign Trading Symbol
[2303.TW]

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

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

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	General Counsel & VP

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 Shares	732,480(1)	D

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. Includes 700,800 shares of Restricted Stock Award (RSA) and a specified number of shares subject to the RSA will vest annually on December 5 from 2026 to 2029.

Remarks:

Exhibit List Exhibit 24: Power of Attorney

	/s/Chitung Liu, attorney-in-fact	05/07/2026
	** 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)