UMC (NYSE: UMC) vice president discloses 650,600-share stake on Form 3

Rhea-AI Filing Summary

UNITED MICROELECTRONICS CORP Vice President Tan Wen Yi filed an initial Form 3 reporting holdings of 650,600 common shares. This filing does not show a new buy or sell; it establishes current beneficial ownership. A footnote explains that 594,500 of these shares are in the form of Restricted Stock Awards (RSAs).

A specified number of the RSA shares will vest each year on December 5 from 2026 through 2029, meaning portions of this equity grant will gradually become fully owned over that period.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider TAN WEN YI

Role Vice President

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

Holdings After Transaction: Common Shares — 650,600 shares (Direct, null)

Footnotes (1)

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Key Figures

Common shares beneficially owned: 650,600 shares Restricted Stock Awards: 594,500 shares RSA vesting period start: December 5, 2026 +1 more

4 metrics

Common shares beneficially owned 650,600 shares Reported on Form 3 as of transaction date 2026-05-01

Restricted Stock Awards 594,500 shares Portion of total holdings classified as RSA

RSA vesting period start December 5, 2026 Annual vesting date for RSA tranches

RSA vesting period end December 5, 2029 Last annual vesting date for RSA tranches

Key Terms

Restricted Stock Award (RSA), Form 3, beneficial ownership

3 terms

Restricted Stock Award (RSA) financial

"Includes 594,500 shares of Restricted Stock Award (RSA) and a specified number of shares subject to the RSA will vest annually"

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.

beneficial ownership financial

"initial Form 3 reporting holdings of 650,600 common shares"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

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

OMB APPROVAL

OMB Number:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

TAN WEN YI

(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)
05/01/2026

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)
	Vice President

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	650,600(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 594,500 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)

FAQ

What does the UMC Form 3 filed by Tan Wen Yi show?

The Form 3 shows Vice President Tan Wen Yi’s initial beneficial ownership of 650,600 common shares of UNITED MICROELECTRONICS CORP. It is a disclosure of existing holdings, not evidence of a new stock purchase or sale.

How many UNITED MICROELECTRONICS CORP (UMC) shares does Tan Wen Yi report?

Tan Wen Yi reports holding 650,600 common shares of UNITED MICROELECTRONICS CORP. This total includes both fully owned shares and a significant portion granted as Restricted Stock Awards that vest over several future years.

What portion of UMC shares are Restricted Stock Awards for Tan Wen Yi?

The filing states that 594,500 shares are Restricted Stock Awards (RSAs). These represent deferred equity compensation that will vest in stages rather than being immediately unrestricted, aligning part of the executive’s ownership with future service.

When will Tan Wen Yi’s UMC Restricted Stock Awards vest?

A specified number of Restricted Stock Award shares will vest annually on December 5 from 2026 through 2029. This schedule gradually turns the awarded RSAs into fully vested shares over four consecutive years, subject to the award terms.

Does this UMC Form 3 indicate insider buying or selling activity?

No, the Form 3 does not reflect a new transaction such as an open-market buy or sell. It is an initial statement of beneficial ownership, listing shares already held, including unvested Restricted Stock Awards.