UMC (NYSE: UMC) VP Cheng discloses 2.87M-share stake and RSAs

Filing Impact

(Neutral)

Filing Sentiment

(Neutral)

Form Type

Rhea-AI Filing Summary

UNITED MICROELECTRONICS CORP executive Cheng Tzyyy-Ming, a Vice President, filed an initial ownership report showing direct holdings of 2,868,080 Common Shares.

The position includes 928,800 Restricted Stock Award (RSA) shares, with a specified number scheduled to vest each year on December 5 from 2026 through 2029.

Insider Trade Summary

1 transaction reported

Mixed 1 txn

Insider CHENG TZYY-MING

Role Vice President

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

Holdings After Transaction: Common Shares — 2,868,080 shares (Direct, null)

Footnotes (1)

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Key Figures

Total beneficial ownership: 2,868,080 Common Shares Restricted Stock Awards: 928,800 shares RSA vesting period: 2026-2029 annually on Dec 5

3 metrics

Total beneficial ownership 2,868,080 Common Shares Direct holdings reported on Form 3

Restricted Stock Awards 928,800 shares RSA included in total beneficial ownership

RSA vesting period 2026-2029 annually on Dec 5 Vesting schedule for RSA shares

Key Terms

Restricted Stock Award (RSA), Common Shares, Form 3

3 terms

Restricted Stock Award (RSA) financial

"Includes 928,800 shares of Restricted Stock Award (RSA) and a specified number of shares"

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.

Understanding Insider Trading Forms →

05/07/2026 - 06:14 AM

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^*

CHENG TZYY-MING

(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)
	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	2,868,080⁽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)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	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)

Explanation of Responses:

1. Includes 928,800 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)

Source: View Original Filing on SEC EDGAR

FAQ

What does UMC’s Form 3 filing by Cheng Tzyyy-Ming show?

The Form 3 shows Vice President Cheng Tzyyy-Ming’s initial beneficial ownership of 2,868,080 UMC Common Shares. This includes both fully owned shares and restricted stock awards that will vest over several future years.

How many UMC shares does Cheng Tzyyy-Ming beneficially own?

Cheng Tzyyy-Ming reports beneficial ownership of 2,868,080 UMC Common Shares. This figure combines currently held stock and 928,800 Restricted Stock Award (RSA) shares that vest gradually between 2026 and 2029 according to the award terms.

What are the Restricted Stock Awards (RSA) reported in UMC’s Form 3?

The filing notes 928,800 Restricted Stock Award (RSA) shares held by Cheng Tzyyy-Ming. A specified number of these RSA shares will vest each year on December 5 from 2026 through 2029, subject to the award’s conditions.

Does the UMC Form 3 indicate recent buying or selling by Cheng Tzyyy-Ming?

The Form 3 is an initial ownership statement and does not report specific buy or sell transactions. It instead discloses Cheng Tzyyy-Ming’s total beneficial holdings and the structure of his restricted stock awards at the reporting date.

How is the vesting schedule structured for Cheng Tzyyy-Ming’s UMC RSAs?

The vesting schedule covers RSA shares through four annual dates. A specified number of the 928,800 Restricted Stock Award shares will vest on December 5 in each year from 2026 to 2029, aligning with typical multi-year equity compensation plans.