United Micro CFO sells 1.6M shares in September

UMC’s CFO and SVP, Liu Chitung, sold 1.6 million common shares in New Taiwan Dollar–denominated transactions while retaining indirect and restricted stock interests.

Rhea-AI Filing Summary

UNITED MICROELECTRONICS CORP (UMC) reported that its chief financial officer and senior vice president, Liu Chitung, sold a total of 1,600,000 Common Shares in mid-September 2026. The sales consisted of 1,200,000 shares on September 16, 2026 at NT$142.333 per share and 400,000 shares on September 17, 2026 at NT$145 per share in open-market or private transactions.

After these transactions, Liu continues to have indirect exposure to UMC through 150,000 Common Shares held by a spouse and 1,000,000 Common Shares held in a CTBC Bank trust. The filing also notes that Liu has 1,126,840 Restricted Stock Awards, with specified portions scheduled to vest annually on December 5 from 2026 to 2029. No Rule 10b5-1 trading plan is reported for these sales.

Insider Trade Summary

Net Seller: 1,600,000 shares

Net Sell 4 txns

Insider Liu Chitung

Role CFO & SVP

Sold 1,600,000 shs ($228.80M)

Type	Security	Shares	Price	Value
Sale	Common Shares F1, F2	400,000	$145.00	$58.00M
Sale	Common Shares F1, F2	1,200,000	$142.333	$170.80M
holding	Common Shares	--	--	--
holding	Common Shares F3	--	--	--

Holdings After Transaction: Common Shares — 2,639,757 shares (Direct); Common Shares — 150,000 shares (Indirect, By Spouse); Common Shares — 1,000,000 shares (Indirect, By CTBC Bank Trust)

Footnotes (3)

1. F1. New Taiwan Dollars
2. F2. Includes 1,126,840 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.
3. F3. The shares are under Trust with Discretion Reserved.

Key Figures

Shares sold on September 16, 2026: 1,200,000 Common Shares Price on September 16, 2026: NT$142.333 per share Shares sold on September 17, 2026: 400,000 Common Shares +5 more

8 metrics

Shares sold on September 16, 2026 1,200,000 Common Shares Sale by UMC CFO and SVP Liu Chitung in open-market or private transactions

Price on September 16, 2026 NT$142.333 per share Consideration per Common Share for the 1,200,000-share sale

Shares sold on September 17, 2026 400,000 Common Shares Additional sale by UMC CFO and SVP Liu Chitung

Price on September 17, 2026 NT$145 per share Consideration per Common Share for the 400,000-share sale

Total shares sold 1,600,000 Common Shares Combined sales reported for September 16–17, 2026

Indirect holdings by spouse 150,000 Common Shares UMC shares reported as held indirectly for Liu Chitung by a spouse

Indirect holdings in CTBC Bank trust 1,000,000 Common Shares UMC shares held under a CTBC Bank trust with discretion reserved

Restricted Stock Awards 1,126,840 Common Shares Shares subject to Restricted Stock Award (RSA) scheduled to vest annually on December 5 from 2026 to 2029

Key Terms

Restricted Stock Award (RSA), New Taiwan Dollars, Trust with Discretion Reserved, Rule 10b5-1 trading plan

4 terms

Restricted Stock Award (RSA) financial

"Includes 1,126,840 shares of Restricted Stock Award (RSA) and a specified number of shares"

New Taiwan Dollars financial

"New Taiwan Dollars"

The New Taiwan Dollar (NTD) is the official currency used in Taiwan for everyday transactions, like buying groceries or paying bills. For investors, it matters because its value can influence Taiwan’s economy and affect the profitability of investments related to the region. Changes in the currency’s strength can also impact international trade and financial markets involving Taiwan.

Trust with Discretion Reserved financial

"The shares are under Trust with Discretion Reserved."

Rule 10b5-1 trading plan regulatory

"No Rule 10b5-1 trading plan is reported for these sales."

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did UMC’s CFO Liu Chitung report on this Form 4 for UMC?

Liu Chitung reported selling 1,600,000 UMC Common Shares in September 2026, consisting of 1,200,000 shares on September 16, 2026 and 400,000 shares on September 17, 2026, in open-market or private transactions at prices stated in New Taiwan Dollars.

At what prices did UMC’s CFO sell shares according to the Form 4?

The filing states that Liu Chitung sold 1,200,000 shares at NT$142.333 per share on September 16, 2026 and 400,000 shares at NT$145 per share on September 17, 2026. The currency is identified in a footnote as New Taiwan Dollars.

How many UMC shares does the CFO hold indirectly after these sales?

After the reported sales, Liu Chitung is reported as having 150,000 UMC Common Shares held by a spouse and 1,000,000 UMC Common Shares held under a CTBC Bank trust. The trust is described as being under Trust with Discretion Reserved.

Does the UMC Form 4 say these trades were under a Rule 10b5-1 plan?

No. The Form 4 for UMC indicates no Rule 10b5-1 trading plan is reported for the September 2026 sales by CFO and SVP Liu Chitung. The transactions are described as sales in open-market or private transactions.

What Restricted Stock Awards does UMC’s CFO have according to the filing?

A footnote explains that Liu Chitung’s position includes 1,126,840 shares of Restricted Stock Award (RSA). A specified number of these RSA shares are scheduled to vest annually on December 5 from 2026 through 2029.

What role does CTBC Bank play in UMC CFO’s shareholdings?

The Form 4 shows 1,000,000 UMC Common Shares held indirectly for Liu Chitung by CTBC Bank Trust. A footnote describes these as shares held under a Trust with Discretion Reserved, indicating they are managed within a trust structure.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/17/2026 - 06:08 AM Accepted by SEC EDGAR 09/17/2026 - 06:07 AM Learn about SEC filing dates

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Liu Chitung

(Last) (First) (Middle)

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

(Street)

TAIPEI 11493

(City) (State) (Zip)

TAIWAN

(Country)

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

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

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

2a. Foreign Trading Symbol
[2303.TW]

3. Date of Earliest Transaction (Month/Day/Year)
09/16/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Shares	09/16/2026		S		1,200,000	D	$142.333(1)	3,039,757(2)	D
Common Shares	09/17/2026		S		400,000	D	$145(1)	2,639,757(2)	D
Common Shares								150,000	I	By Spouse
Common Shares								1,000,000(3)	I	By CTBC Bank Trust

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. New Taiwan Dollars

2. Includes 1,126,840 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.

3. The shares are under Trust with Discretion Reserved.

	/s/Chitung Liu	09/17/2026
	** 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 4 (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 4: SEC 1474 (03-26)