Share buyback tops NT$300M as UMC (NYSE: UMC) cuts capital

Rhea-AI Filing Summary

United Microelectronics Corporation reported two capital actions. The company registered a small capital reduction on 2026/05/12 due to cancellation of restricted stock awards, slightly lowering paid-in capital and shares outstanding while nudging book value per share from NT$32.33 to NT$32.34.

UMC also disclosed that its share repurchase program has now exceeded NT$300 million in total value. On 2026/05/13, it had repurchased 6,500,000 common shares for a total of NT$637,759,742 at an average price of NT$98.12 per share, resulting in cumulative treasury shares of 16,751,000, or 0.13% of issued shares.

Insights

Equity capital markets analyst

UMC makes minor capital reduction and continues modest buybacks.

United Microelectronics Corporation recorded a small capital reduction tied to cancellation of restricted stock awards, with paid-in capital moving from NT$125,785,246,190 to NT$125,769,848,700. Shares outstanding decreased slightly, and book value per share increased marginally.

The company also reports that its ongoing buyback has passed the NT$300 million threshold, with total repurchases of NT$637,759,742 for 6,500,000 shares at an average of NT$98.12. Cumulative treasury shares of 16,751,000, or 0.13% of issued shares, indicate a relatively small-scale program in proportion to total equity.

Key Figures

Paid-in capital before reduction: NT$125,785,246,190 Paid-in capital after reduction: NT$125,769,848,700 Shares outstanding before reduction: 12,578,524,619 shares +5 more

8 metrics

Paid-in capital before reduction NT$125,785,246,190 Before capital reduction approved on 2026/05/12

Paid-in capital after reduction NT$125,769,848,700 After capital reduction on 2026/05/12

Shares outstanding before reduction 12,578,524,619 shares Before capital reduction

Shares outstanding after reduction 12,576,984,870 shares After capital reduction

Book value per share before NT$32.33 Based on Q1 2026 consolidated statements

Book value per share after NT$32.34 After capital reduction, Q1 2026 basis

Total repurchase amount NT$637,759,742 Cumulative shares repurchased as of 2026/05/13

Average repurchase price NT$98.12 per share Current average during repurchase period

Key Terms

capital reduction, paid-in capital, book value per share, shares repurchased, +2 more

6 terms

capital reduction financial

"To announce the registration of capital reduction due to cancellation of the RSA"

A capital reduction is a legal move where a company shrinks the amount of money recorded as its official share capital, either by cancelling shares, lowering the value of each share, or returning cash to shareholders. Investors care because it changes the company’s balance sheet and can alter how much each remaining share represents—like pruning a tree to concentrate fruit or giving back some of the harvest—potentially affecting ownership percentages, per‑share metrics and the stock’s market value.

paid-in capital financial

"The paid-in capital is NT$125,785,246,190; the shares outstanding are 12,578,524,619 shares"

Paid-in capital is the cash and other assets shareholders have given a company in exchange for its stock, including amounts paid above the stock’s nominal value. Investors care because it shows how much funding came directly from owners rather than from borrowing or profits, affecting the company’s financial cushion, ownership dilution and how resilient it may be in tough times — like the extra money people pay above a ticket price to support a project they believe in.

book value per share financial

"book value per share is NT$32.33"

Book value per share is a company’s net worth on paper — total assets minus liabilities — divided by the number of outstanding shares, showing the equity value attributable to each share. Investors use it like a per-slice estimate of a company’s underlying value to compare with the market price; if the market price is far above the book value, the stock may be priced for strong future profits, and if it’s below, the stock might look undervalued or reflect asset concerns.

shares repurchased financial

"To announce accumulative shares repurchased exceeding NTD$300 million in value"

own shares financial

"Cumulative no. of the company's own shares held during the repurchase period"

treasury shares financial

"Cumulative no. of the company’s own shares held during the repurchase period as a percentage"

Treasury shares are a company’s own stock that it has repurchased and keeps on its books instead of canceling or leaving in the hands of outside investors. Think of them like coupons a business puts back in a drawer: they don’t vote or receive dividends while held, but they can be reissued later for employee pay or fundraising. For investors this matters because buybacks change the number of shares that count toward earnings and ownership, can boost per‑share metrics, and use corporate cash that might otherwise go to growth or dividends.

Form 6-K: How Foreign Companies Report to the SEC →

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

OF THE SECURITIES EXCHANGE ACT OF 1934

May 13, 2026

(Commission File Number: 001-15128)

United Microelectronics Corporation

(Translation of registrant’s name into English)

No. 3 Li-Hsin 2nd Road,

Hsinchu Science Park,

Hsinchu, Taiwan, R.O.C.

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F  Form 40-F 

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (1): 

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101 (b) (7): 

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereto duly authorized.

United Microelectronics Corporation
By:	Chitung Liu
Name:	Chitung Liu
Title:	CFO

Date: May 13, 2026

2

EXHIBIT INDEX

Exhibit		Description
99		6K on 05/13/2026

3

www.umc.com

Exhibit

Exhibit Description

99.1 Announcement on 2026/05/13: To announce the registration of capital reduction due to cancellation of the RSA

99.2 Announcement on 2026/05/13: To announce accumulative shares repurchased exceeding NTD$300 million in value

Exhibit 99.1

To announce the registration of capital reduction due to cancellation of the RSA

1. Date of the competent authority’s approval of capital reduction: 2026/05/12

2. Date of completion of capitalization change registration: 2026/05/12

3. Effect on the financial statements (including any discrepancy between the amount of paid-in capital and the no. of shares outstanding, and the effect on net worth per share):

(1) Before the capital reduction: The paid-in capital is NT$125,785,246,190; the shares outstanding are 12,578,524,619 shares; book value per share is NT$32.33

(2) After the capital reduction: The paid-in capital is NT$125,769,848,700; the shares outstanding are 12,576,984,870 shares; book value per share is NT$32.34

(Note: Net worth per share was calculated based on the consolidated financial statements for the first quarter of 2026 reviewed by CPA.)

4. Plan for expected share replacement operations: NA

5. Estimated no. of listed common shares after capital reduction and new issue: NA

6. Estimated no. of listed common shares as a percentage of issued common shares after capital reduction and new issue (No. of common shares after capital reduction/No. of issued common shares): NA

7. Countermeasures for poor circulation of equity if the aforesaid estimated no. of listed common shares does not reach 60 million shares and the percentage does not reach 25% after capital reduction: NA

8. Any other matters that need to be specified: None

Exhibit 99.2

To announce accumulative shares repurchased exceeding NTD$300 million in value

1. Date the cumulative no. of shares currently repurchased accounted for 2 percent or more of the shares issued by the company, or amounted to NT$300 million or more: 2026/05/13

2. No. of shares currently repurchased (shares): 6,500,000 shares

3. Type of shares currently repurchased: Common share

4. Total monetary amount of shares currently repurchased (NTD): NTD$637,759,742

5. Current average repurchase price per share (NTD): NTD$98.12

6. Cumulative no. of the company's own shares held during the repurchase period (shares): 16,751,000 shares

7. Cumulative no. of the company’s own shares held during the repurchase period as a percentage of the total no. of the company’s issued shares: 0.13%

8. Any other matters that need to be specified: None

FAQ

What capital reduction did UMC (UMC) register in May 2026?

UMC registered a small capital reduction on May 12, 2026, linked to cancellation of restricted stock awards. Paid-in capital decreased from NT$125,785,246,190 to NT$125,769,848,700, and book value per share rose slightly from NT$32.33 to NT$32.34 based on Q1 2026 statements.

How did UMC’s share count change after the capital reduction?

UMC’s shares outstanding decreased modestly after the capital reduction, moving from 12,578,524,619 shares to 12,576,984,870 shares. This reflects the cancellation of restricted stock awards and results in only a very small change in the overall equity base.

How large is UMC’s share repurchase program reported on May 13, 2026?

UMC reported total repurchases of NT$637,759,742 as of May 13, 2026. The company bought 6,500,000 common shares at an average price of NT$98.12, with cumulative treasury holdings reaching 16,751,000 shares during the repurchase period.

What percentage of UMC’s issued shares are held as treasury stock?

UMC’s treasury shares represented 0.13% of issued shares during the reported repurchase period. That percentage is based on cumulative own shares held of 16,751,000, indicating the buyback remains small relative to the company’s total share count.

When did UMC’s buybacks exceed NT$300 million in value?

UMC’s cumulative share repurchases exceeded NT$300 million on May 13, 2026. On that date, the total monetary amount of shares repurchased reached NT$637,759,742, triggering disclosure once the program surpassed this reporting threshold.

Did UMC’s book value per share change after the capital reduction?

UMC’s book value per share increased slightly after the capital reduction, from NT$32.33 to NT$32.34. This figure is calculated from consolidated financial statements for the first quarter of 2026 that were reviewed by a certified public accountant.

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