Contents of Significant Accounts (Tables)

12 Months Ended

Dec. 31, 2025

Contents Of Significant Accounts [Line Items]

(1)

Cash and Cash Equivalents


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Cash on hand and petty cash	$	6,258	$	6,655
Checking and savings accounts		25,388,395		25,019,390
Time deposits		73,507,742		77,994,948
Repurchase agreements collateralized by government bonds and corporate notes		6,097,831		7,639,059

Total	$	105,000,226	$	110,660,052

Summary of Fair Value of Each Investment in Equity Instrument

The fair value of each investment in equity instrument to be measured at fair value through other comprehensive income is as follows:


		As of December 31,
Type of securities	Name of securities	2024		2025
		NT$		NT$
		(In Thousands)		(In Thousands)
Common stock	UNIMICRON HOLDING LIMITED	$	2,474,388	$	1,973,011
Common stock	ITE TECH. INC.		2,093,997		1,605,398
Common stock	CHIPBOND TECHNOLOGY CORPORATION		3,423,750		2,865,530
Common stock	NOVATEK MICROELECTRONICS CORP. (NOVATEK)		8,255,183		6,150,275
Common stock	KAI-HONG ENERGY CO., LTD.		64,865		67,347
Common stock	SHIN-ETSU HANDOTAI TAIWAN CO., LTD.		692,265		762,930
Common stock	TAIWAN SMART ELECTRICITY & ENERGY CO., LTD.		—		147,450
Preferred stock	MTIC HOLDINGS PTE. LTD.		204,880		202,808

Summary of Income Recognized in Profit or Loss from Equity Instruments Designated as Fair Value Through Other Comprehensive Income

Dividend income recognized in profit or loss from equity instruments designated as fair value through other comprehensive income were listed below:


	For the years ended December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Held at end of period	$	888,826	$	2,085,166
Derecognized during the period		—		—

Total	$	888,826	$	2,085,166

Summary of Details on Derecognition of Such Investments

The Company reclassified its equity instrument investment in SILICON INTEGRATED SYSTEMS CORP. (SIS) as investments accounted for under the equity method. Details on derecognition of such investments are as follow:


	For the years ended December 31,
	2023			2024		2025
	NT$			NT$		NT$
	(In Thousands)			(In Thousands)		(In Thousands)
Fair value on the date of disposal	$	3,035,999		$	—	$	—

Cumulative gains (losses) reclassified to retained earnings due to derecognition	$	(1,628,388	)	$	—	$	—

Aging Analysis of Accounts Receivable

Aging analysis of accounts receivable:


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Neither past due	$	29,338,097	$	28,105,444

Past due:
≤ 30 days		3,292,457		2,565,097
31 to 60 days		77,929		78,880
61 to 90 days		1,249		3,586
91 to 120 days		1,115		6,860
≥ 121 days		23,575		20,637

Subtotal		3,396,325		2,675,060

Total	$	32,734,422	$	30,780,504

Movement of Loss Allowance

Movement of loss allowance for accounts receivable:


	For the years ended December 31,
	2024			2025
	NT$			NT$
	(In Thousands)			(In Thousands)
Beginning balance	$	79,062		$	10,996
Net recognition (reversal) for the period		(68,066	)		(2,651	)

Ending balance	$	10,996		$	8,345

Inventories, Net

(6)

Inventories, Net


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Raw materials	$	10,731,866	$	10,078,373
Supplies and spare parts		6,238,353		5,996,339
Work in process		16,051,506		18,555,155
Finished goods		2,760,739		2,598,516

Total	$	35,782,464	$	37,228,383

Details of Investments Accounted for Under the Equity Method

(7)

Investments Accounted for Under the Equity Method

Details of investments accounted for under the equity method are as follows:


	As of December 31,
	2024				2025
Investee companies	Amount		Percentage of ownership or voting rights		Amount		Percentage of ownership or voting rights
	NT$				NT$
	(In Thousands)				(In Thousands)
Listed companies
SILICON INTEGRATED SYSTEMS CORP. (SIS) (Note A)	$	1,922,753		19.02	$	2,264,435		17.99
FARADAY TECHNOLOGY CORP. (FARADAY) (Note B)		2,484,001		13.80		2,489,096		13.80
UNIMICRON TECHNOLOGY CORP. (UNIMICRON) (Note C)		13,824,584		13.01		14,388,815		13.01
Unlisted companies
MTIC HOLDINGS PTE. LTD. (Note D)		—		45.44		—		45.44
UNITECH CAPITAL INC.		556,610		42.00		524,403		42.00
TRIKNIGHT CAPITAL CORPORATION (TRIKNIGHT) (Note E)		1,298,112		40.00		759,446		40.00
HSUN CHIEH CAPITAL CORP.		266,066		40.00		233,438		40.00
PURIUMFIL INC. (Note F)		12,340		40.00		—		—
HSUN CHIEH INVESTMENT CO., LTD. (HSUN CHIEH) (Note G)		4,723,930		36.49		4,855,031		36.49
YANN YUAN INVESTMENT CO., LTD. (YANN YUAN)		8,044,460		26.78		11,231,446		26.78
UNITED LED CORPORATION HONG KONG LIMITED		101,468		25.14		122,982		25.14
VSENSE CO., LTD. (VSENSE) (Note D and H)		—		23.98		—		—
TRANSLINK CAPITAL PARTNERS I, L.P. (Note I)		40,545		10.38		—		—

Total	$	33,274,869			$	36,869,092

Note A:

In August 2023, the board chairman of SIS changed and became the same person as the board chairman of UMC. After considering the comprehensive conditions, including ownership interest held and representation on Board of Directors of SIS, etc., the Company determines that it has significant influence over SIS and accounts for its investment in SIS as an associate. SIS was previously measured at fair value through other comprehensive income and reclassified as investments accounted for under the equity method. UMC’s share of the net fair value of SIS’s identifiable assets and liabilities was in excess of the fair value of the previously held investment in SIS at the acquisition date, and the difference was recognized as bargain purchase gain. Cumulative fair value change that was previously recognized in other comprehensive loss up to reclassification date was reclassified to retained earnings in the current period. SIS executed a capital reduction and refunded NT$499 million based on UMC’s stockholding percentage in July 2024.

Note B:

Beginning from June 2015, the Company accounts for its investment in FARADAY as an associate given the fact that UMC obtained the ability to exercise significant influence over FARADAY through representation on its Board of Directors. The Company participated in the capital increase of FARADAY in March 2024. Please refer to Note 7 for the relevant information.

Note C:

Beginning from June 2020, the Company accounts for its investment in UNIMICRON as an associate given the fact that UMC obtained the ability to exercise significant influence over UNIMICRON through representation on its Board of Directors. On January 6, 2023, UNIMICRON issued new shares to merge with SUBTRON TECHNOLOGY CO., LTD. (SUBTRON) through share conversion. The share conversion ratio was 1 common share of SUBTRON to exchange 0.219 common shares of UNIMICRON. The 23 million shares of SUBTRON held by the Company were exchanged to 5 million common shares newly issued by UNIMICRON.

Note D:

When the Company’s share of losses of an associate equals or exceeds its interest in that associate, the Company discontinues recognizing its share of further losses. Additional losses and liabilities are recognized only to the extent that the Company has incurred legal or constructive obligations or made payments on behalf of that associate.

Note E:

TRIKNIGHT executed a capital reduction and refunded NT$760 million and NT$232 million based on UMC’s stockholding percentage in 2024 and 2025, respectively.

Note F:

In August 2025, the Board of Directors of the Company’s subsidiary, TERA ENERGY, resolved to merge with PURIUMFIL INC., with TERA ENERGY as the surviving company. The effective date of merger is October 3, 2025.

Note G:

HSUN CHIEH executed a capital reduction and refunded NT$343 million and NT$343 million based on UMC’s stockholding percentage in 2024 and 2025, respectively.

Note H:

VSENSE has ceased operations. The Company’s subsidiary

longer participates in the financial and operating policy decisions of the investee, therefore losing significant influence over it. Accordingly, the investment was discontinued from being accounted for under the equity method and was reclassified as a financial asset at fair value through profit or loss.

Note I:

The Company follows international accounting practices in equity accounting for limited partnerships and uses the equity method to account for these investees. The investee was dissolved in April 2025.

Property, Plant and Equipment

(8)

Property, Plant and Equipment

2024

Assets Used by the Company:

Cost:


	Land			Buildings			Machinery and equipment			Transportation equipment		Furniture and fixtures			Leasehold improvement			Construction in progress and equipment awaiting inspection			Total
	NT$			NT$			NT$			NT$		NT$			NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
As of January 1, 2024	$	1,430,338		$	38,369,863		$	1,021,498,821		$	71,712	$	8,873,468		$	65,823		$	82,358,651		$	1,152,668,676
Additions		—			32,999			—			—		—			—			76,514,788			76,547,787
Disposals		—			(1,019	)		(2,198,549	)		—		(73,357	)		(43	)		(708	)		(2,273,676	)
Disposal of a subsidiary		—			(119,322	)		—			—		(40,364	)		—			—			(159,686	)
Transfers and reclassifications		—			26,772,957			93,484,809			5,087		717,154			—			(117,585,901	)		3,394,106
Exchange effect		(19,542	)		532,534			13,761,646			1,221		56,331			2,627			3,480,772			17,815,589

As of December 31, 2024	$	1,410,796		$	65,588,012		$	1,126,546,727		$	78,020	$	9,533,232		$	68,407		$	44,767,602		$	1,247,992,796


Accumulated Depreciation and Impairment:
	Land		Buildings			Machinery and equipment			Transportation equipment		Furniture and fixtures			Leasehold improvement			Construction in progress and equipment awaiting inspection		Total
	NT$		NT$			NT$			NT$		NT$			NT$			NT$		NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)		(In Thousands)
As of January 1, 2024	$	—	$	24,028,140		$	884,088,674		$	56,257	$	7,056,013		$	63,038		$	—	$	915,292,122
Depreciation		—		1,474,732			42,716,755			4,663		521,994			1,879			—		44,720,023
Disposals		—		(109	)		(2,153,787	)		—		(72,920	)		(43	)		—		(2,226,859	)
Disposal of a subsidiary		—		(27,083	)		—			—		(20,056	)		—			—		(47,139	)
Exchange effect		—		199,320			12,658,149			813		49,355			2,590			—		12,910,227

As of December 31, 2024	$	—	$	25,675,000		$	937,309,791		$	61,733	$	7,534,386		$	67,464		$	—	$	970,648,374

Net carrying amount:
As of December 31, 2024	$	1,410,796	$	39,913,012		$	189,236,936		$	16,287	$	1,998,846		$	943		$	44,767,602	$	277,344,422

Assets Subject to Operating Leases:

Cost:


	Land			Buildings		Machinery and equipment		Furniture and fixtures		Total
	NT$			NT$		NT$		NT$		NT$
	(In Thousands)			(In Thousands)		(In Thousands)		(In Thousands)		(In Thousands)
As of January 1, 2024	$	539,703		$	2,440,917	$	6,345	$	1,385,740	$	4,372,705
Transfers and reclassifications		—			2,000		—		15,166		17,166
Exchange effect		(2,982	)		18,095		—		8,558		23,671

As of December 31, 2024	$	536,721		$	2,461,012	$	6,345	$	1,409,464	$	4,413,542


Accumulated Depreciation and Impairment:
	Land		Buildings		Machinery and equipment		Furniture and fixtures		Total
	NT$		NT$		NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)		(In Thousands)		(In Thousands)
As of January 1, 2024	$	—	$	1,297,068	$	6,345	$	1,322,598	$	2,626,011
Depreciation		—		39,193		—		14,235		53,428
Exchange effect		—		10,945		—		8,543		19,488

As of December 31, 2024	$	—	$	1,347,206	$	6,345	$	1,345,376	$	2,698,927

Net carrying amount:
As of December 31, 2024	$	536,721	$	1,113,806	$	—	$	64,088	$	1,714,615

2025

Assets Used by the Company:

Cost:


	Land			Buildings			Machinery and equipment			Transportation equipment			Furniture and fixtures			Leasehold improvement			Construction in progress and equipment awaiting inspection			Total
	NT$			NT$			NT$			NT$			NT$			NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
As of January 1, 2025	$	1,410,796		$	65,588,012		$	1,126,546,727		$	78,020		$	9,533,232		$	68,407		$	44,767,602		$	1,247,992,796
Additions		—			210,455			—			—			—			—			45,950,074			46,160,529
Disposals		—			(27,441	)		(3,189,633	)		(550	)		(6,087	)		—			—			(3,223,711	)
Transfers and reclassifications		—			2,908,510			63,912,986			4,388			1,417,913			2,141			(61,713,893	)		6,532,045
Exchange effect		(24,825	)		(1,272,200	)		(8,002,570	)		(702	)		7,477			(2,458	)		(2,037,219	)		(11,332,497	)

As of December 31, 2025	$	1,385,971		$	67,407,336		$	1,179,267,510		$	81,156		$	10,952,535		$	68,090		$	26,966,564		$	1,286,129,162


Accumulated Depreciation and Impairment:
	Land		Buildings			Machinery and equipment			Transportation equipment			Furniture and fixtures			Leasehold improvement			Construction in progress and equipment awaiting inspection		Total
	NT$		NT$			NT$			NT$			NT$			NT$			NT$		NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)		(In Thousands)
As of January 1, 2025	$	—	$	25,675,000		$	937,309,791		$	61,733		$	7,534,386		$	67,464		$	—	$	970,648,374
Depreciation		—		2,281,586			52,737,289			4,096			641,419			2,066			—		55,666,456
Disposals		—		(27,441	)		(3,182,973	)		(550	)		(6,083	)		—			—		(3,217,047	)
Exchange effect		—		(117,329	)		(6,536,050	)		(384	)		(4,873	)		(2,394	)		—		(6,661,030	)

As of December 31, 2025	$	—	$	27,811,816		$	980,328,057		$	64,895		$	8,164,849		$	67,136		$	—	$	1,016,436,753

Net carrying amount:
As of December 31, 2025	$	1,385,971	$	39,595,520		$	198,939,453		$	16,261		$	2,787,686		$	954		$	26,966,564	$	269,692,409

Assets Subject to Operating Leases:

Cost:


	Land			Buildings			Machinery and equipment		Furniture and fixtures			Total
	NT$			NT$			NT$		NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)		(In Thousands)			(In Thousands)
As of January 1, 2025	$	536,721		$	2,461,012		$	6,345	$	1,409,464		$	4,413,542
Disposals		—			(1,250	)		—		(512	)		(1,762	)
Transfers and reclassifications		—			22,190			—		27,754			49,944
Exchange effect		(3,787	)		(8,906	)		—		(917	)		(13,610	)

As of December 31, 2025	$	532,934		$	2,473,046		$	6,345	$	1,435,789		$	4,448,114


Accumulated Depreciation and Impairment:
	Land		Buildings			Machinery and equipment		Furniture and fixtures			Total
	NT$		NT$			NT$		NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)		(In Thousands)			(In Thousands)
As of January 1, 2025	$	—	$	1,347,206		$	6,345	$	1,345,376		$	2,698,927
Depreciation		—		39,458			—		15,754			55,212
Disposals		—		(476	)		—		(512	)		(988	)
Exchange effect		—		(6,540	)		—		(1,384	)		(7,924	)

As of December 31, 2025	$	—	$	1,379,648		$	6,345	$	1,359,234		$	2,745,227

Net carrying amount:
As of December 31, 2025	$	532,934	$	1,093,398		$	—	$	76,555		$	1,702,887

Summary of Interest Expense Capitalized

Details of interest expense capitalized were as follows:


	For the years ended December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Interest expense capitalized	$	13,560	$	6,777

Interest rates applied		1.52% - 1.96%		1.64% - 1.81%

Disclosure Of Detailed Information About Lease Right Of Use Assets Explanatory

The Company as a lessee

(a)

Right-of-use

Assets


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Land (including land use right)	$	5,755,484	$	5,416,282
Buildings		168,568		73,432
Machinery and equipment		2,082,479		1,952,668
Transportation equipment		12,561		13,918
Other equipment		19,923		19,734

Net	$	8,039,015	$	7,476,034


	For the years ended December 31,
	2024		2025
	NT$		NT$
Depreciation	(In Thousands)		(In Thousands)
Land (including land use right)	$	377,882	$	375,604
Buildings		87,486		77,133
Machinery and equipment		220,734		239,391
Transportation equipment		10,852		9,773
Other equipment		1,697		3,808

Total	$	698,651	$	705,709

For the years ended December 31, 2024 and 2025, the Company’s addition to

right-of-use

assets amounted to NT$1,683 million and NT$344 million, respectively.

ii.

Please refer to Note 8 for

right-of-use

assets pledged as collateral.

(b)

Lease Liabilities


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Current	$	636,357	$	624,825
Non-current		5,782,659		5,376,021

Total	$	6,419,016	$	6,000,846

Please refer to Note 6(24) for the interest expenses on the lease liabilities.

Intangible Assets

(10)

Intangible Assets

2024

Cost


	Goodwill		Software			Patents and technology license fees			Others			Total
	NT$		NT$			NT$			NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
As of January 1, 2024	$	15,012	$	5,466,077		$	1,773,541		$	3,310,641		$	10,565,271
Additions		—		1,328,781			95,245			860,615			2,284,641
Write-off		—		(1,290,196	)		(214,874	)		(1,215,013	)		(2,720,083	)
Disposal of a subsidiary		—		(3,151	)		—			—			(3,151	)
Reclassifications		—		7,363			—			—			7,363
Exchange effect		—		(32,375	)		388,567			(4,971	)		351,221

As of December 31, 2024	$	15,012	$	5,476,499		$	2,042,479		$	2,951,272		$	10,485,262

Accumulated Amortization and Impairment


	Goodwill		Software			Patents and technology license fees			Others			Total
	NT$		NT$			NT$			NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
As of January 1, 2024	$	7,398	$	2,890,831		$	908,965		$	2,385,522		$	6,192,716
Amortization		—		1,656,180			216,437			763,921			2,636,538
Write-off		—		(1,290,196	)		(214,874	)		(1,215,013	)		(2,720,083	)
Disposal of a subsidiary		—		(2,025	)		—			—			(2,025	)
Exchange effect		—		(23,675	)		252,269			(4,793	)		223,801

As of December 31, 2024	$	7,398	$	3,231,115		$	1,162,797		$	1,929,637		$	6,330,947

Net carrying amount:
As of December 31, 2024	$	7,614	$	2,245,384		$	879,682		$	1,021,635		$	4,154,315


2025
Cost :
	Goodwill		Software			Patents and technology license fees			Others			Total
	NT$		NT$			NT$			NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
As of January 1, 2025	$	15,012	$	5,476,499		$	2,042,479		$	2,951,272		$	10,485,262
Additions		—		2,450,285			7,684			893,015			3,350,984
Write-off		—		(2,221,557	)		(259,094	)		(514,173	)		(2,994,824	)
Acquisition of a subsidiary		19,565		—			—			—			19,565
Exchange effect		—		(73,952	)		54,411			(5,491	)		(25,032	)

As of December 31, 2025	$	34,577	$	5,631,275		$	1,845,480		$	3,324,623		$	10,835,955

Accumulated Amortization and Impairment


	Goodwill		Software			Patents and technology license fees			Others			Total
	NT$		NT$			NT$			NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
As of January 1, 2025	$	7,398	$	3,231,115		$	1,162,797		$	1,929,637		$	6,330,947
Amortization		—		1,736,793			241,726			772,988			2,751,507
Write-off		—		(2,221,557	)		(259,094	)		(514,173	)		(2,994,824	)
Exchange effect		—		(28,701	)		40,349			(6,199	)		5,449

As of December 31, 2025	$	7,398	$	2,717,650		$	1,185,778		$	2,182,253		$	6,093,079

Net carrying amount:
As of December 31, 2025	$	27,179	$	2,913,625		$	659,702		$	1,142,370		$	4,742,876

Amortization Amounts of Intangible Assets

The amortization amounts of intangible assets were as follows:


	For the years ended December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Operating costs	$	999,321	$	1,246,679

Operating expenses	$	1,637,217	$	1,504,828

Details of Loans

(11)

Short-Term Loans


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Unsecured bank loans	$	8,515,000	$	8,408,772


	As of December 31,
	2024		2025
Interest rates applied		1.87% - 2.99%		1.78% - 4.75%

Financial Liabilities at Fair Value Through Profit or Loss, Current

(12)

Financial Liabilities at Fair Value through Profit or Loss, Current


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Embedded derivatives in exchangeable bonds	$	899,961	$	54,651
Forward exchange contracts		1,039		2,512

Total	$	901,000	$	57,163

Bonds Payable

(13)

Bonds Payable


	As of December 31,
	2024			2025
	NT$			NT$
	(In Thousands)			(In Thousands)
Unsecured domestic bonds payable	$	24,600,000		$	44,600,000
Unsecured exchangeable bonds payable		5,757,373			5,757,373
Less: Discounts on bonds payable		(305,805	)		(129,068	)

Total		30,051,568			50,228,305
Less: Current or exchangeable portion due within one year		(5,466,589	)		(16,157,161	)

Net	$	24,584,979		$	34,071,144

Summary of Terms and Conditions of Bonds

UMC issued domestic unsecured corporate bonds. The terms and conditions of the bonds are as follows:


Term	Issuance date	Issued amount	Coupon rate		Repayment
Five-year	In late April 2021	NT$5,500 million		0.57%	Interest will be paid annually and the principal will be repayable in April 2026 upon maturity.
Seven-year	In late April 2021	NT$2,000 million		0.63%	Interest will be paid annually and the principal will be repayable in April 2028 upon maturity.
Ten-year (Green bond)	In late April 2021	NT$2,100 million		0.68%	Interest will be paid annually and the principal will be repayable in April 2031 upon maturity.
Five-year	In mid-December 2021	NT$5,000 million		0.63%	Interest will be paid annually and the principal will be repayable in December 2026 upon maturity.
Five-year (Green bond)	In mid-September 2023	NT$10,000 million		1.62%	Interest will be paid annually and the principal will be repayable in September 2028 upon maturity.
Five-year (Green bond)	In late June 2025	NT$2,000 million		1.94%	Interest will be paid annually and the principal will be repayable in June 2030 upon maturity.
Five-year	In late June 2025	NT$3,200 million		1.99%	Interest will be paid annually and the principal will be repayable in June 2030 upon maturity.
Three-year	In late August 2025	NT$5,000 million		1.80%	Interest will be paid annually and the principal will be repayable in August 2028 upon maturity.
Three-year	In late October 2025	NT$5,000 million		1.70%	Interest will be paid annually and the principal will be repayable in October 2028 upon maturity.
Three-year	In early December 2025	NT$2,300 million		1.55%	Interest will be paid annually and the principal will be repayable in December 2028 upon maturity.
Five-year	In early December 2025	NT$2,500 million		1.60%	Interest will be paid annually and the principal will be repayable in December 2030 upon maturity.

Defined Benefit Plan Recognized on the Consolidated Balance Sheets

iii.

The defined benefit plan recognized on the consolidated balance sheets were as follows:


	As of December 31,
	2024			2025
	NT$ (In Thousands)			NT$ (In Thousands)
Present value of the defined benefit obligation	$	(4,392,723	)	$	(4,250,522	)
Fair value of plan assets		2,960,474			3,384,303

Funded status		(1,432,249	)		(866,219	)

Net defined benefit liabilities, noncurrent recognized on the consolidated balance sheets	$	(1,432,249	)	$	(866,219	)

Major Categories of Plan Assets as a Percentage of Fair Value of the Total Plan Assets

iv.

The major categories of plan assets as a percentage of the fair value of the total plan assets are as follows:


	As of December 31,
	2024			2025
Cash		21	%		16	%
Equity instruments		47	%		51	%
Debt instruments		21	%		22	%
Others		11	%		11	%

Principal Underlying Actuarial Assumptions

The principal underlying actuarial assumptions are as follows:


	As of December 31,
	2024			2025
Discount rate		1.59	%		1.31	%
Rate of future salary increase		3.50	%		3.50	%

Expected Future Benefit Payments

vi.

Expected future benefit payments are as follows:


Year	As of December 31, 2025
	NT$ (In Thousands)
2026	$	419,212
2027		400,471
2028		395,448
2029		402,632
2030		375,509
2031 and thereafter		2,666,697

Total	$	4,659,969

Sensitivity Analysis

vii.

Sensitivity analysis:


	As of December 31, 2024
	Discount rate					Rate of future salary increase
	0.5% increase		0.5% decrease			0.5% increase			0.5% decrease
	NT$ (In Thousands)		NT$ (In Thousands)			NT$ (In Thousands)			NT$ (In Thousands)
Decrease (increase) in defined benefit obligation	$	154,095	$	(163,088	)	$	(137,421	)	$	131,562


	As of December 31, 2025
	Discount rate					Rate of future salary increase
	0.5% increase		0.5% decrease			0.5% increase			0.5% decrease
	NT$ (In Thousands)		NT$ (In Thousands)			NT$ (In Thousands)			NT$ (In Thousands)
Decrease (increase) in defined benefit obligation	$	141,345	$	(149,276	)	$	(124,357	)	$	119,311

Deferred Government Grants

(16)

Deferred Government Grants


	As of December 31,
	2024			2025
	NT$ (In Thousands)			NT$ (In Thousands)
Beginning balance	$	2,547,022		$	3,961,028
Arising during the period		2,131,264			5,097,841
Recorded in profit or loss:
Other operating income		(841,091	)		(1,520,370	)
Exchange effect		123,833			(271,994	)

Ending balance	$	3,961,028		$	7,266,505

Current (classified under other current liabilities)	$	906,935		$	1,781,746
Non-current (classified under other noncurrent liabilities)		3,054,093			5,484,759

Total	$	3,961,028		$	7,266,505

Summary of Refund Liabilities (classified under other current liabilities)

(17)

Refund Liabilities (classified under other current liabilities)


	As of December 31,
	2024		2025
	NT$ (In Thousands)		NT$ (In Thousands)
Refund liabilities	$	3,918,437	$	4,309,253

Summary of Provisions

(18)

Provisions


	As of December 31,
	2024		2025
	NT$ (In Thousands)		NT$ (In Thousands)
Decommissioning Liabilities (classified under other noncurrent liabilities)	$	695,168	$	898,273
Onerous Contracts (classified under other current liabilities)		281,244		160,114
Others (classified under other current liabilities)		—		69,202

Total	$	976,412	$	1,127,589

Summary of Information about Provisions of Liabilities


	Decommissioning Liabilities			Onerous Contracts			Others
	NT$ (In Thousands)			NT$ (In Thousands)			NT$ (In Thousands)
Balance as of January 1, 2025	$	695,168		$	281,244		$	—
Arising during the period		155,245			84,324			68,899
Unused provision reversed		—			(203,266	)		—
Discount rate adjustment and unwinding of discount from the passage of time		75,027			—			—
Exchange effect		(27,167	)		(2,188	)		303

Balance as of December 31, 2025	$	898,273		$	160,114		$	69,202

Summary of Stock Held by Associates

Details of UMC’s stock (thousand shares) held by the Company’s associates are as follows:


	As of December 31,
	2024		2025
HSUN CHIEH		441,371		441,371
SIS		266,580		266,580
YANN YUAN		192,963		192,963
UNIMICRON and its Subsidiaries		47		27

Total		900,961		900,941

Details of Distribution

The details of appropriation were as follows:


	Appropriation of earnings (in thousand NT dollars)				Cash dividend per share (NT dollars)
	2024		2025		2024		2025
Legal reserve	$	4,738,237	$	4,182,207
Cash dividends		35,787,598		32,704,164	$	2.85	$	2.60

Non-controlling Interests

Non-controlling

interests:


	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Balance as of January 1	$	343,679		$	340,859		$	256,613
Attributable to non-controlling interests:
Net income (loss)		450,184			(104,674	)		(181,501	)
Other comprehensive income (loss)		(14	)		76			(22	)
Share-based payment transactions		5,817			1,913			1,428
Changes in subsidiaries’ ownership		456			(7,910	)		(11,826	)
Others		4,187			26,349			22,483
Derecognition of the non-controlling interests		(463,450	)		—			—

Ending balance	$	340,859		$	256,613		$	87,175

Summary of Disaggregation of Revenue by Product

(21)

Operating Revenues

Disaggregation of revenue

By product


	For the years ended December 31,
	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Wafer	$	211,750,622	$	221,820,412	$	227,595,224
Others		10,782,378		10,482,172		9,957,975

Total	$	222,533,000	$	232,302,584	$	237,553,199

Summary of Disaggregation of Revenue by Geography

ii.

By geography


	For the years ended December 31,
	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Taiwan	$	68,360,231	$	83,758,430	$	91,735,839
China (includes Hong Kong)		27,545,452		37,117,309		37,604,210
Japan		11,612,866		9,107,394		10,370,412
Korea		30,872,198		26,295,063		25,389,728
USA		59,103,051		58,117,650		52,191,603
Europe		24,932,099		17,902,262		20,254,391
Others		107,103		4,476		7,016

Total	$	222,533,000	$	232,302,584	$	237,553,199

Summary of Disaggregation of Revenue by the Timing of Revenue Recognition

iii.

By the timing of revenue recognition


	For the years ended December 31,
	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
At a point in time	$	220,283,306	$	229,505,369	$	234,505,273
Over time		2,249,694		2,797,215		3,047,926

Total	$	222,533,000	$	232,302,584	$	237,553,199

Summary of Balances of Contract Assets and Contract Liabilities

Contract balances

Contract assets, current


	As of January 1,			As of December 31,
	2024			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Sales of goods and services	$	1,132,477		$	1,043,680		$	1,107,419
Less: Loss allowance		(392,949	)		(417,967	)		(402,021	)

Net	$	739,528		$	625,713		$	705,398

The loss allowance was assessed by the Company primarily at an amount equal to lifetime expected credit losses. The loss allowance was mainly resulted from the suspension of the joint technology development agreement due to litigation.

ii.

Contract liabilities


	As of January 1,		As of December 31,
	2024		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Sales of goods and services	$	3,681,352	$	2,660,181	$	4,368,164


Current	$	3,250,712	$	2,200,561	$	2,580,789
Non-current		430,640		459,620		1,787,375

Total	$	3,681,352	$	2,660,181	$	4,368,164

The movement of contract liabilities is mainly caused by the timing difference of the satisfaction of a performance of obligation and the consideration received from customers.

Employee Benefit, Depreciation and Amortization Expenses

The Company’s employee benefit, depreciation and amortization expenses are summarized as follows:


	For the years ended December 31,
	2023						2024						2025
	Operating costs		Operating expenses		Total		Operating costs		Operating expenses		Total		Operating costs		Operating expenses		Total
	NT$						NT$						NT$
	(In Thousands)						(In Thousands)						(In Thousands)
Employee benefit expenses
Salaries	$	26,693,905	$	12,002,205	$	38,696,110	$	25,959,209	$	11,485,738	$	37,444,947	$	25,094,595	$	10,696,857	$	35,791,452
Labor and health insurance		1,502,553		557,543		2,060,096		1,383,016		527,153		1,910,169		1,289,440		500,731		1,790,171
Pension		1,240,577		460,079		1,700,656		1,511,302		501,915		2,013,217		1,573,958		513,437		2,087,395
Other employee benefit expenses		421,871		196,739		618,610		401,329		207,925		609,254		393,893		195,790		589,683
Depreciation		36,006,021		1,545,067		37,551,088		43,740,758		1,595,934		45,336,692		53,321,558		2,979,597		56,301,155
Amortization		1,277,920		1,448,561		2,726,481		1,041,562		1,654,002		2,695,564		1,309,907		1,521,633		2,831,540

Details of Distribution of Employees' Compensation and Directors' Compensation

The details of distribution were as follows:


	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Employees’ compensation – Cash	$	5,439,059	$	4,509,603	$	3,438,287
Directors’ compensation		45,000		45,000		45,000

Net Other Operating Income and Expenses

(23)

Net Other Operating Income and Expenses


	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Government grants	$	3,862,001		$	1,337,458		$	1,890,945
Rental income from property, plant and equipment		202,082			202,010			188,167
Gain on disposal of property, plant and equipment		268,293			72,402			99,178
Others		(330,050	)		(287,961	)		(188,411	)

Total	$	4,002,326		$	1,323,909		$	1,989,879

Non-Operating Income and Expenses

(24)

Non-Operating

Income and Expenses

Other gains and losses


	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Gain (loss) on valuation of financial assets and liabilities at fair value through profit or loss	$	(40,553	)	$	(320,956	)	$	707,129
Gain (loss) on disposal of investments accounted for under the equity method		163,395			(2,093	)		218,088
Others		100,254			20,345			(6	)

Total	$	223,096		$	(302,704	)	$	925,211

Finance costs


	For the years ended December 31,
	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Interest expenses
Bonds payable	$	444,424	$	500,757	$	552,736
Bank loans		833,548		963,263		762,064
Lease liabilities		179,367		196,457		193,942
Others		16,390		18,225		20,321
Financial expenses		96,645		77,398		73,002

Total	$	1,570,374	$	1,756,100	$	1,602,065

Components of Other Comprehensive Income (Loss)

(25)

Components of Other Comprehensive Income (Loss)


	For the year ended December 31, 2023
	Arising during the period			Reclassification adjustments during the period			Other comprehensive income (loss), before tax			Income tax effect			Other comprehensive income (loss), net of tax
	NT$			NT$			NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
Items that will not be reclassified subsequently to profit or loss:
Remeasurements of defined benefit pension plans	$	402,234		$	—		$	402,234		$	(80,447	)	$	321,787
Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income		5,530,359			—			5,530,359			(243,057	)		5,287,302
Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss		1,610,116			—			1,610,116			(90,891	)		1,519,225
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		(2,386,278	)		—			(2,386,278	)		386,660			(1,999,618	)
Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss		(73,005	)		(1,413	)		(74,418	)		3,768			(70,650	)

Total other comprehensive income (loss)	$	5,083,426		$	(1,413	)	$	5,082,013		$	(23,967	)	$	5,058,046


	For the year ended December 31, 2024
	Arising during the period			Reclassification adjustments during the period			Other comprehensive income (loss), before tax			Income tax effect			Other comprehensive income (loss), net of tax
	NT$			NT$			NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
Items that will not be reclassified subsequently to profit or loss:
Remeasurements of defined benefit pension plans	$	188,451		$	—		$	188,451		$	(37,690	)	$	150,761
Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income		(539,327	)		—			(539,327	)		25,123			(514,204	)
Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss		301,134			—			301,134			28,783			329,917
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		8,902,745			—			8,902,745			153,317			9,056,062
Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss		324,191			(817	)		323,374			(24,317	)		299,057

Total other comprehensive income (loss)	$	9,177,194		$	(817	)	$	9,176,377		$	145,216		$	9,321,593


	For the year ended December 31, 2025
	Arising during the period			Reclassification adjustments during the period			Other comprehensive income (loss), before tax			Income tax effect			Other comprehensive income (loss), net of tax
	NT$			NT$			NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
Items that will not be reclassified subsequently to profit or loss:
Remeasurements of defined benefit pension plans	$	145,103		$	—		$	145,103		$	(29,021	)	$	116,082
Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income		(3,423,919	)		—			(3,423,919	)		216,422			(3,207,497	)
Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss		3,090,371			—			3,090,371			(157,629	)		2,932,742
Items that may be reclassified subsequently to profit or loss:
Exchange differences on translation of foreign operations		(5,848,451	)		—			(5,848,451	)		508,067			(5,340,384	)
Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss		(17,326	)		7			(17,319	)		7,292			(10,027	)

Total other comprehensive income (loss)	$	(6,054,222	)	$	7		$	(6,054,215	)	$	545,131		$	(5,509,084	)

Major Components of Income Tax Expense

(26)

Income Tax

The major components of income tax expense (benefit) for the years ended December 31, 2023, 2024 and 2025 were as follows:

Income tax expense (benefit) recorded in profit or loss


	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Current income tax expense (benefit):
Current income tax charge	$	6,426,598		$	6,105,080		$	6,058,083
Adjustments in respect of current income tax of prior periods		(217,891	)		(124,430	)		183,830
Income tax expense affected by the Pillar Two legislation		—			—			151,151
Deferred income tax expense (benefit):
Deferred income tax related to origination and reversal of temporary differences		2,239,309			2,441,278			4,046,336
Deferred income tax related to recognition and derecognition of tax losses and unused tax credits		—			(34,010	)		(2,484,730	)
Deferred income tax related to changes in tax rates		—			68			(15,461	)
Adjustment of prior year’s deferred income tax		(120,230	)		(3,227	)		(22,269	)
Deferred income tax arising from write-down or reversal of write-down of deferred tax assets		(16,516	)		(14,565	)		(14,086	)

Income tax expense recorded in profit or loss	$	8,311,270		$	8,370,194		$	7,902,854

ii.

Deferred income tax related to components of other comprehensive income (loss)


(i) Items that will not be reclassified subsequently to profit or loss:

	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Remeasurements of defined benefit pension plans	$	(80,447	)	$	(37,690	)	$	(29,021	)
Unrealized gains or losses from equity instruments investments measured at fair value through other comprehensive income		(243,057	)		25,123			216,422
Share of other comprehensive income (loss) of associates and joint ventures which will not be reclassified subsequently to profit or loss		(90,891	)		28,783			(157,629	)

Income tax related to items that will not be reclassified subsequently to profit or loss	$	(414,395	)	$	16,216		$	29,772


(ii) Items that may be reclassified subsequently to profit or loss:

	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Exchange differences on translation of foreign operations	$	386,660		$	153,317		$	508,067
Share of other comprehensive income (loss) of associates and joint ventures which may be reclassified subsequently to profit or loss		3,768			(24,317	)		7,292

Income tax related to items that may be reclassified subsequently to profit or loss	$	390,428		$	129,000		$	515,359


iii. Deferred income tax charged directly to equity

	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Share of the net assets of the subsidiary	$	—		$	—		$	(20,703	)
Adjustments of changes in net assets of associates and joint ventures accounted for using equity method		(1,117	)		1,174			(4,556	)

Deferred income tax charged directly to equity	$	(1,117	)	$	1,174		$	(25,259	)

Reconciliation Between Income Tax Expense and Income Before Tax at UMC's Applicable Tax Rate

A reconciliation between income tax expense (benefit) and income before tax at UMC’s applicable tax rate were as follows:


	For the years ended December 31,
	2023			2024			2025
	NT$			NT$			NT$
	(In Thousands)			(In Thousands)			(In Thousands)
Income before tax	$	68,450,404		$	57,044,820		$	48,081,667

At UMC’s statutory income tax rate		13,690,081			11,408,964			9,616,333
Adjustments in respect of current income tax of prior periods		(217,891	)		(124,430	)		183,830
Net changes in loss carry-forward and investment tax credits		(2,179,234	)		(2,026,085	)		(5,737,173	)
Adjustment of deferred tax assets/liabilities for write-downs/reversals and different jurisdictional tax rates		211,639			559,386			(3,354,038	)
Tax effect of non-taxable income and non-deductible expenses:
Tax exempt income		(1,428,035	)		(472,756	)		(617,013	)
Investment loss (gain)		(755,800	)		205,207			6,941,947
Dividend income		(323,182	)		(231,267	)		(224,961	)
Others		(145,520	)		(610,092	)		(32,566	)
Basic tax		43,506			13,414			12,095
Estimated income tax on unappropriated earnings		(1,160,324	)		(743,264	)		(210,104	)
Deferred income tax related to changes in tax rates		—			68			(15,461	)
Effect of different tax rates applicable to UMC and its subsidiaries		234,510			15,673			896,819
Taxes withheld in other jurisdictions		38,346			44,489			105,847
Others		303,174			330,887			337,299

Income tax expense recorded in profit or loss	$	8,311,270		$	8,370,194		$	7,902,854

Significant Components of Deferred Income Tax Assets and Liabilities

Significant components of deferred income tax assets and liabilities were as follows:


	As of December 31,
	2024			2025
	NT$			NT$
	(In Thousands)			(In Thousands)
Deferred income tax assets
Depreciation	$	2,616,538		$	2,692,711
Loss carry-forward		34,089			2,626,791
Pension		281,385			167,955
Refund liabilities		318,156			647,274
Allowance for inventory valuation losses		726,023			971,023
Investment loss		328,241			414,290
Unrealized profit on intercompany sales		471,583			254,047
Others		448,488			801,225

Total deferred income tax assets		5,224,503			8,575,316


Deferred income tax liabilities
Depreciation		(4,387,572	)		(981,906	)
Investment gain		(3,093,367	)		(10,097,893	)
Amortizable assets		(283,111	)		(273,908	)
Others		(354,201	)		(861,730	)

Total deferred income tax liabilities		(8,118,251	)		(12,215,437	)

Net deferred income tax assets (liabilities)	$	(2,893,748	)	$	(3,640,121	)

Movement of Deferred Tax

Movement of deferred tax


	For the years ended December 31,
	2024			2025
	NT$			NT$
	(In Thousands)			(In Thousands)
Balance as of January 1	$	(501,553	)	$	(2,893,748	)
Amounts recognized in profit or loss during the period		(2,389,544	)		(1,509,790	)
Amounts recognized in other comprehensive income (loss)		145,216			545,131
Amounts recognized in equity		1,174			(25,259	)
Exchange adjustments		(149,041	)		243,545

Balance as of December 31	$	(2,893,748	)	$	(3,640,121	)

Earnings Per Share

(27)

Earnings Per Share

Earnings per share-basic


	For the years ended December 31,
	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Net income attributable to the parent company	$	59,688,950	$	48,779,300	$	40,360,314

Weighted-average number of ordinary shares for basic earnings per share (thousand shares)		12,137,954		12,173,188		12,224,783

Earnings per share-basic (NTD)	$	4.92	$	4.01	$	3.30

Earnings per share-diluted


	For the years ended December 31,
	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Net income attributable to the parent company	$	59,688,950	$	48,779,300	$	40,360,314

Weighted-average number of ordinary shares for basic earnings per share (thousand shares)		12,137,954		12,173,188		12,224,783
Effect of dilution
Restricted stocks for employees		114,974		69,881		36,037
Employees’ compensation		129,196		122,400		85,792

Weighted-average number of ordinary shares after dilution (thousand shares)		12,382,124		12,365,469		12,346,612

Earnings per share-diluted (NTD)	$	4.82	$	3.94	$	3.27

Disclosure of Equity-Settled Share-Based Payment of Restricted Stock Plans for Employees

The equity-settled share-based payment of restricted stock plans for employees in each year are as follows:

2024 Plan

2022 Plan

2020 Plan

1st tranche

2nd tranche

1st tranche

2nd tranche

1st tranche

2nd tranche

Resolution date of UMC’s shareholders meeting

May 30, 2024

May 27, 2022

June 10, 2020

Maximum shares to be issued (in thousands)

66,000

50,000

233,200

Eligible employees

Qualified employees

of the Company

Qualified employees
of the Company

Qualified employees of UMC

Issuance of shares (in thousands)

32,956

32,878

23,060

26,728

200,030

1,268

Issuance date

December 5, 2024

December 5, 2025

December 5, 2022

December 5, 2023

September 1, 2020

June 9, 2021

Weighted-average fair value on the grant date (NT$/ per share)

$39.27

$41.70

$44.40

$48.90

$21.80

$53.00

Reconciliation of Liabilities Arising from Financing Activities

(28)

Reconciliation of Liabilities Arising from Financing Activities

For the year ended December 31, 2023


						Non-cash changes
Items	As of January 1, 2023		Cash Flows			Foreign exchange			Others (Note A)			As of December 31, 2023
	NT$		NT$			NT$			NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
Short-term loans	$	—	$	13,530,000		$	—		$	—		$	13,530,000
Bonds payable (current portion included)		28,184,687		9,989,245			—			185,420			38,359,352
Long-term loans (current portion included)		19,279,342		3,857,704			(253,702	)		—			22,883,344
Lease liabilities		5,737,095		(666,439	)		(24,106	)		346,637 (Note B	)		5,393,187
Guarantee deposits (current portion included)		30,757,001		10,423,345			419,040			—			41,599,386 (Note C	)
Other financial liabilities		21,449,487		(21,209,443	)		(330,783	)		90,739			—

For the year ended December 31, 2024


						Non-cash changes
Items	As of January 1, 2024		Cash Flows			Foreign exchange		Others (Note A)			As of December 31, 2024
	NT$		NT$			NT$		NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)		(In Thousands)			(In Thousands)
Short-term loans	$	13,530,000	$	(5,015,000	)	$	—	$	—		$	8,515,000
Bonds payable (current portion included)		38,359,352		(8,500,465	)		—		192,681			30,051,568
Long-term loans (current portion included)		22,883,344		13,178,434			415,131		—			36,476,909
Lease liabilities		5,393,187		(731,138	)		92,617		1,664,350 (Note B	)		6,419,016
Guarantee deposits (current portion included)		41,599,386		(572,321	)		1,847,429		—			42,874,494 (Note C	)

For the year ended December 31, 2025


						Non-cash changes
Items	As of January 1, 2025		Cash Flows			Foreign exchange			Others (Note A)			As of December 31, 2025
	NT$		NT$			NT$			NT$			NT$
	(In Thousands)		(In Thousands)			(In Thousands)			(In Thousands)			(In Thousands)
Short-term loans	$	8,515,000	$	(106,531	)	$	303		$	—		$	8,408,772
Bonds payable (current portion included)		30,051,568		19,984,120			—			192,617			50,228,305
Long-term loans (current portion included)		36,476,909		(21,689,386	)		(455,733	)		—			14,331,790
Lease liabilities		6,419,016		(849,810	)		(8,014	)		439,654 (Note B	)		6,000,846
Guarantee deposits (current portion included)		42,874,494		(780,352	)		(1,226,308	)		23			40,867,857 (Note C	)

Note A: Other

non-cash

changes mainly consisted of discount amortization measured by the effective interest method.

Note B: Mainly due to the addition to lease properties .

Note C: Guarantee deposits mainly consisted of deposits of capacity reservation.

Restricted Stock Plan For Employees [Member]

Contents Of Significant Accounts [Line Items]

Assumptions Used for Share-Based Payment

The compensation cost for these market conditions was measured at fair value initially by using Monte Carlo Simulation on the grant date. The assumptions used are as follows:


	2024 Plan
	1st tranche		2nd tranche
Share price of measurement date (NT$/ per share)	$	44.60	$	47.20
Expected volatility		23.76% - 34.32%		25.11% - 28.65%
Expected life		2 -4 years		2 - 4 years
Risk-free interest rate		1.40% - 1.46%		1.14% - 1.23%

Unused tax losses [member]

Contents Of Significant Accounts [Line Items]

Unused Tax Credits and Losses


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Expiry period
1-5 years	$	19,761,573	$	2,237,668
6-10 years		11,407,986		1,687,059

Total	$	31,169,559	$	3,924,727

Plan assets [member]

Contents Of Significant Accounts [Line Items]

Defined Benefit Plan Recognized on the Consolidated Balance Sheets

ii.

Movements in fair value of plan assets during the year:


	For the years ended December 31,
	2024			2025
	NT$ (In Thousands)			NT$ (In Thousands)
Beginning balance of fair value of plan assets	$	2,460,413		$	2,960,474
Items recognized as profit or loss:
Interest income on plan assets		29,525			47,071
Contribution by employer		619,281			449,449
Benefits paid		(359,975	)		(269,846	)
Remeasurements recognized in other comprehensive income (loss):
Return on plan assets, excluding amounts included in interest income		211,230			197,155

Fair value of plan assets at end of year	$	2,960,474		$	3,384,303

Present value of defined benefit obligation [member]

Contents Of Significant Accounts [Line Items]

Defined Benefit Plan Recognized on the Consolidated Balance Sheets

Movements in present value of defined benefit obligation during the year:


	For the years ended December 31,
	2024			2025
	NT$			NT$
	(In Thousands)			(In Thousands)
Defined benefit obligation at beginning of year	$	(4,665,498	)	$	(4,392,723	)
Items recognized as profit or loss:
Service cost		(8,435	)		(5,749	)
Interest cost		(55,986	)		(69,844	)

Subtotal		(64,421	)		(75,593	)

Remeasurements recognized in other comprehensive income (loss):
Arising from changes in demographic assumptions		(142,117	)		—
Arising from changes in financial assumptions		98,669			(80,095	)
Experience adjustments		20,669			28,043

Subtotal		(22,779	)		(52,052	)

Benefits paid		359,975			269,846

Defined benefit obligation at end of year	$	(4,392,723	)	$	(4,250,522	)

More than 1 year [member]

Contents Of Significant Accounts [Line Items]

Details of Loans

(14)

Long-Term Loans

Details of long-term loans as of December 31, 2024 and 2025 were as follows:


	As of December 31,
Lenders	2024			2025			Redemption
	NT$			NT$
	(In Thousands)			(In Thousands)
NTD secured bank loans	$	494,920		$	382,290		Repayable from October 19, 2015 to October 15, 2031.
RMB secured bank loans		10,025,233			—		Repayable from March 19, 2021 to March 18, 2031.
NTD unsecured bank loans		5,919,266			8,291,500		Repayable from March 24, 2023 to March 15, 2031.
USD unsecured bank loans		1,237,490			—		Repayable from June 24, 2023 to June 24, 2026.
RMB unsecured bank loans		—			2,258,000		Repayable from May 20, 2026 to May 20, 2027.
NTD unsecured revolving bank loans (Note)		17,500,000			3,400,000		Repayable from March 2, 2023 to November 5, 2030.
USD unsecured revolving bank loans (Note)		1,300,000			—		Settlement due on September 26, 2029.

Subtotal		36,476,909			14,331,790
Less: Current portion		(5,528,409	)		(3,030,880	)

Total	$	30,948,500		$	11,300,910


	As of December 31,
	2024			2025
Interest rates applied		1.53% - 5.49%			1.53% - 2.98%

Note :

The bank loans are available on a revolving basis during the contract period. As of December 31, 2024 and 2025, the available revolving line of credit amounted to NT$43.3 billion and NT$54.8 billion, respectively. The abovementioned unused line of credit were NT$24.5 billion and NT$51.4 billion, respectively.

Please refer to Note 8 for property, plant and equipment and

right-of-use

assets pledged as collateral for long-term loans.

In 2016, HEJIAN resolved to provide endorsement for USCXM’s syndicated loan from banks including China Development Bank. The maximum amount of endorsement for the years ended December 31, 2024 and 2025 were NT$1,800 million and NT$1,483 million, respectively. As of December 31, 2024 and 2025, the actual amount provided were NT$1,437 million and nil, respectively.

In 2017, UMC resolved to provide endorsement for USCXM’s syndicated loan from banks including China Development Bank. The maximum amount of endorsement for the years ended December 31, 2024 and 2025 were NT$10,620 million and NT$8,753 million, respectively. As of December 31, 2024 and 2025, the actual amount provided were NT$8,477 million and nil, respectively. USCXM’s syndicated loan from banks including China Development Bank was fully repaid in October 2025.

Aggregated individually immaterial associates [member]

Contents Of Significant Accounts [Line Items]

Aggregate Amount of the Company's Share of its Individually Immaterial Associates

The aggregate amount of the Company’s share of all its individually immaterial associates that are accounted for using the equity method were as follows:


	For the years ended December 31,
	2023		2024		2025
	NT$		NT$		NT$
	(In Thousands)		(In Thousands)		(In Thousands)
Income (loss) from continuing operations	$	4,307,614	$	1,238,628	$	657,163
Other comprehensive income (loss)		1,540,436		570,493		3,106,980

Total comprehensive income (loss)	$	5,848,050	$	1,809,121	$	3,764,143

Trade receivables [member]

Contents Of Significant Accounts [Line Items]

Financial Assets

(5)

Accounts Receivable, Net


	As of December 31,
	2024			2025
	NT$			NT$
	(In Thousands)			(In Thousands)
Accounts receivable	$	32,734,422		$	30,780,504
Less: loss allowance		(10,996	)		(8,345	)

Net	$	32,723,426		$	30,772,159

Financial assets at fair value through profit or loss [member]

Contents Of Significant Accounts [Line Items]

Financial Assets

(2)

Financial Assets at Fair Value through Profit or Loss


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Financial assets mandatorily measured at fair value through profit or loss
Common stocks	$	8,759,564	$	8,823,146
Preferred stocks		3,475,613		3,861,674
Funds		5,792,863		4,956,553
Convertible bonds		363,430		438,024
Forward exchange contracts		2		1,859
Others		65,460		72,660

Total	$	18,456,932	$	18,153,916

Current	$	606,018	$	568,521
Non-current		17,850,914		17,585,395

Total	$	18,456,932	$	18,153,916

Financial assets at fair value through other comprehensive income [member]

Contents Of Significant Accounts [Line Items]

Financial Assets

(3)

Financial Assets at Fair Value through Other Comprehensive Income


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Equity instruments
Common stocks	$	17,004,448	$	13,571,941
Preferred stocks		204,880		202,808

Total	$	17,209,328	$	13,774,749

Current	$	5,893,377	$	4,630,441
Non-current		11,315,951		9,144,308

Total	$	17,209,328	$	13,774,749

Financial assets measured at amortized cost [member]

Contents Of Significant Accounts [Line Items]

Financial Assets

(4)

Financial Assets Measured at Amortized Cost


	As of December 31,
	2024		2025
	NT$		NT$
	(In Thousands)		(In Thousands)
Time deposits with original maturities over three months	$	3,739,224	$	12,506,177

Current	$	3,739,224	$	12,506,177
Non-current		—		—

Total	$	3,739,224	$	12,506,177