UNITED STATES
SECURITIES AND EXCHANGE COMMISSION



Washington,
D.C. 20549



FORM 20-F/A

(AMENDMENT NO.1)





| | ☐ | REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934
| | - | ------------------------------------------------------------------------------------------------



OR



| | ☒ | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934For the fiscal year ended December 31, 2019
| | - | -------------------------------------------------------------------------------------------------------------------------------



OR



| | ☐ | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
| | - | ----------------------------------------------------------------------------------------



OR



| | ☐ | SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF
    1934
| | - | -----------------------------------------------------------------------------------------------



Commission file number: 001-16125





(Exact name of Registrant as specified in
its charter)



ASE Technology Holding Co., Ltd.

(Translation of Registrant’s Name
into English)



REPUBLIC OF CHINA

(Jurisdiction of Incorporation or Organization)



26 Chin Third Road

Nantze Export Processing Zone

Nantze, Kaohsiung, Taiwan

Republic of China

(Address of Principal Executive Offices)



Joseph Tung

Room 1901, No. 333, Section 1 Keelung
Rd.

Taipei, Taiwan, 110

Republic of China



Tel: 886-2-6636-5678

Fax: 882-2-2757-6121

Email: ir@aseglobal.com

(Name, Telephone, Email and/or Facsimile
Number and Address of Company Contact Person)



Securities registered or to be registered
pursuant to Section 12(b) of the Act:



|Title of Each Class                    | Trading Symbol(s) | Name of Each Exchange on which Registered
|-------------------------------------- | ----------------- | -----------------------------------------
|Common Shares, par value NT$10.00 each | ASX               | The New York Stock Exchange*             



*Traded in the form of American Depositary
Receipts evidencing American Depositary Shares (the “ADSs”), each representing two common shares of ASE Technology
Holding Co., Ltd.



Securities registered or to be registered
pursuant to Section 12(g) of the Act:



None



Securities for which there is a reporting
obligation pursuant to Section 15(d) of the Act:



None



Indicate the number of outstanding shares of each of the issuer’s
classes of capital or common stock as of the close of the period covered by the annual report:



As of December 31, 2019, 4,329,883,632 Common Shares, par value
NT$10 each were outstanding.**



Indicate by check mark if the registrant is a well-known seasoned
issuer, as defined in Rule 405 of the Securities Act.



Yes ☒         No
☐



If this report is an annual or transition report, indicate by
check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of
1934.



Yes ☐         No
☒



Indicate by check mark whether the Registrant (1) has filed
all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or
for such shorter period that the Registrant was required to file such reports) and (2) has been subject to such filing requirements
for the past 90 days.



Yes ☒         No
☐



Indicate by check mark whether the registrant has submitted
electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this
chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files).



Yes ☒         No
☐



Indicate by check mark whether the registrant is a large accelerated
filer, an accelerated filer, a non-accelerated filer, or an emerging growth company. See definition of “large accelerated
filer,” “accelerated filer,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.



|Large accelerated filer          ☒ |  | Accelerated filer          ☐ |  | Non-accelerated filer          ☐ |  | Emerging growth company        ☐
|---------------------------------- |  | ---------------------------- |  | -------------------------------- |  | --------------------------------



If an emerging growth company that prepares its financial statements
in accordance with U.S. GAAP, indicate by check mark if the registrant has elected not to use the extended transition period for
complying with any new or revised financial accounting standards † provided pursuant to Section 13(a) of the Exchange Act.		☐



† The term “new or revised financial accounting
standard” refers to any update issued by the Financial Accounting Standards Board to its Accounting Standards Codification
after April 5, 2012.



Indicate by check mark whether the registrant has filed a report
on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under
Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its
audit report. 		☒



Indicate by check mark which basis of accounting the registrant
has used to prepare the financial statements included in this filing:



|U.S. GAAP          ☐ |  | International Financial Reporting Standards as issued by the International Accounting Standards Board          ☒ |  | Other          ☐ | 
|-------------------- |  | ---------------------------------------------------------------------------------------------------------------- |  | ---------------- | 



If “Other” has been checked in response to the previous
question, indicate by check mark which financial statement item the registrant has elected to follow:



Item 17 ☐         Item
18 ☐



If this is an annual report, indicate by check mark whether
the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).



Yes ☐         No
☒



** As a result of the exercise
of employee stock options subsequent to December 31, 2019, as of January 31, 2020, we had 4,331,603,182 Common Shares outstanding.












1





EXPLANATORY
NOTE



This Amendment No. 1 on Form
20-F/A (this “Amendment”) amends our annual report on Form 20-F for the year ended December 31, 2019, which was
filed with the Securities and Exchange Commission on March 31, 2020 (the “Original Filing”). This Amendment is being made solely for the purpose of correcting the disclosure in note 4 to our consolidated financial statements included
in the Original Filing, under the heading “d. Basis of consolidation—2)
Subsidiaries included in consolidated financial statements were as follows:” to include two missing subsidiaries,
namely ASE (Korea) Inc. and J&R Industrial Inc. in a table contained therein.



This Amendment does not
modify or update any other disclosures set forth in the Original Filing, and does not update or discuss any other Company developments
subsequent to the date of the Original Filing.



2





| | 4. | SUMMARY OF SIGNIFICANT
ACCOUNTING POLICIES
| | -- | ------------------------------------------



| | d. | Basis of consolidation
| | -- | ----------------------



| | 2) | Subsidiaries included in
consolidated financial statements were as follows:
| | -- | ---------------------------------------------------------------------------



|                                        |  |                                                        |  | Establishment and      |  | Percentage of Ownership (%) December 31
|--------------------------------------- |  | ------------------------------------------------------ |  | ---------------------- |  | ---------------------------------------
|Name of Investee                        |  | Main Businesses                                        |  | Operating Location     |  | 2018                                   
|                                        |  |                                                        |  |                        |  |                                        
|ASE                                     |  | Engaged in the packaging and testing of semiconductors |  | R.O.C.                 |  |                                        
|A.S.E. Holding Limited                  |  | Holding company                                        |  | Bermuda                |  |                                        
|J & R Holding Limited (“J&R Holding”)   |  | Holding company                                        |  | Bermuda                |  |                                        
|Innosource Limited                      |  | Holding company                                        |  | British Virgin Islands |  |                                        
|Omniquest Industrial Limited            |  | Holding company                                        |  | British Virgin Islands |  |                                        
|ASE Marketing & Service Japan Co., Ltd. |  | Engaged in marketing and sales services                |  | Japan                  |  |                                        
|ASE Test, Inc.                          |  | Engaged in the testing of semiconductors               |  | R.O.C.                 |  |                                        
|Luchu Development Corporation           |  | Engaged in the development of real estate properties   |  | R.O.C.                 |  |                                        



(Continued)



3





|                                                |  |                                                                            |  | Establishment and      |  | Percentage of Ownership (%) December 31
|----------------------------------------------- |  | -------------------------------------------------------------------------- |  | ---------------------- |  | ---------------------------------------
|Name of Investee                                |  | Main Businesses                                                            |  | Operating Location     |  | 2018                                   
|                                                |  |                                                                            |  |                        |  |                                        
|TLJ Intertech Inc.                              |  | Engaged in information software services                                   |  | R.O.C.                 |  |                                        
|MingFeng Information Service Corp., Ltd.        |  | Engaged in information software services, and was established in May 2018. |  | R.O.C.                 |  |                                        
|ASE Embedded Electronics Inc. (“ASEEE”)         |  | Engaged in the sale and manufacturing of embedded substrate                |  | R.O.C.                 |  |                                        
|Advanced Microelectronic Products Inc. (“AMPI”) |  | Engaged in the manufacturing of integrated circuit                         |  | R.O.C.                 |  |                                        
|Alto Enterprises Limited                        |  | Holding company                                                            |  | British Virgin Islands |  |                                        
|Super Zone Holdings Limited                     |  | Holding company                                                            |  | Hong Kong              |  |                                        
|ASE (Kun Shan) Inc.                             |  | Engaged in the packaging and testing of semiconductors                     |  | Kun Shan, China        |  |                                        
|ASE Investment (Kun Shan) Limited               |  | Holding company                                                            |  | Kun Shan, China        |  |                                        
|Advanced Semiconductor Engineering (China) Ltd. |  | Will engage in the packaging and testing of semiconductors                 |  | Shanghai, China        |  |                                        
|ASE Investment (Labuan) Inc.                    |  | Holding company                                                            |  | Malaysia               |  |                                        
|ASE Test Limited (“ASE Test”)                   |  | Holding company                                                            |  | Singapore              |  |                                        



(Continued)

4





|                                                     |  |                                                                                |  | Establishment and      |  | Percentage of Ownership (%) December 31
|---------------------------------------------------- |  | ------------------------------------------------------------------------------ |  | ---------------------- |  | ---------------------------------------
|Name of Investee                                     |  | Main Businesses                                                                |  | Operating Location     |  | 2018                                   
|                                                     |  |                                                                                |  |                        |  |                                        
|ASE (Korea) Inc. (“ASE Korea”)                       |  | Engaged in packing and testing of semiconductors                               |  | Korea                  |  |                                        
|J&R Industrial Inc.                                  |  | Engaged in leasing equipment and investing activity                            |  | R.O.C.                 |  |                                        
|ASE Japan Co., Ltd. (“ASE Japan”)                    |  | Engaged in the packaging and testing of semiconductors                         |  | Japan                  |  |                                        
|ASE (U.S.) Inc.                                      |  | After-sales service and sales support                                          |  | U.S.A.                 |  |                                        
|Global Advanced Packaging Technology Limited         |  | Holding company                                                                |  | British Cayman Islands |  |                                        
|ASE WeiHai Inc.                                      |  | Engaged in the packaging and testing of semiconductors                         |  | Shandong, China        |  |                                        
|Suzhou ASEN Semiconductors Co., Ltd. (“ASEN”)        |  | Engaged in the packaging and testing of semiconductors                         |  | Suzhou, China          |  |                                        
|Anstock Limited                                      |  | Engaged in financing activity                                                  |  | British Cayman Islands |  |                                        
|Anstock II Limited                                   |  | Engaged in financing activity                                                  |  | British Cayman Islands |  |                                        
|ASE (Shanghai) Inc.                                  |  | Engaged in the production of substrates                                        |  | Shanghai, China        |  |                                        
|ASE Corporation                                      |  | Holding company                                                                |  | British Cayman Islands |  |                                        
|ASE Mauritius Inc.                                   |  | Holding company                                                                |  | Mauritius              |  |                                        
|ASE Labuan Inc.                                      |  | Holding company                                                                |  | Malaysia               |  |                                        
|Shanghai Ding Hui Real Estate Development Co., Ltd.  |  | Engaged in the development, construction and sale of real estate properties    |  | Shanghai, China        |  |                                        
|Shanghai Ding Qi Property Management Co., Ltd.       |  | Engaged in the management of real estate properties                            |  | Shanghai, China        |  |                                        
|Advanced Semiconductor Engineering (HK) Limited      |  | Engaged in the trading of substrates                                           |  | Hong Kong              |  |                                        
|Shanghai Ding Wei Real Estate Development Co., Ltd.  |  | Engaged in the development, construction and leasing of real estate properties |  | Shanghai, China        |  |                                        
|Shanghai Ding Yu Real Estate Development Co., Ltd.   |  | Engaged in the development, construction and leasing of real estate properties |  | Shanghai, China        |  |                                        
|Shanghai Ding Fan Department Store Co., Ltd.         |  | Engaged in department store business                                           |  | Shanghai, China        |  |                                        
|Kun Shan Ding Hong Real Estate Development Co., Ltd. |  | Engaged in the development, construction and leasing of real estate properties |  | Kun Shan, China        |  |                                        
|Shanghai Ding Xu Property Management Co., Ltd.       |  | Engaged in the management of real estate properties                            |  | Shanghai, China        |  |                                        
|ASE Electronics Inc.                                 |  | Engaged in the production of substrates                                        |  | R.O.C.                 |  |                                        
|ASE Test Holdings, Ltd.                              |  | Holding company                                                                |  | British Cayman Islands |  |                                        
|ASE Holdings (Singapore) Pte. Ltd.                   |  | Holding company                                                                |  | Singapore              |  |                                        



(Continued)

5







|                                                                            |  |                                                                               |  | Establishment and      |  | Percentage of

Ownership (%)

December 31
|--------------------------------------------------------------------------- |  | ----------------------------------------------------------------------------- |  | ---------------------- |  | -----------------------------------------
|Name of Investee                                                            |  | Main Businesses                                                               |  | Operating Location     |  | 2018                                     
|                                                                            |  |                                                                               |  |                        |  |                                          
|ASE Singapore Pte. Ltd.                                                     |  | Engaged in the packaging and testing of semiconductors                        |  | Singapore              |  |                                          
|ISE Labs, Inc.                                                              |  | Engaged in the testing of semiconductors                                      |  | U.S.A.                 |  |                                          
|ASE Electronics (M) Sdn. Bhd.                                               |  | Engaged in the packaging and testing of semiconductors                        |  | Malaysia               |  |                                          
|ASE Assembly & Test (Shanghai) Limited                                      |  | Engaged in the packaging and testing of semiconductors                        |  | Shanghai, China        |  |                                          
|ISE Labs, China, Ltd.                                                       |  | Engaged in the testing of semiconductors, and was established in October 2018 |  | Shanghai, China        |  |                                          
|Wuxi Tongzhi Microelectronics Co., Ltd.                                     |  | Engaged in the packaging and testing of semiconductors                        |  | Wuxi, China            |  |                                          
|USI Global                                                                  |  | Merged by the Company in January 2019                                         |  | R.O.C.                 |  |                                          
|USIINC                                                                      |  | Engaged in investing activity                                                 |  | R.O.C.                 |  |                                          
|Huntington Holdings International
                                 Co. Ltd. |  | Holding company                                                               |  | British Virgin Islands |  |                                          
|                                                                            |  |                                                                               |  |                        |  |                                          

(Continued)

6





|                                                    |  |                                                                                                                                                |  | Establishment and      |  | Percentage of Ownership (%) December 31
|--------------------------------------------------- |  | ---------------------------------------------------------------------------------------------------------------------------------------------- |  | ---------------------- |  | ---------------------------------------
|Name of Investee                                    |  | Main Businesses                                                                                                                                |  | Operating Location     |  | 2018                                   
|                                                    |  |                                                                                                                                                |  |                        |  |                                        
|Unitech Holdings International Co., Ltd.            |  | Holding company                                                                                                                                |  | British Virgin Islands |  |                                        
|Real Tech Holdings Limited                          |  | Holding company                                                                                                                                |  | British Virgin Islands |  |                                        
|Universal ABIT Holding Co., Ltd.                    |  | In the process of liquidation                                                                                                                  |  | British Cayman Islands |  |                                        
|Rising Capital Investments Limited                  |  | Liquidated in November 2019                                                                                                                    |  | British Virgin Islands |  |                                        
|Rise Accord Limited                                 |  | Liquidated in December 2019                                                                                                                    |  | British Virgin Islands |  |                                        
|Universal Scientific Industrial (Kunshan) Co., Ltd. |  | Engaged in the manufacturing and sale of computer assistance system and related peripherals                                                    |  | Kun Shan, China        |  |                                        
|USI Enterprise Limited (“USIE”)                     |  | Engaged in the services of investment advisory and warehousing management                                                                      |  | Hong Kong              |  |                                        
|USISH                                               |  | Engaged in the designing, manufacturing and sale of electronic components                                                                      |  | Shanghai, China        |  |                                        
|Universal Global Technology Co., Limited            |  | Holding company                                                                                                                                |  | Hong Kong              |  |                                        
|Universal Global Technology (Kunshan) Co., Ltd.     |  | Engaged in the designing and manufacturing of electronic components                                                                            |  | Kun Shan, China        |  |                                        
|Universal Global Technology (Shanghai) Co., Ltd.    |  | Engaged in the processing and sales of computer and communication peripherals as well as business in import and export of goods and technology |  | Shanghai, China        |  |                                        
|Universal Global Electronics (Shanghai) Co., Ltd.   |  | Engaged in the sale of electronic components and telecommunications equipment                                                                  |  | Shanghai, China        |  |                                        
|USI America Inc.                                    |  | Engaged in the manufacturing and processing of motherboards and wireless network communication and provision of related technical service      |  | U.S.A.                 |  |                                        
|Universal Global Industrial Co., Limited            |  | Engaged in manufacturing, trading and investing activity                                                                                       |  | Hong Kong              |  |                                        



(Continued)

7





|                                                          |  |                                                                                                                                                                                                                                                                                          |  | Establishment and  |  | Percentage
of Ownership (%) December 31
|--------------------------------------------------------- |  | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | ------------------ |  | ---------------------------------------
|Name of Investee                                          |  | Main Businesses                                                                                                                                                                                                                                                                          |  | Operating Location |  | 2018                                   
|                                                          |  |                                                                                                                                                                                                                                                                                          |  |                    |  |                                        
|Universal Global Scientific Industrial Co., Ltd. (“UGTW”) |  | Engaged in the manufacturing of components of telecomm and cars and provision of related R&D services                                                                                                                                                                                    |  | R.O.C.             |  |                                        
|Universal Scientific Industrial De Mexico S.A. De C.V.    |  | Engaged in the assembling of motherboards and computer components                                                                                                                                                                                                                        |  | Mexico             |  |                                        
|USI Japan Co., Ltd.                                       |  | Engaged in the manufacturing and sale of computer peripherals, integrated chip and other related accessories                                                                                                                                                                             |  | Japan              |  |                                        
|USI Electronics (Shenzhen) Co., Ltd.                      |  | Engaged in the design, manufacturing and sale of motherboards and computer peripherals                                                                                                                                                                                                   |  | Shenzhen, China    |  |                                        
|Universal Global Electronics Co., Ltd.                    |  | Engaged in accepting and outsourcing orders as well as sales of electronic components and service of technical advisory, and was established in February 2018                                                                                                                            |  | Hong Kong          |  |                                        
|Universal Scientific Industrial Co., Ltd. (“USI”)         |  | Engaged in the manufacturing, processing and sale of computers, computer peripherals and related accessories                                                                                                                                                                             |  | R.O.C.             |  |                                        
|Semicondutores Avancados do Brasil S.A.                   |  | Engaged in the research and manufacturing of multi-functional system-in-package products, and was established in March 2019 and then invested in May 2019                                                                                                                                |  | Brasil             |  |                                        
|Huanrong Electronics (Huizhou) Co., Ltd.                  |  | Engaged in the research and manufacturing of new electronic applications, communications, computers and other electronics products and also provided auxiliary technical services as well as import and export services, and was established in April 2019 and then invested in May 2019 |  | Huizhou, China     |  |                                        



(Continued)

8





|                                                   |  |                                                                                                                                                                              |  | Establishment and      |  | Percentage of Ownership (%) December 31
|-------------------------------------------------- |  | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |  | ---------------------- |  | ---------------------------------------
|Name of Investee                                   |  | Main Businesses                                                                                                                                                              |  | Operating Location     |  | 2018                                   
|                                                   |  |                                                                                                                                                                              |  |                        |  |                                        
|Universal Scientific Industrial (France) (“USIFR”) |  | Engaged in investing activities and was established in August 2019                                                                                                           |  | France                 |  |                                        
|Chung Hong Electronics Poland Sp. z o.o. (“UGPL”)  |  | Engaged in designing, miniaturization, material sourcing, manufacturing, logistics, and after services of electronic devices and modules and was established in October 2019 |  | Poland                 |  |                                        
|SPIL                                               |  | Engaged in the assembly, testing and turnkey services of integrated circuits                                                                                                 |  | R.O.C.                 |  |                                        
|SPIL (B.V.I.) Holding Limited                      |  | Engaged in investing activities                                                                                                                                              |  | British Virgin Islands |  |                                        
|Siliconware Investment Co., Ltd.                   |  | Engaged in investing activities                                                                                                                                              |  | R.O.C.                 |  |                                        
|Siliconware USA, Inc.                              |  | Engaged in marketing activities                                                                                                                                              |  | U.S.A.                 |  |                                        
|SPIL (Cayman) Holding Limited                      |  | Engaged in investing activities                                                                                                                                              |  | British Cayman Islands |  |                                        
|Siliconware Technology (Suzhou) Limited (“SZ”)     |  | Engaged in the packaging and testing of semiconductors                                                                                                                       |  | Suzhou, China          |  |                                        
|Siliconware Electronics (Fujian) Co., Limited      |  | Engaged in the packaging and testing of semiconductors                                                                                                                       |  | Fujian, China          |  |                                        

(Concluded)



9





SIGNATURES



The registrant hereby certifies that
it meets all of the requirements for filing this Amendment and that it has duly caused and authorized the undersigned to sign
this Amendment on its behalf.



| | ASE TECHNOLOGY HOLDING CO., LTD.
| | --------------------------------
| |                                 
| |                                 
| | By:                             
| |                                 
| |                                 



Date: May 15, 2020