UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported) July 31, 2013

AMKOR TECHNOLOGY, INC.

(Exact name of registrant as specified in its charter)

1900 SOUTH PRICE ROAD CHANDLER, AZ 85286

(Address of Principal Executive Offices, including Zip Code)

(480) 821-5000

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

ITEM 1.01. Entry into a Material Definitive Agreement

As previously announced, Amkor Technology, Inc. (the “Company”) and Toshiba Corporation (“Toshiba”) had been engaged in discussions relating to the acquisition of Toshiba Electronics Malaysia Sdn. Bhd (“TEM”), Toshiba’s power discrete semiconductor packaging and test operation in Malaysia.

On July 31, 2013, the Company entered into a share purchase agreement (the “Purchase Agreement”) with Toshiba, pursuant to which Amkor Technology Holding B.V., a wholly-owned subsidiary of the Company (the “Buyer”), acquired 100% of the shares of TEM effective on such date. The total price for the shares is approximately $60 million, based on the estimated net asset value of TEM at closing. The price for the shares is subject to adjustment to the extent the actual net asset value of TEM at closing was more or less than the estimate. We paid $43 million at closing and are obligated to pay the remaining $17 million by March 31, 2014. The Purchase Agreement contains customary representations, warranties and covenants and indemnification provisions.

In connection with the transactions contemplated by the Purchase Agreement, Toshiba and the Company entered into a supplemental agreement to a manufacturing services agreement between the parties, pursuant to which Toshiba agrees to purchase from TEM and TEM agrees to supply to Toshiba packaging and test services for (1) certain discrete semiconductor products for five years, and (2) certain small signal products and analog LSI products for two years, in each case, based on the volume targets set forth in the agreement. The pricing is cost plus for the first two years and market pricing thereafter.

Toshiba also granted to the Company a non-exclusive license to certain intellectual property rights for providing packaging and test services for power discrete and certain other semiconductor products pursuant to a technical assistance and license agreement. The Company will pay to Toshiba a running royalty on net sales from third parties for services using the licensed technology, subject to a royalty cap of JPY 1.5 billion (approximately $15 million).

Toshiba and its affiliates will also provide certain post-closing support to TEM pursuant to a transition services agreement, including but not limited to services related to the use of certain information technology systems by TEM and the secondment of certain employees to TEM.

Item 8.01 Other Events.

On July 31, 2013, the Company and Toshiba issued a joint press release announcing the transaction with Toshiba. A copy of the press release is furnished with this Current Report on Form 8-K as Exhibit 99.1 and is incorporated herein by reference.

ITEM 9.01 Financial Statements and Exhibits.

(d) Exhibits.

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 hereunto duly authorized.

Index to Exhibits