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Item 1.	Business

•	Designing and developing innovative packaging and test technologies;

•	Offering a broad portfolio of cost-effective solutions and services;

•	Focusing on strategic end markets that offer solid growth potential;

•	Cultivating long-standing relationships with our customers, which include many of the world’s leading semiconductor companies;

•	Collaborating with customers, original equipment manufacturers (“OEMs”) and equipment and material suppliers;

•	Developing a competitive cost structure with disciplined capital investment;

•	Building expertise in high-volume manufacturing processes and developing a reputation for high quality and solid execution and

•	Providing a geographically diverse operating base, with research and development, engineering support and production capabilities at various facilities in China, Japan, Korea, Malaysia, the Philippines, Portugal and Taiwan.

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•	An increasing demand for mobile and internet-connected devices, including the world-wide adoption of “smart” phones, tablets and other consumer electronic devices that can access the internet and provide multimedia capabilities.

•	An increase in mobility and connectivity capabilities and growing digital content driving demand for new broadband wired and wireless networking equipment.

•	The proliferation of semiconductor devices into well-established end products such as automotive systems due to increased use of electronics for safety, navigation, fuel efficiency, emission reduction and entertainment systems.

•	An overall increase in the semiconductor content within electronic products to provide greater functionality and higher levels of performance.

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The growth of advanced System-in-Package ("SiP") modules where multiple semiconductor and other electronic components with different functionalities are combined into a single package. The increasing demand for miniaturization and higher functionality at competitive cost is driving the adoption of advanced SiP in new products. Advanced SiPs are the primary vehicle for package-level integration, which allow customers to combine integrated circuits ("ICs") from different silicon nodes and different foundries.

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First, we are increasing our revenue in markets other than smartphones and tablets, such as automotive, which now drives approximately 26% of Amkor's total revenue. Revenue from these markets tends to be more stable, with less pronounced highs and lows from year to year. Sales in these other markets now account for 56% of our overall revenue, up from 47% in 2015, prior to the acquisition of J-Devices.

•	Second, we are expanding our customer base in the smartphone and tablet market, primarily by engaging with fabless companies in Greater China. This allows us to more fully utilize our existing assets and broadens our participation in all tiers of the mobile device market.

•	Third, we continue to focus on share gains in the iOS and high-end Android ecosystems, leveraging our expertise in advanced SiP, MEMS and other advanced packages to expand our content in flagship phones.

•	Finally, we are building and utilizing manufacturing lines which support multiple customers, and increasing factory utilization through more sophisticated planning processes and more intensive efficiency improvement activities.

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•	Offering capacity to absorb large orders and accommodate quick turn-around times;

•	Obtaining favorable pricing on materials and equipment, where possible, by using our purchasing power and leading industry position;

•	Qualifying production of customer devices at multiple manufacturing sites to mitigate the risks of supply disruptions and

•	Providing capabilities and solutions for customer-specific requirements.

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Wafer-level CSP packages (also known as fan-in wafer-level packages) do not utilize a package carrier. The bumped wafer is singulated into individual die, and the wafer-level package is then attached directly to the system board. Wafer-level CSP offers one of the lowest total system costs, enabling higher semiconductor content while leveraging the smallest form factor and one of the highest performing, most reliable, semiconductor package platforms on the market today. We have seen significant growth in our wafer-level CSP business, driven largely by mobile communications. Applications for wafer-level CSP include power management, transceivers, sensors, wireless charging, codecs, and specialty silicon for new or unique functionality.

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Wafer-level fan-out packages (also known as low-density fan-out packages) are utilized for ICs where the die surface area is too small to accommodate all of the bond pads. The fan-out package enlarges the bondable surface area by building a border around the die using low-cost molding compound. Wafer-level CSP and wafer-level fan-out are complementary technologies. Customers can choose between the two package types as their die sizes shrink or grow. With the acquisition of Nanium, we became a leader in low-density fan-out technology.

•	Silicon Wafer Integrated Fan-out Technology ("SWIFT", also known as high-density fan-out) replaces a laminate substrate with a thinner structure. SWIFT solutions enable very thin, very small products combining application processors, memory, baseband and other peripheral ICs.

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•	technical competence;

•	quality;

•	price;

•	breadth of packaging and test services offered, including turnkey services;

•	new package and test design, technology innovation and implementation;

•	cycle times;

•	customer service and

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•	available capacity and ability to invest in capacity, geographic location and scale of manufacturing.

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Item 1A.	Risk Factors

•	fluctuation in demand for semiconductors and conditions in the semiconductor industry generally, as well as by specific customers, such as inventory reductions by our customers impacting demand in key markets;

•	our ability to achieve our major growth objectives, including: transitioning second-wave customers to advanced packages; expanding our sales to customers in Greater China and, in particular, in the mid-level and entry-level tiers of the mobile device market; and increasing our share of the automotive market;

•	changes in our capacity and capacity utilization rates;

•	changes in average selling prices which can occur quickly due to the absence of long-term agreements on price;

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•	changes in the mix of the semiconductor packaging and test services that we sell;

•	the development, transition and ramp to high volume manufacture of more advanced silicon nodes and evolving wafer, packaging and test technologies, may cause production delays, lower manufacturing yields and supply constraints for new wafers and other materials;

•	absence of backlog, the short-term nature of our customers’ commitments, double bookings by customers and deterioration in customer forecasts and the impact of these factors, including the possible delay, rescheduling and cancellation of large orders, or the timing and volume of orders relative to our production capacity;

•	changes in costs, quality, availability and delivery times of raw materials, components and equipment;

•	changes in labor costs to perform our services;

•	wage inflation and fluctuations in commodity prices, including gold, copper and other precious metals;

•	the timing of expenditures in anticipation of future orders;

•	changes in effective tax rates;

•	the availability and cost of financing;

•	intellectual property transactions and disputes;

•	high leverage and restrictive covenants;

•	warranty and product liability claims and the impact of quality excursions and customer disputes and returns;

•	costs associated with legal claims, indemnification obligations, judgments and settlements;

•	political instability and government shutdowns, civil disturbances or environmental or natural events, such as earthquakes like the recent ones in Japan, that impact our operations, and international events, such as the United Kingdom's vote to leave the European Union;

•	pandemic illnesses that may impact our labor force and our ability to travel;

•	costs of acquisitions and divestitures and difficulties integrating acquisitions;

•	our ability to attract and retain qualified personnel to support our global operations;

•	fluctuations in interest rates and currency exchange rates;

•	fluctuations in our manufacturing yields;

•	our ability to penetrate new end markets or expand our business in existing end markets;

•	dependence on key customers or concentration of customers in certain end markets, such as mobile communications and automotive and

•	restructuring charges, asset write-offs and impairments.

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•	changes in consumer demand resulting from deteriorating conditions in local economies;

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laws, rules, regulations and policies imposed by U.S. or foreign governments, such as tariffs, customs, duties and other restrictive trade barriers, national security, data privacy and cybersecurity, antitrust and competition, tax, currency and banking, labor, environmental, health and safety, and in particular the recent increase in tariffs, customs, duties and other restrictive trade barriers considered or adopted by U.S. and foreign governments;

•	laws, rules, regulations and policies within China and other countries that may favor domestic companies over non-domestic companies, including customer- or government-supported efforts to promote the development and growth of local competitors;

•	the payment of dividends and other payments by non-U.S. subsidiaries may be subject to prohibitions, limitations or taxes in local jurisdictions;

•	fluctuations in currency exchange rates, particularly the dollar/yen exchange rate for J-Devices;

•	political and social conditions, and the potential for civil unrest, terrorism or other hostilities;

•	disruptions or delays in shipments caused by customs brokers or government agencies;

•	difficulties in attracting and retaining qualified personnel and managing foreign operations, including foreign labor disruptions;

•	difficulty in enforcing contractual rights and protecting our intellectual property rights;

•	potentially adverse tax consequences resulting from tax laws in the U.S. and in foreign jurisdictions in which we operate and

•	local business and cultural factors that differ from our normal standards and practices, including business practices that we are prohibited from engaging in by the Foreign Corrupt Practices Act and other anti-corruption laws and regulations.

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•	their desire to realize higher utilization of their existing packaging and test capacity, especially during downturns in the semiconductor industry;

•	their unwillingness to disclose proprietary technology;

•	their possession of more advanced packaging and test technologies and

•	the guaranteed availability of their own packaging and test capacity.

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•	make it more difficult for us to satisfy our obligations with respect to our indebtedness, including our obligations under our indentures to purchase notes tendered as a result of a change in control of Amkor;

•	increase our vulnerability to general adverse economic and industry conditions;

•	limit our ability to fund future working capital, capital expenditures, research and development and other business opportunities, including joint ventures and acquisitions;

•	require us to dedicate a substantial portion of our cash flow from operations to service payments of interest and principal on our debt, thereby reducing the availability of our cash flow to fund future working capital, capital expenditures, research and development expenditures and other general corporate requirements;

•	increase the volatility of the price of our common stock;

•	limit our flexibility to react to changes in our business and the industry in which we operate;

•	place us at a competitive disadvantage to any of our competitors that have less debt;

•	limit, along with the financial and other restrictive covenants in our indebtedness, among other things, our ability to borrow additional funds;

•	limit our ability to refinance our existing indebtedness, particularly during periods of adverse credit market conditions when refinancing indebtedness may not be available under interest rates and other terms acceptable to us or at all and

•	increase our cost of borrowing.

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•	we may face delays in the design and implementation of the system;

•	the cost of the systems may exceed our plans and expectations and

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•	disruptions resulting from the implementation or integration of the systems may impact our ability to process transactions and delay shipments to customers, impact our results of operations or financial condition or harm our control environment.

•	increasing the scope, geographic diversity and complexity of our operations;

•	conforming an acquired company's standards, practices, systems and controls with our operations;

•	increasing complexity from combining recent acquisitions of an acquired business;

•	unexpected losses of key employees or customers of an acquired business; other difficulties in the assimilation of acquired operations, technologies or products and

•	diversion of management and other resources from other parts of our operations and adverse effects on existing business relationships with customers.

•	use a significant portion of our available cash;

•	issue equity securities, which may dilute the ownership of current stockholders;

•	incur substantial debt;

•	incur or assume known or unknown contingent liabilities and

•	incur large, immediate accounting write offs and face antitrust or other regulatory inquiries or actions.

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•	our future financial condition, results of operations and cash flows;

•	general market conditions for financing;

•	volatility in fixed income, credit and equity markets and

•	economic, political and other global conditions.

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•	discontinue the use of certain processes or cease to provide the services at issue, which could curtail our business;

•	pay substantial damages;

•	develop non-infringing technologies, which may not be feasible or

•	acquire licenses to such technology, which may not be available on commercially reasonable terms or at all.

•	contaminants in the manufacturing environment;

•	human error;

•	equipment malfunction;

•	changing processes to address environmental requirements;

•	defective raw materials or

•	defective plating services.

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Item 1B.	Unresolved Staff Comments

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Item 2.	Properties

(1)	Land is leased.

(2)	As a result of foreign ownership restrictions in the Philippines, the land is leased. A portion of the land we lease is owned by realty companies in which we own a 40% interest.

Item 3.	Legal Proceedings

Item 4.	Mine Safety Disclosures

Item 5.	Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

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(a)	Represents shares of common stock surrendered to us to satisfy tax withholding obligations associated with the vesting of restricted shares issued to employees.

(b)	Our Board of Directors previously authorized the repurchase of up to $300.0 million of our common stock, $150.0 million in August 2011 and $150.0 million in February 2012, exclusive of any fees, commissions or other expenses. During 2017 and 2018, we made no common stock purchases, and at December 31, 2018, approximately $91.6 million was available pursuant to the stock repurchase program.

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(1)	The preceding Stock Performance Graph is not deemed filed with the SEC and shall not be incorporated by reference in any of our filings under the Securities Act of 1933, as amended, or the Exchange Act, whether made before or after the date hereof and irrespective of any general incorporation language in any such filing.

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Item 6.	Selected Financial Data

(a)	In January 2015, we reached a resolution to a patent license dispute and entered into a settlement agreement. During 2014 we recorded charges of $75.3 million to cost of sales and $13.7 million to interest expense relating to this patent license dispute.

(b)	In May 2017, we sold the land and buildings comprising our K1 factory for $142.4 million which resulted in a pre-tax gain of $108.1 million.

(c)	In July 2017, we recorded a loss on debt retirement of $4.4 million relating to the partial early repayment of our 6.625% Senior Notes due 2021. During 2015, we recorded a loss on debt retirement of $8.9 million relating to the early repayment of our 7.375% Senior Notes due May 2018.

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(d)	In 2017, income tax expense includes an estimated net tax benefit of $41.6 million primarily due to the reversal of a valuation allowance on certain U.S. deferred tax assets as a result of the enactment of the Tax Act. In 2018, we recorded a $22.3 million income tax expense to complete the accounting for the impact of the Tax Act, reducing our estimated net tax benefit of $41.6 million from 2017.

(e)

On June 30, 2014, we sold 100% of the shares of our then wholly-owned subsidiary in Japan to J-Devices, our then unconsolidated equity-method joint venture in Japan. Subsequent to June 30, 2014, the results of the divested entity are included in J-Devices' financial results and in our corresponding equity in earnings of J-Devices. We recognized a net gain on the sale of $9.2 million in other (income) expense, net. In addition, J-Devices recognized a gain on the transaction, which increased our equity in earnings of J-Devices by $8.8 million. The combined net gain we recognized was $18.0 million.

(f)	On May 22, 2017, we completed the purchase of Nanium. Their financial results have been included in our Consolidated Financial Statements from the date of acquisition.

(g)

We increased our investment in J-Devices from 60% to 100% on December 30, 2015 through the exercise of additional options. As a result, our accounting for J-Devices changed from the equity method to the consolidation method effective December 30, 2015. Our balance sheet data as of December 31, 2015 reflects the consolidation of J-Devices. We began consolidating the operating results of J-Devices in 2016. We recognized a net loss of $13.5 million in other (income) expense, net in connection with the acquisition in 2015. The net loss resulted from a loss of $29.6 million related to the release of certain accumulated foreign currency translation adjustments related to J-Devices, offset by a gain of $16.1 million related to the step-up to fair value of our previous investments in J-Devices.

Item 7.	Management’s Discussion and Analysis of Financial Condition and Results of Operations

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(1)	Represents interest payment obligations calculated using stated coupon rates for fixed rate debt and interest rates applicable at December 31, 2018, for variable rate debt.

(2)	Represents off-balance sheet purchase obligations for capital expenditures and long-term supply contracts outstanding at December 31, 2018.

(3)	Represents future minimum lease payments including interest payments.

(4)	Represents estimated benefit payments for our Korean subsidiary severance plan.

•	$55.1 million of foreign pension plan obligations, for which the timing and actual amount of impact on our future cash flow is uncertain.

•	$30.6 million net liability associated with unrecognized tax benefits. Due to the uncertainty regarding the amount and the timing of any future cash outflows associated with our unrecognized tax benefits, we are unable to reasonably estimate the amount and period of ultimate settlement, if any, with the various taxing authorities.

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•	significant under-performance relative to expected historical or projected future operating results;

•	significant changes in the manner of our use of the asset;

•	significant negative industry or economic trends and

•	our market capitalization relative to net book value.

Item 7A.	Quantitative and Qualitative Disclosures about Market Risk

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Item 8.	Financial Statements and Supplementary Data

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1.	Description of Business and Summary of Significant Accounting Policies

•	Designing and developing innovative packaging and test technologies;

•	Offering a broad portfolio of cost-effective solutions and services;

•	Focusing on strategic end markets that offer solid growth potential;

•	Cultivating long-standing relationships with our customers, which include many of the world’s leading semiconductor companies;

•	Collaborating with customers, original equipment manufacturers ("OEMs") and equipment and material suppliers;

•	Developing a competitive cost structure with disciplined capital investment;

•	Building expertise in high-volume manufacturing processes and developing a reputation for high quality and solid execution and

•	Providing a geographically diverse operating base, with research and development, engineering support and production capabilities at various facilities throughout China, Japan, Korea, Malaysia, the Philippines, Portugal and Taiwan.

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2.	New Accounting Standards

•	We do not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less.

•	We do not adjust the promised amount of consideration for the effects of a significant financing component when we expect, at contract inception, that the period between when the entity transfers a promised good or service to a customer and when the customer pays for that good or service will be one year or less.

•	We exclude sales, use, value-added and similar taxes from the transaction price, without performing a jurisdiction-by-jurisdiction assessment.

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(1)	The adjustment to accumulated deficit includes the 2017 and 2016 net income impact for the adoption of Topic 606 of $2.8 million and $11.3 million, respectively. The adjustment also includes the cumulative impact to our 2016 beginning accumulated deficit of $14.8 million.

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3.	Acquisitions

4.	Share-Based Compensation Plans

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5.	Other Income and Expense

6.	Income Taxes

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7.	Earnings Per Share

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8.	Factoring of Accounts Receivable

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9.	Property, Plant and Equipment

10.	Accrued Expenses

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11.	Debt

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(1)

In August 2018, we redeemed all $200 million of our 6.625% Senior Notes due 2021 ("Notes"). In accordance with the terms of the indenture governing the Notes, the redemption price was 100% of the principal amount of the Notes, plus accrued and unpaid interest. We recorded a $0.8 million charge for the write-off of the associated unamortized debt issuance costs.  The redemption of the Notes was funded with proceeds from our ¥26.0 billion ($233.2 million) term loan agreement entered into in July 2018 by J-Devices Corporation and guaranteed by Amkor Technology, Inc. Principal is payable in quarterly installments.

(2)	In June 2018, we extended our $75.0 million credit facility from June 2018 to September 2018 and in September 2018, we replaced it with a $75.0 million term loan due September 2021 at LIBOR plus 2.34%.

(3)	In October 2018, we entered into a revolving credit facility agreement with availability of $30.0 million. Principal will be payable at the maturity date of October 2019. As of December 31, 2018, $30.0 million was available to be drawn.

(4)

In May 2015, we entered into a term loan agreement pursuant to which we may borrow up to $150.0 million for capital expenditures. Principal is payable at maturity in June 2020. Interest is payable quarterly in arrears. In the second quarter of 2018, we borrowed the remaining $64.0 million available under the term loan due June 2020 and repaid $55 million of the term loan due December 2019 and $9 million of the term loan due May 2020.

(5)	We entered into various short-term loans which mature semiannually. Principal is payable in monthly installments. As of December 31, 2018, $4.6 million was available to be drawn.

(6)

In July 2018, the senior secured revolving credit facility of Amkor Technology, Inc. was terminated and replaced by a new facility entered into by our subsidiary, Amkor Technology Singapore Holding Pte, Ltd., and guaranteed by Amkor Technology, Inc. We recorded a $0.4 million charge for the write-off of the associated unamortized debt issuance costs relating to the terminated credit facility. The availability for the new revolving credit facility is based on the amount of eligible accounts receivable. As of December 31, 2018, we had availability of $250.0 million under the new senior secured revolving credit facility with no outstanding standby letters of credit.

(7)	In November 2015, we entered into a $39.0 million revolving credit facility. Principal is payable at maturity. As of December 31, 2018, $19.0 million was available to be drawn.

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13.	Accumulated Other Comprehensive Income (Loss)

14.	Fair Value Measurements

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15.	Commitments and Contingencies

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16.	Business Segments, Customer Concentrations and Geographic Information

•	We are managed under a functionally-based organizational structure with the head of each function reporting directly to the CODM;

•	We assess performance, including incentive compensation, based on consolidated operating performance and financial results;

•	Our CODM allocates resources and makes other operating decisions based on specific customer business opportunities and

•	We have an integrated process for the design, development and manufacturing services we provide to all of our customers. We also have centralized sales and administrative functions.

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(1)	Advanced products include flip chip and wafer-level processing and related test services.

(2)	Mainstream products include wirebond packaging and related test services.

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(a)	In May 2017, we completed the purchase of Nanium. Nanium's financial results have been included in our Consolidated Financial Statements from the date of acquisition.

(b)	In May 2017, we sold the land and buildings comprising our K1 factory for $142.4 million which resulted in a pre-tax gain of $108.1 million.

(c)

In the fourth quarter of 2017, net income includes an estimated net tax benefit of $41.6 million primarily due to the reversal of a valuation allowance on certain U.S. deferred tax assets as a result of the enactment of the Tax Act. In the fourth quarter of 2018, we recorded a $22.3 million income tax expense to complete the accounting for the impact of the Tax Act, reducing our estimated net tax benefit of $41.6 million from 2017.

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(a)	Column represents adjustments to the deferred tax asset valuation allowance established as part of the purchase accounting related to Amkor's acquisition of Nanium in 2017 and adjustments directly through stockholders’ equity for changes in accumulated other comprehensive income (loss) related to our foreign defined benefit pension plans and the adoption of ASU 2016-09 on July 1, 2016.

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Item 9.	Changes In and Disagreements with Accountants on Accounting and Financial Disclosure

Item 9A.	Controls and Procedures

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Item 9B.	Other Information

Item 10.	Directors, Executive Officers and Corporate Governance

Item 11.	Executive Compensation

Item 12.	Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters

(1)	As of December 31, 2018, a total of 7.8 million shares were reserved for issuance under the 2007 Plan. Shares available for issuance under our 2007 Plan can be granted pursuant to stock options, restricted stock, restricted stock units, stock appreciation rights, performance units and performance shares.

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Item 13.	Certain Relationships and Related Transactions, and Director Independence

Item 14.	Principal Accountant Fees and Services

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Item 16.	Form 10-K Summary

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