Exhibit 99.1

Magnachip Reports Results for Third Quarter 2021

SEOUL, South Korea, October 25, 2021 — Magnachip Semiconductor Corporation (NYSE: MX) (“Magnachip” or the “Company”) today announced its financial results for the third quarter 2021.

“Magnachip delivered solid third quarter results driven mainly by higher gross profit margin. Supported by an improved product mix, combined with an increase in average selling price under a favorable pricing environment, and high utilization rate at Fab 3, our gross profit margin reached 36.7%, the highest level reported in the company’s history, enabling us to achieve a very healthy bottom line,” said YJ Kim, Magnachip’s chief executive officer.

“Our Power business posted record revenue again for the third consecutive quarter, driven by strong demand across all our end markets. While demand for Magnachip’s OLED DDICs has been strong and outpacing supply, our Display business revenue continues to be limited by foundry capacity allocation amid global shortages in manufacturing capacities. As the supply constraint is expected to persist for the foreseeable future, we will keep pressing forward relentlessly to navigate the ongoing challenges by focusing on mix management in the near-term while also securing and expanding sustainable supply capacity for 2022 and beyond, which has already yielded some future capacity commitments.”

Magnachip is not hosting a quarterly earnings conference call and has suspended the practice of providing forward-looking guidance while the Agreement and Plan of Merger executed on March 25, 2021 with an investment vehicle formed by an affiliate of Wise Road Capital LTD is in effect. Please review the ‘Investors’ section of the Company’s website for the quarterly financial results and SEC filings for the latest updates on the pending transaction.

Q3 2021 Financial Highlights

Safe Harbor for Forward-Looking Statements

Information in this release regarding Magnachip’s forecasts, business outlook, expectations and beliefs are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 that involve risks and uncertainties. All forward-looking statements included in this release are based upon information available to Magnachip as of the date of this release, which may change, and we assume no obligation to update any such forward-looking statements. These statements are not guarantees of future performance and actual results could differ materially from our current expectations. Factors that could cause or contribute to such differences include, among others: the possibility that any or all of the conditions precedent to the consummation of the pending merger may not be satisfied or waived; unanticipated difficulties or expenditures relating to the proposed merger; the possibility that the merger may not be completed in a timely manner or at all; the diversion of and attention of Magnachip’s management on merger-related issues; legal proceedings, judgments or settlements following the announcement of the proposed merger; disruptions of current plans and operations caused by the announcement and pendency of the proposed merger; potential difficulties in employee retention due to the announcement and pendency of the proposed merger; the response of customers, suppliers, business partners and regulators to the announcement of the proposed merger; the impact of changes in macroeconomic and/or general economic conditions, including those caused by or related to the COVID-19 outbreak, recessions, economic instability and the outbreak of disease; manufacturing capacity constraints or supply chain disruptions that may impact our ability to deliver our products or affect the price of components, which may lead to an increase in our costs, as well as impacting demand for our products from customers who are similarly affected by such capacity constraints or disruptions; the impact of competitive products and pricing; timely design acceptance by our customers; timely introduction of new products and technologies; ability to ramp new products into volume production; industry wide shifts in supply and demand for semiconductor products; industry and/or company overcapacity or supply constraints; effective and cost efficient utilization of manufacturing capacity; financial stability in foreign markets and the impact of foreign exchange rates; unanticipated costs and expenses or the inability to identify expenses which can be eliminated; compliance with U.S. and international trade and export laws and regulations by us and our distributors; change or ratification of local or international laws and regulations, including those related to environment, health and safety; public health issues, including the COVID-19 pandemic; other business

interruptions that could disrupt supply or delivery of, or demand for, Magnachip’s products, including uncertainties regarding the impacts of the COVID-19 pandemic that may result in factory closures, reduced workforces, scarcity of raw materials and goods produced in infected areas, as well as reduced consumer and business spending affecting demand for Magnachip’s products due to government and private sector mandatory business closures, travel restrictions or the like to prevent the spread of disease; and other risks detailed from time to time in Magnachip’s filings with the SEC, including our Form 10-K filed on March 9, 2021 (including that the impact of the COVID-19 pandemic, trade tensions and supply constraints may also exacerbate the risks discussed therein) and subsequent registration statements, amendments or other reports that we may file from time to time with the Securities and Exchange Commission and/or make available on our website. Magnachip assumes no obligation and does not intend to update the forward-looking statements provided, whether as a result of new information, future events or otherwise.

About Magnachip Semiconductor

Magnachip is a designer and manufacturer of analog and mixed-signal semiconductor platform solutions for communications, IoT, consumer, industrial and automotive applications. The Company provides a broad range of standard products to customers worldwide. Magnachip, with more than 40 years of operating history, owns a portfolio of approximately 1,200 registered patents and pending applications, and has extensive engineering, design and manufacturing process expertise. For more information, please visit www.magnachip.com. Information on or accessible through Magnachip’s website is not a part of, and is not incorporated into, this release.

CONTACT:

So-Yeon Jeong

Head of Investor Relations

Tel. +1-408-712-6151

Investor.relations@magnachip.com

MAGNACHIP SEMICONDUCTOR CORPORATION AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF OPERATIONS

(In thousands of U.S. dollars, except share data) (Unaudited)

MAGNACHIP SEMICONDUCTOR CORPORATION AND SUBSIDIARIES

CONSOLIDATED BALANCE SHEETS

(In thousands of U.S. dollars, except share data) (Unaudited)

MAGNACHIP SEMICONDUCTOR CORPORATION AND SUBSIDIARIES

CONSOLIDATED STATEMENTS OF CASH FLOWS

(In thousands of U.S. dollars)

(Unaudited)

MAGNACHIP SEMICONDUCTOR CORPORATION AND SUBSIDIARIES

RECONCILIATION OF OPERATING INCOME TO ADJUSTED OPERATING INCOME

(In thousands of U.S. dollars)

We present Adjusted Operating Income as a supplemental measure of our performance. We define Adjusted Operating Income for the periods indicated as operating income adjusted to exclude (i) Equity-based compensation expense, (ii) Inventory reserve related to Huawei impact of downstream trade restrictions, (iii) Expenses related to Fab 3 power outage and (iv) Other charges.

For the three and nine months ended September 30, 2021, other charges of $1,766 thousand and $17,202 thousand, respectively, related to non-recurring professional service fees and expenses in connection with the pending merger transaction and regulatory requests.

For the nine months ended September 30, 2020, other charges were $554 thousand, which pertained to non-recurring professional service fees and expenses incurred in connection with certain treasury and finance initiatives.

MAGNACHIP SEMICONDUCTOR CORPORATION AND SUBSIDIARIES

RECONCILIATION OF NET INCOME TO ADJUSTED EBITDA AND ADJUSTED NET INCOME

(In thousands of U.S. dollars, except share data)

(Unaudited)

We present Adjusted EBITDA and Adjusted Net Income as supplemental measures of our performance. We define Adjusted EBITDA for the periods indicated as EBITDA (as defined below), adjusted to exclude (i) Equity-based compensation expense, (ii) Foreign currency loss (gain), net, (iii) Derivative valuation loss (gain), net, (iv) Inventory reserve related to Huawei impact of downstream trade restrictions, (v) Expenses related to Fab 3 power outage and (vi) Other charges, net. EBITDA for the periods indicated is defined as Income (loss) from continuing operations before interest expense (income), net, income tax expense (benefit), and depreciation and amortization.

We present Adjusted Net Income by adjusting income (loss) from continuing operations to eliminate the impact of a number of non-cash expenses and other items that may be either one time or recurring that we do not consider to be indicative of our core ongoing operating performance. We believe that Adjusted Net Income is particularly useful because it reflects the impact of our asset base and capital structure on our operating performance. We define Adjusted Net Income for the periods as income (loss) from continuing operations, adjusted to exclude (i) Equity-based compensation expense, (ii) Foreign currency loss (gain), net, (iii) Derivative valuation loss (gain), net, (iv) Inventory reserve related to Huawei impact of downstream trade restrictions, (v) Expenses related to Fab 3 power outage and (vi) Other charges, net.

For the three and nine months ended September 30, 2021, other charges, net included expenses of $1,766 thousand and $17,202 thousand, respectively, related to non-recurring professional service fees and expenses in connection with the pending merger transaction and regulatory requests, both of which were offset in part by $727 thousand legal settlement gain related to certain expenses incurred in prior periods in connection with our legacy Fab 4 (which was sold during the year ended December 31, 2020) and awarded in the current quarter.

For the nine months ended September 30, 2020, other charges, net were $554 thousand, which pertained to non-recurring professional service fees and expenses incurred in connection with certain treasury and finance initiatives.