ACM Research, Inc. 10-K

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations The following discussion and analysis should be read in conjunction with the audited consolidated financial statements and related notes included in this report. In addition to historical information, the following discussion contains forward-looking statements that involves risks, uncertainties and assumptions. See “Forward-Looking Statements and Statistical Data” at page 3 of this report. Please read “Item 1A. Risk Factors” for a discussion of factors that could cause our actual results to differ materially from our expectations 54 Table of Contents Overview ACM Research was incorporated in California in 1998 and redomesticated in Delaware in 2016. We perform strategic planning, marketing, and financial activities at our global corporate headquarters in Fremont, California. ACM Research is neither a mainland China operating company nor do we conduct our operations in mainland China through the use of VIEs. We supply advanced, innovative capital equipment developed for the global semiconductor industry. Fabricators of advanced integrated circuits, or chips, can use our wet-cleaning and other front-end processing tools in numerous steps to improve product yield, even at increasingly advanced process nodes. We have designed these tools for use in fabricating foundry, logic and memory chips, including DRAM 3D NAND-flash memory chips, power semiconductor and compound semiconductor chips. We also develop, manufacture and sell a range of advanced packaging tools to wafer assembly and packaging customers. We are focused on building a strategic portfolio of intellectual property to support and protect our key innovations. Our tools have been developed using our key proprietary technologies: • SAPS technology for flat and patterned wafer surfaces , which employs alternating phases of megasonic waves to deliver megasonic energy in a highly uniform manner on a microscopic level; • TEBO technology for patterned wafer surfaces at advanced process nodes , which provides effective, damage-free cleaning for 2D and 3D patterned wafers with fine feature sizes; • Tahoe technology for cost and environmental savings , which delivers high cleaning performance using significantly less sulfuric acid and hydrogen peroxide than is typically consumed by conventional high-temperature single-wafer cleaning tools; and • ECP technology for advanced metal plating , which includes Ultra ECP ap, or Advanced Packaging, technology for back-end assembly processes, Ultra ECP 3d for through-silicon-via, or tsv, and Ultra ECP map, or Multi-Anode Partial Plating, technology for front-end wafer fabrication processes. In 2021, 2022 and 2023 we introduced and delivered a range of new tools intended to broaden our revenue opportunity with global semiconductor manufacturers. Product extensions include the Ultra SFP ap tool for advanced packaging solutions, the Ultra C VI 18-chamber single wafer cleaning tool for advanced memory devices, and the Ultra ECP 3d platform for through-silicon-via, or tsv, application. New product lines include the Ultra fn Furnace, our first dry processing tool, and a suite of semi-critical cleaning systems which include single wafer back side cleaning, scrubber, and auto bench cleaning tools. We added two major new product categories in 2022 with the launch of the Ultra Pmax™ PECVD tool, which is equipped with a proprietary designed chamber, gas distribution unit and chuck, and is intended to provide better film uniformity, reduced film stress, and improved particle performance, and the introduction of the Ultra Track tool, a 300mm process tool that delivers uniform air downflow, fast robot handling and customizable software to address specific customer requirements, and has multiple features that enhance performance across defectivity, throughput, and cost of ownership. We conduct a substantial majority of our product development, manufacturing, support and services in mainland China, with additional product development and subsystem production in Korea. Substantially all of our integrated tools are built to order at our manufacturing facilities in the Pudong region of Shanghai, which now encompass a tota l of 236,000 squ are feet of floor space for production capacity, with 100,000 square feet having been added in 2021 with the lease of a second building in the Pudong region of Shanghai. In May 2020 ACM Shanghai, through its wholly owned subsidiary ACM Shengwei, entered into an agreement for a land use right in the Lingang region of Shanghai. In 2020 ACM Shengwei began a multi-year construction project for a new 1,000,000 square foot development and production center that will incorporate state-of-the-art manufacturing systems and automation technologies and will provide floor space to support significantly increased production capacity and related R&D activities. We expect to complete construction of the first Lingang manufacturing building and commence initial production in the first half of 2024 timeframe. See “I tem 2. Properties” of Part I of this report. Our experience has shown that chip manufacturers in mainland China and throughout Asia demand equipment meeting their specific technical requirements and prefer building relationships with local suppliers. We will continue to seek to leverage our local presence to address the growing market for semiconductor manufacturing equipment in the region by working closely with regional chip manufacturers to understand their specific requirements, encourage them to adopt our SAPS, TEBO, Tahoe, ECP, furnace, PECVD, Track, and other technologies, and enable us to design innovative products and solutions to address their needs. 55 Table of Contents Our Independent Registered Public Accounting Firm The U.S. Holding Foreign Companies Accountable Act, or the HFCA Act, requires that the Public Company Accounting Oversight Board, or the PCAOB, determine whether it is unable to inspect or investigate completely registered public accounting firms located in a non-U.S. jurisdiction because of a position taken by one or more authorities in any non-U.S. jurisdiction. BDO China Shu Lun Pan Certified Public Accountants LLP, or BDO China, had been our independent registered public accounting firm in recent years, including for the year ended December 31, 2021. On June 22, 2021, the U.S. Senate passed the Accelerating Holding Foreign Companies Accountable Act, which was enacted on December 29, 2022 under the Consolidated Appropriations Act, 2023, as further described below. On December 16, 2021, the PCAOB reported its determination that it was unable to inspect or investigate completely registered public accounting firms headquartered in mainland China and Hong Kong, including BDO China, because of positions taken by mainland China authorities in those jurisdictions. On March 30, 2022, based on this determination, ACM Research was transferred to the SEC’s “Conclusive list of issuers identified under the HFCAA.” See “Item 1A. Risk Factors—Risks Related to International Aspects of Our Business—We could be adversely affected if we are unable to comply with recent and proposed legislation and regulations regarding improved access to audit and other information and audit inspections of accounting firms operating in mainland China” of this report for more information. Under current regulations, if ACM Research were to be included on this list for two consecutive years due to our independent auditor being located in a jurisdiction that does not allow for PCAOB inspections, the SEC would prohibit trading in our securities and this ultimately could cause our securities to be delisted in the U.S., and their value may significantly decline or become worthless. On December 15, 2022, the PCAOB announced that it was able to secure complete access to inspect and investigate PCAOB-registered public accounting firms headquartered in mainland China and Hong Kong in 2022 and vacated its previous December 16, 2021 determination to the contrary. However, whether the PCAOB will continue to be able to satisfactorily conduct inspections of PCAOB-registered public accounting firms headquartered in mainland China and Hong Kong is subject to uncertainty and depends on a number of factors out of our, and our auditor’s, control. mainland China authorities will need to ensure that the PCAOB continues to have full access for inspections and investigations in 2023 and beyond. Each year, the PCAOB will determine whether it can inspect and investigate completely audit firms in mainland China and Hong Kong, among other jurisdictions. If the mainland China authorities do not allow the PCAOB complete access for inspections and investigations for two consecutive years, the SEC would prohibit trading in the securities of issuers engaging those audit firms, as required under the HFCA Act. Further, on December 29, 2022, the Consolidated Appropriations Act, 2023, was signed into law by U.S. President Biden, which, among other things, amended the HFCA Act to reduce the number of consecutive non-inspection years that would trigger the trading prohibition under the HFCA Act from three years to two years (originally such threshold under the HFCA Act was three consecutive years), and so that any foreign jurisdiction could be the reason why the PCAOB does not have complete access to inspect or investigate a company’s public accounting firm (originally the HFCA Act only applied if the PCAOB’s ability to inspect or investigate was due to a position taken by an authority in the jurisdiction where the relevant public accounting firm was located). On June 30, 2022, and June 15, 2023, stockholders of ACM Research ratified the appointment of Armanino as our independent auditor for the years ended December 31, 2022 and 2023, respectively. Armanino was neither headquartered in mainland China or Hong Kong nor was it subject to the determinations announced by the PCAOB on December 16, 2021, which determinations were vacated by the PCAOB on December 15, 2022. On July 21, 2023, we were informed by Armanino, that Armanino would resign as our independent auditor effective as of the earlier of (a) the date we engaged a new independent registered public accounting firm or (b) the filing of our Quarterly Report on Form 10-Q for the fiscal quarter ended September 30, 2023. On September 14, 2023, the Audit Committee completed a competitive selection process to select and appoint a new accounting firm to serve as our independent registered public accounting firm commencing with the audit of our financial statements for the fiscal year ended December 31, 2023. As a result of this process, the Audit Committee approved the engagement of E&Y as our independent registered public accounting firm for the fiscal year ended December 31, 2023. The engagement of E&Y became effective on September 20, 2023. E&Y is a PCAOB-registered firm that is headquartered in mainland China; however, we do not believe ACM Research will appear on the “Conclusive list of issuers identified under the HFCAA” for a second consecutive time, as the determinations announced by the PCAOB on December 16, 2021 were vacated by the PCAOB on December 15, 2022. 56 Table of Contents STAR Listing and IPO On November 18, 2021, ACM’s operating subsidiary ACM Shanghai completed: • a listing, which we refer to as the STAR Listing, of shares of ACM Shanghai on the Shanghai Stock Exchange’s SciTech innovAtion boaRd, known as the STAR Market; and • a concurrent initial public offering, which we refer to as the STAR IPO, of ACM Shanghai shares in mainland China, at a pre-offering valuation of not less than RMB 5.15 billion ($747.1 million). Following the completion of the STAR IPO, ACM Shanghai’s shares began trading on the STAR Market under the stock code 688082. In the STAR IPO, ACM Shanghai issued 43,355,753 shares, representing ten percent of the total 433,557,100 shares outstanding after the STAR IPO. The shares were issued at a public offering price of RMB 85.00 per share, and the proceeds of the STAR IPO totaled approximately $545.5 million, net of fees and expenses. Upon completion of the STAR IPO, ACM owned approximately 82.5% of the outstanding ACM Shanghai shares. However, in May 2023, ACM's ownership declined to 82.1% due to the exercise of 2,150,309 stock options related to ACM Shanghai shares (note 18). We believe the STAR Listing will continue to help scale our business in mainland China, and we continue to seek to broaden our markets in Europe, Japan, Korea, Taiwan and the United States. Our global headquarters are located in Fremont, California, and we are committed to maintaining the listing of Class A common stock on the Nasdaq Global Market. ACM Shanghai Dividend During year ended December 31, 2023, ACM Shanghai paid a dividend to the stockholders of ACM Shanghai (including ACM Research) in the amount of RMB 0.372 per share for an aggregate total of RMB 161.28 million ($22.2 million). Restrictions Imposed by the U.S. Department of Commerce on mainland China-Based Semiconductor Producers In early October 2022 the U.S. government enacted new rules aimed at restricting U.S. support for mainland China’s ability to manufacture advanced semiconductors. The rules included new export license requirements for exports, re-exports or transfers to or within mainland China of additional types of semiconductor manufacturing items, items for use in manufacturing designated types of semiconductor manufacturing equipment in mainland China, and semiconductor manufacturing equipment for use at certain IC manufacturing and development facilities in mainland China. In addition, the U.S. government imposed new restrictions by which U.S. persons anywhere in the world are effectively barred from engaging in certain activities related to the development and production of certain semiconductors at mainland China fabrication facilities meeting specified criteria, even if no items subject to the U.S. Export Administration Regulations (EAR) are involved. These restrictions were later updated to extend to Macau. In October 2023, the U.S. government revised and expanded the October 2022 controls with the release of additional rules. While the release primarily clarified the October 2022 regulations, certain changes have the potential to be more significant. In particular, the U.S. government expanded license requirements on additional types of semiconductors, semiconductor manufacturing items, and items for use in manufacturing certain types of semiconductor manufacturing equipment, and also expanded the scope to include additional countries beyond mainland China and Macau. ACM Shanghai has determined that several of its customers have mainland China-based facilities that meet the restricted criteria set out in the October 2022 and October 2023 rules, and has also determined that several of its products, and/or components for its products, may meet the parameters of export control classification numbers, or ECCNs, affected by the restrictions. ACM and ACM Shanghai have implemented modifications to their existing business policies and practices in response to the October 2022 restrictions, including by imposing limitations on the activities of their U.S. persons and undertaking measures in connection with their supply chains more broadly to comply with the new regulations. ACM Shanghai is continuing to assess the impact of the October 2023 changes, together with the October 2022 rules, and will continually adjust or modify its policies and practices as required to comply with these or other related updates. Bas ed on our ongoing review, we believe these regulations may directly impact ACM Shanghai’s ability to meet its future production plans, or indirectly impact the spending plans of ACM Shanghai’s customer base. ACM may not be able to import, or may face substantial restrictions in importing, certain parts from the United States or parts subject to U.S. export controls from outside the United States to support tool shipments to such facilities, or to be embedded into tools defined by affected ECCNs. 57 Table of Contents ACM and ACM Shanghai believe that as a result of the October 2022 and October 2023 restrictions, several ACM Shanghai customers have significantly reduced production and related capital spending at facilities meeting the restricted advanced node capabilities. In addition, ACM Shanghai has experienced challenges as the companies in its supply chain adapt their policies to the new regulations. These factors had an adverse impact on ACM Shanghai’s shipments and sales for the twelve months ended December 30, 2023. During the twelve months ended December 30, 2023, two prominent exporters of advanced semiconductor manufacturing equipment, the Netherlands and Japan, announced and began to implement plans to join the United States in imposing semiconductor-focused export controls. On May 23, 2023, the Japanese government issued the final amendment to an ordinance implementing new export controls to require licensing for export of certain advanced semiconductor manufacturing equipment, effective as of July 23, 2023. The amendment expands the scope of export controls to prohibit (1) exporting twenty-three additional categories of items relating to semiconductor manufacturing and (2) providing technology relating to manufacturing, development or use of these categories of items, in both cases, without an advance license. While the expanded export controls apply to exports to any jurisdiction, exports to certain jurisdictions, such as the United States, are expected to be permitted by certain types of broad general licenses. However, it remains to be seen whether the Japanese government will authorize any exports of these items to mainland China by a limited general license or specific license, if at all. On June 30, 2023, the Government of the Netherlands published additional export control measures for advanced semiconductor manufacturing equipment. The Regulation on Advanced Semiconductor Manufacturing Equipment took effect on September 1, 2023. From that point on, the export of certain advanced semiconductor manufacturing equipment, as specified in the Annex to the Regulation , has been subject to a national export license authorization requirement by the Dutch Central Import and Export Service. As a result of the new restrictions imposed by the Japanese and Dutch governments, ACM Shanghai and/or several of its customers in mainland China may be impacted by, and required to reduce their production capabilities due to, the lack of, or reduced, ability to source items relating to semiconductor manufacturing from Japan and the Netherlands. See “Part II. Item 1A – Risk Factors – Regulatory Risks – Our ability to sell our tools to customers in mainland China has been impacted, and will likely continue to be materially and adversely impacted, by export license requirements, other regulatory changes, or other actions taken by the U.S. or other governmental agencies” for more information. Key Components of Results of Operations Revenue We develop, manufacture and sell innovative capital equipment to the global semiconductor industry. Since we sell tools to a small number of customers and we customize those tools to fulfill the customers’ specific requirements, our revenue generation fluctuates, depending on the length of the sales, development and evaluation phases: • Sales and Development. During the sale process we may, depending on a prospective customer’s specifications and requirements, need to perform additional research, development and testing to establish that a tool can meet the prospective customer’s requirements. Sales cycles for orders that require limited customization and do not require that we develop new technology usually take from 6 to 12 months, while the product life cycle, including the initial design, demonstration and final assembly phases, for orders requiring development and testing of new technologies can take as long as 2 to 4 years. As we expand our customer base, we expect to gain more repeat purchase orders for tools that we have already developed and tested, which we believe will reduce the need for a demonstration phase and shorten the development cycle. • Evaluation Periods. When a chip manufacturer proposes to purchase a particular type of tool from us for the first time, we offer the manufacturer an opportunity to evaluate the tool for a period that can extend for 24 months or longer. In some cases, we do not receive any payment on first-time purchases until the tool is accepted. As a result, we may spend more than $2.0 million to produce a tool without receiving payment for more than 24 months or, if the tool is not accepted, without receiving any payment. Please see “Item 1A. Risk Factors—Risks Related to Our Business and Our Industry—We may incur significant expenses long before we can recognize revenue from new products, if at all, due to the costs and length of research, development, manufacturing and customer evaluation process cycles.” • Purchase Orders. In accordance with industry practice, sales of our tools are made pursuant to purchase orders. Each purchase order from a customer for one of our tools contains specific technical requirements intended to ensure, among other things, that the tool will be compatible with the customer’s manufacturing process line. Until a 58 Table of Contents purchase order is received, we do not have a binding purchase commitment. Some of our customers to date have provided us with non-binding one- to two-year forecasts of their anticipated demands, and we expect future customers to furnish similar non-binding forecasts for planning purposes. Any of those forecasts would be subject to change, however, by the customer at any time, without notice to us. • Fulfillment. We seek to obtain a purchase order for a tool from three to four months in advance of the expected delivery date. Depending upon the nature of a customer’s specifications, the lead time for production of a tool generally will extend from two to four months. The lead-time can be more than six months, however, and in some cases, we may need to begin producing a tool based on a customer’s non-binding forecast, rather than waiting to receive a binding purchase order. We expect our sales prices generally to range from $0.5 million to more than $5 million for our production tools. The sales price of a particular tool will vary depending upon the required specifications. We have designed equipment models using a modular configuration that we customize to meet customers’ technical specifications. For example, our Ultra C models for SAPS, TEBO and Tahoe solutions use common modular configurations that enable us to create a wet-cleaning tool meeting a customer’s specific requirements, while using pre-existing designs for chamber, electrical, chemical delivery and other modules. Because of the relatively high purchase prices of our tools, customers generally pay in installments. For a customer’s repeat purchase of a particular type of tool, the specific payment terms are negotiated in connection with acceptance milestones of a purchase order. Based on our experience with repeat sales of our tools, we expect that we will receive an initial payment upon delivery of a tool in connection with a repeat purchase, with the balance being paid after the tool has been tested and accepted by the customer. Our sales arrangements for repeat purchases do not include a general right of return. Substantially all of our sales in 2023, 2022, and 2021 were to customers located in Asia, and we anticipate that a substantial majority of our revenue will continue to come from customers located in this region for the near future. We have increased our sales efforts to penetrate the markets in North America and Western Europe. We utilize ASC 606 which was adopted in 2018 set forth in Accounting Standards Update, or ASU, No. 2014-09, Revenue from Contracts with Customers (Topic 606) , of the Financial Accounting Standards Board, or FASB, regarding the recognition, presentation and disclosure of revenue in our financial statements as described below under “—Critical Accounting Estimates—Revenue Recognition.” We offer extended maintenance service contracts to provide services such as trouble-shooting or fine-tuning tools, and installing spare parts, following expiration of applicable initial standard assurance type warranty coverage periods, which for sales to date have extended from 12 to 36 months as described under “—Critical Accounting Estimates—Warranty.” In 2023, 2022, and 2021, we received payments for parts and labor for service activities provided from time to time, but as of December 31, 2023 we had not yet entered into extended maintenance service contracts with respect to the substantial majority of tools for whi ch initial warranty coverage had expired. We expect to enter into extended maintenance service contracts with customers as additional initial warranties expire, but we do not expect revenue from extended maintenance service contracts to represent a material portion of our revenue in the future. The loss or delay of multiple large sale transactions in a quarter could impact our results of operations for that quarter and any future quarters for which revenue from that transaction is lost or delayed, as described under “Item 1A. Risk Factors—Risks Related to Our Business and Our Industry—Our quarterly operating results can be difficult to predict and can fluctuate substantially, which could result in volatility in the price of Class A common stock.” It is difficult to predict accurately when, or even if, we can complete a sale of a tool to a potential customer or to increase sales to any existing customer. Our tool demand forecasts are based on multiple assumptions, including non-binding forecasts received from customers years in advance, each of which may introduce error into our estimates. Difficulties in forecasting demand for our tools make it difficult for us to project future operating results and may lead to periodic inventory shortages or excess spending on inventory or on tools that may not be purchased, as further described in “Item 1A. Risk Factors—Risks Related to Our Business and Our Industry—Difficulties in forecasting demand for our tools may lead to periodic inventory shortages or excess spending on inventory items that may not be used.” Cost of Revenue Cost of revenue for capital equipment consists primarily of: • direct costs, which consist principally of costs of tool components and subassemblies purchased from third-party vendors; 59 Table of Contents • compensation of personnel associated with our manufacturing operations, including stock-based compensation; • depreciation of manufacturing equipment; • amortization of costs of software used for manufacturing purposes; • other expenses attributable to our manufacturing department; • inventory provision; and • allocated overhead for rent and utilities. We are not party to any long-term purchasing agreements with suppliers. Please see “Item 1A. Risk Factors—Risks Related to Our Business and Our Industry—Our customers do not generally enter into long-term purchase commitments, and they may decrease, cancel or delay their projected purchases at any time.” As our customer base and tool installations continue to grow, we may need to hire additional manufacturing personnel. The rates at which we add customers and install tools will affect the level and time of this spending. In addition, because we often import components and spare parts from the United States, we have experienced, and expect to continue to experience, the effect of the currency fluctuations on our cost of revenue. Gross Margin We generally expect gross margin to range between 40% and 45% for the foreseeable future, with direct manufacturing costs approximating 50% to 55% of revenue and overhead costs totaling approximatel y 5% of revenue. We seek to maintain our gross margin by continuing to develop proprietary technologies that avoid pricing pressure for our wet cleaning equipment. We actively manage our operations through principles of operational excellence designed to ensure continuing improvement in the efficiency and quality of our manufacturing operations by, for example, implementing factory constraint management and change control and inventory management systems. In addition, our purchasing department actively seeks to identify and negotiate supply contracts with improved pricing to reduce cost of revenue. A significant portion of our raw materials are denominated in the RMB, while the majority of our purchase orders are denominated in U.S. dollars. As a result, fluctuations in currency exchange rates may have a significant effect on our gross margin. Operating Expenses We have experienced, and expect to continue to experience, growth in the absolute dollar amount of our operating expenses, as we invest to support the anticipated growth of our customer base and the continued development of proprietary technologies. Sales and Marketing Sales and marketing expense consists primarily of: • compensation of personnel associated with pre- and after-sales support and other sales and marketing activities, including stock-based compensation; • sales commissions paid to independent sales representatives; • fees paid to sales consultants; • cost of trade shows; • cost of promotional tools to new potential customers; • travel and entertainment; and • allocated overhead for rent and utilities. Sales and marketing expense can be significant and may fluctuate, in part because of the resource-intensive nature of our sales efforts and the length and variability of our sales cycle. The length of our sales cycle, from initial contact with a customer to the execution of a purchase order, is generally 6 to 24 months. During the sales cycle, we expend significant time and money on sales and marketing activities, including educating customers about our tools, participating in extended tool evaluations and configuring our tools to customer-specific needs. Sales and marketing expense in a given period can be particularly affected by the increase in travel and entertainment expenses associated with the finalization of purchase orders or the installation of tools. 60 Table of Contents Research and Development Research and development expense relates to the development of new products and processes and encompasses our research, development and customer support activities. Research and development expense consists primarily of: • compensation of personnel associated with our research and development activities, including stock-based compensation; • costs of components and other research and development supplies; • costs of tools built for product development purposes; • travel expense associated with the research of technical requirements for product development purposes and testing of concepts under consideration; • amortization of costs of software used for research and development purposes; and • allocated overhead for rent and utilities. Some of our research and development has been funded by grants from the mainland China government, as described in “—mainland China Government Research and Development Funding” below. General and Administrative General and administrative expense consists primarily of: • compensation of executive, accounting and finance, human resources, information technology, and other administrative personnel, including stock-based compensation; • professional fees, including accounting and legal fees; • other corporate expenses; and • allocated overhead for rent and utilities. Stock-Based Compensation Expense We grant stock options to employees and non-employee consultants and directors, and we account for those stock-based awards in accordance with ASC Topic 718, Compensation—Stock Compensation . • Stock-based awards granted to employees and non-employees are measured at the fair value of the awards on the grant date and are recognized as expenses either (a) immediately on grant, if no vesting conditions are required, or (b) using the graded vesting method, net of estimated forfeitures, over the requisite service period. The fair value of stock options is determined using the Black-Scholes valuation model when there are service and performance condition attached, or the Monte Carlo valuation model when there is market condition attached. Stock-based compensation expense, when recognized, is charged to cost of revenue or to the category of operating expense corresponding to the service function of the employee or non-employee. • We also grant discounts to employee s when they subscribe for the new shares o f ACM Shanghai, and we account for those stock-based awards in accordance with Accounting Standards Codification, or ASC, Topic 718, Compensation—Stock Compensation Mainland China Government Research and Development Funding ACM Shanghai has received seven special government grants. The first grant, which was awarded in 2008, relates to the development and commercialization of 65nm to 45nm stress-free polishing technology. The second grant was awarded in 2009 to fund interest expense on short-term borrowings. The third grant was made in 2014 and relates to the development of electro copper-plating technology. The fourth grant was made in June 2018 and related to development of polytetrafluoroethylene. The fifth grant was made in 2020, and relates to the development of Tahoe single bench cleaning technologies. As of December 31, 2021, the fourth and fifth grants had been fully utilized. The sixth grant was made in 2020, and relates to the development of other cleaning technologies. The seventh grant was made in 2021, and relates to the development of the R&D and production center in the Lin-gang Special Area of Shanghai. These governmental authorities provide significant funding, although ACM Shanghai and ACM Shengwei is also required to invest certain amounts in the projects. The governmental grants contain certain operating conditions, and we are required to go through a government due diligence process once the project is complete. The grants therefore are recorded as long-term liabilities upon receipt, 61 Table of Contents although we are not required to return any funds ACM Shanghai receives. Grant amounts are recognized in our statements of comprehensive income (loss) as follows: • Government subsidies relating to current expenses are recorded as reductions of those expenses in the periods in which the current expenses are recorded. For the years ended December 31, 2023, 2022, and 2021, related government subsidies recognized as reductions of relevant expenses in the consolidated statements of comprehensive income (loss) we re $1.7 million, $1.2 million, and $11.3 million, respectively. • Government subsidies related to depreciable assets are credited to income over the useful lives of the related assets for which the grant was received. For the years ended December 31, 2023, 2022, and 2021, related government subsidies recognized as other income in the consolidated statements of comprehensive income (loss) were $0.5 million, $0.3 million, and $0.2 million, respectively. Unearned government subsidies received are deferred for recognition and recorded as other long-term liabilities (see note 13 in the Notes to Consolidated Financial Statements included herein under “Item 8. Financial Statements and Supplementary Data.”) in the consolidated balance sheet until the criteria for such recognition are satisfied. Net Income Attributable to Non-Controlling Interests and Redeemable Non-Controlling Interests In 2019 ACM Shanghai sold a total number of shares representing 8.3% of its outstanding ACM Shanghai shares, after which ACM Research held the remaining 91.7% of ACM Shanghai’s outstanding shares. In 2021 ACM Shanghai sold a total number shares representing an additional 10% of its outstanding ACM Shanghai shares in its STAR IPO, after which ACM Research held the remaining 82.5% of ACM Shanghai’s outstanding shares. During the year-ended December 31,2023, ACM's ownership declined to 82.1 % due to the exercise of 2,150,309 stock options related to ACM Shanghai shares (note 18). As a result, we reflect the portion of our net income allocable to the minority holders of ACM Shanghai shares as net income attributable to non-controlling interests. Critical Accounting Policies and Estimates In preparing our consolidated financial statements in conformity with GAAP, we make assumptions, judgments and estimates in applying our accounting policies that can have a significant impact on our revenue, operating income and net income, as well as on the value of certain assets and liabilities on our consolidated balance sheets. We base our assumptions, judgments and estimates on historical experience and various other factors that we believe to be reasonable under the circumstances. At least quarterly, we evaluate our assumptions, judgments and estimates and make changes as deemed necessary. Actual results could differ materially from these estimates under different assumptions or conditions. We believe that the assumptions, judgments and estimates involved in the accounting for the following accounting policies have the greatest potential impact on our consolidated financial statements, and we therefore consider these to be our critical accounting estimates. For information on our significant accounting policies, see Note 2 in the notes to consolidated financial statements. Revenue Recognition We derive revenue principally from the sale of semiconductor capital equipment. Revenue from contracts with customers is recognized using the following five steps pursuant to ASC Topic 606, Revenue from Contracts with Customers : 1. Identify the contract(s) with a customer; 2. Identify the performance obligations in the contract; 3. Determine the transaction price; 4. Allocate the transaction price to the performance obligations in the contract; and 5. Recognize revenue when, or as, a performance obligation is satisfied. Identify the contract(s) with a customer. We generally consider written documentation including, but not limited to, signed purchase orders, master agreements, and sales orders as contracts, provided it has approval and commitment from the customer, the rights of the parties are identified, payment terms are identified, the contract has commercial substance, and collection is probable. Collectability is assessed based on our management’s assessment of the customer’s creditworthiness, historical payment experience, as well as other relevant factors. 62 Table of Contents Identify the performance obligations in the contract. Performance obligations are accounted for separately if they are distinct. A good or service is distinct if the customer can benefit from the good or service either on its own or together with other resources that are readily available to the customer, and the good or service is distinct in the context of the contract. Our performance obligations generally include sales of tools and spare parts. In addition, customer contracts can contain provisions for installation, training, software updates, most-favored pricing for spare parts, and other items which have been deemed immaterial in the context of the contract. Determine the transaction price. The transaction price for our contracts with customers may include fixed and variable consideration. We include variable consideration in the transaction price to the extent that it is probable that a significant reversal of revenue will not occur in the future based on our historical experience with similar arrangements. Allocate the transaction price to the performance obligations in the contract. For contracts that contain multiple performance obligations, we allocate the transaction price to the performance obligations on a relative standalone selling price basis. We defer revenue associated with spare parts, sold together with its tools, based on its stand-alone observable selling prices or using an expected cost-plus-margin approach when a stand-alone selling price is not directly observable, and recognizes revenue upon subsequent delivery. Recognize revenue when, or as, a performance obligation is satisfied. We recognize revenue from tools and spare parts at a point in time, when we have satisfied our performance obligation. Our sales arrangements do not include a general right of return. For shipments made to a customer that has not previously accepted a specific type of tool in the past, or first tools, revenues are recognized when the goods are accepted by the customer. For shipments made to a customer that has previously accepted a specific type of tool, revenues are recognized upon shipment or delivery because we can objectively demonstrate that the goods meet all the required customer specifications. Stock-based compensation We account for grants of stock options based on their grant date fair value and recognize compensation expense over the vesting periods. We estimate the fair value of the stock options granted with a service period-based condition and/or performance condition at the date of grant using the Black-Scholes option pricing model. We estimate the fair value of the stock options granted with a market-based condition at the date of grant using the Monte Carlo simulation model. For options granted with a service period-based and/or performance condition, we estimate the fair value of these stock option grants using the Black-Scholes option pricing model, which requires the input of subjective assumptions, including (a)Fair value of share of common stock, (b)the risk-free interest rate, (c) volatility, and (d) the expected term of the award. • We use the market closing price for the Class A common stock as reported on the Nasdaq Global Market to determine the fair value of the Class A common stock. We use the market closing price for the ACM Shanghai’s common stock as reported on the STAR Market to determine the fair value of ACM Shanghai’s common stock. • For options granted by ACM Research, risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected term of the share options in effect at the time of grant. For options granted by ACM Shanghai, risk-free interest rate is based on the yields of RMB deposit in mainland China with maturities similar to the expected term of the share options in effect at the time of grant. • We use historical volatility of our shares in the period equal to the expected term of each grant. • The expected term of share options is based on the average of the vesting period and the contractual term for each grant. Inventory Inventories consist of finished goods, raw materials, work-in-process and consumable materials. Finished goods are comprised of direct materials, direct labor, depreciation and manufacturing overhead. Inventory is stated at the lower of cost and net realizable value of the inventory on a moving weighted average basis. The cost of an inventory item purchased specifically for a customized tool is determined using the specific identification method. Market value is determined as the lower of replacement cost and net realizable value, which is the estimated selling price, in the ordinary course of business, less estimated costs to complete or dispose. 63 Table of Contents We assess the recoverability of all inventories quarterly to determine if any adjustments are required. We recognize a loss or impairment if in our judgement the inventory cannot be sold or used for production, if it has been damaged or should be considered as obsolete, or if the net realizable value is lower than the cost. We also assess the status of our raw materials. We recognize a loss or impairment for any raw materials aged more than three years. The three-year aging is based on our assessment of technology change, our requirement to maintain stock for warranty coverage, and other factors. Actual demand may differ from forecasted demand, and those differences may have a material effect on recorded inventory values. Our manufacturing overhead standards for product costs are calculated assuming full absorption of forecasted spending over projected volumes, adjusted for excess capacity. Abnormal inventory costs such as costs of idle facilities, excess freight and handling costs, and spoilage are recognized as current period charges. Allowance for Credit Losses Accounts receivables are reflected in our consolidated balance sheets at their estimated collectible amounts. A substantial majority of our accounts receivable are derived from sales to large multinational semiconductor manufacturers in Asia. We assess collectability by reviewing accounts receivable on a collective basis where similar characteristics exist and on an individual basis when we identify specific customers with known disputes or collectability issues. In determining the amount of the allowance for credit losses, we consider historical collectability based on past due status, the age of the accounts receivable balances, credit quality of our customers based on ongoing credit evaluations, current economic conditions, reasonable and supportable forecasts of future economic conditions, and other factors that may affect our ability to collect from customers. Income Taxes Income taxes are accounted for using the liability method. Under this method, deferred income tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred income tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which these temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. A valuation allowance would be provided for the deferred tax assets if it is more likely than not that the related benefit will not be realized. On a quarterly basis, we provide income tax provisions based upon an estimated annual effective income tax rate. The effective tax rate is highly dependent upon the geographic composition of worldwide earnings, tax regulations governing each region, availability of tax credits and the effectiveness of our tax planning strategies. We carefully monitor the changes in many factors and adjust our effective income tax rate on a timely basis. If actual results differ from these estimates, this could have a material effect on our financial condition and results of operations. We maintained a partial valuation allowance as of December 31, 2023 with respect to certain net deferred tax assets based on our estimates of recoverability. We determined that the partial valuation allowance was appropriate given our historical operating losses and uncertainty with respect to our ability to generate profits from our business model sufficient to take advantage of the deferred tax assets in all applicable tax jurisdictions. The calculation of our tax liabilities involves dealing with uncertainties in the application of complex tax regulations. In accordance with the authoritative guidance on accounting for uncertainty in income taxes, we recognize liabilities for uncertain tax positions based on the two-step process. The first step is to evaluate the tax position for recognition by determining if the weight of available evidence indicates that it is more likely than not that the position will be sustained in audit, including resolution of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than fifty percent likely of being realized upon ultimate settlement. We reevaluate these uncertain tax positions on a quarterly basis. This evaluation is based on factors including changes in facts or circumstances, changes in tax law, effectively settled issues under audit and new audit activity. Any change in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision. Interest and penalties related to uncertain tax positions are recorded in the provision for income tax expense on the consolidated statements of comprehensive income (loss). 64 Table of Contents Warranty We have provided standard assurance type warranty coverage on our tools for 12 to 36 months, covering labor and parts necessary to repair a tool during the warranty period. Warranty obligations are affected by historical failure rates and associated replacement costs. Utilizing historical warranty cost records, we calculate a rate of warranty expenses to revenue to determine the estimated warranty charge. We update these estimated charges on a regular basis. The actual product performance and field expense profiles may differ, and in those cases, we adjust our warranty accruals according ly. As of December 31, 2023 and 2022, we had accrued $9.8 million and $8.8 million, respectively, in liability contingency for potential warranty claims. Recent Accounting Pronouncements For a discussion of recent accounting pronouncements we expect will have an impact when adopted, see note 2 in the Notes to Consolidated Financial Statements included herein under “Item 8. Financial Statements and Supplementary Data.” Results of Operations The following table sets forth our results of operations for the peri ods presented, as percentages of revenue. Year Ended December 31, 2023 2022 2021 Revenue 100.0 % 100.0 % 100.0 % Cost of revenue 50.5 52.8 55.8 Gross margin 49.5 47.2 44.2 Operating expenses: Sales and marketing 8.4 10.3 10.3 Research and development 16.6 16.0 13.2 General and administrative 7.3 5.8 5.9 Total operating expenses, net 32.3 32.0 29.4 Income from operations 17.2 15.2 14.8 Interest income (expense), net 1.0 1.8 (0.1) Realized gain from sale of short-term investments 1.6 0.3 - Unrealized gain (loss) on short-term investments (0.5) (2.0) 0.2 Other income (expense), net (0.3) 0.9 (0.2) Income from equity method investments 1.8 1.2 1.8 Income before income taxes 20.8 17.4 16.5 Income tax expense (3.5) (4.3) (0.1) Net income 17.3 13.0 16.4 Less: Net income attributable to non-controlling interests 3.5 2.9 2.0 Net income attributable to ACM Research, Inc. 13.8 % 10.1 % 14.4 % 65 Table of Contents Comparison of Years Ended December 31, 2023, 2022, and 2021 Revenue Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 (in thousands) Single wafer cleaning, Tahoe and semi-critical cleaning equipment $ 403,851 $ 272,939 $ 189,208 48.0 % 44.3 % ECP (front-end and packaging), furnace and other technologies 103,356 77,482 33,210 33.4 % 133.3 % Advanced packaging (excluding ECP), services & spares 50,516 38,411 37,333 31.5 % 2.9 % Total Revenue By Product Category $ 557,723 $ 388,832 $ 259,751 43.4 % 49.7 % Year Ended December 31, 2023 2022 2021 (in thousands) Mainland China $ 540,969 $ 377,752 $ 258,615 Other Regions 16,754 11,080 1,136 $ 557,723 $ 388,832 $ 259,751 The increase in revenue for 2023 compared to 2022 was driven by higher sales of single wafer cleaning, Tahoe and semi-critical cleaning equipment, ECP (front-end and packaging), furnace and other technologies, and Advance packaging (excluding ECP), and services and spares. We attribute the revenue growth to continued investments in mature process nodes by current and new mainland China-based customers amidst an ongoing target to achieve a greater share of the global semiconductor market, incremental contribution from newly introduced tools, and better penetration of our product portfolio across our customer base. The increase in revenue for 2022 compared to 2021 was driven primarily by higher sales of single wafer cleaning, Tahoe and semi-critical cleaning equipment, and increased contribution from newer ECP (front-end and packaging), furnace and other technologies. Our Shanghai production operations were adversely impacted in the first half of 2022 to COVID-19-related restrictions, with a return to more normal operations in the second half of the year. The U.S. export regulations imposed in October of 2022 had an adverse impact on ACM Shanghai’s shipments and sales in the fourth quarter of 2022. Cost of Revenue and Gross Margin Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 (in thousands) Cost of revenue $ 281,508 $ 205,217 $ 144,895 37.2 % 41.6 % Gross profit 276,215 183,615 114,856 50.4 % 59.9 % Gross margin 49.5 % 47.2 % 44.2 % 2.30 3.00 Cost of revenue and gross profit increased in 2023 as compared to 2022 due to the increased sales volume and an increase in gross margin. The increased gross margin versus the prior-year period was primarily due to improved gross margins for certain products, overall product mix , and a positive impact due to a change in the RMB to U.S. dollar currency exchange rate. Cost of revenue and gross profit increased in 2022 as compared to 2021 due to the increased sales volume and an increase in gross margin. The increased gross margin versus the prior-year period was primarily due to a higher mix of ECP (front- 66 Table of Contents end and packaging), furnace, and other technologies, and a positive impact due to a change in the RMB to U.S. dollar currency exchange rate. Gross margin may vary from period to period, primarily related to the level of utilization and the timing and mix of revenue. We expect gross margin to be between 40.0% and 45.0% for the foreseeable future, with direct manufacturing costs approximating 50.0% to 55.0% of revenue and overhead costs totaling 5.0% of revenue. Operating Expenses Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 (in thousands) Sales and marketing expense $ 47,019 $ 39,889 $ 26,733 17.9 % 49.2 % Research and development expense 92,709 62,226 34,207 49.0 % 81.9 % General and administrative expense 40,648 22,465 15,214 80.9 % 47.7 % Total operating expenses $ 180,376 $ 124,580 $ 76,154 44.8 % 63.6 % Sales and marketing expense increased in 2023 as compared to 2022, and reflected an increase of $8.1 million due to higher costs for personnel, commissions, travel and entertainment and other costs, an increase of $4.7 million due to higher costs for professional services, outside services and other costs, and an increase of $3.8 million due to higher stock -based compensation, partly offset by a decrease of ($9.6 million) for the cost of tools built for promotional purposes. Sales and marketing expense increased in 2022 as compared to 2021, and reflected an increase of $7.9 million due to higher costs of tools built for promotional purposes for potential new customers, and an increase of $5.3 million due to increased costs for personnel, commissions, outside services, travel and entertainment and other costs. We expect that, for the foreseeable future, sales and marketing expense will increase in absolute dollars, as we continue to invest in sales and marketing by hiring additional employees and expanding marketing programs in existing or new markets. We must invest in sales and marketing processes in order to develop and maintain close relationships with customers. We are making dollar-based investments in order to support growth of our customer base in the United States, and the relative strength of the dollar could have a significant effect on our sales and marketing expense. Research and development expense increased in 2023 as compared to 2022, reflecting an increase of $15.4 million in costs of components, costs of tools built for product development purposes, and costs of other research and development supplies, an increase of $7.1 million for personnel-related costs, an increase of $5.9 million in stock-based compensation, and an increase of $4.2 million in travel and entertainment costs to support product development, professional services, and other research and development related expenses, offset by a decrease of ($2.1 million) for outside services. Research and development expense represented 16.6% and 16.0% of our revenue in the years ended December 31, 2023 and 2022, respectively. Without reduction by grant amounts received from mainland China governmental authorities (see “—mainland China Government Research and Development Funding”), gross research and development expense totaled $94.5 million, or 16.9% of total revenue, in the year ended December 31, 2023 as compared to $63.4 million, or 16.3% of revenue, in the corresponding period in 2022. Research and development expense increased in 2022 as compared to 2021, reflecting an increase of $6.9 million in costs of components, costs of tools built for product development purposes, and costs of other research and development supplies, and an increase of $16.7 million for personnel, stock-based compensation, and travel and entertainment costs to support product development, and an increase of $4.4 million for outside services and other research and development related expenses. We expect that, for the foreseeable future, research and development expense will increase in absolute dollars as compared to 2023, as we continue to invest in research and development to advance our technologies. We intend to continue to invest in research and development to support and enhance our cleaning, plating, advanced packaging, furnace and future product offerings to build and maintain our technology leadership position. 67 Table of Contents General and administrative expense increased in 2023 as compared to 2022, reflecting an increase of $9.0 million in stock-based compensation, $3.3 million in personnel and professional services costs, $2.7 million in allowance for credit losses, and $3.1 million for travel & entertainment, depreciation and amortization, outside services, taxes and other general and administrative expenses. General and administrative expense increased in 2022 as compared to 2021, primarily due to an increase in stock-based compensation, increased employee count, and an increase in legal, payroll tax and other fees. We expect that, for the foreseeable future, general and administrative expense will increase in absolute dollars, as we incur additional costs associated with growing our business and operating as a public company. Stock-Based Compensation Expense Cost of revenue and operating expenses during the periods presented below have included stock-based compensation as follows: Year Ended December 31, 2023 2022 2021 (in thousands) Stock-Based Compensation Expense: Cost of revenue $ 1,406 $ 520 $ 397 Sales and marketing expense 5,684 1,877 1,802 Research and development expense 8,459 2,565 1,115 General and administrative expense 11,789 2,768 1,803 $ 27,338 $ 7,730 $ 5,117 Interest income (expense), net, Other Income (expense), net Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 (in thousands) Interest Income $ 8,354 $ 8,740 $ 505 -4.4 % 1,630.7 % Interest Expense (2,681) (1,655) (765) 62.0 % 116.3 % Interest Income (expense), net $ 5,673 $ 7,085 $ (260) -19.9 % -2,825.0 % Other income (expense), net $ (1,558) $ 3,315 $ (631) -147.0 % -625.4 % Interest income (expense), net, decreased in 2023 compared to 2022, principally as a result of reduced interest income from lower interest income on reduced cash balances, offset by increase in interest expenses incurred from a higher balance of total bank loans. Interest income (expense), net, increased in 2022 compared to 2021, principally as a result of reduced interest income from lower interest rates on reduced cash balances, offset by increase in interest expenses incurred from short-term and long-term bank loans. Other income (expense), net primarily reflects (a) gains or losses recognized from the impact of exchange rates on our foreign currency-denominated working-capital transactions and (b) depreciation of assets acquired with government subsidies, as described under “—Government Research and Development Funding” above. We realized $1.6 million of other expense in the year ended December 31, 2023, of which $2.0 million was due to loss realized from transactions that resulted from changes in the RMB-to-U.S. dollar exchange rate, as compared to a foreign exchange gain of 1.7 million in the corresponding period in 2022. 68 Table of Contents Other income (expense) increased by $3.3 million in the year ended December 31, 2022, of which $1.7 million was due to gains realized from transactions that resulted from changes in the RMB-to-U.S. dollar exchange rate, as compared to a loss of ($0.6 million) in the corresponding period in 2021. Realized gain and unrealized loss from short-term investments, and income from equity method investments . Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 Absolute Change 2023 v 2022 (in thousands) Realized gain from sale of short-term investments $ 9,047 $ 1,116 $ - 710.7 % 100.0 % $ 7,931 Unrealized gain (loss) on short-term investments $ (2,737) $ (7,855) $ 607 -65.2 % -1394.1 % $ 5,118 Income from equity method investments $ 9,952 $ 4,666 $ 4,637 113.3 % 0.6 % $ 5,286 We recorded a realized gain on sale of short-term investments of $9.0 million for the year ended December 31, 2023 as compared to a realized gain of $1.1 million for the same period in 2022 primarily due to the sales of ACM Shanghai’s indirect investment in publicly traded shares. We recorded an unrealized loss on short-term investments of $2.7 million for the year ended December 31, 2023 as compared to an unrealized loss of $7.9 million for the same period in 2022, due primarily to a change in market value of ACM Shanghai’s indirect investment in publicly traded shares. We recorded an unrealized loss on short-term investments of $7.9 million for the year ended December 31, 2022 as compared to an unrealized gain of $0.7 million for the same period in 2021, due primarily to a change in market value of ACM Shanghai’s indirect investment in publicly traded shares. Income from equity method investments for the year ended December 31, 2023 increased by $5.3 million compared to the year ended December 31, 2022 primarily due to higher net income from equity method investments. Income from equity method investments for the year ended December 31, 2022 was unchanged versus the year ended December 31, 2021. Income from equity method investments increased by $4.0 million for the year ended December 31, 2021 due to higher net income from equity method investments. 69 Table of Contents Tax Benefit (Expense) Year Ended December 31, 2023 2022 2021 (in thousands) Current: U.S. federal $ (12,757) $ (479) $ (91) U.S. state (150) (18) (2) Foreign (19,696) (11,139) (2,195) Total current tax expense (32,603) (11,636) (2,288) Deferred: U.S. federal 7,316 (10,927) 2,089 U.S. state 63 8 - Foreign 5,860 5,757 65 Total deferred tax benefit (expense) 13,239 (5,162) 2,154 Total income tax expense $ (19,364) $ (16,798) $ (134) We recognized a tax expense of $19.4 million for the year ended December 31, 2023 as compared to a tax expense of $16.8 million for the prior year period. The increased tax expense in 2023 primarily resulted from the tax effect of increased operating profit generated. As we collect and prepare necessary data, and interpret the guidance issued by the U.S. Treasury Department, the Internal Revenue Service, and other standard-setting bodies, we may make adjustments to the provisional amounts. Those adjustments may materially affect our provision for income taxes and effective tax rate in the period in which the adjustments are made. There were no adjustments made in 2023. Our effective tax rate differs from statutory rates of 21% for U.S. federal income tax purposes and 12.5% to 25% for mainland China income tax purposes due to the effects of the valuation allowance and certain permanent differences as it pertains to book-tax differences in the treatment of stock-based compensation and non-U.S. research expenses. Our four mainland China subsidiaries, ACM Shanghai, ACM Wuxi, ACM Beijing, and ACM Lingang, are liable for mainland China corporate income taxes at the rates of 15%, 25%, 25%, and 15%, respectively. Pursuant to the Corporate Income Tax Law of mainland China, our mainland China subsidiaries generally would be liable for mainland China corporate income taxes at a rate of 25%. According to Guoshuihan 2009 No. 203, an entity certified as an “advanced and new technology enterprise” is entitled to a preferential income tax rate of 15%. ACM Shanghai was certified as an “advanced and new technology enterprise” in 2012 and again in 2016, 2018, and 2021, effective until December 31, 2023, and is expected to be re-certified for future years in 2024 . In 2021, ACM Shanghai was certified as an eligible integrated circuit production enterprise and is entitled to a preferential income tax rate of 12.5% from January 1, 2020 to December 31, 2022. Certain entities which meet requirements according to the Policy of the Lingang New area in China (Shanghai) Pilot Free Trade Zone are entitled to a preferential income tax rate of 15%. ACM Lingang was certified for this in 2021, and this preferential income tax rate is valid from December 31, 2020 until December 31, 2024. We file income tax returns in the United States and state and foreign jurisdictions. All tax returns will remain open for examination by the federal and state authorities for three and four years, respectively, from the date of utilization of any net operating loss or credits. Certain tax years are subject to foreign income tax examinations by tax authorities until the statute of limitations expire. 70 Table of Contents Net Income Attributable to Non-Controlling Interests Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 (in thousands) Net income attributable to non-controlling interests $ 19,503 $ 11,301 $ 5,164 72.6 % 118.8 % ACM Research owns 82.1% of ACM Shanghai’s (note 1) outstanding shares which is reflected in our consolidated financial statements (note 2). We reflect the portion of net income allocable to the minority holders of ACM Shanghai shares as net income attributable to non-controlling interests. Foreign currency translation adjustment Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 (in thousands) Foreign currency translation adjustment $ (10,617) $ (59,102) $ 4,695 -82.0 % -1358.8 % We recorded a foreign currency translation adjustment of ($10.6 million) for the year ended December 31, 2023, as compared to $(59.1) million for 2022, based on the net effect of RMB to dollar exchange rate fluctuations for the period on the converted value of ACM Shanghai’s RMB-denominated balances to U.S. dollar equivalents. The 2022 amount was especially large due to a weakening of the RMB versus the U.S. dollar during the year ended December 31, 2022 together with a more significant RMB-denominated asset balance in 2022. Comprehensive income (loss) attributable to non-controlling interests Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 % Change 2022 v 2021 (in thousands) Comprehensive income (loss) attributable to non-controlling interests $ 17,689 $ 1,854 $ 5,607 854.1 % -66.9 % Comprehensive income attributable to non-controlling interest increased by $15.8 million compared to a decrease of $(3.8) million for the years ended December 31, 2023 and 2022 compared to the prior year, due to a significant change in net income generated from the non-controlling interests as impacted from foreign exchange rate fluctuations. 71 Table of Contents Liquidity and Capital Resources The following chart depicts our corporate organization as of December 31, 2023: A detailed description of how cash is transferred through our organization is set forth unde r “Note 2 – Summary of Significant Accounting Policies – Cash and Cash Equivalents” to the Consolidated Financial Statements of this report. During the year ended December 31, 2023, we funded our technology development and operations principally through our beginning global cash balances, including the cash balances at ACM Shanghai, borrowings by ACM Shanghai from local financial institutions and our loan from China CITIC Bank. Cash and cash equivalents, restricted cash, short-term time deposits and long-term time deposits were $304.5 million at December 31, 2023, compared to $420.9 million at December 31, 2022. The ($116.4 million) decrease was primarily driven by ($75.3 million) of cash used in operations, ($60.2 million) used in investing activities excluding the change in time deposits, $18.5 million net cash provided by financing activitie s, a $1.7 million decrease from the effect of exchange rate on cash, cash equivalents and restricted cash, and a $2.4 million incr ease from the effect of exchange rate on time deposits. The table below represents the cash an d cash equivalents, restricted cash, and time deposits as of December 31, 2023 and 2022: December 31, 2023 2022 (In thousands) Cash and cash equivalents, restricted cash, and time deposits: Cash and cash equivalents and restricted cash $ 183,173 $ 248,451 Short-term time deposits 80,524 70,492 Long-term time deposits 40,818 101,956 Total $ 304,515 $ 420,899 Our future working capital needs beyond the next twelve months will depend on many factors, including the rate of our business and revenue growth, the payment schedules of our customers, the timing and magnitude of our capital expenditures, and the timing of investment in our research and development as well as sales and marketing. We believe our existing cash and cash equivalents and short-term and long-term time deposits, our cash flow from operating activities, and bank borrowings by us and ACM Shanghai will be sufficient to meet our anticipated cash needs within our longer-term planning horizon. ACM Shanghai has historically participated in certain mainland China government-sponsored grant and subsidy programs, as described under “—Key Components of Results of Operations—mainland China Government Research and Development Funding” and “—Contractual Obligations” and we expect that ACM Shanghai will continue to take 72 Table of Contents advantage of these programs when they are available and fit with our business strategy. ACM Shanghai generally applies for these grants and subsidies through the applicable mainland China government agency’s defined processes. Periodically, the public relations department researches the availability of these grants and subsidies through mainland China government agencies with whom ACM Shanghai files business surveys and taxes. Management of ACM Shanghai then assesses which grants and subsidies for which ACM Shanghai may be eligible and submits the relevant application. The decision to award the grant to ACM Shanghai is made by the relevant mainland China government agencies based on suitability and the merits of the application. Neither ACM Research, nor ACM Shanghai or any of our other subsidiaries, has any direct relationship with any mainland China government agency, and our anticipated cash needs for the next twelve months neither anticipate, nor require, receipt of any mainland China government grants or subsidies. To the extent our cash and cash equivalents, cash flow from operating activities and short-term bank borrowings are insufficient to fund our future activities in accordance with our strategic plan, we may determine to raise additional funds through public or private debt or equity financings or additional bank credit arrangements. We also may need to raise additional funds in the event we determine in the future to effect one or more acquisitions of businesses, technologies and products. If additional funding is necessary or desirable, we may not be able to obtain bank credit arrangements or to affect an equity or debt financing on terms acceptable to us or at all. Restrictions under mainland China laws and regulations as well as restrictions under ACM Shanghai’s bank loan agreements, may significantly restrict ACM Shanghai’s ability to transfer a portion of ACM Shanghai’s net assets to ACM Research, other subsidiaries of ACM Research and to holders of ACM Research Class A common stock. See “Item 1A. Risk Factors–Regulatory Risks–Mainland China’s currency exchange control and government restrictions on investment repatriation may impact our ability to transfer funds outside of mainland China, which could materially and adversely affect our ability to grow, make investments or acquisitions that could benefit our business, otherwise fund and conduct our business, or pay dividends on our common stock.” For the years ended December 31, 2023 and 2022, with the exception of sales and services-related transfer-pricing payments in the ordinary course of business, and dividends paid by ACM Shanghai to ACM Research, no transfers or distributions have been made between ACM Research, and its subsidiaries, including ACM Shanghai, or to holders of ACM Research Class A common stock. Our cash and cash equivalents at December 31, 2023 were held for working capital purposes and other potential investments. ACM Shanghai, our only direct mainland China subsidiary, is, however, subject to mainland China restrictions on distributions to equity holders. The use of proceeds raised by the STAR Market IPO, without further approvals, are limited to specific usage. We currently intend for ACM Shanghai to retain all available funds from any future earnings for use in the operation of its business and do not anticipate it paying any cash dividends. Our accounts receivable balance fluctuates from period to period, which affects our cash flow from operating activities. Fluctuations vary depending on cash collections, client mix, and the timing of shipment and acceptance of our tools. We have never declared or paid cash dividends on our capital stock. We intend to retain all available funds and any future earnings to support the operation of and to finance the growth and development of our business and do not anticipate paying any cash dividends in the foreseeable future. 73 Table of Contents Cash Flow Used in Operating Activities. Net cash used by operations of ($75.3 million) during the year ended December 31, 2023 consisted of: Year Ended December 31, 2023 2022 2021 (in thousands) Net Income $ 96,852 $ 50,564 $ 42,921 Non-cash operating lease cost 3,580 2,816 2,451 Provision for inventory 575 2,248 75 Provision for credit losses 2,741 - - Gain on disposals of property plant and equipment (2) (12) - Depreciation and amortization 8,092 5,366 2,353 Realized gain on short-term investments (9,047) (1,116) - Income from equity method investments (9,952) (4,666) (4,637) Unrealized loss (gain) on short-term investments 2,737 7,855 (607) Deferred income taxes (13,647) 4,027 (1,840) Stock-based compensation 27,338 7,730 5,117 Net changes in operating assets and liabilities: (184,590) (137,006) (85,926) Net cash flow used in operating activities $ (75,323) $ (62,194) $ (40,093) Significant changes in operating asset and liability accounts during the year-ended December 31, 2023 included the following uses of cash: increases of inventories of $164.0 million (Note 5), and an increase of accounts receivable of $108.7 million (Note 4). As described under “—Key Components of Results of Operations—mainland China Government Research and Development Funding,” ACM Shanghai has received research and development grants from local and central mainland China governmental author ities. ACM Shanghai receiv ed $51,000 of payments related to such grants in the year ended December 31, 2023, as compared to cash receipts of $1.1 million in the same period of 2022. The uses of cash are offset by the following significant sources of cash: an increase in advances from customers of $30.0 (Note 3), an increase in other payables and accrued expenses of $21.4 million, and an increase in accounts payable of $42.3 million. Cash Flow Used in Investing Activities. Net cash used in investing activities for the year ended December 31, 2023, excluding net cash proceeds from the sale of time deposits, was ($60.2 million), primarily consisting of ($64.3 million) purchase of property and equipment and intangible assets, and ($7.5 million) purchase of long-term investments (note 14), partly offset by $3.4 million net proceeds from the sale of short-term investments, and $8.2 million of dividends received from long-term investments (note 14). Cash Flow provided by Financing Activities. Net cash provided by financing for the year ended December 31, 2023 was $18.5 million, primarily consisting of $16.3 million net proceeds from short and long-term borrowings, and $6.1 million in proceeds from the exercise of stock options, partly offset by ($4.0 million) of dividends paid by ACM Shanghai. We and ACM Shanghai, together with the subsidiaries of ACM Shanghai, have short-term and long-term borrowings with six banks, as follows: 74 Table of Contents Lender Agreement Date Maturity Date Annual Interest Rate Maximum Borrowing Amount(1) Amount Outstanding at December 31, 2023 (in thousands) China CITIC Bank (2) July 2023 Repayable by installments and the last installments repayable in December 2025 4.50 % RMB200,000 RMB100,000 $ 28,240 $ 14,120 China Everbright Bank July 2021 August 2024 3.00 % RMB150,000 RMB17,440 $ 21,180 $ 2,463 Bank of China September 2023 September 2024 2.87 % RMB40,000 RMB40,000 $ 5,648 5536 $ 5,648 China Merchants Bank August 2023 September 2024 3.00 % RMB200,000 RMB153,000 $ 28,240 $ 21,603 China Merchants Bank November 2020 Repayable by installments and the last installments repayable in November 2030 3.95 % RMB128,500 RMB94,633 $ 18,144 $ 13,362 Bank of China June 2021 Repayable by installments and the last installments repayable in June 2024 2.60 % RMB10,000 RMB7,500 $ 1,412 $ 1,059.00 Bank of China September, 2021 Repayable by installments and the last installments repayable in September 2024 2.60 % RMB35,000 RMB28,000 $ 4,942 $ 3,954 Bank of Shanghai December,2022 October 2024 2.85 % RMB100,000 RMB100,000 $ 14,120 $ 14,120 China CITIC Bank August 2023 Repayable by installments and the last installments repayable in August 2025 3.10 % RMB100,000 RMB100,000 $ 14,120 $ 14,120 Industrial Bank of Korea July 2023 July 2024 6.03 % KRW500,000 KRW100,000 $ 386 $ 77 Industrial Bank of Korea December 2023 December 2024 4.27 % KRW2,000,000 KRW2,000,000 $ 1,544 $ 1,544 $ 137,976 $ 92,070 75 Table of Contents (1) Converted from RMB to dollars as of December 31, 2023. The loan from China Merchants Bank is secured by a pledge of the property of ACM Lingang and guaranteed by ACM Shanghai, as described above under “—Contractual Obligations.” (2) This China CITIC bank facility agreement is with ACM Research, Inc. Effect of exchange rate changes on cash, cash equivalents and restricted cash. The impact of fluctuations of the RMB to U.S. dollar currency exchange rate on a significant balance of our cash, and cash equivalents held in RMB-denominated accounts (Note 2) contributed t o a $1.7 million decrease in the value of these items during the year ended December 31, 2023. Contractual Obligations Grant Contract for State-owned Construction Land Use Right in Shanghai City In 2020 ACM Shanghai, through its wholly-owned subsidiary ACM Lingang, entered into a Grant Contract for State-owned Construction Land Use Right in Shanghai City (Category of R&D Headquarters and Industrial Projects), or the Grant Agreement, with the China (Shanghai) Pilot Free Trade Zone Lin-gang Special Area Administration, or the Grantor. ACM Lingang obtained rights to use approximately 43,000 square meters (10.6 acres) of land in the Lingang Heavy Equipment Industrial Zone of Lin-gang Special Area of China (Shanghai) Pilot Free Trade Zone, or the Land Use Right, for a period of fifty years, commencing on the date of delivery of the land in July 2020, which we refer to as the Delivery Date. In exchange for its land use rights, ACM Lingang paid aggregate grant fees of RMB 61.7 million ($9.5 million), or the Grant Fees, and a performance deposit of RMB 12.3 million ($1.9 million), which is equal to 20% of the aggregate Grant Fees, to secure its achievement of the following performance milestones: • the start of construction within 6 months after the Delivery Date (60% of the performance deposit), or Construction Start Milestone; • the completion of construction within 30 months after the Delivery Date (20% of the performance deposit), or Construction Completion Milestone; and • the start of production within 42 months after the Delivery Date (20% of the performance deposit), or Production Start Milestone. Upon satisfaction of a milestone, the portion of the performance deposit attributable to that milestone will be repayable to ACM Shengwei within ten business days. If the achievement of any of the above milestones is delayed or abandoned, ACM Shengwei may be subject to additional penalties and may lose its rights to both the use of the granted land and any partially completed facilities on that land. The status of the performance milestones for the period ended December 31 , 2023 is as follows: • ACM Lingang achieved the Construction Start Milestone and 60% of the performance deposit was refunded to ACM Shanghai in 2020. • The Construction Completion Milestone was required to be met by January 9, 2024 but was not achieved. However, ACM Lingang believes it will receive the refund without penalty based on its explanation to the respective regulatory authorities of logistic-related delays, and expectations that it will meet the milestone before July 9, 2024. We cannot guarantee that ACM Lingang will achieve the missed milestone in 2024, or even if it does achieve the milestone in 2024, that it will be refunded some or all of the 20% portion of the performance deposit of RMB 2.5 million ($0.4 million). Contractual penalties in the case of a delay of Construction Completion Milestone : ◦ If ACM Lingang fails to complete the construction pursuant to the date agreed under the Grant Agreement or any extended completion date approved by the Grantor, ACM Lingang shall pay 50% of the deposit for timely completion of construction as liquidated damages; ◦ If ACM Lingang delays the completion for more than six months beyond the date agreed under the Grant Agreement, or beyond any extended completion date approved by the Grantor, it shall pay the total deposit for timely completion of construction as liquidated damages. 76 Table of Contents ◦ If the delay is more than one year, the Grantor is entitled to terminate the Grant Agreement and take back the Land Use Right. In such case, the Grantor shall refund the Grant Fees for the remaining land use term after deducting the deposit agreed under the Grant Agreement and refund the deposit for timely commencement of production and relevant bank interests in full to ACM Lingang. • The Production Start Milestone is now required to be met by January 9, 2025. The Production Start Milestone was originally required to be met prior to January 9, 2024, but due to COVID-related delays, ACM filed multiple requests for extensions, the latest of which was granted on July 7, 2023. We cannot guarantee that ACM Lingang will meet any extended deadline or be refunded this 20% portion of the performance deposit. Contractual penalties in the case of a delay of Production Start Milestone : ◦ If ACM Lingang fails to commence production pursuant to the date agreed under the Grant Agreement or any extended commencement date approved by the Grantor, ACM Lingang shall pay the total deposit for timely commencement of production as liquidated damages; ◦ If ACM Lingang fails to commence production pursuant to the extended commencement of production date (more than six months beyond the production start milestone), the Grantor is entitled to terminate the Grant Agreement and take back the Land Use Right. In such case, the Grantor shall refund the Grant Fees for the remaining land use term after deducting the deposit agreed under the Grant Agreement to ACM Lingang. In addition to the milestones, covenants in the Grant Agreement require that, among other things, ACM Lingang will be required to pay liquidated damages in the event that: (a) it does not make a total investment (including the costs of construction, fixtures, equipment and grant fees) of at least RMB 450.0 million ($63.4 million). ACM Lingang shall pay the liquidated damages equal to the same proportion of the Grant Fees as the proportion of the actual shortfall amount of investment in the total agreed investment amount or the investment intensity. (b) within six years after the Delivery Date, or prior to July 9, 2026, it does not (i) generate a minimum specified amount of annual sales of products manufactured on the granted land or (ii) pay at least RMB 157.6 million ($22.2 million) in annual total taxes (including value-added taxes, corporate income tax, personal income taxes, urban maintenance and construction taxes, education surcharges, stamp taxes, and vehicle and shipping taxes) as a result of operations in connection with the granted land. If the total tax revenue of the project fails to reach but is no less than 80% of the standard agreed under the Grant Agreement, ACM Lingang shall pay 20% of the actual shortfall amount of the tax revenue as liquidated damages. If the total tax revenue of the project fails to reach 80% of the standard agreed under the Grant Agreement within 1 month after the agreed date of reaching target production, the Grantor is entitled to terminate the Grant Agreement, take back the Land Use Right, and shall refund the Grant Fees for the remaining land use term to ACM Lingang. If the Grant Agreement is terminated because of breach of any terms above, the Grantor shall take back the buildings, fixtures and auxiliary facilities on the land area and provide ACM Lingang with corresponding compensation according to the residual value of the buildings, fixtures and auxiliary facilities when they are taken back. The total cumulative investment of land, buildings and construction in progress related to ACM Lingang amounted to $116.9 million and $35.4 million at December 31, 2023 and December 31, 2022, respectively. How We Evaluate Our Operations We present information below with respect to four measures of financial performance: • We define “shipments” of tools to include (a) a “repeat” delivery to a customer of a type of tool that the customer has previously accepted, for which we recognize revenue upon delivery, and (b) a “first-time” delivery of a “first tool” to a customer on an approval basis, for which we may recognize revenue in the future if contractual conditions are met, or if a purchase order is received. • We define “adjusted EBITDA” as net income excluding interest expense (net), income tax benefit (expense), depreciation and amortization, unrealized (gain) loss on short-term investments, and stock-based compensation. We define adjusted EBITDA to also exclude restructuring costs, although we have not incurred any such costs to date. • We define “free cash flow” as net cash provided by operating activities less purchases of property and equipment (net of proceeds from disposals). 77 Table of Contents • We define “adjusted operating income (loss)” as our income (loss) from operations excluding stock-based compensation. These financial measures are not based on any standardized methodologies prescribed by accounting principles generally accepted in the United States, or GAAP, and are not necessarily comparable to similarly titled measures presented by other companies. We have presented shipments, adjusted EBITDA, free cash flow and adjusted operating income (loss) because they are key measures used by our management and board of directors to understand and evaluate our operating performance, to establish budgets and to develop operational goals for managing our business. We believe that these financial measures help identify underlying trends in our business that could otherwise be masked by the effect of the expenses that we exclude. In particular, we believe that the exclusion of the expenses eliminated in calculating adjusted EBITDA and adjusted operating income (loss) can provide useful measures for period-to-period comparisons of our core operating performance and that the exclusion of property and equipment purchases from operating cash flow can provide a usual means to gauge our capability to generate cash. Accordingly, we believe that these financial measures provide useful information to investors and others in understanding and evaluating our operating results, enhancing the overall understanding of our past performance and future prospects, and allowing for greater transparency with respect to key financial metrics used by our management in its financial and operational decision-making. Shipments, adjusted EBITDA, free cash flow and adjusted operating income (loss) are not prepared in accordance with GAAP, and should not be considered in isolation of, or as an alternative to, measures prepared in accordance with GAAP. Shipments We consider shipments a key operating metric as it reflects the total value of products delivered to customers and prospective customers by our productive assets. Shipments consist of two components: • a shipment to a customer of a type of tool that the customer has previously accepted, for which we recognize revenue when the tool is delivered; and • a shipment to a customer of a type of tool that the customer is receiving and evaluating for the first time, in each case a “first tool,” for which we may recognize revenue at a later date, subject to the customer’s acceptance of the tool upon the tool’s satisfaction of applicable contractual requirements or subject to the customer’s subsequent discretionary commitment to purchase the tool. “First tool” shipments can be made to either an existing customer that has not previously accepted that specific type of tool in the past ─ for example, a delivery of a SAPS V tool to a customer that previously had received only SAPS II tools ─ or to a new customer that has never purchased any tool from us. Shipments for the years ended December 31, 2023, 2022, and 2021 totaled $597 million, $539 million, and $372 million, respectively. Repeat tool shipments in the years ended December 31, 2023, 2022, and 2021 totaled $310 million, $288 million and $210 million, respectively. First tool shipments for the years ended December 31, 2023, 2022, and 2021 totaled $286 million, $251 million, and $162 million, respectively. The dollar amount attributed to a “first tool” shipment is equal to the consideration we expect to receive if any and all contractual requirements are satisfied and the customer accepts the tool, or if the customer subsequently determines in its discretion to purchase the tool. There are a number of limitations related to the use of shipments in evaluating our business, including that customers have significant, or in some cases total, discretion in determining whether to accept or purchase our tools after evaluation and their decision not to accept or purchase delivered tools is likely to result in our inability to recognize revenue from the delivered tools. “First tool” shipments reflect the value of incremental new products under evaluation delivered to our customers or prospective customers for a given period and is used as an internal key metric to reflect future potential revenue opportunity. The cumulative cost of “first tool” shipments under evaluation at customers which have not been accepted by the customer is carried at cost and reflected in finished goods inventory (see note 5 to the condensed consolidated financial statements included in this report). “First tool” shipments exclude deliveries to customers for which ACM does not have a basis to expect future revenue. 78 Table of Contents Adjusted EBITDA There are a number of limitations related to the use of adjusted EBITDA rather than net income (loss), which is the nearest GAAP equivalent. Some of these limitations are: • adjusted EBITDA excludes depreciation and amortization and, although these are non-cash expenses, the assets being depreciated or amortized may have to be replaced in the future; • we exclude stock-based compensation expense from adjusted EBITDA and adjusted operating income (loss), although (a) it has been, and will continue to be for the foreseeable future, a significant recurring expense for our business and an important part of our compensation strategy and (b) if we did not pay out a portion of our compensation in the form of stock-based compensation, the cash salary expense included in operating expenses would be higher, which would affect our cash position; • the expenses and other items that we exclude in our calculation of adjusted EBITDA may differ from the expenses and other items, if any, that other companies may exclude from adjusted EBITDA when they report their operating results; • adjusted EBITDA does not reflect changes in, or cash requirements for, working capital needs; • adjusted EBITDA does not reflect interest expense, or the requirements necessary to service interest or principal payments on debt; • adjusted EBITDA does not reflect income tax expense (benefit) or the cash requirements to pay taxes; • adjusted EBITDA does not reflect historical cash expenditures or future requirements for capital expenditures or contractual commitments; • although depreciation and amortization charges are non-cash charges, the assets being depreciated and amortized will often have to be replaced in the future, and adjusted EBITDA does not reflect any cash requirements for such replacements; and • adjusted EBITDA includes expense reductions and non-operating other income attributable to mainland China governmental grants, which may mask the effect of underlying developments in net income, including trends in current expenses and interest expense, and free cash flow includes the mainland China governmental grants, the amount and timing of which can be difficult to predict and are outside our control. The following table reconciles net income, the most directly comparable GAAP financial measure, to adjusted EBITDA: Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 Absolute Change 2023 v 2022 (in thousands) Adjusted EBITDA Data: Net Income $ 96,852 $ 50,564 $ 42,921 91.5 % $ 46,288 Interest expense (income), net (5,673) (7,085) 260 -19.9 % 1,412 Income tax expense 19,364 16,798 134 15.3 % 2,566 Depreciation and amortization 8,092 5,366 2,353 50.8 % 2,726 Stock based compensation 27,338 7,730 5,117 253.7 % 19,608 Unrealized (gain) loss on short-term investments 2,737 7,855 (607) -65.2 % (5,118) Adjusted EBITDA $ 148,710 $ 81,228 $ 50,178 83.1 % $ 67,482 The $67.5 million increase in adjusted EBITDA for the year ended December 31, 2023 as compared to the year ended December 31, 2022 reflected higher income tax expense, a decrease in unrealized loss on short-term investments, an increase in net income, an increase in stock-based compensation, and an increase in depreciation and amortization, partly offset by a negative impact from an increase in interest income, net. We do not exclude from adjusted EBITDA expense reductions and non-operating other income attributable to mainland China governmental grants because we consider and incorporate the expected amounts and timing of those grants in incurring expenses and capital expenditures. If we did not receive the grants, our cash expenses therefore would be lower, 79 Table of Contents and our cash position would not be affected, to the extent we have accurately anticipated the amounts of the grants. For additional information regarding our mainland China grants, please see “—Key Components of Results of Operations—mainland China Government Research and Development Funding.” Free Cash Flow The following table reconciles net cash provided by (used in) operating activities, the most directly comparable GAAP financial measure, to free cash flow: Year Ended December 31, 2023 2022 2021 % Change 2023 v 2022 Absolute Change 2023 v 2022 (in thousands) Free Cash Flow Data: Net cash used in operating activities $ (75,323) $ (62,194) $ (40,093) 21.1 % $ (13,129) Purchase of property and equipment (61,876) (91,094) (9,153) -32.1 % 29,218 Purchase of long-term investments (7,508) (4,279) - 75.5 % (3,229) Free cash flow $ (144,707) $ (157,567) $ (49,246) -8.2 % $ 12,860 The changes in free cash flow for the years ended December 31, 2023, 2022, and 2021 reflected the factors driving net cash used in operating activities, and an increase of purchases of property and equipment. Consistent with our methodology for calculating adjusted EBITDA, we do not adjust free cash flow for the effects of mainland China government subsidies, because we take those subsidies into account in incurring expenses and capital expenditures. We do not adjust free cash flow for the effects of time-deposits, which for our internal purposes are considered as largely similar to cash. Adjusted Operating Income Adjusted operating income excludes stock-based compensation from income from operations. Although stock-based compensation is an important aspect of the compensation of our employees and executives, determining the fair value of certain of the stock-based instruments we utilize involves a high degree of judgment and estimation and the expense recorded may bear little resemblance to the actual value realized upon the vesting or future exercise of the related stock-based awards. Furthermore, unlike cash compensation, the value of stock options, which is an element of our ongoing stock-based compensation expense, is determined using a complex formula that incorporates factors, such as market volatility, that are beyond our control. Management believes it is useful to exclude stock-based compensation in order to better understand the long-term performance of our core business and to facilitate comparison of our results to those of peer companies. The use of non-GAAP financial measures excluding stock-based compensation has limitations. If we did not pay out a portion of our compensation in the form of stock-based compensation, the cash salary expense included in 80 Table of Contents operating expenses would be higher and our cash holdings would be less. The following tables reflect the exclusion of stock-based compensation, or SBC, from line items comprising income from operations: Year Ended December 31, 2023 2022 2021 Actual (GAAP) SBC Adjusted (Non-GAAP) Actual (GAAP) SBC Adjusted (Non-GAAP) Actual (GAAP) SBC Adjusted (Non-GAAP) (in thousands) Revenue $ 557,723 $ - $ 557,723 $ 388,832 $ - $ 388,832 $ 259,751 $ - $ 259,751 Cost of revenue (281,508) (1,406) (280,102) (205,217) (520) (204,697) (144,895) (397) (144,498) Gross profit 276,215 (1,406) 277,621 183,615 (520) 184,135 114,856 (397) 115,253 Operating expenses: Sales and marketing (47,019) (5,684) (41,335) (39,889) (1,877) (38,012) (26,733) (1,802) (24,931) Research and development (92,709) (8,459) (84,250) (62,226) (2,565) (59,661) (34,207) (1,115) (33,092) General and administrative (40,648) (11,789) (28,859) (22,465) (2,768) (19,697) (15,214) (1,803) (13,411) Income (loss) from operations $ 95,839 $ (27,338) $ 123,177 $ 59,035 $ (7,730) $ 66,765 $ 38,702 $ (5,117) $ 43,819 Adjusted operating income for the year ended December 31, 2023, as compared with the year ended December 31, 2022, increased by $56.4 million due to a $36.8 million increase in income from operations and a $19.6 million increase in stock-based compensation expense. Adjusted operating income for the year ended December 31, 2022, as compared with the year ended December 31, 2021, increased by $22.9 million due to a $20.3 million increase in income from operations and a $2.6 million increase in stock-based compensation expense.